Resonant Absorption in GaAs-Based Nanowires by Means of Photo-Acoustic Spectroscopy

Semiconductor nanowires made of high refractive index materials can couple the incoming light to specific waveguide modes that offer resonant absorption enhancement under the bandgap wavelength, essential for light harvesting, lasing and detection applications. Moreover, the non-trivial ellipticity of such modes can offer near field interactions with chiral molecules, governed by near chiral field. These modes are therefore very important to detect. Here, we present the photo-acoustic spectroscopy as a low-cost, reliable, sensitive and scattering-free tool to measure the spectral position and absorption efficiency of these modes. The investigated samples are hexagonal nanowires with GaAs core; the fabrication by means of lithography-free molecular beam epitaxy provides controllable and uniform dimensions that allow for the excitation of the fundamental resonant mode around 800 nm. We show that the modulation frequency increase leads to the discrimination of the resonant mode absorption from the overall absorption of the substrate. As the experimental data are in great agreement with numerical simulations, the design can be optimized and followed by photo-acoustic characterization for a specific application

”Yhen päivän aikanaki sää voit kyllä kokea niinku kaikki tunteiden kirjo”:tunteet ammatti-identiteetin muovaajina varhaiskasvatuksen opettajien kertomuksissa

Tiivistelmä. Tarkastelen tutkimuksessani varhaiskasvatuksen opettajien työssä kokemia tunteita sekä niiden suhdetta ammatti-identiteetin rakentumiseen. Tutkimuksen taustalla vaikuttavat sekä kokemukset kentältä että aikaisempi tutkimustieto, jonka pohjalta opettajan työtä pidetään emotionaalisena työnä. Vaikka varhaiskasvatuksen haasteet ovat olleet vahvasti esillä julkisessa keskustelussa, kohdistetaan huomio tässä tutkielmassa yleisesti työn herättämiin tunteisiin ja tunnekokemuksiin. Tutkimukseni on toteutettu kerronnallisella lähestymistavalla, ja aineistona toimii kolmen varhaiskasvatuksen opettajan haastattelut. Haastatteluaineisto on kerätty toukokuun 2022 aikana. Aineiston analyysi on toteutettu narratiivisia analyysejä mukaillen. Selvitän tutki-mukseni avulla millaisia tunteita varhaiskasvatuksen opettajat kokevat työssään ja mitkä asiat tunteita herättävät, sekä millä tavalla opettajat säätelevät omia tunteitaan. Lisäksi selvitän, miten opettajat kokevat oman ammatti-identiteettinsä rakentuvan suhteessa tunteisiin. Aineistoni kertomusten pohjalta varhaiskasvatuksen opettajan työ näyttäytyy tunnepitoisena työnä, jossa voidaan kokea saman päivän aikanakin useita erilaisia tunteita. Tunteita herättävinä tekijöinä toimivat resurssipula, lapset, vanhemmat, työyhteisö, ylempi valta/ yhteis-työtaho ja media. Kertomuksissa haastavimpana tunteena yleisimmin näyttäytyi turhautuminen, mutta vastaavasti työssä koettiin myös iloa, levollisuutta ja onnistumisen tunteita. Opettajat kokivat työssään myös tunteiden ristiriitaisuutta sekä riittämättömyyden tunnetta, mutta kielteiseksi koetut tunteet saattoivat myös kokemuksen myötä muuttua lopulta myönteisiksi. Omien tunteiden säätelyssä korostuivat ammatillisuuteen pohjautuva tunteiden hillitseminen, sosiaalinen ja kollegiaalinen tuki sekä tiedolliset säätelykeinot. Opettajat rakensivat tunnekokemustensa pohjalta omaa ammatti-identiteettiään persoonallisen ja ammatillisen välisenä vuoropuheluna, jossa kontekstilla nähtiin myös olevan olennainen rooli. Työssä kokemiensa tunteiden ja tunnekokemusten pohjalta opettajat näkivät oman ammatillisuutensa kehittyneen sekä omaan opettajuuteen kuuluvan pedagogisen ajattelun ja osaamisen vahvistuneen

From multiple perspectives to shared understanding

The aim of this study was to explore how learners operating in a small group reach shared understanding as they work out joint research questions and build a theoretical framework and to identify the resources and tools they used in the process. The learners’ own interpretations of their group activities and learning were also taken into account. The data, consisting of group discussions and the documents produced by the group, were subjected to a qualitative content analysis. The group members employed a variety of resources and tools to exchange their individual perspectives and achieve shared understanding. Summaries of relevant literature laid a foundation for the group’s theoretical discussions. Reflective comparisons between their book knowledge and their personal experiences of online interaction and collaboration were frequent, suggesting that such juxtapositions may have enhanced their learning by intertwining the content to be mastered and the activities entailed by this particular content

