Photofocusing: Light and flow of phototactic microswimmer suspension

We explore in this paper the phenomenon of photofocusing: a coupling between flow vorticity and biased swimming of microalgae toward a light source that produces a focusing of the microswimmer suspension. We combine experiments that investigate the stationary state of this phenomenon as well as the transition regime with analytical and numerical modeling. We show that the experimentally observed scalings on the width of the focalized region and the establishment length as a function of the flow velocity are well described by a simple theoretical model

Hole growth dynamics in a two dimensional Leidenfrost droplet

International audienceWe studied the behaviors of Leidenfrost droplets confined in a Hele-Shaw cell. These droplets are unstable above a critical size and a hole grows at their center. We experimentally investigate two different systems for which the hole growth dynamics exhibits peculiar features that are driven by capillarity and inertia. We report a first regime characterized by the liquid reorganization from a liquid sheet to a liquid torus with similarities to the burst of micron-thick soap films. In the second regime the liquid torus expands and thins before fragmentation. Finally we propose models to account for the experimental results

Motor learning in golf—a systematic review

Golf is a sport that consists of complex movement skills that need to be executed with utmost precision. Consequently, motor skill learning plays a crucial role in golf, and large numbers of studies address various methods of motor learning. In the present review, we give a systematic overview of randomized controlled trials (RCTs) on motor learning of golf-specific motor skills. Three electronic databases were searched for RCTs looking at the effect of at least one learning method on performance in a golf-specific motor task. We grouped the studies depending on the learning strategies “cognitive training”, “practice scheduling”, “augmented feedback”, “implicit and explicit learning” and “focus of attention”. Fifty-two RCTs met the eligibility criteria and were included in the systematic review. Superior methods within their respective strategies were an external focus of attention and increasing contextual interference, as well as errorless learning. For “cognitive training” and “augmented feedback”, no single method can be considered the most favorable. The overall biggest limitations were the lack of statistical power for more than half of the RCTs, and the fact that most studies of the present review investigated simple putting tasks in novices only. Although we have shown superiority of specific learning methods, transferability of the recommendations that can be derived from simple golf tasks in novices to sport-specific tasks in advanced players still has to be demonstrated and require study designs with the intention to provide practical recommendations for coaches and athletes in the sport of golf

Preliminary results of in vitro culture of pea and lupin embryos for the reduction of generation cycles in single seed descent technique

The aim of the studies was to establish in vitro conditions for the culture of pea and lupin embryos as the first step in the development of an in vitro assisted single seed descent technique for the attainment of homozygous populations. Materials for the study included of pea, and narrow-leafed and yellow lupin cultivars. Embryos dissected from mature but still-green seeds were cultured in vitro on two modified MS media and under three temperature regimes. Shoot and root lengths of regenerated plants were measured after 7, 14 and 21 days of culture. For pea plants full-strength MS medium with 4 g l−1 agar and temperature 22/ 20°C (day/night) appeared to be the most conducive to shoot and root development, whereas for lupin plants lower temperatures were more propitious: 12°C in the dark for narrow-leafed lupin and 16/ 12°C (day/night) for yellow lupin. Almost all the cultured embryos developed into plants, but not all the regenerated plants survived acclimation to ex vitro conditions

The case of giant lipoma of the neck

Tłuszczak jest najczęstszym nowotworem łagodnym tkanki podskórnej, wywodzącym się z dojrzałej tkanki tłuszczowej. Jest to guz zazwyczaj pojedynczy, palpacyjnie miękki, dobrze odgraniczony torebką od otoczenia, pokryty niezmienioną skórą. Rośnie wolno i bezboleśnie, osiągając najczęściej rozmiary od kilku do kilkunastu centymetrów. Leczenie polega na radykalnym, chirurgicznym wycięciu zmiany. Opisano przypadek 60-letniej kobiety z olbrzymim guzem szyi przyjętej do Oddziału Laryngologii Wojewódzkiego Szpitala Specjalistycznego nr 4 w Bytomiu celem leczenia operacyjnego. Na szczególne podkreślenie zasługuje naszym zdaniem fakt, iż osoba mieszkająca w XXI wieku w ponad 100-tysięcznym mieście, z nieograniczonym dostępem do lekarza rodzinnego, pomimo znacznego defektu kosmetycznego i uciążliwości związanej z masą guza, obejmującego tak istotną i widoczną okolicę, przez wiele lat nie decydowała się na diagnostykę i leczenie. Najprawdopodobniej strach przed interwencją chirurgiczną był zasadniczą przyczyną odkładania leczenia, gdyż według obiegowych opinii docierających do chorej zabieg operacyjny mógł spowodować zezłośliwienie guza.Lipomas, the most common lipomatous tumors and the most common benign tumors are often located in the subcutaneous tissues of limbs, back and region of head and neck but can occur in any part of human body. Those tumors are characterized by slow, painless growth. Lipomas are soft at palpation and very well encapsulated. The diagnostic processis based on clinical course, radiological visualization and biopsy. The treatment is always surgical. New methods are recommended in order to improve cosmetic effect of surgical intervention such as liposuction in addition to surgical removal for huge lipomas especially in head and neck region. It involves very small incision, liposuction of lipoma and surgical removal of the lipoma’s capsule. Similar idea is conducted by injection of steroids that leads to atrophy of the lipomatous tissue. Other substance that can be injected into lipoma before surgery is phosphatidylocholine. Recurrence is very uncommon and caused by incompleted removal. The case of the 60 year old female patient with giant tumor of the neck was shown in this paper. She neglected earlier treatment despite of very unaesthetic aspect. She was admitted to the ENT Depar tment with 11 x 16 cm diameter of tumor inorder to surgical treatment. The computer tomography visualized huge tumor of the neck. The tumor of 500 g in weigh was completely removed and plastic surgery was performed. The diagnose of lipoma was confirmed by pathologist. The epidemiology, clinical course, diagnostic and therapy were described

