Influence of an Overshoot Layer on the Morphological, Structural, Strain, and Transport Properties of InAs Quantum Wells.

InAs quantum wells (QWs) are promising material systems due to their small effective mass, narrow bandgap, strong spin-orbit coupling, large g-factor, and transparent interface to superconductors. Therefore, they are promising candidates for the implementation of topological superconducting states. Despite this potential, the growth of InAs QWs with high crystal quality and well-controlled morphology remains challenging. Adding an overshoot layer at the end of the metamorphic buffer layer, i.e., a layer with a slightly larger lattice constant than the active region of the device, helps to overcome the residual strain and provides optimally relaxed lattice parameters for the QW. In this work, we systematically investigated the influence of overshoot layer thickness on the morphological, structural, strain, and transport properties of undoped InAs QWs on GaAs(100) substrates. Transmission electron microscopy reveals that the metamorphic buffer layer, which includes the overshoot layer, provides a misfit dislocation-free InAs QW active region. Moreover, the residual strain in the active region is compressive in the sample with a 200 nm-thick overshoot layer but tensile in samples with an overshoot layer thicker than 200 nm, and it saturates to a constant value for overshoot layer thicknesses above 350 nm. We found that electron mobility does not depend on the crystallographic directions. A maximum electron mobility of 6.07 × 105 cm2/Vs at 2.6 K with a carrier concentration of 2.31 × 1011 cm-2 in the sample with a 400 nm-thick overshoot layer has been obtained.

Structural and Photoelectronic Properties of κ-Ga2O3 Thin Films Grown on Polycrystalline Diamond Substrates.

Orthorhombic κ-Ga2O3 thin films were grown for the first time on polycrystalline diamond free-standing substrates by metal-organic vapor phase epitaxy at a temperature of 650 °C. Structural, morphological, electrical, and photoelectronic properties of the obtained heterostructures were evaluated by optical microscopy, X-ray diffraction, current-voltage measurements, and spectral photoconductivity, respectively. Results show that a very slow cooling, performed at low pressure (100 mbar) under a controlled He flow soon after the growth process, is mandatory to improve the quality of the κ-Ga2O3 epitaxial thin film, ensuring a good adhesion to the diamond substrate, an optimal morphology, and a lower density of electrically active defects. This paves the way for the future development of novel hybrid architectures for UV and ionizing radiation detection, exploiting the unique features of gallium oxide and diamond as wide-bandgap semiconductors.

Computer Vision in Human Analysis: From Face and Body to Clothes.

For decades, researchers of different areas, ranging from artificial intelligence to computer vision, have intensively investigated human-centered data, i [...].

Molecular Barcoding: A Tool to Guarantee Correct Seafood Labelling and Quality and Preserve the Conservation of Endangered Species.

The recent increase in international fish trade leads to the need for improving the traceability of fishery products. In relation to this, consistent monitoring of the production chain focusing on technological developments, handling, processing and distribution via global networks is necessary. Molecular barcoding has therefore been suggested as the gold standard in seafood species traceability and labelling. This review describes the DNA barcoding methodology for preventing food fraud and adulteration in fish. In particular, attention has been focused on the application of molecular techniques to determine the identity and authenticity of fish products, to discriminate the presence of different species in processed seafood and to characterize raw materials undergoing food industry processes. In this regard, we herein present a large number of studies performed in different countries, showing the most reliable DNA barcodes for species identification based on both mitochondrial (COI, cytb, 16S rDNA and 12S rDNA) and nuclear genes. Results are discussed considering the advantages and disadvantages of the different techniques in relation to different scientific issues. Special regard has been dedicated to a dual approach referring to both the consumer's health and the conservation of threatened species, with a special focus on the feasibility of the different genetic and genomic approaches in relation to both scientific objectives and permissible costs to obtain reliable traceability.

Electrical properties and chemiresistive response to 2,4,6 trinitrotoluene vapours of large area arrays of Ge nanowires.

We study the electrical and morphological properties of random arrays of Ge nanowires (NW) deposited on sapphire substrates. NW-based devices were fabricated with the aim of developing chemiresistive-type sensors for the detection of explosive vapours. We present the results obtained on pristine and annealed NWs and, focusing on the different phenomenology observed, we discuss the critical role played by NW-NW junctions on the electrical conduction and sensing performances. A mechanism is proposed to explain the high efficiency of the annealed arrays of NWs in detecting 2,4,6 trinitrotoluene vapours. This study shows the promising potential of Ge NW-based sensors in the field of civil security.

