Seed Invasion Filters and Forest Fire Severity

Forest seed dispersal is altered after fire. Using seed traps, we studied impacts of fire severity on timing of seed dispersal, total seed rain, and seed rain richness in patches of high and low severity fire and unburned Douglas-fir (Pseudotsuga menziesii) forests in the Fischer and Tyee fire complexes in the eastern Washington Cascades. Unburned plots had the lowest average seed production. The high severity fire patches in the Fischer Fire Complex had a higher total seed production than low severity fire patches of the same complex. At the Tyee Fire Complex, the total seed production for each of the two fire severities was similar, but the period of maximum seed dispersal was later for high severity than low severity fire. Seed rain at the Fischer Fire patches (sampled one year after the fire) was predominantly composed of annual species, while that of the Tyee Fire patches (sampled nine years after fire) was predominantly perennial species. Seed rain richness was greater in Tyee high severity patches than paired low severity fire patches. In these paired Tyee patches the average number of new seed species (species not found in the extant plot vegetation) was greater for high severity than low severity fire. Our results suggest that high severity fire plots are more porous to seed rain than low severity plots. Intact forest canopies may filter seed rain and reduce seed influx, while high severity fires are more open to invasion by seed dispersal

Deconstructing compassionate conservation

Compassionate conservation focuses on 4 tenets: first, do no harm; individuals matter; inclusivity of individual animals; and peaceful coexistence between humans and animals. Recently, compassionate conservation has been promoted as an alternative to conventional conservation philosophy. We believe examples presented by compassionate conservationists are deliberately or arbitrarily chosen to focus on mammals; inherently not compassionate; and offer ineffective conservation solutions. Compassionate conservation arbitrarily focuses on charismatic species, notably large predators and megaherbivores. The philosophy is not compassionate when it leaves invasive predators in the environment to cause harm to vastly more individuals of native species or uses the fear of harm by apex predators to terrorize mesopredators. Hindering the control of exotic species (megafauna, predators) in situ will not improve the conservation condition of the majority of biodiversity. The positions taken by so-called compassionate conservationists on particular species and on conservation actions could be extended to hinder other forms of conservation, including translocations, conservation fencing, and fertility control. Animal welfare is incredibly important to conservation, but ironically compassionate conservation does not offer the best welfare outcomes to animals and is often ineffective in achieving conservation goals. Consequently, compassionate conservation may threaten public and governmental support for conservation because of the limited understanding of conservation problems by the general public

Beyond land cover change: Towards a new generation of Land Use Models

Land use models play an important role in exploring future land change dynamics and are instrumental to support the integration of knowledge in land system science. However, only modest progress has been made in achieving these aims due to insufficient model evaluation and limited representation of the underlying socio-ecological processes. We discuss how land use models can better represent multi-scalar dynamics, human agency and demand-supply relations, and how we can achieve learning from model evaluation. By addressing these issues we outline pathways towards a new generation of land use models that allow not only the assessment of future land cover pattern changes, but also stimulate envisioning future land use by society to support debate on sustainability solutions and help design alternative solutions

Herpes simplex encephalitis is linked with selective mitochondrial damage; a post-mortem and in vitro study

Herpes simplex virus type-1 (HSV-1) encephalitis (HSE) is the most commonly diagnosed cause of viral encephalitis in western countries. Despite antiviral treatment, HSE remains a devastating disease with high morbidity and mortality. Improved understanding of pathogenesis may lead to more effective therapies. Mitochondrial damage has been reported during HSV infection in vitro. However, whether it occurs in the human brain and whether this contributes to the pathogenesis has not been fully explored. Minocycline, an antibiotic, has been reported to protect mitochondria and limit brain damage. Minocycline has not been studied in HSV infection. In the first genome-wide transcriptomic study of post-mortem human HSE brain tissue, we demonstrated a highly preferential reduction in mitochondrial genome (MtDNA) encoded transcripts in HSE cases (n = 3) compared to controls (n = 5). Brain tissue exhibited a significant inverse correlation for immunostaining between cytochrome c oxidase subunit 1 (CO1), a MtDNA encoded enzyme subunit, and HSV-1; with lower abundance for mitochondrial protein in regions where HSV-1 was abundant. Preferential loss of mitochondrial function, among MtDNA encoded components, was confirmed using an in vitro primary human astrocyte HSV-1 infection model. Dysfunction of cytochrome c oxidase (CO), a mitochondrial enzyme composed predominantly of MtDNA encoded subunits, preceded that of succinate dehydrogenase (composed entirely of nuclear encoded subunits). Minocycline treated astrocytes exhibited higher CO1 transcript abundance, sustained CO activity and cell viability compared to non-treated astrocytes. Based on observations from HSE patient tissue, this study highlights mitochondrial damage as a critical and early event during HSV-1 infection. We demonstrate minocycline preserves mitochondrial function and cell viability during HSV-1 infection. Minocycline, and mitochondrial protection, offers a novel adjunctive therapeutic approach for limiting brain cell damage and potentially improving outcome among HSE patients

