Sea-ice production over the Laptev Sea shelf inferred from historical summer-to-winter hydrographic observations of 1960s-1990s

The winter net sea-ice production (NSIP) over the Laptev Sea shelf is inferred from continuous summer-to-winter historical salinity records of 1960s–1990s. While the NSIP strongly depends on the assumed salinity of newly formed ice, the NSIP quasi-decadal variability can be linked to the wind-driven circulation anomalies in the Laptev Sea region. The increased wind-driven advection of ice away from the Laptev Sea coast when the Arctic Oscillation (AO) is positive implies enhanced coastal polynya sea-ice production and brine release in the shelf water. When the AO is negative, the NSIP and seasonal salinity amplitude tends to weaken. These results are in reasonable agreement with sea-ice observations and modeling

Vortex manipulation in a superconducting matrix with view on applications

We show how a single flux quantum can be effectively manipulated in a superconducting film with a matrix of blind holes. Such a sample can serve as a basic memory element, where the position of the vortex in a [k x l] matrix of pinning sites defines the desired combination of n bits of information (2^n=k*l). Vortex placement is achieved by strategically applied current and the resulting position is read-out via generated voltage between metallic contacts on the sample. Such a device can also act as a controllable source of a nanoengineered local magnetic field for e.g. spintronics applications

The implementation of problem-based learning in Ukrainian higher educational institutions

The article deals with the problem-based learning (PBL) that combines theoretical knowledge and practice in the educational process. PBL is an effective learning method through which the students become responsible and initiative. PBL main goals, principles and steps of implementation are observed in the article. PBL is a constructive, self-directed, collaborative and contextual process and has the potential to prepare students more effectively for future learning and profession. The main objectives of PBL are described in the article: constructing an extensive and flexible knowledge base; developing effective problem-solving abilities; becoming effective collaborators; being motivated to learn, work and research. It is cleared up that PBL focuses on practical learning where students solve real life badly structured problems. It is shown that the educational process is organized around the interdisciplinary problems and it can help students to learn integrally. The participants of problem-based learning process have to plan, monitor and evaluate the learning process actively, interpret prior knowledge and experience and after their self-study and mutual interaction within the group, they are able to construct and reconstruct their knowledge networks. The author states that implementation of PBL in the educational process gives students a sense of ownership over their learning and empowers participants with valuable skills that motivate students to learn and ability to achieve good results. The main ways of implementation of PBL in Ukrainian higher educational institutions and some recommendations are given in the article

Implementation of problem-based learning in tutorials at higher educational institution

The article deals with the basic aspects of implementation of problem-based learning in tutorials at higher educational institution. The author highlights the main characteristics and features of problem-based learning; considers levels of the problem and requirements to creation of a problem situation; offers the model and stages of implementation of problem-based learning in a tutorial and draws reader’s attention to student’s role and teacher’s competences in problem-based learning. The results of the study can be applied in the process of implementation of problem-based learning in tutorials at higher educational institution in a variety of academic disciplines with taking into account their specificity. Keywords: problem-based learning, facilitator, tutor, multidisciplinary approach, self-education, problem situation В статті розглянуто основні аспекти впровадження проблемно-орієнтованого навчання на заняттях у вищому навчальному закладі. Автором висвітлено основні характеристики і риси проблемно-орієнтованого навчання; розглянуто рівні проблемності та вимоги до створення проблемної ситуації; запропоновано модель і етапи реалізації проблемно-орієнтованого навчання на занятті, а також звернено увагу на роль студента та компетенції викладача у проблемно-орієнтованому навчанні. Результати дослідження можуть бути застосовані у процесі впровадження проблемно-орієнтованого навчання на заняттях у вищому навчальному закладі з різних навчальних дисциплін із урахуванням їх специфіки.  Ключові слова: проблемно-орієнтоване навчання, фасилітатор, тьютер, мультидисциплінарний підхід, самоосвіта, проблемна ситуаці

Laser scanning imaging and local characterization of superconducting properties in high-Tc thin film multiturn coil

