276 research outputs found
Reproduction and longevity of the predatory mite, Phytoseiulus persimilis (Acari: Phytoseiidae) and its prey, Tetranychus urticae (Acari: Tetranychidae) on different host plants
The biological control of twos potted spider mites by the predator Phytoseiulus persimilis is usually unsuccessful on greenhouse tomato crops in British Columbia. Experiments were conducted to determine the influence of host plant on the longevity and reproduction of the predator, and on the suitability of twospotted spider mites as prey. Lifespan and reproduction of P. persimilis were lower on tomato leaves than on bean leaves but feeding on spider mites that had been reared on tomato or bean leaves had no effect on the reproduction or lifespan of P. persimilis. A strain of twospotted spider mites that came from an outbreak on a greenhouse tomato crop lived for shorter periods and laid fewer eggs when confined on tomato leaves than on bean leaves. A strain of twospotted spider mites that had been maintained on bean leaves was unable to reproduce on tomato leaves. Exudates from glandular hairs were toxic to P. persimilis. Glandular hairs are important in pest management on tomato crops. Their removal through breeding might make plants more susceptible to herbivores. Therefore it would be preferable to develop other methods for biological control of twospotted spider mites on tomato
Soil moisture–precipitation coupling: observations from the Oklahoma Mesonet and underlying physical mechanisms
Interactions between soil moisture and the atmosphere are driven by the
partitioning of sensible and latent heating, through which soil moisture
has been connected to atmospheric modifications that could potentially lead
to the initiation of convective precipitation. The majority of previous studies
linking the land surface to subsequent precipitation have used atmospheric
reanalysis or model data sets. In this study, we link in situ observations of soil
moisture from more than 100 stations in Oklahoma to subsequent unorganized
afternoon convective precipitation. We use hourly next generation (NEXRAD) radar-derived
precipitation to identify convective events, and then compare the location
of precipitation initiation to underlying soil moisture anomalies in the
morning. Overall we find a statistically significant preference for
convective precipitation initiation over drier than normal soils, with over
70 % of events initiating over soil moisture below the long-term median.
The significant preference for precipitation initiation over drier than
normal soils is in contrast with previous studies using satellite-based
precipitation to identify the region of maximum precipitation accumulation.
We evaluated 19 convective events occurring near Lamont, Oklahoma, where
soundings of the atmospheric profile at 06:00 and 12:00 LST are also
available. For these events, soil moisture has strong negative correlations
with the level of free convection (LFC), planetary boundary layer (PBL) height, and
surface temperature changes between 06:00 and 12:00 LST. We also find strong
positive correlations between morning soil moisture and morning-to-afternoon
changes in convective available potential energy and convective inhibition.
In general, the results of this study demonstrate that both positive and
negative soil moisture feedbacks are important in this region of the
USA
Diversity, distribution and phenology of Lygus species (Hemiptera: Miridae) in relation to vegetable greenhouses in the lower Fraser Valley, British Columbia, and southwestern Ontario
Lygus spp. were collected from near and inside vegetable greenhouses during three years in the lower Fraser Valley, British Columbia (BC) and in Leamington, Ontario (ON). In BC, the dominant species was Lygus shulli, followed in abundance by L. elisus and L. hesperus; L. lineolaris was not collected in the lower Fraser Valley. In ON, only L. lineolaris was collected. In BC, L. shulli was generally distributed throughout the region, whereas L. hesperus was captured in sweep net samples only in coastal areas. Lygus hesperus appeared to be univoltine in BC. All other species in ON and BC were apparently bivoltine. In ON, numbers of adults collected outside of greenhouses correlated with numbers collected inside greenhouses whereas this was not the case in BC. Differences in flight behaviour, abundance and greenhouse construction may account for this latter difference. Our results highlight the need for different approaches to IPM of pest Lygus species in the ON and BC greenhouse industries
Towards integrated superconducting detectors on lithium niobate waveguides
Superconducting detectors are now well-established tools for low-light
optics, and in particular quantum optics, boasting high-efficiency, fast
response and low noise. Similarly, lithium niobate is an important platform for
integrated optics given its high second-order nonlinearity, used for high-speed
electro-optic modulation and polarization conversion, as well as frequency
conversion and sources of quantum light. Combining these technologies addresses
the requirements for a single platform capable of generating, manipulating and
measuring quantum light in many degrees of freedom, in a compact and
potentially scalable manner. We will report on progress integrating tungsten
transition-edge sensors (TESs) and amorphous tungsten silicide superconducting
nanowire single-photon detectors (SNSPDs) on titanium in-diffused lithium
niobate waveguides. The travelling-wave design couples the evanescent field
from the waveguides into the superconducting absorber. We will report on
simulations and measurements of the absorption, which we can characterize at
room temperature prior to cooling down the devices. Independently, we show how
the detectors respond to flood illumination, normally incident on the devices,
demonstrating their functionality.Comment: 7 pages, 4 figure
Mid-upper arm circumference (MUAC) measurement usage among children with disabilities: A systematic review
Background: Anthropometric measurements, including mid-upper arm circumference (MUAC), are used for monitoring and evaluating children's nutritional status. Evidence is limited on optimal nutritional assessment for children with disabilities, who are at high risk for malnutrition. Aim: This study describes MUAC use among children with disabilities. Methods: Four databases (Embase, Global Health, Medline, and CINHAL) were searched from January 1990 through September 2021 using a predefined search strategy. Of the 305 publications screened, 32 papers were included. Data included children 6 months to 18 years old with disabilities. Data including general study characteristics, methods for MUAC measurement, terminology, and measurement references were extracted into Excel. Due to heterogeneity of the data, a narrative synthesis was used. Results: Studies from 24 countries indicate that MUAC is being used as part of nutritional assessment, but MUAC measurement methods, references, and cutoffs were inconsistent. Sixteen (50%) reported MUAC as a mean ± standard deviation (SD), 11 (34%) reported ranges or percentiles, 6 (19%) reported z-scores, and 4 (13%) used other methods. Fourteen (45%) studies included both MUAC and weight-for-height but nonstandard reporting limited comparability of the indicators for identifying those at risk of malnutrition. Conclusion: Although its speed, simplicity, and ease of use afford MUAC great potential for assessing children with disabilities, more research is needed to understand its appropriateness, and how it performs at identifying nutritionally high-risk children in comparison to other measures. Without validated inclusive measures to identify malnutrition and monitor growth and health, millions of children could have severe consequences for their development
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