Sharp-tailed Grouse Research Articles

Analysis of eigenvalue condition numbers for a class of randomized numerical methods for singular matrix pencils

The numerical solution of the generalized eigenvalue problem for a singular matrix pencil is challenging due to the discontinuity of its eigenvalues. Classically, such problems are addressed by first extracting the regular part through the staircase form and then applying a standard solver, such as the QZ algorithm, to that regular part. Recently, several novel approaches have been proposed to transform the singular pencil into a regular pencil by relatively simple randomized modifications. In this work, we analyze three such methods by Hochstenbach, Mehl, and Plestenjak that modify, project, or augment the pencil using random matrices. All three methods rely on the normal rank and do not alter the finite eigenvalues of the original pencil. We show that the eigenvalue condition numbers of the transformed pencils are unlikely to be much larger than the δ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\delta $$\\end{document}-weak eigenvalue condition numbers, introduced by Lotz and Noferini, of the original pencil. This not only indicates favorable numerical stability but also reconfirms that these condition numbers are a reliable criterion for detecting simple finite eigenvalues. We also provide evidence that, from a numerical stability perspective, the use of complex instead of real random matrices is preferable even for real singular matrix pencils and real eigenvalues. As a side result, we provide sharp left tail bounds for a product of two independent random variables distributed with the generalized beta distribution of the first kind or Kumaraswamy distribution.

Interval evaluation of wind power prediction based on skew-slash t distribution

Wind resources have characteristics of stochastic volatility, resulting in wind power forecast errors greatly. The short and medium-term wind power forecast error distribution of the actual wind farm operating system is analyzed, and a sharp peak and thick tail, with heavy tail and skewness characteristics, are presented. A skew-slash t distribution (SST distribution) is proposed to describe the error distribution of short-term wind power prediction, and the parameter estimation is carried out by probability density curve fitting. The fitting results of the wind power forecast error historical data of the Wind power plant based on SST distribution, t distribution, and t Location-slash distribution (TLS distribution) are obtained, and the fitting goodness and prediction accuracy are compared. The results show that the SST distribution can more effectively estimate the wind power prediction interval.

The changes in the annual distribution of mountain runoff during the period of 1965–2018 in Hexi Corridor, Northwest China

The annual distribution characteristics of river runoff in arid regions have significant implications for water resource stability and management. Based on the mountain runoff data from 1965 to 2018, this study examines the annual change characteristics of monthly runoff of the Shiyang River Basin, Heihe River Basin, and Shule River Basin in the Hexi Corridor, Northwest China. Many indexes are used and analyzed, including the coefficient of variance, the complete regulation coefficient, the concentration degree and concentration period, the magnitude of change, the skewness coefficient, and the kurtosis coefficient of the annual distribution curves. The results reveal the following: (1) The inhomogeneity of annual runoff distribution in the Taolai River and the rivers to the west of it, except the Shiyou River, show an increasing trend. Conversely, the inhomogeneity of the rivers to the east of the Taolai River generally show a downward trend, but the coefficient of variance value is still very high. (2) In the Shiyang River Basin, the annual distribution of the concentration period is characterized by a relatively discrete pattern. Conversely, the Heihe River Basin exhibits a relatively concentrated pattern, and the distribution pattern of the Shule River Basin is quite different. Notably, all concentration periods in the three basins have shifted backward after the 2000s. (3) The Shiyang River Basin exhibits disordered annual distribution curves of runoff in different years. In contrast, the Heihe River Basin presents a typical ‘single-peak’ pattern with a prominent right-skewed. The Shule River Basin has regular distribution curves, with a gradually significant ‘double-peak’ pattern from east to west. Overall, there has been a slight change in runoff in the Shiyang River Basin, while the Heihe River Basin and Shule River Basin have experienced significant increases in runoff. The annual distribution curves of runoff in the Liyuan River and the rivers to the east of it exhibit a gentle peak pattern, and the appearance probability of extreme runoff during the year is low. Conversely, the rivers to the west of the Liyuan River, excluding the Danghe River, display a sharp peak and thick tail pattern, indicating that the appearance probability of extreme runoff during the year is high. These findings have practical implications for the planning and management of water resources in the Hexi Corridor. Moreover, they provide a solid foundation for predicting future changes in regional water resources.

