Assessing the value of trees in sustainable grazing systems

The retention of trees in strips provides an option for managing non-remnant woody vegetation in native and sown pastures in northern Australia. However, the impact of tree strips on pasture production has not been previously researched in detail in southern Queensland. The influence of existing tree strips on pasture production in southern Queensland was measured at three grazing properties during 2004 and 2005. Soil and pasture attributes were sampled along transects 80 to 300 metres in length positioned perpendicular to tree strips. The tree strips ranged from 15 to 75 metres wide and were 120 to 500 metres apart. The effects of tree strips along the pasture transect were quantified in terms of pasture microclimate (e.g. temperature, humidity and, at one location, wind), pasture growth in grazed and exclosed situations, soil water, soil nutrients and condition, and nutrient availability. An experimental approach using exclosed pasture transects provided a useful ‘bioassay’ potentially integrating beneficial and competitive effects of tree strips on pasture growth as well as other factors (e.g. soil variability). Averaged across two locations and two years, the competitive effects of the tree strip were compensated to some extent by enhanced pasture growth at distances of 1-6 x tree height from the tree strip edge. However, the observed effects on pasture growth along the transect were likely to be due to different causes: pasture microclimate at one site, soil texture and microtopography at a second site and pasture establishment history at a third site. Thus, the trial highlighted the difficulty of attributing effects in real-world situations, given the number of possible causes including the tree strip effects on pasture microclimate and nutrient availability, soil surface disturbance, and systematic variation on soil and water redistribution due to soil micro-topography and felled timber. Despite these many sources of variation, general effects were derived from the field data consistent with other studies on tree strips and wind breaks across Australia. To extrapolate the project results to other locations, tree strip configurations and climates, a new version of the soil waterpasture growth simulation model GRASP was developed allowing simulation of tree and pasture effects and processes for various distances along a pasture transect perpendicular from the tree strip

Humans Strengthen Bottom-Up Effects and Weaken Trophic Cascades in a Terrestrial Food Web

Ongoing debate about whether food webs are primarily regulated by predators or by primary plant productivity, cast as top-down and bottom-up effects, respectively, may becoming superfluous. Given that most of the world\u27s ecosystems are human dominated we broadened this dichotomy by considering human effects in a terrestrial food-web. We studied a multiple human-use landscape in southwest Alberta, Canada, as opposed to protected areas where previous terrestrial food-web studies have been conducted. We used structural equation models (SEMs) to assess the strength and direction of relationships between the density and distribution of: (1) humans, measured using a density index; (2) wolves (Canis lupus), elk (Cervus elpahus) and domestic cattle (Bos taurus), measured using resource selection functions, and; (3) forage quality, quantity and utilization (measured at vegetation sampling plots). Relationships were evaluated by taking advantage of temporal and spatial variation in human density, including day versus night, and two landscapes with the highest and lowest human density in the study area. Here we show that forage-mediated effects of humans had primacy over predator-mediated effects in the food web. In our parsimonious SEM, occurrence of humans was most correlated with occurrence of forage (beta = 0.637, p \u3c 0.0001). Elk and cattle distribution were correlated with forage (elk day: beta = 0.400, p \u3c 0.0001; elk night: beta = 0.369, p \u3c 0.0001; cattle day: beta = 0.403, p \u3c 0.0001; cattle, night: beta = 0.436, p \u3c 0.0001), and the distribution of elk or cattle and wolves were positively correlated during daytime (elk: beta = 0.293, p \u3c 0.0001, cattle: beta = 0.303, p \u3c 0.0001) and night-time (elk: beta = 0.460, p \u3c 0.0001, cattle: beta = 0.482, p \u3c 0.0001). Our results contrast with research conducted in protected areas that suggested human effects in the food web are primarily predator-mediated. Instead, human influence on vegetation may strengthen bottom-up predominance and weaken top-down trophic cascades in ecosystems. We suggest that human influences on ecosystems may usurp top-down and bottom-up effects

Outcomes Associated With Early vs Late Initiation of Exclusive Enteral Feeding Regimens Following Laparoscopic Gastrostomy Tube Placement in the Pediatric Patient

ObjectivesDespite frequent placement of pediatric laparoscopic gastrostomy tubes (GTs), no rigorous evaluation of initial feeding and advancement regimens exists. Therefore, the aim of this study was to determine whether early enteral feeding after GT placement is associated with increased symptoms, procedural complications, or length of stay (LOS).MethodsIn this retrospective cohort study, the records of all patients at a tertiary care pediatric hospital who had gastrostomy placement were reviewed. Only patients fed exclusively via gastrostomy were included. Feeding was monitored starting with the first postoperative feed and subsequently in 24- hour increments. Adverse events were recorded based on clinical documentation.ResultsA total of 480 patients met inclusion criteria. Patients who started feeds between 24 and 36 hours had a shorter LOS compared with those who started at 36- 48 hours (P = .0072) or >48 hours (P < .0001). Patients requiring - ¥60 hours to reach goal feeds had significantly longer LOS than the other groups. There was no difference in the distribution of the LOS based on percentage of goal feeds initiated. Patients who required - ¥60 hours to attain goal feeds had the most feeding complications.ConclusionsMore aggressive feeding advancement and earlier initiation of feeds were associated with decreased LOS without an associated increase in adverse clinical events.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162797/2/ncp10503.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162797/1/ncp10503_am.pd