Genomic epidemiology of SARS-CoV-2 in a UK university identifies dynamics of transmission

AbstractUnderstanding SARS-CoV-2 transmission in higher education settings is important to limit spread between students, and into at-risk populations. In this study, we sequenced 482 SARS-CoV-2 isolates from the University of Cambridge from 5 October to 6 December 2020. We perform a detailed phylogenetic comparison with 972 isolates from the surrounding community, complemented with epidemiological and contact tracing data, to determine transmission dynamics. We observe limited viral introductions into the university; the majority of student cases were linked to a single genetic cluster, likely following social gatherings at a venue outside the university. We identify considerable onward transmission associated with student accommodation and courses; this was effectively contained using local infection control measures and following a national lockdown. Transmission clusters were largely segregated within the university or the community. Our study highlights key determinants of SARS-CoV-2 transmission and effective interventions in a higher education setting that will inform public health policy during pandemics.</jats:p

Capturing Difficult Botanical Concepts with a Net of Previous Knowledge

Modern biology has a wealth of concepts that are difficult for students to grasp. Several botanical topics in particular have been described as difficult for student understanding (Wood-Robinson, 1991). Laboratory exercises allow hands- on work with these concepts and are critical to their understanding. This fact not withstanding, lecture- lab scheduling often results in lecture coverage of a topic as much as a full week prior to laboratory study of the material. Such a separation between lecture and lab can result in several days of student confusion before they can explore the concepts with laboratory methods. While we may hope for lab study to be seamlessly integrated with lecture, in many educational settings this is not always possible. This confusion can be reduced if, during lecture, students are engaged in thought experiments and/or simple in-lecture experiments that are conceptually accessible to their current understanding

Product Variety and Firm Survival in the Microcomputer Software Industry

*Wiley: submitted version can be posted to DSpace/website with the following statement: ‘This is the pre-peer reviewed version of the following article: Cottrell, T., and Nault, B.R., "Product Variety and Firm Survival in the Microcomputer Software Industry," Strategic Management Journal 25, 10 (October 2004), 1005-1026., which has been published in final form at [http://onlinelibrary.wiley.com/doi/10.1002/smj.408/epdf] Policy: http://media.wiley.com/assets/1540/90/ctabglobal.pdf. Article has been deposited according to publisher's policy 06/16/2015This article provides an analysis of product variety and scope economies in the microcomputer software industry by using detailed firm-level and product-level information on firms’ bundling of functionalities over application categories and computing platforms. We find that the management of product variety through the way different application categories are integrated in products and the platforms on which these products are offered can be as important as the significance of scope economies at the more aggregated firm level. Specifically, we find that there is little evidence of firm benefits from economies of scope in production, but there is substantial evidence that products benefit from economies of scope in consumption. In addition, we find that firms with products that encapsulate more application categories perform better, and those with products that cover more computing platforms perform worse. Finally, changes in product variety through new product introductions improve firm performance, but extensions to existing products hinder the performance of the firm and the product. We conclude that research in scope economies can benefit from a more detailed model of the evolution of product variety that includes data and analysis at the firm level and at the product level.Ye

Summer Soil Temperatures On Algific Talus Slopes In Northeast Iowa

Soil temperatures at 15 cm depth were recorded on a single occasion at multiple grid points on two algific talus slopes during the summer of 1999. To represent and compare soil temperatures over a wider area, soil temperatures were measured (less intensively) at five other algific slopes and three non-algific forested slopes. Algific slopes appear to have greater variation in soil temperatures than non-algific sites. Spatial variation in algific slope soil temperatures ranged from 4-25°C. During the 10 day sample period temporal variation in air temperature at a nearby weather station had a similar range. Isotherm plots reveal a heterogeneous distribution of cold temperatures on these slopes, suggesting that cold air flow is restricted to certain localized pockets on already small, isolated, and fragmented sites. The localized nature of these coldest temperatures suggest that cold air flow is linked to substrata layering. Because these cold air vents are apparently easily disturbed by walking on the talus slopes, we suggest use of a ladder to allow sampling fragile algific slopes. This sampling method will lessen slope damage and disturbance, while providing access to sites for study