U–Pb zircon geochronology and implications of Cambrian plutonism in the Ellsworth belt, Maine

The Ellsworth belt is one of several fault-bounded blocks exposed along the southeastern coast of Maine that formed within Ganderia. New ID-TIMS U–Pb geochronological data integrated with field relationships provide additional insights into the timing of magmatism and deformation in the Ellsworth belt. The deformed Lamoine Granite was selected for U–Pb zircon analysis in order to: i) establish the protolith age; ii) provide direct temporal constraints on regional low-grade metamorphism and deformation; and iii) elucidate relationships between the Ellsworth belt and coeval rocks elsewhere in the Appalachian orogen. The Lamoine Granite was emplaced within the Ellsworth Schist at 492 ± 1.7 Ma; this is the first unequivocal evidence for a Furongian magmatic event in the Ellsworth belt. The schistosity in the Lamoine Granite is parallel to the main fabric of the host Ellsworth Schist and provides a maximum estimate for timing of the regional metamorphic overprint. Widespread deformation in the Ellsworth belt where kinematic indicators indicate a top-to-northwest sense of shear is attributed to thrusting during which progressive horizontal shortening, caused crustal thickening and peak greenschist facies metamorphism. The Cambrian U–Pb age permits correlation of the Lamoine Granite with the Cameron Road Granite in the Annidale belt of New Brunswick where subduction-related magmas intruded the Penobscot arc–back-arc and were subsequently deformed during the Penobscot Orogeny.

Validation of a type 1 diabetes algorithm using electronic medical records and administrative healthcare data to study the population incidence and prevalence of type 1 diabetes in Ontario, Canada

IntroductionWe aimed to develop algorithms distinguishing type 1 diabetes (T1D) from type 2 diabetes in adults ≥18 years old using primary care electronic medical record (EMRPC) and administrative healthcare data from Ontario, Canada, and to estimate T1D prevalence and incidence.Research design and methodsThe reference population was a random sample of patients with diabetes in EMRPC whose charts were manually abstracted (n=5402). Algorithms were developed using classification trees, random forests, and rule-based methods, using electronic medical record (EMR) data, administrative data, or both. Algorithm performance was assessed in EMRPC. Administrative data algorithms were additionally evaluated using a diabetes clinic registry with endocrinologist-assigned diabetes type (n=29 371). Three algorithms were applied to the Ontario population to evaluate the minimum, moderate and maximum estimates of T1D prevalence and incidence rates between 2010 and 2017, and trends were analyzed using negative binomial regressions.ResultsOf 5402 individuals with diabetes in EMRPC, 195 had T1D. Sensitivity, specificity, positive predictive value and negative predictive value for the best performing algorithms were 80.6% (75.9–87.2), 99.8% (99.7–100), 94.9% (92.3–98.7), and 99.3% (99.1–99.5) for EMR, 51.3% (44.0–58.5), 99.5% (99.3–99.7), 79.4% (71.2–86.1), and 98.2% (97.8–98.5) for administrative data, and 87.2% (81.7–91.5), 99.9% (99.7–100), 96.6% (92.7–98.7) and 99.5% (99.3–99.7) for combined EMR and administrative data. Administrative data algorithms had similar sensitivity and specificity in the diabetes clinic registry. Of 11 499 711 adults in Ontario in 2017, there were 24 789 (0.22%, minimum estimate) to 102 140 (0.89%, maximum estimate) with T1D. Between 2010 and 2017, the age-standardized and sex-standardized prevalence rates per 1000 person-years increased (minimum estimate 1.7 to 2.56, maximum estimate 7.48 to 9.86, p<0.0001). In contrast, incidence rates decreased (minimum estimate 0.1 to 0.04, maximum estimate 0.47 to 0.09, p<0.0001).ConclusionsPrimary care EMR and administrative data algorithms performed well in identifying T1D and demonstrated increasing T1D prevalence in Ontario. These algorithms may permit the development of large, population-based cohort studies of T1D.

Estimating maximum global land surface wind power extractability and associated climatic consequences

The availability of wind power for renewable energy extraction is ultimately limited by how much kinetic energy is generated by natural processes within the Earth system and by fundamental limits of how much of the wind power can be extracted. Here we use these considerations to provide a maximum estimate of wind power availability over land. We use several different methods. First, we outline the processes associated with wind power generation and extraction with a simple power transfer hierarchy based on the assumption that available wind power will not geographically vary with increased extraction for an estimate of 68 TW. Second, we set up a simple momentum balance model to estimate maximum extractability which we then apply to reanalysis climate data, yielding an estimate of 21 TW. Third, we perform general circulation model simulations in which we extract different amounts of momentum from the atmospheric boundary layer to obtain a maximum estimate of how much power can be extracted, yielding 18–34 TW. These three methods consistently yield maximum estimates in the range of 18–68 TW and are notably less than recent estimates that claim abundant wind power availability. Furthermore, we show with the general circulation model simulations that some climatic effects at maximum wind power extraction are similar in magnitude to those associated with a doubling of atmospheric CO2. We conclude that in order to understand fundamental limits to renewable energy resources, as well as the impacts of their utilization, it is imperative to use a "top-down" thermodynamic Earth system perspective, rather than the more common "bottom-up" engineering approach.