Shanghai Crude Oil Futures Yield Volatility Study

Since the listing of Shanghai crude oil futures in March 2018 its market performance has gradually attracted attention. The closing price data of the futures for the period from March 26, 2018 to April 17, 2023 are selected as observations, and a GARCH model is fitted to the futures log return series to analyze the development of Shanghai crude oil futures and its future trend. The study finds that extreme events such as the New Crown epidemic and the Russia-Ukraine conflict had led to high volatility of Shanghai crude oil futures, but the volatility gradually stabilized in the context of the double cycle at home and abroad. The study compares the effectiveness of the GARCH(1,1)-T model and the GARCH(1,1)-GED model in fitting the logarithmic returns of the Shanghai crude oil futures market. the GARCH(1,1)-T model is able to better capture the asymmetry of the market volatility and the phenomenon of sharp peaks and thick tails after taking into account the distributional characteristics of the residuals. In the paper, the closing price of Shanghai crude oil futures in the next 10 days is predicted according to the GARCH(1,1)-T model, and the short-term prediction effect is better.

Short-Wave Infrared Detection and Imaging Employing Size-Customized HgTe Nanocrystals.

HgTe nanocrystals (NCs) possess advantages including tunable infrared absorption spectra, solution processability, and low fabrication costs, offering new avenues for the advancement of next-generation infrared detectors. In spite of great synthetic advances, it remains essential to achieve customized synthesis of HgTe NCs in terms of industrial applications. Herein, by taking advantage of a high critical nucleation concentration of HgTe NCs, a continuous-dropwise (CD) synthetic approach that features the addition of the anion precursors in a feasible drop-by-drop fashion is demonstrated. The slow reaction dynamics enable size-customized synthesis of HgTe NCs with sharp band tails and wide absorption range fully covering the short- and mid-infrared regions. More importantly, the intrinsic advantages of CD process ensure high-uniformity and scale-up synthesis from batch to batch without compromising the excitonic features. The resultant HgTe nanocrystal photodetectors show a high room-temperature detectivity of 8.1 × 1011 Jones at 1.7µm cutoff absorption edge. This CD approach verifies a robust method for controlled synthesis of HgTe NCs and might have important implications for scale-up synthesis of other nanocrystal materials.

NUMERICAL SIMULATION OF THE RISE OF TWO PARALLEL UNEQUAL BUBBLES IN A VISCOELASTIC FLUID

The interaction of two parallel unequal bubbles in a viscoelastic fluid is investigated numerically using OpenFoam, the volume of fluid method (VOF) combined with a surface tension model to trace the gas-liquid interface, and the Giesekus model to characterise the rheological properties of the fluid. The numerical results are in good agreement with experimental results from the literature. The effects of bubble diameter, initial spacing between bubbles and rheological properties of the fluid on the rise, and separation and convergence of the two bubbles are investigated. The flow field properties and viscoelastic stress distribution around the bubbles are explored. As the bubble spacing increases, the maximum and terminal velocities of the two bubbles increase, and the relative positions of the bubbles change when they come into contact. As the relaxation time λ increases, the contact time of the bubbles decreases, and the small bubbles tend to have an inverted teardrop shape and the large bubbles have less deformation and no sharp tail. The relaxation time directly affects the accumulation of viscoelastic stress, leading to changes in the velocity of the bubbles at contact, and their maximum and terminal velocities increase. Bubbles in highly elastic fluids are more prone to negative wake phenomena.

Comparison of in‐person and remote camera lek surveys for prairie grouse (Tympanuchus spp.)