Expanding Acutuncus: Phylogenetics and morphological analyses reveal a considerably wider distribution for this tardigrade genus.

The tardigrade genus Acutuncus has been long thought to be an Antarctic endemism, well adapted to this harsh environment. The Antarctic endemicity of Acutuncus was recently dispelled with the description of Acutuncus mariae Zawierucha, 2020 found in the Svalbard archipelago. The integrated analyses on two newly found Acutuncus populations from UK and Italy, and a population of Acutuncus antarcticus found close to its type locality allowed us to expand the climatic and geographic range of the genus Acutuncus. These findings also allowed us to re-evaluate the morphological diagnoses of Acutuncus and accommodate it in the newly proposed monotypic family Acutuncidae fam. nov. Two new Acutuncus species morpho-groups are instituted based on eggs morphology: one (Acutuncus antarcticus morphogroup) including the Antarctic Acutuncus taxa characterized by eggs with long pillars within the chorion and eggs laid freely to the environment, the other (Acutuncus mariae morphogroup) including the European species, characterized by eggs with short pillars within the chorion and eggs laid in the exuvium. Finally, we describe two new Acutuncus species from Europe: Acutuncus mecnuffisp. nov. and Acutuncus giovanniniaesp. nov.

Would Your Clothes Look Good on Me? Towards Transferring Clothing Styles with Adaptive Instance Normalization.

Several applications of deep learning, such as image classification and retrieval, recommendation systems, and especially image synthesis, are of great interest to the fashion industry. Recently, image generation of clothes gained lot of popularity as it is a very challenging task that is far from being solved. Additionally, it would open lots of possibilities for designers and stylists enhancing their creativity. For this reason, in this paper we propose to tackle the problem of style transfer between two different people wearing different clothes. We draw inspiration from the recent StarGANv2 architecture that reached impressive results in transferring a target domain to a source image and we adapted it to work with fashion images and to transfer clothes styles. In more detail, we modified the architecture to work without the need of a clear separation between multiple domains, added a perceptual loss between the target and the source clothes, and edited the style encoder to better represent the style information of target clothes. We performed both qualitative and quantitative experiments with the recent DeepFashion2 dataset and proved the efficacy and novelty of our method.

Detection of Nitroaromatic Explosives in Air by Amino-Functionalized Carbon Nanotubes.

Nitroaromatic explosives are the most common explosives, and their detection is important to public security, human health, and environmental protection. In particular, the detection of solid explosives through directly revealing the presence of their vapors in air would be desirable for compact and portable devices. In this study, amino-functionalized carbon nanotubes were used to produce resistive sensors to detect nitroaromatic explosives by interaction with their vapors. Devices formed by carbon nanotube networks working at room temperature revealed trinitrotoluene, one of the most common nitroaromatic explosives, and di-nitrotoluene-saturated vapors, with reaction and recovery times of a few and tens of seconds, respectively. This type of resistive device is particularly simple and may be easily combined with low-power electronics for preparing portable devices.

Macro- and Micro-Expressions Facial Datasets: A Survey.

Automatic facial expression recognition is essential for many potential applications. Thus, having a clear overview on existing datasets that have been investigated within the framework of face expression recognition is of paramount importance in designing and evaluating effective solutions, notably for neural networks-based training. In this survey, we provide a review of more than eighty facial expression datasets, while taking into account both macro- and micro-expressions. The proposed study is mostly focused on spontaneous and in-the-wild datasets, given the common trend in the research is that of considering contexts where expressions are shown in a spontaneous way and in a real context. We have also provided instances of potential applications of the investigated datasets, while putting into evidence their pros and cons. The proposed survey can help researchers to have a better understanding of the characteristics of the existing datasets, thus facilitating the choice of the data that best suits the particular context of their application.

A Sparse and Locally Coherent Morphable Face Model for Dense Semantic Correspondence Across Heterogeneous 3D Faces.

The 3D Morphable Model (3DMM) is a powerful statistical tool for representing 3D face shapes. To build a 3DMM, a training set of face scans in full point-to-point correspondence is required, and its modeling capabilities directly depend on the variability contained in the training data. Thus, to increase the descriptive power of the 3DMM, establishing a dense correspondence across heterogeneous scans with sufficient diversity in terms of identities, ethnicities, or expressions becomes essential. In this manuscript, we present a fully automatic approach that leverages a 3DMM to transfer its dense semantic annotation across raw 3D faces, establishing a dense correspondence between them. We propose a novel formulation to learn a set of sparse deformation components with local support on the face that, together with an original non-rigid deformation algorithm, allow the 3DMM to precisely fit unseen faces and transfer its semantic annotation. We extensively experimented our approach, showing it can effectively generalize to highly diverse samples and accurately establish a dense correspondence even in presence of complex facial expressions. The accuracy of the dense registration is demonstrated by building a heterogeneous, large-scale 3DMM from more than 9,000 fully registered scans obtained by joining three large datasets together.

