An Arctic Kelp Community in the Alaskan Beaufort Sea

The discovery of the "Boulder Patch", an area of cobbles and boulders with attached kelp and invertebrate life, is reported from Stefansson Sound, near Prudhoe Bay, Alaska. Geophysical surveys using side-scan sonar and low-frequency recording fathometers reveal that cobbles and boulders occur in patches of various sizes and densities. Despite a seasonal influx of sediments, the Boulder Patch is a nondepositional environment. Physical disruption of cobbles and boulders by deep draft ice is minimal due to offshore islands and shoals which restrict the passage of large ice floes into Stefansson Sound. The apparent absence of similar concentrations of rocks with attached biota along the Alaskan Beaufort Sea coast is explained by the scarcity of rocks in areas protected from ice abrasion and with no net sediment deposition. In Stefansson Sound, the rocks provide a substratum for a diverse assortment of invertebrates and several species of algae. Recolonization by the biota was minimal on twelve boulders denuded and then left undisturbed for a three-year period. Sedimentation and grazing activity appear to be the major factors inhibiting recolonization. Linear growth in the kelp, Laminaria solidungula, is greatest in winter and early spring when nutrients are available for new tissue growth. The plant draws on stored food reserves to complete over 90% of its annual linear growth during the nine months of darkness under a turbid ice canopy. These reserves are accumulated by photosynthetic activity during the preceding summer. The total carbon contribution made by kelp in Steffansson Sound under these conditions is about 146 million g/yr or 7 g/m²/yr. A small percentage of this carbon is consumed directly by herbivores, but its importance to other organisms in not known and is under investigation.Key words: kelp, Laminaria solidungula, Flaxman boulders, Beaufort Sea, Boulder Patch, productivity, recolonization, geophysical surveys, side-scan sonar, lag depositsMots clés: varech, Laminaria solidungula, grosses pierres Flaxman, mer de Beaufort, Boulder Patch, productivité, recolonisation, levées géophysiques, sonar à balayage latéral, accumulations de pierres par déflatio

RP-LC and HPTLC Methods for the Determination of Olmesartan Medoxomil and Hydrochlorothiazide in Combined Tablet Dosage Forms

Two new, rapid, precise, accurate and specific chromatographic methods were described for the simultaneous determination of olmesartan medoxomil and hydrochlorothiazide in combined tablet dosage forms. The first method was based on reversed phase liquid chromatography using an Eurosphere 100 RP C18 column (250 × 4.6 mm ID, 5 μm). The mobile phase was methanol–0.05% o-phosphoric acid (60:40 v/v) at a flow rate of 1.0 mL min−1. Commercially available tablets and laboratory mixtures containing both drugs were assayed and detected using a UV detector at 270 nm. The second method involved silica gel 60 F254 high performance thin layer chromatography and densitometric detection at 254 nm using acetonitrile–ethyl acetate–glacial acid (7:3:0.4 v/v/v) as the mobile phase. Calibration curves ranged between 200–600 and 125–375 ng spot−1 for olmesartan and hydrochlorothiazide, respectively

Mode-resolved reciprocal space mapping of electron-phonon interaction in the Weyl semimetal candidate Td-WTe2_2

The selective excitation of coherent phonons provides unique capabilities to control fundamental properties of quantum materials on ultrafast time scales. For instance, in the presence of strong electron-phonon coupling, the electronic band structure can become substantially modulated. Recently, it was predicted that by this means even topologically protected states of matter can be manipulated and, ultimately, be destroyed: For the layered transition metal dichalcogenide Td-WTe$_2$, pairs of Weyl points are expected to annihilate as an interlayer shear mode drives the crystalline structure towards a centrosymmetric phase. By monitoring the changes in the electronic structure of Td-WTe$_2$ with femtosecond resolution, we provide here direct experimental evidence that the coherent excitation of the shear mode acts on the electronic states near the Weyl points. Band structure data in comparison with our results imply, furthermore, the periodic reduction in the spin splitting of bands near the Fermi energy, a distinct electronic signature of the non-centrosymmetric Td ground state of WTe$_2$. The comparison with higher-frequency coherent phonon modes finally proves the shear mode-selectivity of the observed changes in the electronic structure. Our real-time observations reveal direct experimental insights into electronic processes that are of vital importance for a coherent phonon-induced topological phase transition in Td-WTe$_2$.Comment: 28 pages, 17 figure

A fast and intuitive method for calculating dynamic network reconfiguration and node flexibility

