111 research outputs found

    True bugs and beetles new to Montenegro and Bulgaria (Insecta: Heteroptera, Coleoptera)

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    From Montenegro, one species of Heteroptera, Lethocerus patruelis, and eight species of Coleoptera, Ampedus cardinalis, Cardiophorus anticus (Elateridae), Diaperis boleti, Iphthiminus italicus croaticus, Opatrum verrucosum, Pedinus helopioides (Tenebrionidae), Prostomis mandibularis (Prostomidae), Camptorhinus simplex (Curculionidae) are recorded for the first time. Pytho depressus (Pythidae) is recorded for the first time from Bulgaria

    Larvicidal efficacy of Verbascum spp. methanol extracts against Plodia interpunctella (Hübner, 1813) (Lepidoptera: Pyralidae)

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    Verbascum species (fam. Scrophulariaceae) contain a high concentration of rotenone and verbascoside and traditionally have long been used as insecticides. This study is aimed to investigate the larvicidal efficacy of Verbascum thapsus L. and V. phlomoides L. methanolic extracts in the suppression of the Plodia interpunctella (Hübner, 1813), under laboratory conditions. The experiment was set up in two separate blocks (for two different extracts), each as 3˟3˟3 factorial trial: three concentrations of extracts (1, 2 and 5%) were tested against the three larval age groups (14, 14-28 and 28 days old) and each treatment was repeated three times. Mortality was recorded after 24, 48, 72, and 96 h. Both tested extracts were the most effective 96 h after the exposure in 5% concentration applied on the youngest larvae. Extract of V. thapsus caused the mortality of 64.00%, while in treatment with V. phlomoides extract mortality was 48.00%. Tested Verbascum extracts have shown moderate potential for application as botanical larvicides.Publishe

    Simulating rewetting events in intermittent rivers and ephemeral streams: a global analysis of leached nutrients and organic matter

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    Climate change and human pressures are changing the global distribution and extent of intermittent rivers and ephemeral streams (IRES), which comprise half of the global river network area. IRES are characterized by periods of flow cessation, during which channel substrates accumulate and undergo physico‐chemical changes (preconditioning), and periods of flow resumption, when these substrates are rewetted and release pulses of dissolved nutrients and organic matter (OM). However, there are no estimates of the amounts and quality of leached substances, nor is there information on the underlying environmental constraints operating at the global scale. We experimentally simulated, under standard laboratory conditions, rewetting of leaves, riverbed sediments, and epilithic biofilms collected during the dry phase across 205 IRES from five major climate zones. We determined the amounts and qualitative characteristics of the leached nutrients and OM, and estimated their areal fluxes from riverbeds. In addition, we evaluated the variance in leachate characteristics in relation to selected environmental variables and substrate characteristics. We found that sediments, due to their large quantities within riverbeds, contribute most to the overall flux of dissolved substances during rewetting events (56‐98%), and that flux rates distinctly differ among climate zones. Dissolved organic carbon, phenolics, and nitrate contributed most to the areal fluxes. The largest amounts of leached substances were found in the continental climate zone, coinciding with the lowest potential bioavailability of the leached organic matter. The opposite pattern was found in the arid zone. Environmental variables expected to be modified under climate change (i.e. potential evapotranspiration, aridity, dry period duration, land use) were correlated with the amount of leached substances, with the strongest relationship found for sediments. These results show that the role of IRES should be accounted for in global biogeochemical cycles, especially because prevalence of IRES will increase due to increasing severity of drying events

    Simulating rewetting events in intermittent rivers and ephemeral streams: A global analysis of leached nutrients and organic matter

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    Climate change and human pressures are changing the global distribution and the ex‐ tent of intermittent rivers and ephemeral streams (IRES), which comprise half of the global river network area. IRES are characterized by periods of flow cessation, during which channel substrates accumulate and undergo physico‐chemical changes (precon‐ ditioning), and periods of flow resumption, when these substrates are rewetted and release pulses of dissolved nutrients and organic matter (OM). However, there are no estimates of the amounts and quality of leached substances, nor is there information on the underlying environmental constraints operating at the global scale. We experi‐ mentally simulated, under standard laboratory conditions, rewetting of leaves, river‐ bed sediments, and epilithic biofilms collected during the dry phase across 205 IRES from five major climate zones. We determined the amounts and qualitative character‐ istics of the leached nutrients and OM, and estimated their areal fluxes from riverbeds. In addition, we evaluated the variance in leachate characteristics in relation to selected environmental variables and substrate characteristics. We found that sediments, due to their large quantities within riverbeds, contribute most to the overall flux of dis‐ solved substances during rewetting events (56%–98%), and that flux rates distinctly differ among climate zones. Dissolved organic carbon, phenolics, and nitrate contrib‐ uted most to the areal fluxes. The largest amounts of leached substances were found in the continental climate zone, coinciding with the lowest potential bioavailability of the leached OM. The opposite pattern was found in the arid zone. Environmental vari‐ ables expected to be modified under climate change (i.e. potential evapotranspiration, aridity, dry period duration, land use) were correlated with the amount of leached sub‐ stances, with the strongest relationship found for sediments. These results show that the role of IRES should be accounted for in global biogeochemical cycles, especially because prevalence of IRES will increase due to increasing severity of drying event

