Airborne LiDAR detects selectively logged tropical forest even in an advanced stage of recovery

Identifying historical forest disturbances is difficult, especially in selectively logged areas. LiDAR is able to measure fine-scale variations in forest structure over multiple kilometers. We use LiDAR data from ca. 16 km2 of forest in Sierra Leone, West Africa, to discriminate areas of old-growth from areas recovering from selective logging for 23 years. We examined canopy height variation and gap size distributions. We found that though recovering blocks of forest differed little in height from old-growth forest (up to 3 m) they had a greater area of canopy gaps (average 10.2% gap fraction in logged areas, compared to 5.6% in unlogged area); and greater numbers of gaps penetrating to the forest floor (162 gaps at 2 m height in logged blocks, and 101 in an unlogged block). Comparison of LiDAR measurements with field data demonstrated that LiDAR delivered accurate results. We found that gap size distributions deviated from power-laws reported previously, with substantially fewer large gaps than predicted by power-law functions. Our analyses demonstrate that LiDAR is a useful tool for distinguishing structural differences between old-growth and old-secondary forests. That makes LiDAR a powerful tool for REDD+ (Reduction of Emissions from Deforestation and Forest Degradation) programs implementation and conservation planning.This research was funded by the European Union under the EuropeAid Programme, as a part of the Across the River Transboundary Peace Park Project DCI/ENV/2008/151-577; by a Cambridge Conservation Initiative Collaborative Fund grant “Applications of airborne remote sensing to the conservation management of a West African National Park”; and by the ERC grant Africa GHG #247349. We would also like to thank the British Technion Society for the generous funding of the post-doctoral Coleman-Cohen fellowship of R. Kent.This is the final version of the article. It first appeared from MDPI via http://dx.doi.org/10.3390/rs7070834

Transport of video over partial order connections

A Partial Order and partial reliable Connection (POC) is an end-to-end transport connection authorized to deliver objects in an order that can differ from the transmitted one. Such a connection is also authorized to lose some objects. The POC concept is motivated by the fact that heterogeneous best-effort networks such as Internet are plagued by unordered delivery of packets and losses, which tax the performances of current applications and protocols. It has been shown, in several research works, that out of order delivery is able to alleviate (with respect to CO service) the use of end systems’ communication resources. In this paper, the efficiency of out-of-sequence delivery on MPEG video streams processing is studied. Firstly, the transport constraints (in terms of order and reliability) that can be relaxed by MPEG video decoders, for improving video transport, are detailed. Then, we analyze the performance gain induced by this approach in terms of blocking times and recovered errors. We demonstrate that POC connections fill not only the conceptual gap between TCP and UDP but also provide real performance improvements for the transport of multimedia streams such MPEG video

Seasonal and Spatial Variation in the Location and Reactivity of a Nitrate‐Contaminated Groundwater Discharge Zone in a Lakebed

Groundwater discharge delivering anthropogenic N from surrounding watersheds can impact lake nutrient budgets. However, upgradient groundwater processes and changing dynamics in N biogeochemistry at the groundwater‐lake interface are complex. In this study, seasonal water‐level variations in a groundwater flow‐through lake altered discharge patterns of a wastewater‐derived groundwater contaminant plume, thereby affecting biogeochemical processes controlling N transport. Pore water collected 15 cm under the lakebed along transects perpendicular to shore varied from oxic to anoxic with increasing nitrate concentrations (10–75 μM) and corresponding gradients in nitrite and nitrous oxide. Pore water depth profiles of nitrate concentrations and stable isotopic compositions largely reflected upgradient groundwater N sources and N cycle processes, with minor additional nitrate reduction in the near‐surface lakebed sediments. Potential denitrification rates determined in laboratory microcosms were 10–100 times higher in near‐surface sediments (0–5 cm) than in deeper sediments (5–30 cm) and were correlated with sediment carbon content and abundance of denitrification genes (nirS, nosZI, and nosZII). Potential anammox‐driven N2 production was detectable in deeper anoxic sediments. Injection of bromide and nitrite in the lake sediments showed that the highest net nitrite consumption rates were within the top 10 cm. However, short transit times owing to rapid upward pore water velocities (4–5 cm hr−1) limited removal of the contaminant nitrate transiting through the sediments. Results demonstrate that local hydrologic and biogeochemical processes at the point of discharge affect the distribution and discharge rate of N through lakebed sediments, but processes in the upgradient groundwater can be more important for affecting N speciation and concentration

