In-vivo two-photon imaging of the honey bee antennal lobe

Due to the honey bee's importance as a simple neural model, there is a great need for new functional imaging modalities. Herein we report on the use of two-photon microscopy for in-vivo functional and morphological imaging of the honey bee's olfactory system focusing on its primary centers, the antennal lobes (ALs). Our imaging platform allows for simultaneously obtaining both morphological measurements of the AL and in-vivo calcium recording of neural activities. By applying external odor stimuli to the bee's antennas, we were able to record the characteristic odor response maps. Compared to previous works where conventional fluorescence microscopy is used, our approach offers all the typical advantages of multi-photon imaging, providing substantial enhancement in both spatial and temporal resolutions while minimizing photo-damages and autofluorescence contribution with a four-fold improvement in the functional signal. Moreover, the multi-photon associated extended penetration depth allows for functional imaging within profound glomeruli.Comment: 3 pages, 3 figure

A General Method to Determine the Optimal Profile of Porting Grooves in Positive Displacement Machines: the Case of External Gear Machines

In all common hydrostatic pumps, compressibility affects the commutation phases of the displacing chambers, as they switch their connection from/to the inlet to/from the outlet port, leading to pressure peaks, localized cavitation, additional port flow fluctuations and volumetric efficiency reduction. In common pumps, these effects are reduced by proper grooves that realizes gradual port area variation in proximity of these transition regions. This paper presents a method to automatically find the optimal designs of these grooves, taking as reference the case of external gear pumps. The proposed procedure does not assume a specific geometric morphology for the grooves, and it determines the best feasible designs through a multi-objective optimization procedure. A commercial gear pump is used to experimentally demonstrate the potentials of the proposed method, for a particular case aimed at reducing delivery flow oscillations

Synchronous vibration parameters identification by tip timing measurements

The Blade Tip Timing (BTT) measurement system is a technique to measure vibration parameters of a rotating bladed disk. In particular for synchronous vibrations the BTT provides signals versus the rotation speed of the disk starting from the measurement of the time of arrival (TOA) of each blade under the tip timing probes. The signals must be post processed in order to obtain the interesting parameters of each blade vibration. The paper presents a method to extract the main parameters (amplitude and frequency) in resonance condition from the tip timing measurements. The proposed method is a revision of the already existing well known Two-Parameter Plot (2PP) method which requires a minimum of two probes. Improvements to the existing 2PP method are here suggested mainly in the part of engine order identification. The proposed method is then applied to the BTT measured signals coming from a rotating bladed disk excited at different engine orders. At the same time on the disk the vibration of one blade was detected by strain gauges. The strain gauges were calibrated and they provide the reference values of the vibration parameters. The vibration parameters derived by the proposed method are in agreement with those obtained by the strain gages methodolog

A right antenna for social behaviour in honeybees

Sophisticated cognitive abilities have been documented in honeybees, possibly an aspect of their complex sociality. In vertebrates brain asymmetry enhances cognition and directional biases of brain function are a putative adaptation to social behaviour. Here we show that honeybees display a strong lateral preference to use their right antenna in social interactions. Dyads of bees tested using only their right antennae (RA) contacted after shorter latency and were significantly more likely to interact positively (proboscis extension) than were dyads of bees using only their left antennae (LA). The latter were more likely to interact negatively (C-responses) even though they were from the same hive. In dyads from different hives C-responses were higher in RA than LA dyads. Hence, RA controls social behaviour appropriate to context. Therefore, in invertebrates, as well as vertebrates, lateral biases in behaviour appear to be associated with requirements of social life

Synchronous vibration parameters identification by tip timing measurements

The Blade Tip Timing (BTT) measurement system is a technique to measure vibration parameters of a rotating bladed disk. In particular for synchronous vibrations the BTT provides signals versus the rotation speed of the disk starting from the measurement of the time of arrival (TOA) of each blade under the tip timing probes. The signals must be post processed in order to obtain the interesting parameters of each blade vibration. The paper presents a method to extract the main parameters (amplitude and frequency) in resonance condition from the tip timing measurements. The proposed method is a revision of the already existing well known Two-Parameter Plot (2PP) method which requires a minimum of two probes. Improvements to the existing 2PP method are here suggested mainly in the part of engine order identification. The proposed method is then applied to the BTT measured signals coming from a rotating bladed disk excited at different engine orders. At the same time on the disk the vibration of one blade was detected by strain gauges. The strain gauges were calibrated and they provide the reference values of the vibration parameters. The vibration parameters derived by the proposed method are in agreement with those obtained by the strain gages methodolog