AbstractIn‐person lek count surveys are commonly used for estimating population size and trends for prairie grouse. However, the emergence of noninvasive camera trap survey methods holds promise for more cost‐effective and precise estimates of lekking species. To evaluate the efficacy of using camera traps, we deployed a remote camera study at lekking grounds over 3 years in conjunction with in‐person surveys. Our objectives were to 1) develop an effective remote camera survey for greater prairie‐chickens (GRPC; Tympanuchus cupido) and sharp‐tailed grouse (STGR; T. phasianellus), 2) compare metrics of male detection, maximum male counts, and male abundance estimates derived from in‐person versus remote camera surveys, 3) assess lek activity over the survey season to inform survey timing, and 4) evaluate costs for each survey type. We found that in‐person surveys resulted in maximum male GRPC and STGR counts. The estimated number of male GRPC and STGR on leks were comparable between in‐person surveys and camera monitoring when accounting for detection probability with N‐mixture models. Camera traps constantly monitored leks over the season which provided daily and seasonal activity patterns of prairie grouse. Total cost of GRPC remote camera surveys was higher than in‐person surveys, but hourly cost was less ($0.77 vs. $160 per hour). Remote camera survey costs for GRPC were high because of time classifying photos which could be reduced by decreasing the amount of time remote cameras were operated or using automated classification software to remove blank photos. We believe the use of remote cameras could supplement in‐person surveys for future lek monitoring and aid future survey efforts by identifying yearly differences in activity and presence at leks inconsistently visited by birds.

On the distribution of partial quotients of reduced fractions with fixed denominator

In this paper, we study distributional properties of the sequence of partial quotients in the continued fraction expansion of fractions a / N a/N , where N N is fixed and a a runs through the set of mod N N residue classes which are coprime with N N . Our methods cover statistics such as the sum of partial quotients, the maximal partial quotient, the empirical distribution of partial quotients, Dedekind sums, and much more. We prove a sharp concentration inequality for the sum of partial quotients, and sharp tail estimates for the maximal partial quotient and for Dedekind sums, all matching the tail behavior in the limit laws which are known under an extra averaging over the set of possible denominators N N . We show that the distribution of partial quotients of reduced fractions with fixed denominator gives a very good fit to the Gauß–Kuzmin distribution. As corollaries we establish the existence of reduced fractions with a small sum of partial quotients resp. a small maximal partial quotient.

Assessment of lesser prairie‐chicken translocation through survival and lek surveys

AbstractTranslocation is a management tool used to restore or augment wildlife populations, but outcomes of translocations are often poorly documented and can have varying levels of success for improving wildlife population declines. The lesser prairie‐chicken (Tympanuchus pallidicinctus) is a prairie grouse endemic to the southern Great Plains. In response to declining abundance and distribution, in 2023 lesser prairie‐chickens were listed as threatened or endangered under the Endangered Species Act in different states. Translocation is a potential management response to population declines when there is an availability of unoccupied habitats, but translocation efficacy has not been evaluated for lesser prairie‐chickens. We translocated 411 lesser prairie‐chickens seasonally from 2016‐2019 and monitored the translocated lesser prairie‐chicken population from 2017–2022. To assess translocation as a management tool for lesser prairie‐chickens, we estimated survival for 2017–2020 and conducted lek surveys during 2017–2022. Over a fifth (22.8%, n = 94) of translocated birds either died or went missing within the first 2 weeks following release. Survival rates of translocated birds during the breeding (0.44 ± 0.02 [SE]) and nonbreeding (0.55 ± 0.03 [SE]) seasons were relatively low compared to nontranslocated lesser prairie‐chickens in other studies (0.63–0.93 for breeding season; 0.43–0.87 for non‐breeding season). Twenty‐seven percent of translocated birds survived to the breeding season after release (i.e., >1 year). Translocated lesser prairie‐chickens initiated 28 lekking sites over the study period. We estimated 77% of males available >2 weeks post release participated in lekking activity. The number of leks and male high counts on leks in the study area increased after translocation, peaking one year post‐translocation (an overall increase of 250% and 340%, respectively). However, both the number of leks and male high counts decreased (48% and 39%, respectively) within 3 years after translocation cessation. Establishment of leks and increasing lek attendance directly following translocation initially suggested that translocation could be a viable management tool. However, survival rates after translocation and declining lek counts following translocation indicates that the increased population abundance and occupied range from this translocation effort may be unsustainable. Our results highlight the necessity of monitoring to determine outcomes of a large lesser prairie‐chicken translocation. Other management strategies, such as targeted grassland restoration and management in areas of greatest lesser prairie‐chicken density, could be more beneficial for conservation of lesser prairie‐chicken populations.

