Production of a potential liquid plant bio-stimulant by immobilized Piriformospora indica in repeated-batch fermentation process

Piriformospora indica, a mycorrhizal-like fungus able to establish associations with roots of a wide range of plants, supporting plant nutrition and increasing plant resistance and tolerance to stress, was shown to solubilise phosphate applied in the form of animal bone char (HABO) in fermentation systems. The process of P solubilisation was caused most likely by proton extrusion and medium pH lowering. The fungal mycelium was successfully immobilized/retained in a polyurethane foam carrier. Further employment of the immobilized mycelium in repeated-batch fermentation process resulted in at least 5 cycles of P solubilization. The concentration of soluble P increased during the experiment with 1.0 and 3.0 g HABO l−1 and at the end of the 5th batch cycle reached 40.8 and 120 mg l−1, respectively. The resulting final liquid product, without or with solubilized phosphate, was found to significantly increase plant growth and P plant uptake. It can be used as a biostimulant containing microbial plant growth-promoting substances and soluble P derived from renewable sources (HABO) thus supporting the development of sustainable agro-ecosystems.This work was supported by Project CTM2014-53186-R, Ministerio de Economia y Competitividad-ES/EC FEDER Fund and the sabbatical Grant PRX16/00277 to NV

Cylindrical equilibrium shapes of fluid membranes

Within the framework of the well-known curvature models, a fluid lipid bilayer membrane is regarded as a surface embedded in the three-dimensional Euclidean space whose equilibrium shapes are described in terms of its mean and Gaussian curvatures by the so-called membrane shape equation. In the present paper, all solutions to this equation determining cylindrical membrane shapes are found and presented, together with the expressions for the corresponding position vectors, in explicit analytic form. The necessary and sufficient conditions for such a surface to be closed are derived and several sufficient conditions for its directrix to be simple or self-intersecting are given.Comment: 17 pages, 4 figures. Published in J. Phys. A: Math. Theore

Flux-free conductance modulation in a helical Aharonov-Bohm interferometer

A novel conductance oscillation in a twisted quantum ring composed of a helical atomic configuration is theoretically predicted. Internal torsion of the ring is found to cause a quantum phase shift in the wavefunction that describes the electron's motion along the ring. The resulting conductance oscillation is free from magnetic flux penetrating inside the ring, which is in complete contrast with the ordinary Aharonov-Bohm effect observed in untwisted quantum rings.Comment: 10 pages, 4 figure

Risk assessment of non-native fishes in the Balkans Region using FISK, the invasiveness screening tool for non-native freshwater fishes

A high level of freshwater fish endemism in the Balkans Region emphasizes the need for non-native species risk assessments to inform management and control measures, with pre-screening tools, such as the Fish Invasiveness Screening Kit (FISK) providing a useful first step. Applied to 43 non-native and translocated freshwater fishes in four Balkan countries, FISK reliably discriminated between invasive and non-invasive species, with a calibration threshold value of 9.5 distinguishing between species of medium and high risk sensu lato of becoming invasive. Twelve of the 43 species were assessed by scientists from two or more Balkan countries, and the remaining 31 species by a single assessor. Using the 9.5 threshold, three species were classed as low risk, 10 as medium risk, and 30 as high risk, with the latter category comprised of 26 moderately high risk, three high risk, and one very high risk species. Confidence levels in the assessments were relatively constant for all species, indicating concordance amongst assessors

Etude expérimentale et numérique de la topologie d'une interface gaz/liquide

La topologie interfaciale d'une poche de gaz de grand allongement soumise à un écoulement liquide permanent et immobilisée en amont d'un obstacle, est étudiée expérimentalement et numériquement. Les ondes figées apparaissent dans une zone limitée de l'interface lorsque le nombre de Reynolds est suffisamment important (Re > 16000). Au-delà de ces valeurs de Re, leur longueur d'onde diminue progressivement. Ce comportement peut être expliqué par un modèle basé sur la théorie irrotationnelle des ondes en eau profonde. Il montre que les ondes figées sont générées par la présence de l'obstacle. Il permet également de prédire que les effets capillaires prédominent sur les effets gravitaires. Ceci est particulièrement valable pour Re > 20000. En revanche, la modélisation numérique ne prédit l'existence que d'une seule zone interfaciale, siège d'ondes progressives dont la longueur d'onde correspond à la longueur caractéristique des recirculations au sein de la poche