Investigation of Two-Dimensional Transition Metal Dichalcogenides by Optical and Scanning Tunneling Spectroscopy

The goal of this dissertation is not only to present works completed and projects initiated and accomplished, but to also attempt to teach some of the material to readers who have limited exposure to condensed matter. I will offer an introduction to two-dimensional transition metal dichalcogenide materials (2D TMDCs) and the mathematics required to understand the research conducted. Some effort will be given on explaining the experimental setups and preparations. Projects that required elaborate sample fabrication and the yielded results will be summarized. These results have heavy implications for the science behind bound electron-hole pairs, the effects of magnetic fields on such pairs, and extracting the useful optical properties from the material systems in which these pairs reside. Specialized fabrication techniques of samples for longer term projects that I led will also be presented, namely those of constructing heterostructures by stacking various 2D TMDCs for exploring the modulated properties of these novel arrangements. The latter portion of this dissertation will cover the nanoscopic dynamics of TMDC heterostructures. The Kramers-Kronig relations will be derived and discussed in detail. Data and results regarding the electronic structure of these materials, their heterostructures, and their custom alloys measured via scanning tunneling microscopy will be presented. Coupled with the measured optical properties, significant numerical quantities that characterize these materials are extracted. There will be several appendices that offer some supplementary information and basic summaries about all the projects that were initiated

CFD Analyses of Textured Surfaces for Tribological Improvements in Hydraulic Pumps

In any hydraulic machine there are lubricated couplings that could become critical beyond certain operating conditions. This paper presents the simulation results concerning textured surfaces with the aim of improving the performance of lubricated couplings in relative motion. The texturing design requires much care to obtain good improvements, and it is essential to analyze both the geometric features of the dimples and the characteristics of the coupled surfaces, like the sliding velocity and gap height. For this purpose, several CFD simulations have been performed to study the behavior of the fluid bounded in the coupling, considering dimples with different shapes, size, and spatial distribution. The simulations consider the onset of gaseous cavitation to evaluate the influence of this phenomenon on the pressure distribution generated by the textured surface. The analyses have pointed out that it is critical to correctly predict the behavior of the textured surface in the presence of local cavitation, in fact, when cavitation occurs, the characteristic time of the transient in which the phase of the fluid change is very rapid and it is comparable to the time taken by the fluid to move from one dimple to the next

Quantum Entropic Effects in the Liquid Viscosities of Hydrogen, Deuterium, and Neon

The extremely low temperatures have limited the availability and accuracy of experimental thermophysical property measurements for cryogens, particularly transport properties. Traditional scaling techniques such as corresponding states theory have long been known to be inaccurate for fluids with strong quantum effects. To address this need, this paper investigates how quantum effects impact thermodynamics and momentum transfer (shear viscosity) in the fluid phases of hydrogen, deuterium, and neon. We utilize experimental viscosity measurements and reference empirical equations of state to show that conventional entropy scaling is inadequate for quantum-dominated systems. We then provide a simple empirical correction to entropy scaling based on the ratio of quantum to packing length scale that accounts for the deviations

