Forest Development and Carbon Dynamics After Mountain Pine Beetle Outbreaks

Mountain pine beetles periodically infest pine forests in western North America, killing many or most overstory pine stems. The surviving secondary stand structure, along with recruited seedlings, will form the future canopy. Thus, even-aged pine stands become multiaged and multistoried. The species composition of affected stands will depend on the presence of nonpines and outbreak severity, among other factors, and can range from continued dominance by pines to hastened conversion to more shade-tolerant species. The loss of mature host trees results in reductions of ecosystem carbon productivity. The surviving and recruited stems, however, grow more quickly in response to the reduced competition, and carbon productivity and live basal area recover to preoutbreak levels within a few years or decades. Infestations may result in system carbon storage reductions, relative to storage among undisturbed developmental trajectories, mostly because of the temporary decrease in carbon productivity. Carbon losses in infested stands are slow as a result of recalcitrance of snags and coarse woody debris. Recalcitrant dead pools combined with recovering live pools results in fairly stable total ecosystem carbon storage among infested stands. Infested stands may switch from net carbon sinks to net carbon sources but typically recover within 5–20 years

A global view of shifting cultivation: Recent, current, and future extent

Mosaic landscapes under shifting cultivation, with their dynamic mix of managed and natural land covers, often fall through the cracks in remote sensing–based land cover and land use classifications, as these are unable to adequately capture such landscapes’ dynamic nature and complex spectral and spatial signatures. But information about such landscapes is urgently needed to improve the outcomes of global earth system modelling and large-scale carbon and greenhouse gas accounting. This study combines existing global Landsat-based deforestation data covering the years 2000 to 2014 with very high-resolution satellite imagery to visually detect the specific spatio-temporal pattern of shifting cultivation at a one-degree cell resolution worldwide. The accuracy levels of our classification were high with an overall accuracy above 87%. We estimate the current global extent of shifting cultivation and compare it to other current global mapping endeavors as well as results of literature searches. Based on an expert survey, we make a first attempt at estimating past trends as well as possible future trends in the global distribution of shifting cultivation until the end of the 21st century. With 62% of the investigated one-degree cells in the humid and sub-humid tropics currently showing signs of shifting cultivation—the majority in the Americas (41%) and Africa (37%)—this form of cultivation remains widespread, and it would be wrong to speak of its general global demise in the last decades. We estimate that shifting cultivation landscapes currently cover roughly 280 million hectares worldwide, including both cultivated fields and fallows. While only an approximation, this estimate is clearly smaller than the areas mentioned in the literature which range up to 1,000 million hectares. Based on our expert survey and historical trends we estimate a possible strong decrease in shifting cultivation over the next decades, raising issues of livelihood security and resilience among people currently depending on shifting cultivation

Computational Bounds for Doing Harmonic Analysis on Permutation Modules of Finite Groups

We develop an approach to finding upper bounds for the number of arithmetic operations necessary for doing harmonic analysis on permutation modules of finite groups. The approach takes advantage of the intrinsic orbital structure of permutation modules, and it uses the multiplicities of irreducible submodules within individual orbital spaces to express the resulting computational bounds. We conclude by showing that these bounds are surprisingly small when dealing with certain permutation modules arising from the action of the symmetric group on tabloids.Comment: 19 page

Environmental Quality Management in a Region with External Development Pressures

The objective of this study was to examine the problems of managing residuals and environmental quality in a region facing potentially rapid growth as a consequence of externally made development decisions. The research adapted and applied the residuals environmental management concept which recognizes the need for an integration of physical methods, implementation incentives and institutional arrangements in controlling air, water and solid residuals. The area selected for study, the Uintah Basin in Southeastern utah, has the potential for extensive energy resource and mineral development and could experience a large population influx and accelerated economic growth as a result. in the face of a wide range of possible resource developments, the study used an alternative futures approach, in which combinations of exogenous events leading to different types and levels of economic activities and employment inpacts were identified. Economic and land use simulation models were applied to project the effects of the futures on the basin. Materials balances were then drawn up for major polluting activities to determine the residuals that would be produced and discharged to the environment if there were not controls. An environmental impact and management model, structured as al inear programming model, was used to evaluate environmental management strategies. The model incorporated various production processes and residuals treatment methods. Air and water quality simulation models were applied to assess environmental impacts and generate model constraints. Several dimesnsions of environmental management strategies were analyzed including alternative production processes, waste treatment methods, and various implementation incentives such as effluent charges, effluent standards and effects of legal restructions. This report was submitted in fulfillment of Contract No. R-803203 by the Utah Water Research Laboratory, Utah State University under the sponsorship of the U.S. Environmental Protection Agency. This report covers the period July 22, 1974 to january 31, 1977, and was completed as of February 21, 1977

Analysis of Time to Treatment and Survival Among Adults Younger Than 50 Years of Age With Colorectal Cancer in Canada

