59 research outputs found
Many-to-Many Graph Matching: a Continuous Relaxation Approach
Graphs provide an efficient tool for object representation in various
computer vision applications. Once graph-based representations are constructed,
an important question is how to compare graphs. This problem is often
formulated as a graph matching problem where one seeks a mapping between
vertices of two graphs which optimally aligns their structure. In the classical
formulation of graph matching, only one-to-one correspondences between vertices
are considered. However, in many applications, graphs cannot be matched
perfectly and it is more interesting to consider many-to-many correspondences
where clusters of vertices in one graph are matched to clusters of vertices in
the other graph. In this paper, we formulate the many-to-many graph matching
problem as a discrete optimization problem and propose an approximate algorithm
based on a continuous relaxation of the combinatorial problem. We compare our
method with other existing methods on several benchmark computer vision
datasets.Comment: 1
Impacts of hydroclimate change on climate-resilient agriculture at the river basin management
Abstract This paper focuses on exploring the potential of Climate resilient agriculture CRA for river basin scale management Our analysis is based on long term historical and future climate and hydrological datasets within a GIS environment focusing on the Ajoy River basin in West Bengal Eastern India The standardized anomaly index SAI and slope of the linear regression SLR methods were employed to analyse the spatial pattern of the climate variables precipitation Tmax and Tmin and hydrological variables actual evapotranspiration AET runoff Q vapor pressure deficit VPD potential evapotranspiration PET and climate water deficit DEF using the TerraClimate dataset spanning from 1958 to 2020 Future climate trend analysis spanning 2021 to 2050 was conducted using the CMIP6 based GCMs MIROC6 and EC Earth3 dataset under shared socio economic pathway SSP2 4 5 SSP5 8 5 and historical For spatiotemporal water storage analysis we relied on Gravity Recovery and Climate Experiment GRACE from the Center for Space Research CSR and the Jet Propulsion Laboratory JPL data covering the period from 2002 to 2021 Validation was performed using regional groundwater level data employing various machine learning classification models Our findings revealed a negative precipitation trend approximately 0 04 mm year in the southern part whereas the northern part exhibited a positive trend approximately 0 10 mm yea
Pilot Study to Assess the Effectiveness of the Sustainable Culturally adaptive Nutrition Program (Scan) to Improve adherence to the National Diabetes Prevention Program
PURPOSE: The Sustainable Culturally Adapted Nutrition Program (SCAN) is a novel adaptation to the National Diabetes Prevention Program (NDPP) that aims to improve attendance and effectiveness. This paper presents its feasibility and impact through the initial 6-month outcomes.
DESIGN: A pragmatic quasi-experimental pilot study with intervention (DPP plus SCAN) and control (DPP only) groups.
SAMPLES AND INCLUSION CRITERIA: Sustainable Culturally Adapted Nutrition Program participants were recruited from federally qualified health center (FQHC) clinic patients enrolled in a NDPP in Houston, Texas. Participants needed to be (1) ≥18 years old, (2) body mass index \u3e25, (3) no prior diagnosis of diabetes, and (4) not pregnant.
INTERVENTION: Sustainable Culturally Adapted Nutrition Program cooking classes were designed to teach skills to prepare fresh produce, and utilized Motivational Interviewing (MI) techniques to encourage participants to adapt these skills for foods that were culturally important to them.
OUTCOME MEASURES: (1) National Diabetes Prevention Program attendance, (2) BMI and (3) percent weight loss.
ANALYSIS: We used linear mixed models to test the association between weights and NDPP attendance.
RESULTS: 22 intervention and 15 control participants completed the program to the 6-month point. Intervention participants had increased DPP attendance over controls (7.14 vs 6.87 session). Intervention participants also demonstrated on average, 1.5% weight loss for each additional SCAN class attended (
CONCLUSIONS: The SCAN adaptation shows promising results for effectively increasing both NDPP attendance and weight loss
Microorganisms from aphid honeydew attract and enhance the efficacy of natural enemies
Aphids are one of the most serious pests of crops worldwide, causing major yield and economic losses. To control aphids, natural enemies could be an option but their efficacy is sometimes limited by their dispersal in natural environment. Here we report the first isolation of a bacterium from the pea aphid Acyrthosiphon pisum honeydew, Staphylococcus sciuri, which acts as a kairomone enhancing the efficiency of aphid natural enemies. Our findings represent the first case of a host-associated bacterium driving prey location and ovipositional preference for the natural enemy. We show that this bacterium has a key role in tritrophic interactions because it is the direct source of volatiles used to locate prey. Some specific semiochemicals produced by S. sciuri were also identified as significant attractants and ovipositional stimulants. The use of this host-associated bacterium could certainly provide a novel approach to control aphids in field and greenhouse systems
Self-Assemblage and Quorum in the Earthworm Eisenia fetida (Oligochaete, Lumbricidae)
Despite their ubiquity and ecological significance in temperate ecosystems, the behavioural ecology of earthworms is not well described. This study examines the mechanisms that govern aggregation behaviour specially the tendency of individuals to leave or join groups in the compost earthworm Eisenia fetida, a species with considerable economic importance, especially in waste management applications. Through behavioural assays combined with mathematical modelling, we provide the first evidence of self-assembled social structures in earthworms and describe key mechanisms involved in cluster formation. We found that the probability of an individual joining a group increased with group size, while the probability of leaving decreased. Moreover, attraction to groups located at a distance was observed, suggesting a role for volatile cues in cluster formation. The size of earthworm clusters appears to be a key factor determining the stability of the group. These findings enhance our understanding of intra-specific interactions in earthworms and have potential implications for extraction and collection of earthworms in vermicomposting processes