Monocular 3D Body Shape Reconstruction under Clothing.

Estimating the 3D shape of objects from monocular images is a well-established and challenging task in the computer vision field. Further challenges arise when highly deformable objects, such as human faces or bodies, are considered. In this work, we address the problem of estimating the 3D shape of a human body from single images. In particular, we provide a solution to the problem of estimating the shape of the body when the subject is wearing clothes. This is a highly challenging scenario as loose clothes might hide the underlying body shape to a large extent. To this aim, we make use of a parametric 3D body model, the SMPL, whose parameters describe the body pose and shape of the body. Our main intuition is that the shape parameters associated with an individual should not change whether the subject is wearing clothes or not. To improve the shape estimation under clothing, we train a deep convolutional network to regress the shape parameters from a single image of a person. To increase the robustness to clothing, we build our training dataset by associating the shape parameters of a "minimally clothed" person to other samples of the same person wearing looser clothes. Experimental validation shows that our approach can more accurately estimate body shape parameters with respect to state-of-the-art approaches, even in the case of loose clothes.

Germanium Nanowires as Sensing Devices: Modelization of Electrical Properties.

In this paper, we model the electrical properties of germanium nanowires with a particular focus on physical mechanisms of electrical molecular sensing. We use the Tibercad software to solve the drift-diffusion equations in 3D and we validate the model against experimental data, considering a p-doped nanowire with surface traps. We simulate three different types of interactions: (1) Passivation of surface traps; (2) Additional surface charges; (3) Charge transfer from molecules to nanowires. By analyzing simulated I-V characteristics, we observe that: (i) the largest change in current occurs with negative charges on the surfaces; (ii) charge transfer provides relevant current changes only for very high values of additional doping; (iii) for certain values of additional n-doping ambipolar currents could be obtained. The results of these simulations highlight the complexity of the molecular sensing mechanism in nanowires, that depends not only on the NW parameters but also on the properties of the molecules. We expect that these findings will be valuable to extend the knowledge of molecular sensing by germanium nanowires, a fundamental step to develop novel sensors based on these nanostructures.

Action Unit Detection by Learning the Deformation Coefficients of a 3D Morphable Model.

Facial Action Units (AUs) correspond to the deformation/contraction of individual facial muscles or their combinations. As such, each AU affects just a small portion of the face, with deformations that are asymmetric in many cases. Generating and analyzing AUs in 3D is particularly relevant for the potential applications it can enable. In this paper, we propose a solution for 3D AU detection and synthesis by developing on a newly defined 3D Morphable Model (3DMM) of the face. Differently from most of the 3DMMs existing in the literature, which mainly model global variations of the face and show limitations in adapting to local and asymmetric deformations, the proposed solution is specifically devised to cope with such difficult morphings. During a training phase, the deformation coefficients are learned that enable the 3DMM to deform to 3D target scans showing neutral and facial expression of the same individual, thus decoupling expression from identity deformations. Then, such deformation coefficients are used, on the one hand, to train an AU classifier, on the other, they can be applied to a 3D neutral scan to generate AU deformations in a subject-independent manner. The proposed approach for AU detection is validated on the Bosphorus dataset, reporting competitive results with respect to the state-of-the-art, even in a challenging cross-dataset setting. We further show the learned coefficients are general enough to synthesize realistic 3D face instances with AUs activation.

Compressive strain formation in surface-damaged crystals.

The mechanism of formation of residual strain in crystals with a damaged surface has been studied by transmission electron microscopy in GaAs wafers ground with sandpaper. The samples showed a dislocation network located near the sample surface penetrating to a depth of a few micrometres, comparable to the size of abrasive particles used for the treatment, and no other types of defects were observed. A simple model for the formation of a compressive strain induced by the dislocation network in the damaged layer is proposed, in satisfactory agreement with the measured strain. The strain is generated by the formation of dislocation half-loops at the crystal surface, having the same component of the Burgers vectors parallel to the surface of the crystal. This is equivalent to the insertion of extra half-planes from the crystal surface to the depth of the damaged zone. This model can be generalized for other crystal structures. An approximate calculation of the strain generated from the observed dislocation distribution in the sample agrees with the proposed model and permits the conclusion that this mechanism is in general sufficient to explain the observed compressive strain, without the need to consider other types of defects.