The role of sand lances (Ammodytes sp.) in the Northwest Atlantic ecosystem: a synthesis of current knowledge with implications for conservation and management

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Staudinger, M. D., Goyert, H., Suca, J. J., Coleman, K., Welch, L., Llopiz, J. K., Wiley, D., Altman, I., Applegate, A., Auster, P., Baumann, H., Beaty, J., Boelke, D., Kaufman, L., Loring, P., Moxley, J., Paton, S., Powers, K., Richardson, D., Robbins, J., Runge, J., Smith, B., Spiegel, C., & Steinmetz, H. The role of sand lances (Ammodytes sp.) in the Northwest Atlantic ecosystem: a synthesis of current knowledge with implications for conservation and management. Fish and Fisheries, 00, (2020): 1-34, doi:10.1111/faf.12445.The American sand lance (Ammodytes americanus, Ammodytidae) and the Northern sand lance (A. dubius, Ammodytidae) are small forage fishes that play an important functional role in the Northwest Atlantic Ocean (NWA). The NWA is a highly dynamic ecosystem currently facing increased risks from climate change, fishing and energy development. We need a better understanding of the biology, population dynamics and ecosystem role of Ammodytes to inform relevant management, climate adaptation and conservation efforts. To meet this need, we synthesized available data on the (a) life history, behaviour and distribution; (b) trophic ecology; (c) threats and vulnerabilities; and (d) ecosystem services role of Ammodytes in the NWA. Overall, 72 regional predators including 45 species of fishes, two squids, 16 seabirds and nine marine mammals were found to consume Ammodytes. Priority research needs identified during this effort include basic information on the patterns and drivers in abundance and distribution of Ammodytes, improved assessments of reproductive biology schedules and investigations of regional sensitivity and resilience to climate change, fishing and habitat disturbance. Food web studies are also needed to evaluate trophic linkages and to assess the consequences of inconsistent zooplankton prey and predator fields on energy flow within the NWA ecosystem. Synthesis results represent the first comprehensive assessment of Ammodytes in the NWA and are intended to inform new research and support regional ecosystem‐based management approaches.This manuscript is the result of follow‐up work stemming from a working group formed at a two‐day multidisciplinary and international workshop held at the Parker River National Wildlife Refuge, Massachusetts in May 2017, which convened 55 experts scientists, natural resource managers and conservation practitioners from 15 state, federal, academic and non‐governmental organizations with interest and expertise in Ammodytes ecology. Support for this effort was provided by USFWS, NOAA Stellwagen Bank National Marine Sanctuary, U.S. Department of the Interior, U.S. Geological Survey, Northeast Climate Adaptation Science Center (Award # G16AC00237), an NSF Graduate Research Fellowship to J.J.S., a CINAR Fellow Award to J.K.L. under Cooperative Agreement NA14OAR4320158, NSF award OCE‐1325451 to J.K.L., NSF award OCE‐1459087 to J.A.R, a Regional Sea Grant award to H.B. (RNE16‐CTHCE‐l), a National Marine Sanctuary Foundation award to P.J.A. (18‐08‐B‐196) and grants from the Mudge Foundation. The contents of this paper are the responsibility of the authors and do not necessarily represent the views of the National Oceanographic and Atmospheric Administration, U.S. Fish and Wildlife Service, New England Fishery Management Council and Mid‐Atlantic Fishery Management Council. This manuscript is submitted for publication with the understanding that the United States Government is authorized to reproduce and distribute reprints for Governmental purposes. Any use of trade, firm or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government

Severe Acute Respiratory Syndrome (SARS) in Singapore: Clinical Features of Index Patient and Initial Contacts

Severe acute respiratory syndrome (SARS) is an emerging viral infectious disease. One of the largest outbreaks of SARS to date began in Singapore in March 2003. We describe the clinical, laboratory, and radiologic features of the index patient and the patient’s initial contacts affected with probable SARS

Antibracket, Antifields and Gauge-Theory Quantization

The antibracket formalism for gauge theories, at both the classical and quantum level, is reviewed. Gauge transformations and the associated gauge structure are analyzed in detail. The basic concepts involved in the antibracket formalism are elucidated. Gauge-fixing, quantum effects, and anomalies within the field-antifield formalism are developed. The concepts, issues and constructions are illustrated using eight gauge-theory models.Comment: 191 pages in three files which must be put together, in Latex, to appear in Physics Report

Forgotten Plotlanders: Learning from the survival of lost informal housing in the UK.