Foraging Behavior ofPraon volucre(Hymenoptera: Braconidae) a Parasitoid ofSitobion avenae(Hemiptera: Aphididae) on Wheat

Host stage preference, functional response and, mutual interference ofPraon volucre(Haliday) (Hym.: Braconidae) parasitizing the grain aphid,Sitobion avenae(Fabricius) (Hem.: Aphididae), were investigated under laboratory conditions. Host stage preference was evaluated at25±1°C,60±5% relative humidity and a photoperiod of 16:8 h (L : D), under choice and no-choice tests. Functional response was done under five constant temperatures (10, 15, 20, 25, and 30°C),60±5% relative humidity and a photoperiod of 16:8 h. (L : D).Praon volucreparasitized all nymphal instars and adults of the grain aphid but strongly preferred to oviposit into second-instar nymphs in both choice and no-choice conditions. Results of logistic regression revealed a type II functional response for all temperatures tested. The handling time (Th) and searching efficiency (a) were estimated using the Rogers equation. The maximum estimate of searching efficiency occurred at 15°C and 20°C (both0.05±0.01 h-1) and decreased to0.01±0.01 h-1at30±1°C. The minimum estimate of handling time was1.02±0.11 h at 25°C and increased to5.31±0.82 h at30±1°C. The maximum rate of parasitism was 23.52 aphids/female/day at 25°C. With parasitoid density increasing from 1 to 8, the per capita searching efficiency decreased from 0.12 h-1to 0.06 h-1. The results suggested thatP. voluvrehas the potential to be a biocontrol agent ofS. avenae. However, evaluation of foraging behavior warrants further investigation under field conditions.

Estimating maximum global land surface wind power extractability and associated climatic consequences

The availability of wind power for renewable energy extraction is ultimately limited by how much kinetic energy is generated by natural processes within the Earth system and by fundamental limits of how much of the wind power can be extracted. Here we use these considerations to provide a maximum estimate of wind power availability over land. We use three different methods. First, we use simple, established estimates of the energetics of the atmospheric circulation, which yield about 38 TW of wind power available for extraction. Second, we set up a simple momentum balance model to estimate maximum extractability which we then apply to reanalysis climate data, yielding an estimate of 17 TW. Finally, we perform climate model simulations in which we extract different amounts of momentum from the atmospheric boundary layer to obtain a maximum estimate of how much power can be extracted, yielding 36 TW. These three methods consistently yield maximum estimates in the range of 17–38 TW and are notably less than recent estimates that claim abundant wind power availability. Furthermore, we show with the climate model simulations that the climatic effects at maximum wind power extraction are similar in magnitude to those associated with a doubling of atmospheric CO2. We conclude that in order to understand fundamental limits to renewable energy resources, as well as the impacts of their utilization, it is imperative to use a thermodynamic, Earth system perspective, rather than engineering specifications of the latest technology.

Rumen dynamics of neutral detergent fiber in cattle fed low-quality tropical forage and supplemented with nitrogenous compounds

The aim of this work was to evaluate the effects of supplementation with nitrogenous compounds on rumen dynamics of neutral detergent fiber (NDF) in cattle fed low-quality tropical forage. Five crossbred heifers with average live weight of 180 kg and fitted with rumen cannulae were used. The animals were fed ad libitum with signal grass (Brachiaria decumbens Stapf.) hay, which had crude protein (CP) content of 4.86% of dry matter (DM). The five treatments were proposed in order to raise the CP level of diets to 0, 2, 4, 6, and 8 percentile points above the CP level of the forage. The supplement was a mixture of urea, ammonium sulfate, and albumin (4.5:0.5:1.0, respectively). The experiment was carried out according to a 5 × 5 Latin square design, with five experimental periods. The average CP levels in the diets were: 5.19, 7.11, 8.60, 11.67, and 13.02% on DM basis. The potentially degradable NDF was linearly increased according to the CP levels in diet up to 6.97% of CP. From this point, there was stabilization of estimates (47.87% of NDF). The degradation rate of potentially degradable NDF was linearly increased with the CP levels in diets. The rumen flow of fibrous particles (L) showed a linear-response-plateau pattern according to the CP levels in diets. The plateau (maximum estimate) began on 7.24% of CP. The mean retention time in the rumen and the rumen fill effect of undegradable NDF were affect by the CP levels similarly to L, with plateau (minimum) beginning on 6.90 and 6.97% of CP, respectively.