Dynamic interactions between brain regions, either during rest or performance of cognitive tasks, have been studied extensively using a wide variance of methods. Although some of these methods allow elegant mathematical interpretations of the data, they can easily become computationally expensive or difficult to interpret and compare between subjects or groups. Here, we propose an intuitive and computationally efficient method to measure dynamic reconfiguration of brain regions, also termed flexibility. Our flexibility measure is defined in relation to an a-priori set of biologically plausible brain modules (or networks) and does not rely on a stochastic data-driven module estimation, which, in turn, minimizes computational burden. The change of affiliation of brain regions over time with respect to these a-priori template modules is used as an indicator of brain network flexibility. We demonstrate that our proposed method yields highly similar patterns of whole-brain network reconfiguration (i.e., flexibility) during a working memory task as compared to a previous study that uses a data-driven, but computationally more expensive method. This result illustrates that the use of a fixed modular framework allows for valid, yet more efficient estimation of whole-brain flexibility, while the method additionally supports more fine-grained (e.g. node and group of nodes scale) flexibility analyses restricted to biologically plausible brain networks.</p

Моделирование солнечной электростанции для электрификации сельских районов Мьянмы

In the recent years substantial growth of the demand for electricity took place in Myanmar; energy generation by existing sources (mainly hydropower) is not enough to provide constantly increasing consumption. The problem is most obvious in rural areas (more than 61 percent of the population) where grid extension is not justified economically whereas the cost of electricity produced by autonomous diesel generators is extremely high. (Research purpose) The purpose of this research is the evaluation of economic and technical feasibility of small off-grid (standalone) photovoltaic (PV only) and hybrid photovoltaic-diesel (PV-diesel) power generation systems providing rural household electricity consumption in Myanmar. (Materials and methods) Computer simulation using Homer pro simulation software was used. Three different load scenarios were envisaged – low, medium and high (1; 6 and 16 kilowatt-hour per day). Simulation was done for Tha Ngar village tract  with a population of about 3,000 people, which is typical in Myanmar. (Results and discussion) The results of the simulation reveal that the levelized cost of energy (LCOE) for optimal hybrid (PV-diesel) systems lies in the range 0.37-0.51 US$, for PV only systems –  0.46-0.49 US$. It proves their economic feasibility compared to conventional diesel generator systems with LCOE 0.56-1.56 US$ boosted by high fuel prices in remote areas (2-3 times higher than urban price). For the high load scenario hybrid systems are more preferable, for low load (night time lighting only) PV only systems may be more effective. Conclusions) It can be concluded that implementing solar energy is not only environmentally friendlier but also economically justified approach for providing household electricity demands of rural settlements in Myanmar without constructing expensive grid extensions.В последние годы существенный рост потребления электроэнергии в Мьянме уже не может быть удовлетворен за счет существующих источников генерации, главным образом гидроэлектростанций. Особенно остро проблема стоит в сельских районах, где проживает более 61 процента населения страны: подключение к централизованным электрическим сетям экономически не оправдано, а стоимость электроэнергии, вырабатываемой автономными дизельными генераторами, очень высока.(Цель исследования) Оценить технико-экономическую целесообразность создания и использования солнечных и гибридных солнечно-дизельных малых автономных электростанций для обеспечения базовых потребностей домохозяйств в сельских поселениях Мьянмы.(Материалы и методы) Использовали метод компьютерного моделирования в специализированной программе Homer pro. Проанализировали три сценария энергопотребления: низкий – 1 киловатт-час в день, средний – 6 киловатт-часов и высокий – 16 киловатт-часов. Моделирование проводили на примере типичного для страны сельского поселения Та Нгар с населением 3000 человек.(Результаты и обсуждение) Определили, что нормированная стоимость электроэнергии для оптимизированных гибридных систем лежит в диапазоне 0,37-0,51 доллара США, для чисто фотовольтаических электростанций – 0,46-0,49 доллара. Выявили более высокую экономическую эффективность гибридных систем по сравнению с дизельными генераторами, для которых нормированная стоимость электроэнергии составляет 0,56-1,56 доллара США с учетом сложившихся цен на топливо в отдаленных районах страны, которые превышают городские цены в 2-3 раза. Показали, что при высоком энергопотреблении предпочтительнее использование гибридных систем, для малого потребления (только ночное освещение) более эффективны чисто фотовольтаические.(Выводы) Доказали, что для удовлетворения потребностей в электроэнергии сельских поселений в Мьянме целесообразно использование солнечной энергии, что обусловлено не только экологически, но и экономически, так как исключает необходимость дорогостоящего подключения к электрическим сетям

