Species distribution models (SDMs) are statistical tools used to develop continuous predictions of species occurrence. ‘Integrated SDMs’ (ISDMs) are an elaboration of this approach with potential advantages that allow for the dual use of opportunistically collected presence-only data and site-occupancy data from planned surveys. These models also account for survey bias and imperfect detection through the use of a hierarchical modelling framework that separately estimates the species–environment response and detection process. This is particularly helpful for conservation applications and predictions for rare species, where data are often limited and prediction errors may have significant management consequences. Despite this potential importance, ISDMs remain largely untested under a variety of scenarios. We performed an exploration of key modelling decisions and assumptions on an ISDM using the endangered Baird’s tapir (Tapirus bairdii) as a test species. We found that site area had the strongest effect on the magnitude of population estimates and underlying intensity surface and was driven by estimates of model intercepts. Selecting a site area that accounted for the individual movements of the species within an average home range led to population estimates that coincided with expert estimates. ISDMs that do not account for the individual movements of species will likely lead to less accurate estimates of species intensity (number of individuals per unit area) and thus overall population estimates. This bias could be severe and highly detrimental to conservation actions if uninformed ISDMs are used to estimate global populations of threatened and data-deficient species, particularly those that lack natural history and movement information. However, the ISDM was consistently the most accurate model compared to other approaches, which demonstrates the importance of this new modelling framework and the ability to combine opportunistic data with systematic survey data. Thus, we recommend researchers use ISDMs with conservative movement information when estimating population sizes of rare and data-deficient species. ISDMs could be improved by using a similar parameterization to spatial capture–recapture models that explicitly incorporate animal movement as a model parameter, which would further remove the need for spatial subsampling prior to implementation.

Potassium-bentonites have been found in the Courceyan Lower Limestone Shales near Burrington Combe and Oakhill, Somerset, consisting of thin, greenish yellow, plastic clays interbedded within a mudrock and limestone sequence. Mineralogically, the clay fraction is composed of virtually monomineralic interstratified illite-smectite containing 7–10% smectite layers. The clay fraction of the surrounding mudrocks, however, consists of an illite-chlorite dominated assemblage. Their mineral composition, trace element content, and the relative abundance of zircon crystals suggest an origin from burial of montmorillonite originally formed from volcanic ash. The presence of anomalously high trace element contents with both euhedral and rounded zircon grains in the Oakhill K-bentonites suggests a secondary or reworked origin for these samples. In contrast, the presence of a non-anomalous trace element content and large (>100 μm) euhedral zircon grains suggests that the Burrington K-bentonite is primary in origin. Modelling of whole-rock rare-earth element (REE) patterns shows that the Oakhill REE pattern can be derived from the Burrington pattern by the addition of small contributions from zircon and monazite, two major heavy minerals present. These K-bentonites probably represent the oldest Carboniferous K-bentonites so far recorded in the British Isles.

Throughout its range in Latin America the jaguar Panthera onca is threatened by habitat loss and fragmentation, and conflict with humans. Protected areas in Panama harbour some of the last remaining suitable habitat for jaguars and are vital to conservation. However, no previous studies had assessed which factors in particular affect the tolerance of rural Panamanians towards jaguars and National Park conservation, which is important to jaguar persistence. Whether these factors are consistent with previous research on human–carnivore coexistence is unclear. To address this we estimated the number of instances of depredation of cattle by jaguars, and assessed attitudes and perceptions of rural Panamanians. We conducted semi-structured interviews in two disparate study areas: Cerro Hoya National Park and Darién National Park. Depredation events were more frequent in the latter, but only residents of the former reported conflict between people and coyotes Canis latrans. Positive perceptions of jaguars and National Parks, and criticism of park management, increased with level of education and land ownership. Men were more open to receiving help on their farms to mitigate impacts of jaguars, and more tolerant of the presence of jaguars, than women. Residents from both study areas indicated high appreciation for their respective National Parks. We provide recommendations to improve community outreach and education initiatives, and suggest priority areas for future mitigation efforts concerning human–jaguar interactions in Panama.

A field study was conducted from 1987 to 1992 to determine the effectiveness of several treatments consisting of combinations of glyphosate and/or quizalofop with tillage to control quackgrass in legume plowdown and continuous annual crop rotations. The treatments were imposed on the quackgrass in 1987 and/or 1988, evaluated in 1989 (cycle 1), reimposed on the same plots in 1990 and/or 1991 and re-evaluated in 1992 (cycle 2). Where continuous barley was grown, glyphosate applied at 0.45 kg/ha before seeding in 1987 (cycle 1) and 1990 (cycle 2), and combined with fall tillage in the first two years of each cycle, reduced quackgrass shoot density and rhizome dry weight by more than 96%. In a legume plowdown rotation, consisting of barley underseeded to red clover followed by plowdown and barley in subsequent years, quackgrass was reduced by a similar amount by glyphosate at 0.45 kg/ha applied in 1987 and 1990 before seeding or in 1988 and 1991 at 5 d before or 6 wk after red clover plowdown. Quackgrass reduction from all of these treatments was as effective as the labelled rate of glyphosate (0.90 kg/ha) applied at the same times, and also as effective as glyphosate applied at 0.45 kg/ha in combination with tillage in a year of fallow. Without fall tillage the efficacy of glyphosate applied before seeding was reduced. Quizalofop at 0.20 kg/ha applied to canola in a rotation of canola followed by two years of barley, reduced quackgrass, but was less effective than glyphosate treatments with fall tillage. Reducing quackgrass populations resulted in significant increases in crop yields.

