Application of a maximum likelihood processor to acoustic backscatter for the estimation of seafloor roughness parameters

Maximum likelihood (ML) estimation is used to extract seafloor roughness parameters from records of acoustic backscatter. The method relies on the Helmholtz–Kirchhoff approximation under the assumption of a power‐law roughness spectrum and on the statistical modeling of bottom reverberation. The result is a globally optimum, highly automated technique that is a useful tool in the context of seafloor classification via remote acoustic sensing. The general geometry of the Sea Beam bathymetric system is incorporated into the design of the ML processor in order to make it applicable to real acoustic data collected by this system. The processor is initially tested on simulated backscatter data and is shown to be very effective in estimating the seafloor parameters of interest. The simulated data are also used to study the effect of data averaging and normalization in the absence of system calibration information. The same estimation procedure is applied to real data collected over two central North Pacific seamounts, Horizon Guyot and Magellan Rise. The Horizon Guyot results are very close to estimates obtained through a curve‐fitting procedure presented by de Moustier and Alexandrou [J. Acoust. Soc. Am. 90, 522–531 (1991)]. In the case of Magellan Rise, discrepancies are observed between the results of ML estimation and curve fitting

Metabolic scavenging by cancer cells: when the going gets tough, the tough keep eating

Cancer is fundamentally a disease of uncontrolled cell proliferation. Tumour metabolism has emerged as an exciting new discipline studying how cancer cells obtain the necessary energy and cellular ‘building blocks’ to sustain growth. Glucose and glutamine have long been regarded as the key nutrients fuelling tumour growth. However, the inhospitable tumour microenvironment of certain cancers, like pancreatic cancer, causes the supply of these nutrients to be chronically insufficient for the demands of proliferating cancer cells. Recent work has shown that cancer cells are able to overcome this nutrient insufficiency by scavenging alternative substrates, particularly proteins and lipids. Here, we review recent work identifying the endocytic process of macropinocytosis and subsequent lysosomal processing as an important substrate-acquisition route. In addition, we discuss the impact of hypoxia on fatty acid metabolism and the relevance of exogenous lipids for supporting tumour growth as well as the routes by which tumour cells can access these lipids. Together, these cancer-specific scavenging pathways provide a promising opportunity for therapeutic intervention

Mejora de la interacción social entre niños con trastorno del espectro autista en entornos Inclusivos mediante la intervención mediada por compañeros

In recent, years general and special education teachers are often called to support students with autism educating in mainstream Greek schools. Their peers are a key factor in everyday life of an ASD student in a school setting as they spend together the one third of each day. Consequently, the purpose of the present study was to explore the effects of a PMI program through an activity that they have in common in improving language and communication abilities among ASD students and their typical peers in inclusive school settings. A metanalysis introduced the efficacy of PMI prior to the intervention research. The research involved 25 typical students and 5 ASD students aged 7-10 who served in the school's Parallel support1. In the beginning of the project, Parallel Support Teachers of ASD students completed the Gilliam autism rating scale (GARS, 2006) in cooperation with their parents. The peers of ASD students were trained through a PMI program and a common interest activity to interact with them during school recess. A multiple baseline design was used on each participant in order to define the effects of the intervention. Through observation probes, the responses and the initiations of all ASD students were noted by trained school staff. At the end of follow-up phase, the social validity data was collected through questionnaires conducted by the researcher to peer participants and teachers. Results indicated that the social skills intervention had direct and vigorous improvements on social initiations and responses in all five participants. Some changes were noticed in all study variables, keeping up a positive slant within the rates of initiating and responding to interactions, and a negative slant within the rate of time the ASD students maintained low interactions. More specifically, the results of the intervention phase showed an increase in both of these two variables. Then, the followup phase depicted important results for the academic community, also showing an increase in all ASD students’ responses and initiations. Generally, the current study supplements the existing PMI research, which leads to the possible use of this valid tool that could be used in school settings in order to increase the socialization of ASD students.En los últimos años, los maestros de educación general y especial a menudo son llamados para ayudar a los estudiantes con autismo a educar en las escuelas griegas convencionales. Sus compañeros son un factor clave en la vida cotidiana de un estudiante con TEA en un entorno escolar, ya que pasan juntos la tercera parte de cada día. En consecuencia, el propósito del presente estudio fue explorar los efectos de un programa PMI a través de una actividad que tienen en común para mejorar las habilidades de lenguaje y comunicación entre los estudiantes con TEA y sus compañeros típicos en entornos escolares inclusivos. Un metanálisis presentó la eficacia del PMI antes de la investigación de la intervención. La investigación involucró a 25 estudiantes típicos y 5 estudiantes ASD de 7 a 10 años que sirvieron en el apoyo paralelo 2 de la escuela. Al comienzo del proyecto, los maestros-terapeutas de educación especial de estudiantes con TEA completaron la escala de calificación de autismo de Gilliam (GARS) en cooperación con sus padres. Los compañeros de los estudiantes ASD fueron capacitados a través de un programa de PMI y una actividad de interés común para interactuar con ellos durante el recreo escolar. Se utilizó un diseño de línea de base múltiple en cada participante para definir los efectos de la intervención. A través de sondeos de observación, el personal escolar capacitado tomó nota de las respuestas y las iniciaciones de todos los estudiantes con TEA. Al final de la fase de seguimiento, los datos de validez social se recopilaron a través de cuestionarios realizados por el investigador a los compañeros participantes y profesores. Los resultados indicaron que la intervención de habilidades sociales tuvo mejoras directas y vigorosas en las iniciaciones y respuestas sociales en los cinco participantes. Se notaron algunos cambios en todas las variables del estudio, manteniéndose un sesgo positivo en los índices de iniciar y responder interacciones, y un sesgo negativo en el índice de tiempo que los estudiantes TEA mantuvieron interacciones bajas. Más específicamente, los resultados de la fase de intervención mostraron un aumento en estas dos variables. Luego, la fase de seguimiento mostró resultados importantes para la comunidad académica, mostrando también un aumento en las respuestas e iniciaciones de todos los estudiantes TEA. En general, el estudio actual complementa la investigación existente del PMI, lo que conduce al posible uso de esta herramienta válida que podría usarse en entornos escolares para aumentar la socialización de los estudiantes con TEA. En general, el estudio actual complementa la investigación existente del PMI, lo que conduce al posible uso de esta herramienta válida que podría usarse en entornos escolares para aumentar la socialización de los estudiantes con TEA