Phylogenomics of the extinct Heath Hen provides support for sex-biased introgression among extant prairie grouse

Rapid divergence and subsequent reoccurring patterns of gene flow can complicate our ability to discern phylogenetic relationships among closely related species. To what degree such patterns may differ across the genome can provide an opportunity to extrapolate better how life history constraints may influence species boundaries. By exploring differences between autosomal and Z (or X) chromosomal-derived phylogenetic patterns, we can better identify factors that may limit introgression despite patterns of incomplete lineage sorting among closely related taxa. Here, using a whole-genome resequencing approach coupled with an exhaustive sampling of subspecies within the recently divergent prairie grouse complex (genus: Tympanuchus), including the extinct Heath Hen (T. cupido cupido), we show that their phylogenomic history differs depending on autosomal or Z-chromosome partitioned SNPs. Because the Heath Hen was allopatric relative to the other prairie grouse taxa, its phylogenetic signature should not be influenced by gene flow. In contrast, all the other extant prairie grouse taxa, except Attwater’s Prairie-chicken (T. c. attwateri), possess overlapping contemporary geographic distributions and have been known to hybridize. After excluding samples that were likely translocated prairie grouse from the Midwest to the eastern coastal states or their resulting hybrids with mainland Heath Hens, species tree analyses based on autosomal SNPs consistently identified a paraphyletic relationship with regard to the Heath Hen with Lesser Prairie-chicken (T. pallidicinctus) sister to Greater Prairie-chicken (T. c. pinnatus) regardless of genic or intergenic partitions. In contrast, species trees based on the Z-chromosome were consistent with Heath Hen sister to a clade that included its conspecifics, Greater and Attwater’s Prairie-chickens (T. c. attwateri). These results were further explained by historic gene flow, as shown with an excess of autosomal SNPs shared between Lesser and Greater Prairie-chickens but not with the Z-chromosome. Phylogenetic placement of Sharp-tailed Grouse (T. phasianellus), however, did not differ among analyses and was sister to a clade that included all other prairie grouse despite low levels of autosomal gene flow with Greater Prairie-chicken. These results, along with strong sexual selection (i.e., male hybrid behavioral isolation) and a lek breeding system (i.e., high variance in male mating success), are consistent with a pattern of female-biased introgression between prairie grouse taxa with overlapping geographic distributions. Additional study is warranted to explore how genomic components associated with the Z-chromosome influence the phenotype and thereby impact species limits among prairie grouse taxa despite ongoing contemporary gene flow.

Acoustically driven microswimmer with real-time controllable motion direction

The development of modern biomedicine needs a kind of microrobot with controllable motion direction, which relies on the driving mode of non-destructive and non-invasive biocompatibility. Acoustic drive technology is a very attractive method for driving microrobots, but most of the existing microrobots driven by acoustic wave have a single direction of motion, which is still difficult to meet the needs of biomedicine fields. In this paper, we present an microswimmer with asymmetric double tails, which is driven by the oscillation of the flexible sharp tails actuated with the acoustic wave. One or two flexible sharp tails can be selectively induced to dominate the driving force by adjusting the frequency of the acoustic wave, which makes it possible to control motion direction only changing the frequency of the acoustic wave generated by one piezoelectric transducer. The flexible microswimmer is made of polyethylene glycol diacrylate using UV photopolymerization technology with a specially designed in situ fabricated chip. The experimental results show that the microswimmer have good directional response and speed control, which is of great significance for the application research of microswimmer in biomedicine, targeted delivery and other fields.

A Highly Contiguous and Annotated Genome Assembly of the Lesser Prairie-Chicken (Tympanuchus pallidicinctus).

The Lesser Prairie-Chicken (Tympanuchus pallidicinctus; LEPC) is an iconic North American prairie grouse, renowned for ornate and spectacular breeding season displays. Unfortunately, the species has disappeared across much of its historical range, with corresponding precipitous declines in contemporary population abundance, largely due to climatic and anthropogenic factors. These declines led to a 2022 US Fish and Wildlife decision to identify and list two distinct population segments (DPSs; i.e., northern and southern DPSs) as threatened or endangered under the 1973 Endangered Species Act. Herein, we describe an annotated reference genome that was generated from a LEPC sample collected from the southern DPS. We chose a representative from the southern DPS because of the potential for introgression in the northern DPS, where some populations hybridize with the Greater Prairie-Chicken (Tympanuchus cupido). This new LEPC reference assembly consists of 206 scaffolds, an N50 of 45 Mb, and 15,563 predicted protein-coding genes. We demonstrate the utility of this new genome assembly by estimating genome-wide heterozygosity in a representative LEPC and in related species. Heterozygosity in a LEPC sample was 0.0024, near the middle of the range (0.0003-0.0050) of related species. Overall, this new assembly provides a valuable resource that will enhance evolutionary and conservation genetic research in prairie grouse.