Herbicide-resistant canola dominates the canola market in Canada. A multiyear field experiment was conducted at three locations to investigate the effect of time of weed removal (two-, four-, or six-leaf canola) and herbicide rate (50 or 100% recommended) in three herbicide-resistant canola systems. Weeds were controlled in glufosinate-resistant canola (GLU) with glufosinate, in glyphosate-resistant canola (GLY) with glyphosate, and in imidazolinone-resistant canola (IMI) with a 50:50 mixture of imazamox and imazethapyr. Canola yields were similar among the three canola cultivar–herbicide systems. Yields were not influenced by 50 vs. 100% herbicide rates. Timing of weed removal had the greatest effect on canola yield, with weed removal at the four-leaf stage giving the highest yields in most cases. Percent dockage was often greater for GLU and IMI than for GLY. In comparison with the other treatments, dockage levels doubled for GLU after application at 50% herbicide rates. The consistency of monocot weed control was usually greater for GLY than for GLU or IMI systems. However, weed biomass data revealed no differences in dicot weed control consistency between IMI and GLY systems. Greater dockage and weed biomass variability after weed removal at the six-leaf stage or after low herbicide rates suggests higher weed seed production, which could constrain the adoption of integrated weed management practices in subsequent years.

There is no published information on the impact of volunteer barley on wheat yield loss or on the economics of controlling barley with a herbicide. With the registration of imazamox-resistant wheat, it is now possible to control volunteer barley in wheat. Thus, the likelihood of growing wheat in rotation with barley may increase. Field experiments were conducted in 2003 and 2004 at Beaverlodge, Lacombe, and Edmonton, AB, Canada, and Saskatoon, SK, Canada, to determine the impact of volunteer barley on yield of imazamox-resistant spring wheat seeded at relatively low (100 kg ha−1) and high (175 kg ha−1) rates. Barley was seeded at different densities to simulate volunteer barley infestations. Regression analysis indicated that wheat-plant density influenced the effects of volunteer barley interference on wheat yield loss, economic threshold values, and volunteer barley fecundity among locations and years. Economic thresholds varied from as few volunteer barley plants as 3 m−2 at Beaverlodge in 2003 and 2004 to 48 m−2 at Lacombe in 2003. In most cases, wheat yield loss and volunteer barley fecundity were lower and economic thresholds were higher when wheat was seeded at the higher rate. For example, averaged over both years at Beaverlodge initial slope values (percentage of wheat yield loss at low barley density) were 4.5 and 1.7%, and economic threshold values of volunteer barley plants were 3 m−2 and 8 m−2 at low and high wheat seeding rates, respectively. Results indicate that volunteer barley can be highly competitive in wheat, but yield losses and wheat seed contamination due to volunteer barley can be alleviated by seeding wheat at a relatively high rate.

Alfalfa seed producers have a limited number of herbicide options to manage weed problems. MON-37500 (proposed name sulfosulfuron) is a sulfonylurea herbicide that controls dandelion and quackgrass, two common weeds in alfalfa fields. A study was conducted in two alfalfa fields at Valparaiso and Carrot River, Saskatchewan, Canada, from 1999 to 2001 to evaluate perennial weed control and alfalfa production responses with 0.5×, 1×, and 1.5× label-recommended rates of MON-37500 and also 2,4-DB and hexazinone. MON-37500 applied at the 1× and 1.5× rates at both locations reduced mid-May alfalfa vigor from 100% to between 80 and 90% and increased early-season control of dandelion and quackgrass by about 10 to 40 percentage units, when compared with other herbicide treatments. Improved weed control with 1× and 1.5× MON-37500 rates was sustained into mid-June only at Carrot River and was completely eliminated (100% vigor and 0% weed control), or almost so, by mid-July. MON-37500 did not control Canada thistle. Improved early-season weed control with the 1× MON-37500 rate apparently compensated for the loss of alfalfa vigor at Valparaiso, thus resulting in 27% (57 kg/ha) greater seed yield than with the other herbicide treatments. At Carrot River, hexazinone generally provided levels of weed control similar to MON-37500 but did not injure alfalfa. Consequently, alfalfa yields were highest and the proportion of dead (decaying) seed was least with this treatment. The 0.5× MON-37500 rate often resulted in inferior weed control relative to the 1× and 1.5× rates and never was among the herbicide treatments providing the greatest seed yield. Managing the residual activity of MON-37500 and its negative effect on alfalfa growth, especially at locations with soils having coarse texture and low organic matter content, represents the greatest challenge in making MON-37500 a reliable weed management tool for alfalfa seed producers.