New K-Ar Cooling Ages of Granitoids from the Strzegom-Sobótka Massif, SW Poland

New K-Ar Cooling Ages of Granitoids from the Strzegom-Sobótka Massif, SW Poland The Strzegom-Sobótka Variscan Massif (Fore-Sudetic Block, NE Bohemian Massif) consists of various post-kinematic Variscan granitoids emplaced into Palaeozoic low grade metamorphic rocks. Biotite from five samples representing the hornblende-biotite monzogranite, biotite monzogranite and biotite granodiorite has been dated using the K-Ar method for two size-fractions (0.25-0.35 and 0.35-0.5 mm). Finer fractions show more intense chloritization and therefore the results for them were rejected in further discussion. Coarser fractions with higher potassium content were accepted as yielding a maximum estimate approaching the true K-Ar biotite cooling ages. The results are clustered in two groups. The older age group (308.8±4.6 Ma and 305.5±4.3 Ma) comprises results obtained from the biotite granodiorites. They are generally consistent with the zircon crystallization age of 308.4±1.7 Ma reported by Turniak et al. (2005) and imply rapid cooling of the biotite granodiorite from magmatic temperatures down to the closure temperature of K-Ar isotopic system in biotite. The younger group is defined by 291.0±4.4 Ma and 298.7±5.2 Ma ages for the hornblende-biotite monzogranite and 294.2±4.3 Ma age for the biotite monzogranite. In the absence of precise U-Pb or Pb-Pb zircon data further geochronological studies are needed to decipher precisely the cooling history of the monzogranites.

Stomatal Function and Cuticular Conductance in Whole Tissue-cultured Apple Shoots

The relative contribution of stomatal and cuticular conductance to transpiration from whole tissue-cultured apple shoots of Malus pumila Mill. M.26 was determined with a modified steady state porometer. When shoots were exposed to 90% RH and high boundary layer conductance, large (73%) and, in some eases, rapid (2 to 3 hours) reductions in leaf conductance occurred, indicating functional stomata. Stomatal closure was also observed microscopically. A maximum estimate for the cuticular conductance of these apple leaves was 18 to 40 mmol·m-2·s-1, which is lower than previous estimates and close to the upper limit of naturally occurring leaf cuticular conductances. Hence, both stomatal and cuticular restrictions of water loss appear to be of importance in determining the water balance of tissue-cultured apple loots. The pathway of water transport in relation to water stress of tissue-cultured shoots is also discussed.

Population status, distribution, and movements of woodland caribou in west central Alberta

Twenty-four woodland caribou (Rangifer tarandus caribou) in the mountains and foothills of west central Alberta were radio collared to obtain information on seasonal movements, location and extent of seasonal ranges, rutting and calving areas, and population status. The study was conducted from December 1979 to June 1984 (fall composition surveys continued to 1986). Two populations of woodland caribou resided in the foothills winter range: a migratory mountain variety that moved west to the mountains in spring and returned in fall, and a more sedentary woodland variety that remained year round in the forested foothills. Calving and rutting grounds of the two populations were widely separated (minimum of 60 km). The mountain population ranged over a much larger area (11 000 km2) than the woodland population (4000 km2). Woodland caribou were fewer (maximum estimate 50) than the mountain caribou (maximum estimate 200). Population sex–age structure of the mountain caribou population, based on six surveys during the rut (October), averaged 54 males: 100 females: 27 calves (15% calves). Annual minimum adult mortality was 22% for the mountain and woodland populations, and both populations appeared to be declining. Predation, primarily by wolves, was strongly implicated in adult mortality, but causes of calf mortality were not determined. Human-caused mortality was an additional factor. Intensive management is required to ensure the viability of these caribou populations in the face of increasing industrial and recreational development. A short-term wolf reduction program and long-term public education, law enforcement, and habitat protection programs are recommended.

Reliability of Singing Bird Surveys: Changes in Observer Efficiency with Avian Density

Field trials in which paired observers were used and indoor simulations in which recorded bird songs were used indicated that, as the number of singing birds audible from a listening station increased from 1 to 4, the fraction of them recorded by observers declined by up to 50%. This reduction in efficiency violates one of the basic assumptions of any index-that the proportion of animals detected remains constant-and could cause surveyors who rely primarily on auditory cues to underestimate changes in population density by up to 25% for common species and 33% for abundant species. The change in efficiency, which is best regarded as measurement error, cannot be detected by a statistical examination of the data and thus may pass undetected in many field studies. It seems unlikely that any general procedure for "correcting" the error would be reliable. The results indicate that singing bird surveys of common species should be supplemented by other methods if accurate estimates of changes in density are needed. A general conclusion of the study is that whenever animals "compete" for a place in the survey, for example by filling up traps or suppressing one another's songs, then the index tends to underestimate a change in density. If efficiency increases with density, then the survey tends to overestimate a change in density. If the sign of the bias can be determined, the survey can be used to provide a minimum or maximum estimate of a change in density even if the magnitude of the bias cannot be estimated.