Дуготрајне промене трофије у бугарско-румунском делу Дунава и околних мочвара на територији бугарске током њене рестаурације

Based mainly on literature data and results of the monitoring program of the Bulgarian Ministry of Environment and Water, the long-term changes of nutrients (nitrogen and phosphorus), suspended solids and chlorophyll-concentrations in the Bulgarian–Romanian section of the Lower Danube during the period 1950–2014 were studied. The addition of more recent data from years 2008–2014 revealed stable lowering with values of PO4 3- concentrations close to those reported in the earliest 1962–1965 interval. The calculated load of dissolved inorganic nitrogen (DIN) showed a continuous but not significant decrease, while the PO4-P load dropped at the end of the 1950–2014 period to the values of its beginning. These changes of nitrogen and phosphorus led to a substantial shift of the N P-1 ratio towards phosphorus limitation of phytoplankton growth in the 2008–2014 period. The second part of the paper presented and analyzed the process of restoration of wetlands on the example of Srebarna Lake. The primary goal of this restoration was to sustain the valuable biodiversity supported by this lake, but as a wetland it should provide also most other services, one of which was nutrient removal. The monitoring of lake restoration started in 1990 and lasted with gaps until 2015. The main force driving the changes of other lake characteristics was the lake water level. Thus the lake water level correlated positively with water column transparency and negatively with chlorophyll-a, phytoplankton biovolume and the share of blue-greens from it. Since 1994 only one canal connected the lake with the Danube River, which seemed to be the reason for the limited success of the wetland restoration.На основу, пре свега, података из литературе и резултата програма праћења Министарства за животну средину и воде Бугарске, проучене су дугорочне промене нутријената (азота и фосфора), суспендованих чврстих честица и концентрација хлорофила у бугарско-румунском делу доњег тока Дунава током периода 1950–2014. године. Анализом и скоријих података за године 2008–2014, регистровано је стабилно снижавање са вредностима концентрација PO4 3- близу онима које су забележене у најранијем интервалу – у годинама 1962–1965. Израчунатo оптерећење раствореног неорганског азота (DIN) показало је стално, али не значајно смањење, док је оптерећење PO4-P пало крајем периода 1950–2014. на вредности са почетка. Те промене азота и фосфора довеле су до значајне промене показатеља N P-1 ка фосфорном ограничењу раста фитопланктона у периоду 2008–2014. године. У другом делу рада представљен је и анализиран процес санације мочварних подручја на примеру језера Сребарна. Главни циљ санације јесте одржавање вредног биодиверзитета који подржава то језеро; међутим, као мочварно подручје, оно треба да пружи и већину других услуга, које укључују, између осталог, уклањање нутријената. Праћење санације језера почело је 1990. и с прекидима трајало до 2015. године. Главни покретач промена других карактеристика језера био је ниво воде у језеру. Постојала је позитивна корелација између нивоа воде у језеру и прозирности воденог стуба и негативна корелација са хлорофилом а, биозапремином фитопланктона и уделом њихових плавозелених облика. Од 1994. године, само један канал повезује језеро са Дунавом, што вероватно представља разлог ограниченог успеха санације мочварног подручја.8. Конференција академија подунавске региј

Section on Prospects for Dark Matter Detection of the White Paper on the Status and Future of Ground-Based TeV Gamma-Ray Astronomy

This is a report on the findings of the dark matter science working group for the white paper on the status and future of TeV gamma-ray astronomy. The white paper was commissioned by the American Physical Society, and the full white paper can be found on astro-ph (arXiv:0810.0444). This detailed section discusses the prospects for dark matter detection with future gamma-ray experiments, and the complementarity of gamma-ray measurements with other indirect, direct or accelerator-based searches. We conclude that any comprehensive search for dark matter should include gamma-ray observations, both to identify the dark matter particle (through the charac- teristics of the gamma-ray spectrum) and to measure the distribution of dark matter in galactic halos.Comment: Report from the Dark Matter Science Working group of the APS commissioned White paper on ground-based TeV gamma ray astronomy (19 pages, 9 figures