Ultralong Copper Phthalocyanine Nanowires with New Crystal Structure and Broad Optical Absorption

The development of molecular nanostructures plays a major role in emerging organic electronic applications, as it leads to improved performance and is compatible with our increasing need for miniaturisation. In particular, nanowires have been obtained from solution or vapour phase and have displayed high conductivity, or large interfacial areas in solar cells. In all cases however, the crystal structure remains as in films or bulk, and the exploitation of wires requires extensive post-growth manipulation as their orientations are random. Here we report copper phthalocyanine (CuPc) nanowires with diameters of 10-100 nm, high directionality and unprecedented aspect ratios. We demonstrate that they adopt a new crystal phase, designated eta-CuPc, where the molecules stack along the long axis. The resulting high electronic overlap along the centimetre length stacks achieved in our wires mediates antiferromagnetic couplings and broadens the optical absorption spectrum. The ability to fabricate ultralong, flexible metal phthalocyanine nanowires opens new possibilities for applications of these simple molecules

Критерии энергоаудита сельскохозяйственных предприятий: новые подходы и оценки (по промежуточным результатам российско-финляндского проекта)

Currently implemented project “Russian-Finnish Bioeconomy Competence Сentre – BioCom” within South-East Finland – Russia Cross-Border Cooperation Programme 2014-2020 aims to integrate the BioEconomy principles and approaches into the agricultural sector of the neighbouring border areas of Russia and Finland. The energy efficiency of farming and sustainable use of energy resources is one of the fundamentals of the bio-economy concept. The energy audit is the first step in identifying opportunities to reduce the energy inputs on the farms.(Research purpose) To discover the new approaches to the energy auditing of agricultural enterprises and new assessment indicators following the project experience.(Materials and methods) Four farms were selected for the energy inspection – two farms located in the Leningrad Region, Russia, and two farms located in the South Savo Region, Finland. In Russia the standard energy auditing, measurement, and calculation procedure was applied. The systems of electrical power supply, heat supply, water supply, sewage, and building envelopes on the farms were examined and estimated.(Results and discussion) Following the outcomes of the energy audits in the project framework and the previous relevant experience, the basic energy-saving and efficiency improvement measures were established. Three new approaches to the energy auditing of agricultural enterprises were suggested – energy and environmental assessment of applied technologies and equipment; consideration of the application of renewable energy-generating sources; consideration of the conversion of vehicles to biogas.(Conclusions) The study outcomes proved the energy audits to play an important role in improving the energy efficiency of agricultural production provided they are mandatory, take into account the energy environmental assessment criteria, consider the application of renewable energy-generating sources and the conversion of vehicles to biogas.Реализуемый в настоящее время проект «Российско-финляндский центр компетенции в области биоэкономики – BioCom» в рамках Программы приграничного сотрудничества Юго-Восточной Финляндии и России на 2014-2020 годы направлен на интеграцию принципов и подходов биоэкономики в сельскохозяйственный сектор соседних приграничных районов России и Финляндии. Подтвердили, что энергоэффективность сельского хозяйства и устойчивое использование энергоресурсов составляют одну из основ концепции биоэкономики. Показали необходимость проведения энергоаудита при определении возможностей для снижения энергозатрат в сельском хозяйстве.(Цель исследования) Выявить новые подходы к энергоаудиту сельхозпредприятий и показатели оценки на основе опыта реализации проекта.(Материалы и методы) Для энергетического обследования выбрали четыре хозяйства – два в Ленинградской области, Россия, и два в регионе Южное Саво, Финляндия. В России применяли стандартную процедуру энергоаудита, измерений и расчетов. Обследовали и оценили системы электро-, тепло-, водоснабжения, канализации и ограждающих конструкций.(Результаты и обсуждение). По результатам энергетических аудитов в рамках проекта и предыдущего соответствующего опыта установили основные меры по энергосбережению и повышению энергоэффективности. Предложили три новых подхода к энергоаудиту сельскохозяйственных предприятий: энергоэкологическую оценку применяемых технологий и оборудования; рассмотрение вопроса об использовании возобновляемых источников энергии; изучение возможности перевода транспорта на биогаз.(Выводы) Подтвердили необходимость энергоаудита в целях повышения энергоэффективности сельскохозяйственного производства. Показали, что энергетические обследования должны учитывать критерии энергоэкологической оценки, возможность применения возобновляемых источников энергии и перевода транспортных средств на биогаз