Early weed removal in canola gives the crop a competitive advantage over weeds and is therefore widely recommended for optimal crop production, but no studies have been undertaken previously to determine the effect of this practice on insect infestations. Four field experiments were conducted at Lacombe and Beaverlodge, AB, Canada, in 1999–2001 for a total of 10 site-years to determine the effect of time of weed removal on root maggot (Delia spp.) egg deposition and larval damage to taproots. The experiments also investigated the effects of other factors such as cultivar, seeding date, herbicide application rate, fertilizer rate and placement, and use of a nitrification inhibitor on root maggot damage and oviposition. Damage to taproots and oviposition declined by approximately 6 and 23%, respectively, with a delay in weed removal from the two- to six-leaf stage of canola development. The effect of time of weed removal on root maggot damage and egg density sometimes varied with site and cultivar, but the main effect of time of weed removal was more prominent (smaller P values) than interactions with site. The most plausible explanation for this effect relates to the behavioral sequence of events that precedes oviposition in mated, gravid female flies. Heterogeneous environments, such as weedy backgrounds in canola plantings, minimize opportunities for females of Delia spp. to complete the behavioral sequence required for oviposition, leading to reduced infestation levels in weedy systems. However, yield improvements achieved with early weed removal exceeded the yield benefit derived by lowered root maggot pressure when weeds were removed later. Nevertheless, current efforts to reduce pesticide use in agriculture may promote broader adoption of cultural control strategies for weed and root maggot management. In some situations, it may then be appropriate to ameliorate root maggot damage by maintaining some weedy background.

Weed control in organic onion production is often difficult and expensive,requiring numerous cultivations and extensive hand weeding. Onion safety andweed control with mustard seed meal (MSM) derived from Sinapis alba was evaluated in greenhouse and field trials. MSM appliedat 110, 220, and 440 g m−2 severely injured onions and reducedonion stand by 25% or more when applied from planting to the one-leaf stageof onions in greenhouse trials. MSM derived from mustard cultivars ‘IdaGold’and ‘AC Pennant’ reduced plant dry weight of redroot pigweed with aneffective dose that provided 90% weed control (ED90) of 14.5 and3.2 g m−2, respectively, in greenhouse trials, whereas the ED90 of MSM from a low-glucosinolate cultivar ‘00RN29D10’ was128 g m−2, suggesting that glucosinolate content and ionicthiocyanate (SCN−) production contribute to phytotoxicity of MSM.In field trials, weed emergence, onion injury, and onion yield were recordedfollowing single or three sequential applications of MSM from 1.1 to 4.5 MT ha−1 beginning at the two-leaf stage of onions in 2008, 2009,and 2010. By 8 wk after treatment (WAT), onion injury following MSMsequential applications was 10% or less in all 3 yr. Combined over 2008 and2009, 48 and 68% fewer weeds emerged 3 WAT with MSM at 2.2 and 4.5 MT ha−1, respectively. In 2010, MSM at 2.2 and 4.5 MT ha−1 reduced the number of weeds emerged 4 WAT by 91 and 76%,respectively. MSM treatment did not significantly affect onion yield or sizein 2008 and 2009, but in 2010 onion total yield was reduced by 29% by threesequential applications of MSM at 2.2 MT ha−1. MSM has potentialto be used as a weed-suppressive amendment in organic production systems,but the risk of crop injury is substantial.

Quantum information and computing are at the forefront of computer science, but their implementation relies on significant developments in materials science. In particular, suitable, lattice-matched substrates for two promising approaches—electrostatically defined quantum dots in Si/SiGe heterostructures, and superconducting circuits containing Josephson junctions—do not exist. Instead, these approaches rely on metamorphic substrates. In this article, we focus on the general structure and requirements of SiGe quantum dot heterostructures, the demands they impose on the underlying substrate, and the impact that properties of the metamorphic substrate have on device performance. Superconductor Josephson junction materials are briefly discussed in a similar fashion, and opportunities for future developments in both systems are described.

Direct optimisation techniques using different methods are presented and compared for the solution of two common flows: a two dimensional diffuser and a drag minimisation problem of a fixed area body. The methods studied are a truncated Newton algorithm (gradient method), a simplex approach (direct search method) and a genetic algorithm (stochastic method). The diffuser problem has a known solution supported by experimental data, it has one design performance measure (the pressure coefficient) and two design variables. The fixed area body also has one performance measure (the drag coefficient), but this time there are four design variables; no experimental data is available, this computation is performed to assess the speed/progression of solution.

In all cases the direct search approach (simplex method) required significantly smaller number of evaluations than the generic algorithm method. The simplest approach, the gradient method (Newton) performed equally to the simplex approach for the diffuser problem but it was unable to provide a solution to the four-variable problem of a fixed area body drag minimisation. The level of robustness obtained by the use of generic algorithm is in principle superior to the other methods, but a large price in terms of evaluations has to be paid.