Assimilating ecological theory with empiricism: Using constrained generalized additive models to enhance survival analyses

AbstractIntegrating ecological theory with empirical methods is ubiquitous in ecology using hierarchical Bayesian models. However, there has been little development focused on integration of ecological theory into models for survival analysis. Survival is a fundamental process, linking individual fitness with population dynamics, but incorporating life history strategies to inform survival estimation can be challenging because mortality processes occur at multiple scales.We develop an approach to survival analysis, incorporating model constraints based on a species' life history strategy using functional analytical tools. Specifically, we structurally separate intrinsic patterns of mortality that arise from age‐specific processes (e.g. increasing survival during early life stages due to growth or maturation, versus senescence) from extrinsic mortality patterns that arise over different periods of time (e.g. seasonal temporal shifts). We use shape constrained generalized additive models (CGAMs) to obtain age‐specific hazard functions that incorporate theoretical information based on classical survivorship curves into the age component of the model and capture extrinsic factors in the time component.We compare the performance of our modelling approach to standard survival modelling tools that do not explicitly incorporate species life history strategy in the model structure, using metrics of predictive power, accuracy, efficiency and computation time. We applied these models to two case studies that reflect different functional shapes for the underlying survivorship curves, examining age‐period survival for white‐tailed deerOdocoileus virginianusin Wisconsin, USA and Columbian sharp‐tailed grouseTympanuchus phasianellus columbianusin Colorado, USA.We found that models that included shape constraints for the age effects in the hazard curves using CGAMs outperformed models that did not include explicit functional constraints. We demonstrate a data‐driven and easily extendable approach to survival analysis by showing its utility to obtain hazard rates and survival probabilities, accounting for heterogeneity across ages and over time, for two very different species. We show how integration of ecological theory using constrained generalized additive models, with empirical statistical methods, enhances survival analyses.

Exploring Old Data with New Tricks: Long-Term Monitoring Indicates Spatial and Temporal Changes in Populations of Sympatric Prairie Grouse in the Nebraska Sandhills

The contiguous grasslands of the Sandhills region in Nebraska, USA, provide habitat for two sympatric, grassland-obligate species of grouse, the greater prairie-chicken (Tympanuchus cupido pinnatus) and the plains sharp-tailed grouse (Tympanuchus phasianellus jamesi). Collectively referred to as prairie grouse, these birds are monitored and managed jointly by wildlife practitioners who face the novel challenge of conserving historically allopatric species in shared range. We reconstructed region-wide and route-specific prairie grouse population trends in the Sandhills, using a 63-year timeseries of breeding ground counts aggregated from old reports and paper archives. Our objective was to repurpose historical data collected for harvest management to address questions pertinent to the conservation of prairie grouse, species whose populations have declined precipitously throughout their respective ranges. Because we cannot change the sampling protocol of historical data to answer new questions, we applied 3 different methods of data analysis—traditional regional mean counts used to adjust harvest regulations, spatially implicit, site-specific counts, and spatially explicit trends. Prairie-chicken populations have increased since the 1950s, whereas sharp-tailed grouse populations have remained stable or slightly declined. However, each species exhibited unique shifts in abundance and distribution over time, and regional indices masked important aspects of population change. Our findings indicate that legacy data have the capacity to tell new stories apart from the questions they were collected to answer. By integrating concepts from landscape ecology—a discipline that emerged decades after the collection of our count data began—we demonstrate the potential of historical data to address questions of modern-day conservation concern, using prairie grouse as a case study.