On dimension reduction in Gaussian filters

A priori dimension reduction is a widely adopted technique for reducing the computational complexity of stationary inverse problems. In this setting, the solution of an inverse problem is parameterized by a low-dimensional basis that is often obtained from the truncated Karhunen-Loeve expansion of the prior distribution. For high-dimensional inverse problems equipped with smoothing priors, this technique can lead to drastic reductions in parameter dimension and significant computational savings. In this paper, we extend the concept of a priori dimension reduction to non-stationary inverse problems, in which the goal is to sequentially infer the state of a dynamical system. Our approach proceeds in an offline-online fashion. We first identify a low-dimensional subspace in the state space before solving the inverse problem (the offline phase), using either the method of "snapshots" or regularized covariance estimation. Then this subspace is used to reduce the computational complexity of various filtering algorithms - including the Kalman filter, extended Kalman filter, and ensemble Kalman filter - within a novel subspace-constrained Bayesian prediction-and-update procedure (the online phase). We demonstrate the performance of our new dimension reduction approach on various numerical examples. In some test cases, our approach reduces the dimensionality of the original problem by orders of magnitude and yields up to two orders of magnitude in computational savings

Global mapping of maximum emission heights and resulting vertical profiles of wildfire emissions

The problem of characteristic vertical profile of smoke released from wildland fires is considered. A methodology for bottom-up evaluation of this profile is suggested and a corresponding global dataset is calculated. The profile estimation is based on: (i) a semi-empirical formula for plume-top height recently suggested by the authors, (ii) satellite observations of active wildland fires, and (iii) meteorological conditions evaluated for each fire using output of the numerical weather prediction model. Injection profiles of the plumes from all fires recorded globally from March 2000 till November 2012 are estimated with a time step of 1 h. The resulting 4-dimensional dataset is split into daytime and nighttime subsets. The subsets are projected onto a global grid with a resolution of 1° × 1° × 500 m, aggregated to a monthly level, and normalised by total emissions in each vertical column. Evaluation of the obtained dataset was performed in several ways. Firstly, the quality of the semi-empirical formula for plume-top computations was evaluated using updated MISR fire Plume Height Project data. Secondly, the upper percentiles of the profiles are compared with an independent dataset of space lidar CALIOP. Thirdly, the results are compared with the distribution suggested for AEROCOM modelling community. Finally, the inter-annual variations of the calculated profiles are estimated

A germline exome analysis reveals harmful POT1 variants in multiple myeloma patients and families

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Food and nutrient intake in relation to mental wellbeing

BACKGROUND: We studied food consumption and nutrient intake in subjects with depressed mood, anxiety and insomnia as indices of compromised mental wellbeing. METHODS: The study population consisted of 29,133 male smokers aged 50 to 69 years who entered the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study in 1985–1988. This was a placebo-controlled trial to test whether supplementation with alpha-tocopherol or beta-carotene prevents lung cancer. At baseline 27,111 men completed a diet history questionnaire from which food and alcohol consumption and nutrient intake were calculated. The questionnaire on background and medical history included three symptoms on mental wellbeing, anxiety, depression and insomnia experienced in the past four months. RESULTS: Energy intake was higher in men who reported anxiety or depressed mood, and those reporting any such symptoms consumed more alcohol. Subjects reporting anxiety or depressed mood had higher intake of omega-3 fatty acids and omega-6 fatty acids. CONCLUSIONS: Our findings conflict with the previous reports of beneficial effects of omega-3 fatty acids on mood

Biomarkers and prediction of myocardial triglyceride content in non-diabetic men

Background and aims: Lipid oversupply to cardiomyocytes or decreased utilization of lipids leads to cardiac steatosis. We aimed to examine the role of different circulating metabolic biomarkers as predictors of myocardial triglyceride (TG) content in non-diabetic men. Methods and results: Myocardial and hepatic TG contents were measured with 1.5 T magnetic resonance (MR) spectroscopy, and LV function, visceral adipose tissue (VAT), abdominal subcutaneous tissue (SAT), epicardial and pericardial fat by MR imaging in 76 non-diabetic men. Serum concentration of circulating metabolic biomarkers [adiponectin, leptin, adipocyte-fatty acid binding protein 4 (A-FABP 4), resistin, and lipocalin-2] including beta-hydroxybuturate (beta-OHB) were measured. Subjects were stratified by tertiles of myocardial TG into low, moderate, and high myocardial TG content groups. Concentrations of beta-OHB were lower (p = 0.003) and serum levels of A-FABP 4 were higher (p <0.001) in the group with high myocardial TG content compared with the group with low myocardial TG content. beta-OHB was negatively correlated with myocardial TG content (r = -0.316, p = 0.006), whereas A-FABP 4 was not correlated with myocardial TG content (r = 0.192, p = 0.103). In multivariable analyses beta-OHB and plasma glucose levels were the best predictors of myocardial TG content independently of VAT and hepatic TG content. The model explained 58.8% of the variance in myocardial TG content. Conclusion: Our data showed that beta-OHB and fasting glucose were the best predictors of myocardial TG content in non-diabetic men. These data suggest that hyperglycemia and alterations in lipid oxidation may be associated with cardiac steatosis in humans. (C) 2015 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.Peer reviewe