Creation of dense polymer brush layers by the controlled deposition of an amphiphilic responsive comb polymer

We introduce a copolymer with a comb topology that has been engineered to assemble in a brush configuration at an air-water interface. The molecule comprises a 6.1 kDa poly(methyl methacrylate) backbone with a statistical amount of poly[2-(dimethyl amino)ethyl methacrylate] polybase side chains averaging 2.43 per backbone.. Brush layers deposited with the hydrophobic PMMA backbone adsorbed to hydrophobized silicon are stable in water even when stored at pH values less than 2.0 for over 24 h. The use of a Langmuir trough allows a simple controlled deposition of the layers at a variety of grafting densities. Depth profiling of brush layers was performed using neutron reflectometry and reveals a significant shifting of the responsiveness of the layer upon changing the grafting density. The degree of swelling of the layers at a pH value of 4 (below the pK(b)) decreases as grafting density increases. Lowering the pH of the subphase during deposition causes the side chains to become charged and more hydrophilic extending to a brush-like configuration while at neutral pH the side chains lie in a "pancake" conformation at the interface. (C) 2009 Elsevier Ltd. All rights reserved

The magnitude and timing of recalled immunity after breakthrough infection is shaped by SARS-CoV-2 variants

Vaccination against SARS-CoV-2 protects from infection and improves clinical outcomes in breakthrough infections, likely reflecting residual vaccine-elicited immunity and recall of immunological memory. Here, we define the early kinetics of spike-specific humoral and cellular immunity after vaccination of seropositive individuals and after Delta or Omicron breakthrough infection in vaccinated individuals. Early longitudinal sampling revealed the timing and magnitude of recall, with the phenotypic activation of B cells preceding an increase in neutralizing antibody titers. While vaccination of seropositive individuals resulted in robust recall of humoral and T cell immunity, recall of vaccine-elicited responses was delayed and variable in magnitude during breakthrough infections and depended on the infecting variant of concern. While the delayed kinetics of immune recall provides a potential mechanism for the lack of early control of viral replication, the recall of antibodies coincided with viral clearance and likely underpins the protective effects of vaccination against severe COVID-19

A Multi-Faceted Strategy for Evidence Translation Reduces Healthcare Waiting Time: A Mixed Methods Study Using the RE-AIM Framework

Background: Waiting lists are often thought to be inevitable in healthcare, but strategies that address patient flow by reducing complexity, combining triage with initial management, and/or actively managing the relationship between supply and demand can work. One such model, Specific Timely Appointments for Triage (STAT), brings these elements together and has been found in multiple trials to reduce waiting times by 30–40%. The next challenge is to translate this knowledge into practice.Method: A multi-faceted knowledge translation strategy, including workshops, resources, dissemination of research findings and a community of practice (CoP) was implemented. A mixed methods evaluation of the strategy was conducted based on the RE-AIM (Reach, Effectiveness, Adoption, Implementation, and Maintenance) framework, drawing on an internal database and a survey of workshop and CoP participants.Results: Demonstrating reach, at July 2020 an internal database held details of 342 clinicians and managers from 64 health services who had participated in the workshop program (n = 308) and/or elected to join an online CoP (n = 227). 40 of 69 (58%) respondents to a survey of this population reported they had adopted the model, with some providing data demonstrating that the STAT model had been efficacious in reducing waiting time. Perceived barriers to implementation included an overwhelming existing waiting list, an imbalance between supply and demand and lack of resources.Conclusion: There is high quality evidence from trials that STAT reduces waiting time. Using the RE-AIM framework, this evaluation of a translation strategy demonstrates uptake of evidence to reduce waiting time in health services.</jats:p