Nucleosynthetic osmium isotope anomalies in acid leachates of the Murchison meteorite

We present osmium isotopic results obtained by sequential leaching of the Murchison meteorite, which reveal the existence of very large internal anomalies of nucleosynthetic origin. The Os isotopic anomalies are correlated, and can be explained by the variable contributions of components derived from the s, r and p-processes of nucleosynthesis. Much of the s-process rich osmium is released by relatively mild leaching, suggesting the existence of an easily leachable s-process rich presolar phase, or alternatively, of a chemically resistant r-process rich phase. The s-process composition of Os released by mild leaching diverges slightly from that released by aggressive digestion techniques, perhaps suggesting that the presolar phases attacked by these differing procedures condensed in different stellar environments. The correlation between 190Os and 188Os can be used to constrain the s-process 190Os/188Os ratio to be 1.275 pm 0.043. Such a ratio can be reproduced in a nuclear reaction network for a MACS value for 190Os of ~200 pm 22 mbarn at 30 keV. We also present evidence for extensive internal variation of 184Os abundances in the Murchison meteorite. This suggests that p process rich presolar grains (e.g., supernova condensates) may be present in meteorites in sufficient quantities to influence the Os isotopic compositions of the leachates.Comment: 40 pages, 9 figures, 2 tables. Accepted for publication in Earth and Planetary Science Letter

Preliminary results of in vitro culture of pea and lupin embryos for the reduction of generation cycles in single seed descent technique

The aim of the studies was to establish in vitro conditions for the culture of pea and lupin embryos as the first step in the development of an in vitro assisted single seed descent technique for the attainment of homozygous populations. Materials for the study included of pea, and narrow-leafed and yellow lupin cultivars. Embryos dissected from mature but still-green seeds were cultured in vitro on two modified MS media and under three temperature regimes. Shoot and root lengths of regenerated plants were measured after 7, 14 and 21 days of culture. For pea plants full-strength MS medium with 4 g l−1 agar and temperature 22/ 20°C (day/night) appeared to be the most conducive to shoot and root development, whereas for lupin plants lower temperatures were more propitious: 12°C in the dark for narrow-leafed lupin and 16/ 12°C (day/night) for yellow lupin. Almost all the cultured embryos developed into plants, but not all the regenerated plants survived acclimation to ex vitro conditions

Presolar He and Ne Isotopes in Single Circumstellar SiC Grains

Noble gas isotopes in presolar silicon carbide (SiC) dust grains from primitive meteorites provide, together with major element isotopic compositions, insight into the nucleosynthetic output of different types of evolved stars >4.5 Gyr ago. We report here new results from helium and neon isotopic analyses of single presolar SiC grains with sizes between 0.6 and 6.3 μm using an ultrahigh sensitivity mass spectrometer. These noble gas studies were complemented by an ion microprobe study (NanoSIMS) of Si, C, and N isotopic compositions of the same grains. About 40%, or 46 of the 110 grains analyzed, contain nucleosynthetic 22Ne and/or 4He from their parent stars above our mass spectrometer's detection limit. We discuss the possible stellar sources using isotopic ratios as constraints combined with new model predictions for low- to intermediate-mass (1.5, 2, 3, and 5 M☉) asymptotic giant branch (AGB) stars of different metallicities (1, 1/2, 1/3, and 1/6 Z☉). Most SiC grains are of the mainstream type and originated in low-mass AGB stars. We find a higher-than-expected percentage of A/B type grains, with some containing 22Ne and/or 4He. In addition, we find one noble gas-rich nova grain candidate, one supernova grain (X-type grain), and one 22Ne-rich X- or Z-type grain candidate