Low-temperature scanning laser microscopy has been used to investigate the spatial variation of the critical temperature Tc and critical current Ic in thin-film high-Tc multilayer structures that include dielectric layers. The method is described and measurements are presented on an YBa2Cu3O7-x-based multiturn coil with SrTiO3 insulating layer. We found that the critical temperature Tc of the YBa2Cu3O7-x top layer, from which the return strip of the coil is formed, is higher than that of the YBa2Cu3O7-x base layer. The critical current of the coil is limited by the quality of the YBa2Cu3O7-x base layer and not by the edges of the crossovers

OSpace: towards a systematic exploration of olfactory interaction spaces

When designing olfactory interfaces, HCI researchers and practitioners have to carefully consider a number of issues related to the scent delivery, detection, and lingering. These are just a few of the problems to deal with. We present OSpace - an approach for designing, building, and exploring an olfactory interaction space. Our paper is the first to explore in detail not only the scent-delivery parameters but also the air extraction issues. We conducted a user study to demonstrate how the scent detection/lingering times can be acquired under different air extraction conditions, and how the impact of scent type, dilution, and intensity can be investigated. Results show that with our setup, the scents can be perceived by the user within ten seconds and it takes less than nine seconds for the scents to disappear, both when the extraction is on and off. We discuss the practical application of these results for HCI

Observation of superluminal geometrical resonances in Bi2Sr2CaCu2O8+x intrinsic Josephson junctions

We study Fiske steps in small Bi2Sr2CaCu2O8+x mesa structures, containing only few stacked intrinsic Josephson junctions. Careful alignment of magnetic field prevents penetration of Abrikosov vortices and facilitates observation of a large variety of high quality geometrical resonances, including superluminal with velocities larger than the slowest velocity of electromagnetic waves. A small number of junctions limits the number of resonant modes and allows accurate identification of modes and velocities. It is shown that superluminal geometrical resonances can be excited by subluminal fluxon motion and that flux-flow itself becomes superluminal at high magnetic fields. We argue that observation of high-quality superluminal geometrical resonances is crucial for realization of the coherent flux-flow oscillator in the THz frequency range

The TRANSDRIFT III expedition: freeze-up studies in the Laptev Sea

The Russian icebreaker KAPITAN DRANITSYN carried out the TRANSDRIFT III expedition to the Laptev Sea (October 1 to 30., 1995), the largest ice factory in the Arctic Ocean and source region of the Transpolar Drift. In this shelf region, ice free for only three months a year, a comprehensive interdisciplinary working program concerning the causes and effects of annual freeze-up was performed. Unlike our previous expeditions to the Laptev Sea, which focused On oceanographical, hydrochemical, ecological, and sedimentological processes during the brief ice-free period in summer, this expedition studied these processes during the extreme physical change through the onset of ice formation in autumn. This is the first study of its kind under these conditions, and gave important clues to the rapid (14 to 40 days) freeze-up, which has significant year-round effects for the Laptev Sea and global environment. Freeze-up began one month later than usual (a 40 year record) close to the Novosibirskie Islands in low salinity surface waters due to heat stored in an intermediate water layer between 10 and 25 m water depth. Later, huge tracts of turbid, dirty ice were found off the Lena Delta where an unusually high phytoplankton concentration for this time of year occurred. The origin of these anomalies, and whether they are anomalies at all, and their relationship to global environment in real time are the focus of continuing research

Preparation of Neutron-activated Xenon for Liquid Xenon Detector Calibration

We report the preparation of neutron-activated xenon for the calibration of liquid xenon (LXe) detectors. Gamma rays from the decay of xenon metastable states, produced by fast neutron activation, were detected and their activities measured in a LXe scintillation detector. Following a five-day activation of natural xenon gas with a Cf-252 (4 x 10^5 n/s) source, the activities of two gamma ray lines at 164 keV and 236 keV, from Xe-131m and Xe-129m metastable states, were measured at about 95 and 130 Bq/kg, respectively. We also observed three additional lines at 35 keV, 100 keV and 275 keV, which decay away within a few days. No long-lifetime activity was observed after the neutron activation.Comment: to be published in NIM A, corrected typos in Table 1 and Fig.6 of the previous versio