The Extragalactic Distance Scale without Cepheids IV

The Cepheid period-luminosity relation is the primary distance indicator used in most determinations of the Hubble constant. The tip of the red giant branch (TRGB) is an alternative basis. Using the new ANU SkyMapper Telescope, we calibrate the Tully Fisher relation in the I band. We find that the TRGB and Cepheid distance scales are consistent.Comment: ApJ in press 201

Assessing and reporting heterogeneity in treatment effects in clinical trials: a proposal

Mounting evidence suggests that there is frequently considerable variation in the risk of the outcome of interest in clinical trial populations. These differences in risk will often cause clinically important heterogeneity in treatment effects (HTE) across the trial population, such that the balance between treatment risks and benefits may differ substantially between large identifiable patient subgroups; the "average" benefit observed in the summary result may even be non-representative of the treatment effect for a typical patient in the trial. Conventional subgroup analyses, which examine whether specific patient characteristics modify the effects of treatment, are usually unable to detect even large variations in treatment benefit (and harm) across risk groups because they do not account for the fact that patients have multiple characteristics simultaneously that affect the likelihood of treatment benefit. Based upon recent evidence on optimal statistical approaches to assessing HTE, we propose a framework that prioritizes the analysis and reporting of multivariate risk-based HTE and suggests that other subgroup analyses should be explicitly labeled either as primary subgroup analyses (well-motivated by prior evidence and intended to produce clinically actionable results) or secondary (exploratory) subgroup analyses (performed to inform future research). A standardized and transparent approach to HTE assessment and reporting could substantially improve clinical trial utility and interpretability

How accurately is ncRNA aligned within whole-genome multiple alignments?

<p>Abstract</p> <p>Background</p> <p>Multiple alignment of homologous DNA sequences is of great interest to biologists since it provides a window into evolutionary processes. At present, the accuracy of whole-genome multiple alignments, particularly in noncoding regions, has not been thoroughly evaluated.</p> <p>Results</p> <p>We evaluate the alignment accuracy of certain noncoding regions using noncoding RNA alignments from Rfam as a reference. We inspect the MULTIZ 17-vertebrate alignment from the UCSC Genome Browser for all the human sequences in the Rfam seed alignments. In particular, we find 638 instances of chimeric and partial alignments to human noncoding RNA elements, of which at least 225 can be improved by straightforward means. As a byproduct of our procedure, we predict many novel instances of known ncRNA families that are suggested by the alignment.</p> <p>Conclusion</p> <p>MULTIZ does a fairly accurate job of aligning these genomes in these difficult regions. However, our experiments indicate that better alignments exist in some regions.</p

Antlia Dwarf Galaxy: Distance, quantitative morphology and recent formation history via statistical field correction

We apply a statistical field correction technique originally designed to determine membership of high redshift galaxy clusters to Hubble Space Telescope imaging of the Antlia Dwarf Galaxy; a galaxy at the very edge of the Local Group. Using the tip of the red giant branch standard candle method coupled with a simple Sobel edge detection filter we find a new distance to Antlia of 1.31 +/- 0.03 Mpc. For the first time for a Local Group Member, we compute the concentration, asymmetry and clumpiness (CAS) quantitative morphology parameters for Antlia from the distribution of resolved stars in the HST/ACS field, corrected with a new method for contaminants and complement these parameters with the Gini coefficient (G) and the second order moment of the brightest 20 per cent of the flux (M_20). We show that it is a classic dwarf elliptical (C = 2.0, A = 0.063, S = 0.077, G = 0.39 and M_20 = -1.17 in the F814W band), but has an appreciable blue stellar population at its core, confirming on-going star-formation. The values of asymmetry and clumpiness, as well as Gini and M_20 are consistent with an undisturbed galaxy. Although our analysis suggests that Antlia may not be tidally influenced by NGC 3109 it does not necessarily preclude such interaction.Comment: Accepted for publication in MNRA