Multi‐scale effects of land cover, weather, and fire on Columbian sharp‐tailed grouse

AbstractColumbian sharp‐tailed grouse (Tympanuchus phasianellus columbianus) are endemic to grassland and shrub‐steppe ecosystems of western North America, yet their distribution has contracted to <10% of their historical range. Primary threats to Columbian sharp‐tailed grouse include loss of native habitat and conversion to agriculture, reductions in habitat once provided by the Conservation Reserve Program (CRP), wildfire, and drought conditions, yet population‐level consequences of these threats and their spatio‐temporal scales of effect are poorly understood. We evaluated multi‐scale effects of land cover, weather, and fire histories on patterns of abundance and productivity for Columbian sharp‐tailed grouse populations during 1995–2020 in Idaho, USA, using mixed‐effects generalized regression and remotely sensed data. We demonstrated negative effects of fire, tree encroachment, and bare ground, positive effects of spring and summer precipitation and cover of shrubs and perennial forbs and grasses, and positive effects of CRP on grouse abundance that changed in magnitude with cover of perennials and shrubs near leks (i.e., strongest effects when average cover of shrubs and perennial forbs and grasses were less abundant). We also demonstrated per capita recruitment of Columbian sharp‐tailed grouse is positively associated with late‐summer greenness. Our results show that several suspected threats have measurable, population‐level impacts to Columbian sharp‐tailed grouse within Idaho. Moreover, our results suggest ongoing changes occurring within the core range of Columbian sharp‐tailed grouse, including loss of CRP cover to tilled agriculture and changes to wildfire and precipitation dynamics are likely to have negative effects on populations.

Seasonal changes of stable isotope signals in the primary feathers of plains sharp‐tailed grouse

AbstractStable isotopes of a consumer organism can be used to estimate the proportional utilization of food items that have different isotopic signals to estimate changes in diet over time. Using stable isotopes as biotracers has become a useful tool for investigating trophic dynamics in ecosystems. Recent advances in the theory of stable isotope dynamics and food web modeling have extended the utility of natural variations in stable isotope abundance. However, as a growing field, some potentially useful approaches to using stable isotopes remain untested. Here, we used stable isotopes of nitrogen (δ15N) and carbon (δ13C) to validate their utility in examining the feeding relationships of plains sharp‐tailed grouse (Tympanuchus phasianellus jamesi; hereafter sharp‐tailed grouse) in southern Alberta, Canada. Sharp‐tailed grouse are known to consume mostly plants and opportunistically utilize insects and spiders as a high protein food source between May and October. Primary feathers obtained from hunter harvested grouse were analysed and used to estimate diet proportions of vegetation and arthropods during this time frame. Stable isotope measurements of primary feathers were able to show seasonal changes in sharp‐tailed grouse diet. Our results indicated that sharp‐tailed grouse may primarily utilize nutrients obtained from insect prey (mainly grasshoppers) for feather synthesis during molt, and that the isotope signals found in primary feathers may be a result of isotopic routing. Stable isotope data also reflected known differences among adult female and male, and juvenile grouse feeding ecology. However, model uncertainty existed due to isotopic similarity of some plant and animal food sources.

Sharp Probability Tail Estimates for Portfolio Credit Risk

Portfolio credit risk is often concerned with the tail distribution of the total loss, defined to be the sum of default losses incurred from a collection of individual loans made out to the obligors. The default for an individual loan occurs when the assets of a company (or individual) fall below a certain threshold. These assets are typically modeled according to a factor model, thereby introducing a strong dependence both among the individual loans, and potentially also among the multivariate vector of common factors. In this paper, we derive sharp tail asymptotics under two regimes: (i) a large loss regime, where the total number of defaults increases asymptotically to infinity; and (ii) a small default regime, where the loss threshold for an individual loan is allowed to tend asymptotically to negative infinity. Extending beyond the well-studied Gaussian distributional assumptions, we establish that—while the thresholds in the large loss regime are characterized by idiosyncratic factors specific to the individual loans—the rate of decay is governed by the common factors. Conversely, in the small default regime, we establish that the tail of the loss distribution is governed by systemic factors. We also discuss estimates for Value-at-Risk, and observe that our results may be extended to cases where the number of factors diverges to infinity.

Demographic effects of a megafire on a declining prairie grouse in the mixed-grass prairie.