    FIGURES 11 – 16 in New records of water mites (Acari, Hydrachnidia) from Iran, with the description of a new species

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    FIGURES 11 – 16. Axonopsis gereckei sp. nov. (11, 12, 15 = male; 13, 14, 16 = female): 11 = idiosoma, ventral view; 12 = I­Leg; 13 = dorsal shield; 14 = postocularia; 15 = palp; 16 = genital field. Scale Bars = 0.1 mm

    On dynamic scheduling of a parallel server system with certain graph structure

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    We consider a problem of dynamic scheduling for a parallel server system. This system consists of finitely many infinite capacity buffers (classes) for holding incoming jobs awaiting service and finitely many non-identical servers working in parallel. Jobs within each buffer are served on a first-in-first-out basis. Each job requires a single service before it leaves the system. Each server can work on at most one job at a time, but it may be capable of processing several different classes of jobs over time, and it may suspend service of a job to work on a job of another class. Jobs of a given class incur holding costs at a rate proportional to the number of jobs in the class at each instant of time. The system manager seeks to minimize a cumulative discounted holding cost by dynamically scheduling waiting jobs to available servers. Following a method introduced by Harrison, for this parallel server system in heavy traffic we approximate the scheduling control problem by a Brownian control problem (BCP), which can be reduced to an Equivalent Workload Formulation (EWF). We first prove that the server-buffer graph, consisting of servers and buffers linked by basic activities, is a forest of trees. Then we give sufficient conditions for a least control process to be the optimal solution of the EWF. Under these conditions, we propose a continuous review threshold-type control policy that exploits partial pooling of servers. We conjecture that this policy is asymptotically optimal for the original parallel server system in the heavy traffic limit. To illustrate the solution of the EWF, and our proposed control policy for the original network we give a three buffer, three server example. We prove that this control policy is asymptotically optimal for this example in the heavy traffic limit. This is the first instance of a proof of asymptotic optimality for a parallel server system with partial pooling is the usual heavy traffic regim

    Contribution to the study of some water mites (Acari, Hydrachnidia) from Hungary

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    A new records of water mites from Hungary is based on the material collected by T. Kovács et al., from the investigated area. Six species are identified, one of which (Lebertia insignis Neuman, 1880) are new for the fauna of Hungary. Tiphys convexipalpis L. Ponyi, 1956, are synonymized with Typhis ornatus Koch, 1836. The ecological significance of the new records is briefly discussed

    Stygohydracarus karanovici sp. n., and Atractides inflatipes Lundblad, 1956, two water mites species (Acari: Hydrachnidia) from Montenegro (SE Europe)

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    Pesic, Vladimir M. (2001): Stygohydracarus karanovici sp. n., and Atractides inflatipes Lundblad, 1956, two water mites species (Acari: Hydrachnidia) from Montenegro (SE Europe). Zootaxa 17: 1-

    Trichothyas K. Viets

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    Genus Trichothyas K. Viets Trichothyas petrophila (Michael) Iranian records: Mazandaran, Tehran Province (Aderan) – “ Trichotyas alborzensis Bader & Sepasgozarian” Bader & Sepasgozarian (1979 b); Tehran (Aderan), Mazandaran Province – “ Trichotyas alborzensis Bader & Sepasgozarian” Sepasgosarian (1999); Mazandaran Province – Pesic et al. (2005 a). Distributio n: S and W Europe, Turkey, Iran.Published as part of Pesic, Vladimir & Saboori, Alireza, 2007, A checklist of the water mites (Acari: Hydrachnidia) of Iran, pp. 45-68 in Zootaxa 1473 on page 48, DOI: 10.5281/zenodo.17671

    Frontipodopsis Walter

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    Genus Frontipodopsis Walter Frontipodopsis reticulatifrons persicus Schwoerbel & Sepasgosarian Iranian records: Fars Province – Schwoerbel & Sepasgosarian (1980). Distribution: Iran.Published as part of Pesic, Vladimir & Saboori, Alireza, 2007, A checklist of the water mites (Acari: Hydrachnidia) of Iran, pp. 45-68 in Zootaxa 1473 on page 59, DOI: 10.5281/zenodo.17671
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