Direct growth of germanium nanowires on glass.

We report a detailed characterization of Ge NWs directly grown on glass by a MOVPE system, showing how different growth parameters can affect the final outcome and comparing NWs grown on a monocrystalline Ge(111) substrate with NWs grown on amorphous glass. Our experimental results indicate that the choice of the substrate does not affect any of the relevant morphological, crystallographic or electrical properties of Ge NWs. Lengths are in the 20-30 micrometer range with minimal tapering, while growth rates are very similar to to NWs grown on Ge(111); TEM and Raman characterization show a very good crystallinity of measured nanostructures. We have also analyzed the growth process on glass and we were able to reach a conclusion on the specific growth mechanism for Ge NWs on amorphous substrates. Our findings demonstrate that glass is a valid option as cheap substrate for the mass production of these nanostructures.

Growth of germanium nanowires with isobuthyl germane.

We demonstrate the feasibility of the use of isobutyl germane, a novel germanium source, for the vapor-liquid-solid growth of germanium nanowires (NWs) on Si (111) substrates, using a thin gold layer as catalyst. The density and the diameter of the NWs were controlled by varying the Au layer thickness and the isobutyl germane flow. The NWs grow along (111) directions and show perfect crystallinity and lengths from several hundreds of nm to 3-4 µm. The use of isobutyl germane gives a considerable technological advantage in the growth of germanium NWs since it is a safer and more manageable germanium source and it allows to grow Ge NWs in a standard vapor phase epitaxy system at 400 °C.

Investigating Nuisances in DCNN-based Face Recognition.

Face recognition "in the wild" has been revolutionized by the deployment of deep learning based approaches. In fact, it has been extensively demonstrated that Deep Convolutional Neural Networks (DCNNs) are powerful enough to overcome most of the limits that affected face recognition algorithms based on hand-crafted features. These include variations in illumination, pose, expression and occlusion, to mention some. The DCNNs discriminative power comes from the fact that low- and high-level representations are learned directly from the raw image data. As a consequence, we expect the performance of a DCNN to be influenced by the characteristics of the image/video data that are fed to the network, and their preprocessing. In this work, we present a thorough analysis of several aspects that impact on the use of DCNN for face recognition. The evaluation has been carried out from two main perspectives: the network architecture and the similarity measures used to compare deeply learned features; the data (source and quality) and their preprocessing (bounding box and alignment). Results obtained on the IJB-A, MegaFace, UMDFaces and YouTube Faces datasets indicate viable hints for designing, training and testing DCNNs. Taking into account the outcomes of the experimental evaluation, we show how competitive performance with respect to the state-of-the-art can be reached even with standard DCNN architectures and pipeline.

Cross-sectional TEM study of subsurface damage in SPDT machining of germanium optics.

In addition to surface roughness and shape precision, the subsurface damage (SSD) generated by single point diamond turning (SPDT) of Ge and Si crystal optics is of increasing importance with decreasing wavelength from infrared through visible, UV, and x-ray. There are various components of SSD, e.g., microcracks, dislocations, strain, and a near-surface amorphous layer, and there are also several techniques to evaluate various components of SSD. Cross-sectional transmission electron microscopy (XTEM) is expensive and not often directly used in the optics laboratory. However, because of its very high sensitivity to SSD and down to atomic resolution, it is often used as an external service for developing SPDT technology and other surface processing techniques. It is shown in the paper that improper sample preparation can generate near-surface amorphization. Measures to avoid this artifact and a test of reliability of XTEM sample preparation are proposed.

A "miracle" cancer drug in the era of social media: A survey of Brazilian oncologists' opinions and experience with phosphoethanolamine.