Recent studies have documented benefits of small, prescribed fire and wildfire for grassland-dependent wildlife, such as lesser prairie-chickens (Tympanuchus pallidicintus), but wildlife demographic response to the scale and intensity of megafire (wildfire >40,000 ha) in modern, fragmented grasslands remains unknown. Limited available grassland habitat makes it imperative to understand if increasing frequency of megafires could further reduce already declining lesser prairie-chicken populations, or if historical evolutionary interactions with fire make lesser prairie-chickens resilient. To evaluate lesser prairie-chicken demographic response to megafires, we compared lek counts, nest density, and survival rates of adults, nests, and chicks before (2014-2016) and after (2018-2020) a 2017 megafire in the mixed-grass prairie of Kansas, USA (Starbuck fire ~254,000 ha). There was a 67% decline in attending males on leks post-fire and a 57% decline in occupied leks post-fire. Despite population declines as indicated by lek counts, adult female breeding season survival ( ) was similar pre- ( =0.65 ± 0.08 [SE]) and post-fire (0.61 ± 0.08), as was chick survival (pre-fire: 0.23 ± 0.07; post-fire: 0.27 ± 0.11). Nest survival appeared lower post-fire (pre-fire: 0.38 ± 0.06; post-fire: 0.20 ± 0.06), but did not differ at the 95% confidence interval. Nest density of marked females declined 73% in areas burned by megafire. Although lesser prairie-chickens persisted in the study area and we documented minimal effects on most demographic rates, reduced lesser prairie-chicken abundance and reproductive output suggests full recovery may take >3 years. Increased propensity for megafire resulting from suppression of smaller fires, compounded by climate change and woody encroachment, may impose a short-term (3-5year) threat to already declining lesser prairie-chicken populations.

Monte-Carlo Stimulation for European Rainbow Call Options BASED on Meta and NEM’s Case Study

Recently, investors have paid great attention to the metaverse sector and the investing instruments for metaverse. Metaverse has become the most popular investment sector since 2021. Due to the rapid development of the industry, coupled with the social instability, it is critical to search for the appropriate investment. Previous literature proposed many advantages of the rainbow options and the expected growth of the metaverse industry. However, there is currently a lack of research on the combination of metaverse assets and the rainbow options. Based on this, this paper chooses the stocks of the metaverse enterprise META and the gold enterprise NEM as the safe-haven asset to construct a two-color European rainbow call options and chooses yahoo Finance's transaction data and excel and python as analysis software. The rainbow options return is given by Monte Carlo simulation method, and complete sensitivity analysis of the four parameters. At the end, the pros cons of rainbow options are compared. Besides three findings are obtained, including that options have cost advantages, could gain return from the market volatility by changing the portfolio, and have sharp peaks and thick tails in the distribution.

Role of landscape features in resource selection by female Greater Prairie-chickens within a constrained environment

Greater Prairie-chickens ( Tympanuchus cupido ) historically occupied 20 states within the contiguous United States; however, due to habitat degradation and loss, they are currently found in 11 states, only four of which have a stable population. Kansas supports a relatively large abundance of Greater Prairie-chickens, where the Flint Hills ecoregion historically supported the largest population density of all ecoregions. In the past decade, the Flint Hills population has declined by 75 % to an estimated 8,334 individuals in 2021 from 34,180 individuals in 2015 due to landscape changes and intensification of grassland management practices. The Fort Riley Military Reservation in the northwest portion of the Flint Hills ecoregion is one of a few areas within the ecoregion that does not implement grazing or vast annual burning. The Greater Prairie-chicken population within Fort Riley has remained relatively stable over the past 25 years despite being constrained by surrounding landscape features and development. We analyzed multiple scales of resource selection by 46 female Greater Prairie-chickens during March-April 2019–2021 on Fort Riley to investigate why this population is doing relatively well compared to populations in surrounding areas. We tested landscape feature, vegetation, and burn mosaic variables to evaluate which variables had the greatest influence on resource selection. Landscape features had the greatest influence on resource selection. Females avoided trees within Fort Riley for both breeding season use and nest-site selection at a greater margin than any other study in Kansas. Additionally, fourth-order selection was not evident within this study system, contrary to studies within surrounding areas. Our findings join a growing body of literature that suggests containment of woody encroachment as a high priority for managers to maintain or expand prairie grouse habitat in many different environments. This containment is especially critical on Fort Riley because of its constrained environment, and further woody encroachment could lead to loss of habitat that is inescapable by the Greater Prairie-chicken population on Fort Riley. Spatially-explicit evaluations of habitat availability are increasingly important as more areas within the Greater Prairie-chicken range become constrained by urbanization, agricultural expansion, and intensive management practices.