Colin Ward’s discourses on the arcadian landscape of ‘plotlander’ housing are unique documentations of the anarchistic birth, life, and death of the last informal housing communities in the UK. Today the forgotten history of ‘plotlander’ housing documented by Ward can be re-read in the context of both the apparently never-ending ‘housing crisis’ in the UK, and the increasing awareness of the potential value of learning from comparable informal housing from the Global South. This papers observations of a previously unknown and forgotten plotlander site offers a chance to begin a new conversation regarding the positive potential of informal and alternative housing models in the UK and wider Westernised world

Quantifying HIV transmission flow between high-prevalence hotspots and surrounding communities: a population-based study in Rakai, Uganda

Background International and global organisations advocate targeting interventions to areas of high HIV prevalence (ie, hotspots). To better understand the potential benefits of geo-targeted control, we assessed the extent to which HIV hotspots along Lake Victoria sustain transmission in neighbouring populations in south-central Uganda. Methods We did a population-based survey in Rakai, Uganda, using data from the Rakai Community Cohort Study. The study surveyed all individuals aged 15–49 years in four high-prevalence Lake Victoria fishing communities and 36 neighbouring inland communities. Viral RNA was deep sequenced from participants infected with HIV who were antiretroviral therapy-naive during the observation period. Phylogenetic analysis was used to infer partial HIV transmission networks, including direction of transmission. Reconstructed networks were interpreted through data for current residence and migration history. HIV transmission flows within and between high-prevalence and low-prevalence areas were quantified adjusting for incomplete sampling of the population. Findings Between Aug 10, 2011, and Jan 30, 2015, data were collected for the Rakai Community Cohort Study. 25 882 individuals participated, including an estimated 75·7% of the lakeside population and 16·2% of the inland population in the Rakai region of Uganda. 5142 participants were HIV-positive (2703 [13·7%] in inland and 2439 [40·1%] in fishing communities). 3878 (75·4%) people who were HIV-positive did not report antiretroviral therapy use, of whom 2652 (68·4%) had virus deep-sequenced at sufficient quality for phylogenetic analysis. 446 transmission networks were reconstructed, including 293 linked pairs with inferred direction of transmission. Adjusting for incomplete sampling, an estimated 5·7% (95% credibility interval 4·4–7·3) of transmissions occurred within lakeside areas, 89·2% (86·0–91·8) within inland areas, 1·3% (0·6–2·6) from lakeside to inland areas, and 3·7% (2·3–5·8) from inland to lakeside areas. Interpretation Cross-community HIV transmissions between Lake Victoria hotspots and surrounding inland populations are infrequent and when they occur, virus more commonly flows into rather than out of hotspots. This result suggests that targeted interventions to these hotspots will not alone control the epidemic in inland populations, where most transmissions occur. Thus, geographical targeting of high prevalence areas might not be effective for broader epidemic control depending on underlying epidemic dynamics. Funding The Bill & Melinda Gates Foundation, the National Institute of Allergy and Infectious Diseases, the National Institute of Mental Health, the National Institute of Child Health and Development, the Division of Intramural Research of the National Institute for Allergy and Infectious Diseases, the World Bank, the Doris Duke Charitable Foundation, the Johns Hopkins University Center for AIDS Research, and the President's Emergency Plan for AIDS Relief through the Centers for Disease Control and Prevention

Photoprotection in the Lichen Parmelia sulcata: The Origins of Desiccation-Induced Fluorescence Quenching1

Lichens, a symbiotic relationship between a fungus (mycobiont) and a photosynthetic green algae or cyanobacteria (photobiont), belong to an elite group of survivalist organisms termed resurrection species. When lichens are desiccated, they are photosynthetically inactive, but upon rehydration they can perform photosynthesis within seconds. Desiccation is correlated with both a loss of variable chlorophyll a fluorescence and a decrease in overall fluorescence yield. The fluorescence quenching likely reflects photoprotection mechanisms that may be based on desiccation-induced changes in lichen structure that limit light exposure to the photobiont (sunshade effect) and/or active quenching of excitation energy absorbed by the photosynthetic apparatus. To separate and quantify these possible mechanisms, we have investigated the origins of fluorescence quenching in desiccated lichens with steady-state, low temperature, and time-resolved chlorophyll fluorescence spectroscopy. We found the most dramatic target of quenching to be photosystem II (PSII), which produces negligible levels of fluorescence in desiccated lichens. We show that fluorescence decay in desiccated lichens was dominated by a short lifetime, long-wavelength component energetically coupled to PSII. Remaining fluorescence was primarily from PSI and although diminished in amplitude, PSI decay kinetics were unaffected by desiccation. The long-wavelength-quenching species was responsible for most (about 80%) of the fluorescence quenching observed in desiccated lichens; the rest of the quenching was attributed to the sunshade effect induced by structural changes in the lichen thallus