INTRODUCTION: Patients who are treating cancer have often used alternative therapies. In the internet era, information can be broadcasted widely, and this happened with phosphoethanolamine in Brazil, where this substance was claimed by the population to be the "cure for cancer." METHOD: This is a cross-sectional study developed by the Brazilian Society of Clinical Oncology (SBOC). An objectively structured questionnaire was sent by e-mail and SMS to active MDs members of the SBOC. Descriptive statistics was used to evaluate the data. Statistical significance between the variables was tested by Pearson's Chi-squared test (p<0.05 was considered significance). RESULTS: The survey was sent to 1,072 oncologists, and 398 (37.1%) answered at least part of it. One hundred and fifteen (28.9%) had followed patients who had used phosphoethanolamine. Among these, 14 (12.2%) observed adverse events and four (3.5%) attributed clinical benefit to the substance. Most of the oncologists (n=331; 83.2%) believe that it should only be used as part of a clinical trial protocol. Most physicians did not recommend this drug to their patients (n=311; 78.1%). Oncologists in Southeast, South and Midwest Brazil were more likely to have patients taking the drug compared to the Northern and Northeastern regions. CONCLUSION: This is the first survey to assess the opinion and experience of oncologists about this alternative therapy. Most oncologists in Brazil do not believe that synthetic phosphoethanolamine is active in cancer treatment, do not recommend its use without proper evaluation, and state that it should only be available to patients in the context of clinical trials.

A "miracle" cancer drug in the era of social media: A survey of Brazilian oncologists' opinions and experience with phosphoethanolamine / Uma "milagrosa" droga contra o câncer na era da mídia social: uma pesquisa sobre a opinião e a experiência dos oncologistas brasileiros com a fosfoetanolamina

Summary Introduction: Patients who are treating cancer have often used alternative therapies. In the internet era, information can be broadcasted widely, and this happened with phosphoethanolamine in Brazil, where this substance was claimed by the population to be the "cure for cancer." Method: This is a cross-sectional study developed by the Brazilian Society of Clinical Oncology (SBOC). An objectively structured questionnaire was sent by e-mail and SMS to active MDs members of the SBOC. Descriptive statistics was used to evaluate the data. Statistical significance between the variables was tested by Pearson's Chi-squared test (p<0.05 was considered significance). Results: The survey was sent to 1,072 oncologists, and 398 (37.1%) answered at least part of it. One hundred and fifteen (28.9%) had followed patients who had used phosphoethanolamine. Among these, 14 (12.2%) observed adverse events and four (3.5%) attributed clinical benefit to the substance. Most of the oncologists (n=331; 83.2%) believe that it should only be used as part of a clinical trial protocol. Most physicians did not recommend this drug to their patients (n=311; 78.1%). Oncologists in Southeast, South and Midwest Brazil were more likely to have patients taking the drug compared to the Northern and Northeastern regions. Conclusion: This is the first survey to assess the opinion and experience of oncologists about this alternative therapy. Most oncologists in Brazil do not believe that synthetic phosphoethanolamine is active in cancer treatment, do not recommend its use without proper evaluation, and state that it should only be available to patients in the context of clinical trials.

Resumo Introdução: Alguns pacientes com diagnóstico de câncer utilizam terapias alternativas. Na era da internet, as informações podem se dissipar de forma rápida e abrangente, como foi o caso da fosfoetanolamina no Brasil, onde foi aclamada pela população como sendo a "cura para o câncer". Método: Trata-se de um estudo transversal desenvolvido pela Sociedade Brasileira de Oncologia Clínica (SBOC). Através de e-mail e SMS, enviou-se um questionário com perguntas objetivas para oncologistas membros ativos da SBOC. Os dados foram avaliados por meio de estatística descritiva. A significância estatística entre as variáveis ​​foi testada pelo teste Qui-quadrado de Pearson (p<0,05 foi considerado significativo). Resultados: O questionário foi enviado para 1.072 oncologistas, tendo 398 (37,1%) respondido pelo menos parte dele. Cento e quinze (28,9%) tinham pacientes que fizeram uso da fosfoetanolamina. Desses, 14 (12,2%) observaram eventos adversos e quatro (3,5%) atribuíram benefício clínico para a substância. A maioria (n=331; 83,2%) acreditava que ela só deveria ser utilizada dentro de um ensaio clínico. A principal recomendação dada aos pacientes foi contra o seu uso (n=311; 78,1%). Oncologistas das regiões Sudeste, Sul e Centro-Oeste tiveram mais pacientes que tomaram a substância quando comparados com as regiões Norte e Nordeste. Conclusão: Este é o primeiro estudo que avalia a opinião dos oncologistas sobre essa terapia alternativa e sua experiência. A maioria dos oncologistas brasileiros não acredita que a fosfoetanolamina sintética seja ativa no tratamento do câncer, não recomendando seu uso sem avaliação adequada, e afirmam que a substância só deve estar disponível no contexto de ensaios clínicos.