Side differences during odour processing in the honey bee brain

Trabalho de projecto de mestrado em Medicina (Pneumologia), apresentado à Faculdade de Medicina da Universidade de CoimbraA pneumonia adquirida na comunidade (PAC) é uma doença que revela morbilidade e mortalidade significativas. Os doentes mais graves necessitam de hospitalização e por vezes reúnem critérios de gravidade que condicionam o seu internamento na unidade de cuidados intensivos (UCI), constituindo uma das entidades mais frequentes nestes serviços. Apesar de controverso, o termo “severa” é frequentemente atribuído à doença que requer internamento na UCI, constituindo a definição mais comum. Pelos recursos exigidos com o internamento quer ao nível da enfermaria, quer na UCI, reconhece-se como uma entidade com impacto socioeconómico significativo, daí a importância de escalonar correctamente os doentes que reúnem critérios de severidade e que necessitam de internamento. Objectivo do trabalho Propõe-se a realização de uma revisão da literatura que permita elucidar à luz dos conhecimentos actuais diversos aspectos relativos a esta entidade, designadamente clarificar a sua definição, caracterizando aspectos particulares da sua prevalência e história natural, e congregar diferentes directivas já existentes visando definir claramente o grau de severidade, o que determinará um melhor prognóstico e rentabilização de recursos pela instituição precoce da terapêutica adequada. Pretende-se ainda um esclarecimento quanto à identificação sistematizada dos doentes que reúnem critérios para admissão em UCI bem como quanto às implicações em termos de prognóstico resultante da condição de severidade. Desenvolvimento Para definir a PAC severa (PACS) há que atender a parâmetros que incluem a fisiopatogenia, os factores risco/co-morbilidades associados e o processo diagnóstico em termos clínicos, PAC Severa: Definição, Particularidades e Factores Preditivos para Admissão em Unidade de Cuidados Intensivos R Ferreira, S Freitas 3 laboratoriais (diagnóstico etiológico) e imagiológicos. Desenvolveram-se vários scores/índices de gravidade para escalonar apropriadamente os doentes que requerem internamento. A sua aplicação estratifica a severidade e prediz o prognóstico. Vários factores estão implicados no prognóstico, nomeadamente a maior duração do internamento ou um timing de admissão mais tardio. Avaliou-se igualmente a utilidade prognóstica de biomarcadores como a pró-calcitonina, proteína C reactiva, algumas interleucinas e o cortisol plasmático, bem como o status socioeconómico, variabilidade genética, toma de anti-inflamatórios não esteróides, ventilação mecânica e o seguimento das guidelines. Conclusões A definição mais consensual de PACS continua a ser a que implica internamento em UCI, apresentando-se o Streptococcus pneumoniae como o agente etiológico mais frequente. Dos diversos scores de gravidade disponíveis, as directivas IDSA/ATS 2007 revelaram-se como as mais equilibradas, pelo que a sua aplicação se traduziu num impacto prognóstico positivo significativo. Em termos futuros, prevê-se que o desenvolvimento da investigação na área dos biomarcadores inflamatórios poderá incrementar a acuidade diagnóstica e prognóstica nesta patologiaThe community-acquired pneumonia (CAP) is a disease responsible for significant morbidity and mortality. The most critical patients require hospitalization and sometimes meet severity criteria that determine their admission in the intensive care unit (ICU), being one of the most common situations in these services. Although controversial, the term "severe" is often attributed to the disease that requires admission to ICU, being the most common definition. Given the amount of resources it requires, not only in the ward but also in the ICU, the CAP is recognized as an entity with significant economic impact, hence the importance of properly scaling the patients who meet the criteria for severe CAP and require hospitalization. This article seeks to review the literature to clarify the current knowledge over several aspects of this entity, including its definition, its prevalence and natural history, and to sum up various existing directives in order to clearly define the degree of severity, which determines the prognosis and allows a faster appropriate response as well as a better resources management. This review also aims at establishing a method of identifying the patients that meet the ICU admission criteria and at assessing the prognosis implications of their severity level. To define severe CAP (SCAP) one should consider parameters that include the pathophysiology, risk factors/comorbidities and associated diagnostic elements such as clinical, laboratory (etiology) and imaging findings. Several severity scores were developed to scale appropriately patients requiring hospitalization. Their application stratifies the severity and predicts prognosis. Several factors are implicated in worse prognosis, including length of stay in ICU and delayed admission. The prognostic value of biomarkers such as procalcitonin, C-reactive protein, plasma cortisol and some interleukins, as well as socioeconomic status, genetic variability, anti-inflammatory drugs intake, mechanical ventilation and monitoring of guidelines was also assessed. In conclusion, the most commonly agreed definition of SCAP continues to be a CAP that requires hospitalization in ICU, being the Streptococcus pneumoniae the most frequent etiologic agent. Among the various severity scores available, the directives IDSA / ATS 2007 turned out to be the most balanced and its application has resulted in a significant positive impact on prognosis. It is expected that future research on inflammatory biomarkers may improve the diagnostic accuracy and prognosis in this diseas