Importance: Colorectal cancer (CRC) is uncommon in adults younger than 50 years of age, so this population may experience delays to treatment that contribute to advanced stage and poor survival. Objective: To investigate whether there is an association between time from presentation to treatment and survival in younger adults with CRC. Design, Setting, and Participants: This retrospective cohort study used linked population-based data in Ontario, Canada. Participants included patients with CRC aged younger than 50 years who were diagnosed in Ontario between 2007 and 2018. Analysis was performed between December 2019 and December 2022. Exposure: Administrative and billing codes were used to identify the number of days between the date of first presentation and treatment initiation (overall interval). Main Outcomes and Measures: The associations between increasing overall interval, overall survival (OS), and cause-specific survival (CSS) were explored with restricted cubic spline regression. Multivariable Cox proportional hazards models were also fit for OS and CSS, adjusted for confounders. Analyses were repeated in a subset of patients with lower urgency, defined as those who did not present emergently, did not have metastatic disease, did not have cross-sectional imaging or endoscopy within 14 days of first presentation, and had an overall interval of at least 28 days duration. Results: Among 5026 patients included, the median (IQR) age was 44.0 years (40.0-47.0 years); 2412 (48.0%) were female; 1266 (25.2%) had metastatic disease and 1570 (31.2%) had rectal cancer. The lower-urgency subset consisted of 2548 patients. The median (IQR) overall interval was 108 days (55-214 days) (15.4 weeks [7.9-30.6 weeks]). Patients with metastatic CRC had shorter median (IQR) overall intervals (83 days [39-183 days]) compared with those with less advanced disease. Five-year overall survival was 69.8% (95% CI, 68.4%-71.1%). Spline regression showed younger patients with shorter overall intervals (&lt;108 days) had worse OS and CSS with no significant adverse outcomes of longer overall intervals. In adjusted Cox models, overall intervals longer than 18 weeks were not associated with significantly worse OS or CSS compared with those waiting 12 to 18 weeks (OS: HR, 0.83 [95% CI, 0.67-1.03]; CSS: HR, 0.90 [95% CI, 0.69-1.18]). Results were similar in the subset of lower-urgency patients, and when stratified by stage. Conclusions and relevance: In this cohort study of 5026 patients with CRC aged younger than 50 years of age in Ontario, time from presentation to treatment was not associated with advanced disease or poor survival. These results suggest that targeting postpresentation intervals may not translate to improved outcomes on a population level.</p

Continuity of medication management in Medicaid patients with chronic comorbid conditions: An examination by mental health status

Patients with serious mental illness (SMI) often have comorbid cardiometabolic conditions (CMCs) that may increase the number of prescribers involved in treatment. This study examined whether patients with SMI (depression and schizophrenia) and comorbid CMCs experience greater discontinuity of prescribing than patients with CMCs alone

High-resolution Near-Infrared Images and Models of the Circumstellar Disk in HH 30

We present Hubble Space Telescope (HST) Near-Infrared Camera and Multi-object Spectrometer (NICMOS) observations of the reflection nebulosity associated with the T Tauri star HH 30. The images show the scattered light pattern characteristic of a highly inclined, optically thick disk with a prominent dustlane whose width decreases with increasing wavelength. The reflected nebulosity exhibits a lateral asymmetry in the upper lobe on the opposite side to that reported in previously published Wide Field Planetary Camera 2 (WFPC2) images. The radiation transfer model which most closely reproduces the data has a flared accretion disk with dust grains larger than standard interstellar medium grains by a factor of approximately 2.1. A single hotspot on the stellar surface provides the necessary asymmetry to fit the images and is consistent with previous modeling of the light curve and images. Photometric analysis results in an estimated extinction of Av>~80; however, since the photometry measures only scattered light rather than direct stellar flux, this a lower limit. The radiative transfer models require an extinction of Av = 7,900.Comment: Accepted for publication in Ap.

Assessing Novel Lidar Modalities for Maximizing Coverage of a Spaceborne System through the Use of Diode Lasers

Current satellite lidars have sparse spatial coverage, leading to uncertainty from sampling. This complicates robust change detection and does not allow applications that require continuous coverage. One potential way to increase lidar sampling density is to use more efficient lasers. All current spaceborne lidars use solid-state lasers with a limited efficiency of 5–8%. In this paper, we investigate the potential for using diode lasers, with their higher efficiencies, as an alternative. Diode lasers have reported efficiencies of about 25% and are much smaller and lighter than solid-state lasers. However, they can only emit good beam quality at lower peak powers, which has so far prevented them from being used in spaceborne lidar applications. In this paper, we assess whether the novel lidar modalities necessitated by these lower peak powers are suitable for satellite lidar, determined by whether they can match the design performance of GEDI by being able to accurately measure ground elevation through 98% canopy cover, referred to as having “98% beam sensitivity”. Through this, we show that a diode laser can be operated in pulse train or pulse compressed lidar (PCL) mode from space, using a photon-counting detector. In the best case scenario, this setup requires a detected energy of Edet=0.027 fJ to achieve a beam sensitivity of 98%, which is less than the 0.28 fJ required by a full-waveform solid-state lidar instrument, exemplified by GEDI. When also accounting for the higher laser and detector efficiency, the diode laser in pulse train mode requires similar shot energy as a photon counting solid-state laser such as ICESat-2 which along with the higher laser efficiency could result in a doubling of coverage. We conclude that there is a clear opportunity for diode lasers to be used in spaceborne lidars, potentially allowing wider coverage through their higher efficiencies