Μελέτη επιπέδων ραδιενέργειας και συγκεντρώσεων βαρέων μετάλλων σε παράκτιες περιοχές του Λαυρίου

Εθνικό Μετσόβιο Πολυτεχνείο. Μεταπτυχιακή εργασία. Διεπιστημονικό - Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.

Recruitment of African Americans for Obsessive Compulsive Disorder Treatment Research

A systematic review of recruitment approaches was conducted as a step towards creating a culturally sensitive approach to enhance participation of African Americans into our Obsessive Compulsive Disorder (OCD) treatment research. From this review, a recruitment plan providing a collaborative partnership between the African American community and the clinical investigators was adopted. We sought to increase participation in OCD research by developing culturally sensitive educational materials, implementing strategies such as recruiter ethnic match, encouraging individuals to participate by a pastor, and providing education in the community that attempted to decrease stigmatization of mental illness and target cultural suspicion of institutional research. Despite positive responses from direct community involvement at churches and efforts to increase minority participation by utilizing recruiters and recruitment materials representative of the population, difficulties in recruitment remained

Влияние технологических факторов на прочность торфяных термобрикетов

На основании изложенного ранее представления о сущности процессов, протекающих при термобрикетировании торфа дано объяснение влияния на прочностные свойства термобрикетов следующих технологических факторов: температуры нагрева торфа перед наложением давления, времени выдержки нагретого торфа перед наложением давления, давления брикетирования, времени выдержки под давлением, степени измельчения торфа

Seabed classification using physics-based modeling and machine learning

In this work model-based methods are employed along with machine learning techniques to classify sediments in oceanic environments based on the geoacoustic properties of a two-layer seabed. Two different scenarios are investigated. First, a simple low-frequency case is set up, where the acoustic field is modeled with normal modes. Four different hypotheses are made for seafloor sediment possibilities and these are explored using both various machine learning techniques and a simple matched-field approach. For most noise levels, the latter has an inferior performance to the machine learning methods. Second, the high-frequency model of the scattering from a rough, two-layer seafloor is considered. Again, four different sediment possibilities are classified with machine learning. For higher accuracy, 1D Convolutional Neural Networks (CNNs) are employed. In both cases we see that the machine learning methods, both in simple and more complex formulations, lead to effective sediment characterization. Our results assess the robustness to noise and model misspecification of different classifiers

Volleyball coaches behavior assessment through systematic observation

The purpose of this study was to record and evaluate the practice behaviors of 12 Greek Volleyball National Division coaches, mean age 47.36 (SD=6.1) through feedback that they provided to their athletes throughout the 2010-11 seasons. Verbal and non verbal behaviors were video recorded during four practices, of each coach. A total of 13.400 behaviors were observed and were coded using the Revised Coaching Behavior Recording Form which corresponded to the 12 categories of the instrument. The analyses of videotaped behaviors were made by two trained observers who were checked in the internal and external reliability. Results indicated that there were 279.11 coded coaching behaviors in each training session. A large proportion of reported coaching behaviors 17.38% (n=48.34) were about "Tactical Instruction", followed by "General Instruction" 15.92% (n=44.45) and "Technical Instruction" 12.42% (n=34.68). "Encouragement" and "Motivation" were 10.76% and 10.73% respectively. "Other Comments" (8.67%) and "Demonstration" (8.26%) were in lower rate. ANOVA revealed that there were not differences between 1st and 2nd division coaching behavior, instead of "Criticism" (p < 0.05) with 2nd division coaches have more comments and "Non verbal reward" (p < 0.05) which 1st division coaches were used more often