Aphid and Plant Volatiles Induce Oviposition in an Aphidophagous Hoverfly
Episyrphus balteatus DeGeer (Diptera, Syrphidae) is an abundant and efficient aphid-specific predator. We tested the electroantennographic (EAG) response of this syrphid fly to the common aphid alarm pheromone, (E)-β-farnesene (EβF), and to several plant volatiles, including terpenoids (mono- and sesquiterpenes) and green leaf volatiles (C6 and C9 alcohols and aldehydes). Monoterpenes evoked significant EAG responses, whereas sesquiterpenes were inactive, except for the aphid alarm pheromone (EβF). The most pronounced antennal responses were elicited by six and nine carbon green leaf alcohols and aldehydes [i.e., (Z)-3-hexenol, (E)-2-hexenol, (E)-2-hexenal, and hexanal]. To investigate the behavioral activity of some of these EAG-active compounds, E. balteatus females were exposed to R-(+)-limonene (monoterpene), (Z)-3-hexenol (green leaf alcohol), and EβF (sesquiterpene, common aphid alarm pheromone). A single E. balteatus gravid female was exposed for 10 min to an aphid-free Vicia faba plant that was co-located with a semiochemical dispenser. Without additional semiochemical, hoverfly females were not attracted to this plant, and no oviposition was observed. The monoterpene R-(+)-limonene did not affect the females’ foraging behavior, whereas (Z)-3-hexenol and EβF increased the time of flight and acceptance of the host plant. Moreover, these two chemicals induced oviposition on aphid-free plants, suggesting that selection of the oviposition site by predatory hoverflies relies on the perception of a volatile blend composed of prey pheromone and typical plant green leaf volatiles
Changing Bee and Hoverfly Pollinator Assemblages along an Urban-Rural Gradient
The potential for reduced pollination ecosystem service due to global declines of bees and other pollinators is cause for considerable concern. Habitat degradation, destruction and fragmentation due to agricultural intensification have historically been the main causes of this pollinator decline. However, despite increasing and accelerating levels of global urbanization, very little research has investigated the effects of urbanization on pollinator assemblages. We assessed changes in the diversity, abundance and species composition of bee and hoverfly pollinator assemblages in urban, suburban, and rural sites across a UK city.Bees and hoverflies were trapped and netted at 24 sites of similar habitat character (churchyards and cemeteries) that varied in position along a gradient of urbanization. Local habitat quality (altitude, shelter from wind, diversity and abundance of flowers), and the broader-scale degree of urbanization (e.g. percentage of built landscape and gardens within 100 m, 250 m, 500 m, 1 km, and 2.5 km of the site) were assessed for each study site. The diversity and abundance of pollinators were both significantly negatively associated with higher levels of urbanization. Assemblage composition changed along the urbanization gradient with some species positively associated with urban and suburban land-use, but more species negatively so. Pollinator assemblages were positively affected by good site habitat quality, in particular the availability of flowering plants.Our results show that urban areas can support diverse pollinator assemblages, but that this capacity is strongly affected by local habitat quality. Nonetheless, in both urban and suburban areas of the city the assemblages had fewer individuals and lower diversity than similar rural habitats. The unique development histories of different urban areas, and the difficulty of assessing mobile pollinator assemblages in just part of their range, mean that complementary studies in different cities and urban habitats are required to discover if these findings are more widely applicable
A linear programming approach for the weighted graph matching problem
Abstract- A linear programming (LP) approach is proposed for the weighted graph matching problem. A linear program is obtained by formulating the graph matching problem in L1 norm and then transforming the resulting quadratic optimization problem to a linear one. The linear program is solved using a Simplex-based algorithm. Then, approximate 0-1 integer solutions are obtained by applying the Hungarian method on the real solutions of the linear program. The complexity of the proposed algorithm is polynomial time, and it is O(72'L) for matching graphs of size n. The developed algorithm is compared to two other algorithms. One is based on an eigendecomposition approach and the other on a symmetric polynomial transform. Experimental results showed that the LP approach is superior in matching graphs than both other methods
Tomato-aphid-hoverfly: A tritrophic interaction incompatible for pest management
peer reviewedTrichome-based tomato resistance offers the potential to reduce pesticide use, but its compatibility with biological control remains poorly understood. We evaluated
Episyrphus balteatus De Geer (Diptera, Syrphidae), an efficient aphidophagous predator, as a potential biological control agent of Myzus persicae Sulzer (Hemiptera, Aphididae)
on trichome-bearing tomato cultivars. Episyrphus balteatus’ foraging and oviposition behavior, as well as larval mobility and aphid accessibility, were compared between two tomato cultivars (Lycopersicon esculentum Mill. ‘Moneymaker’ and ‘Roma’) and two other crop plants;
broad bean (Vicia faba L.) and potato (Solanum tuberosum L.). Hoverfly adults landed and laid more eggs on broad beans than on three species of Solanaceae. Hoverfly larval movement was drastically reduced on tomato, and a high proportion of hoverfly larvae fell from the plant before
reaching aphid prey. After quantifying trichome abundance on each of these four plants, we suggest that proprieties of the plant surface, specifically trichomes, are a key factor contributing to reduced efficacy of E. balteatus as a biological agent for aphid control on tomatoes
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