A Portable Device for the Measurement of Venous Pulse Wave Velocity

Pulse wave velocity in veins (vPWV) has recently been reconsidered as a potential index of vascular filling, which may be valuable in the clinic for fluid therapy. The measurement requires that an exogenous pressure pulse is generated in the venous blood stream by external pneumatic compression. To obtain optimal measure repeatability, the compression is delivered synchronously with the heart and respiratory activity. We present a portable prototype for the assessment of vPWV based on the PC board Raspberry Pi and equipped with an A/D board. It acquires respiratory and ECG signals, and the Doppler shift from the ultrasound monitoring of blood velocity from the relevant vein, drives the pneumatic cuff inflation, and returns multiple measurements of vPWV. The device was tested on four healthy volunteers (2 males, 2 females, age 33 & PLUSMN;13 years), subjected to the passive leg raising (PLR) manoeuvre simulating a transient increase in blood volume. Measurement of vPWV in the basilic vein exhibited a low coefficient of variation (3.6 & PLUSMN;1.1%), a significant increase during PLR in all subjects, which is consistent with previous findings. This device allows for carrying out investigations in hospital wards on different patient populations as necessary to assess the actual clinical potential of vPWV

Venous pulse wave velocity

Central venous pressure and volume status are relevant parameters for the characterization of the patient's haemodynamic condition and for the management of fluid therapy however, their invasive assessment is affected by various risks and complications while non-invasive approaches provide only imprecise and subjective indications. Aim of the present study is to explore the possibility to assess changes in venous pressure from changes in the venous pulse wave velocity (vPWV). In 9 healthy subjects, pressure pulses were generated artificially in the veins by a PC-driven rapid inflation of a pneumatic cuff (300mmHg in <1sec) placed around a foot. Passage of the pulse wave in the superficial femoral vein distally to the inguinal ligament was detected by Doppler flowmeter and the latency from the pressure stimulus was measured. The vPWV was then calculated as the ratio between traveling distance and latency. Changes in leg venous pressure were obtained by raising the trunk of the subject from the initial supine position by 30 and 60 deg. In each position 15 pressure pulses were delivered every 30 s, at the end-expiratory phase for vPWV assessment. Venous pressure in the leg was non-invasively estimated by assessing the point of collapse of the jugular or axillary vein. The vPWV increased from 1.64±0.06(supine) to 2.13±0.26 (60 deg) (Student’s t- test, p<.01) and exhibited a very strong correlation with leg venous pressure (overall r=0.76). Differences in vPWV among the three positions were statistically significant also on an individual basis in 8/9 subjects (ANOVA + Tukey's HSD post-hoc, p<.01). These preliminary results show that vPWV may be easily assessed in healthy subjects and may constitute a good non-invasive indicator of venous pressurechanges

Venous Pulse Wave Velocity variation in response to a simulated fluid challenge in healthy subjects

Purpose: The evaluation of a mini or simulated fluid challenge is still a complex and open issue in the clinical setting and it is of paramount significance for the fluid therapy optimization. We here investigated the capacity of a new hemodynamic parameter, the venous Pulse Wave Velocity (vPWV), to detect the effect of passive leg raising (PLR). Materials and methods: In 15 healthy volunteers (7 M, 8 F, age 26 ± 3) venous pressure pulses were elicited by pneumatic compressions of the left hand and proximally detected by ultrasound for calculation of the vPWV. We also non-invasively measured the basilic vein (BV) cross-sectional perimeter, and peripheral venous pressure (PVP). The PLR manoeuvre was performed twice to evaluate reliability of the assessment. Results: The PLR had an overall statistically significant effect on the entire set of variables (MANOVA, p < 0.05): vPWV increased from 2.11 ± 0.46 to 2.30 ± 0.47 m/s (p = 0.01; average increase: 10%). This effect was transient and dropped below 5% after about 3 min. A significant increase was also exhibited by BV size and PVP. In consecutive measurements vPWV showed little intra-subject variability (CoV = 8%) and good reliability (ICC = 0.87). Finally, the vPWV responses to the two PLRs exhibited good agreement (paired T-test: p = 0.96), and moderate reliability (ICC = 0.57). Conclusion: These results demonstrated that vPWV can be non-invasively, objectively and reliably measured in healthy subjects and that it is adequate to detect small pressure/volume variations, as induced by PLR-from-supine. These characteristics make it suitable for clinical applications

Multilingual Word Sense Induction to Improve Web Search Result Clustering

In [12] a novel approach to Web search result clustering based on Word Sense Induction, i.e. the automatic discovery of word senses from raw text was presented; key to the proposed approach is the idea of, first, automatically in- ducing senses for the target query and, second, clustering the search results based on their semantic similarity to the word senses induced. In [1] we proposed an innovative Word Sense Induction method based on multilingual data; key to our approach was the idea that a multilingual context representation, where the context of the words is expanded by considering its translations in different languages, may im- prove the WSI results; the experiments showed a clear per- formance gain. In this paper we give some preliminary ideas to exploit our multilingual Word Sense Induction method to Web search result clustering

Adattamento di opentrack v2.0 per piattaforma embedded

OpenPTrack è un progetto open source lanciato nel 2013 da UCLA REMAP e Open Perception, in collaborazione con l’Università degli Studi di Padova. Il progetto aveva come obiettivo la creazione di un sistema di tracking real-time per applicazioni di teatro e arte, ed è stato migliorato ed espanso negli anni fino alla più recente versione datata 2017. Il sistema si basa sull’utilizzo di ROS (Robot Operative System, piattaforma Linux) e di una serie di applicazioni realizzate in C++ per svolgere determinati compiti, come il tracking della persona (human detection), il tracking di un determinato oggetto (object detection) o il rilevamento dello skeleton della persona nella scena, così da riconoscerne la posa (pose detection). Il team di sviluppo originale ha con successo sviluppato una versione embedded della prima release del progetto su schede NVIDIA Jetson TX1 e TK1, mentre l’ultima versione non è ancora stata adattata per piattaforma embedded. L’obiettivo del lavoro qui presentato è quello di compiere questa trasposizione anche per l’ultima e più completa versione su scheda NVIDIA Jetson TX2, ed effettuare una caratterizzazione del sistema in configurazione multicamera embedded

Impacto de perdas acumuladas de N-ureia por volatilização de amônia na produtividade do feijão-comum.

A ureia é a principal fonte de N para as culturas no Brasil, mas apresenta a desvantagem do alto potencial de perdas de N por volatilização de NH3 que pode reduzir sua eficiência agronômica, em comparação com fontes que contem N-NO3 e N-NH4 em sua formulação. Objetivando determinar os efeitos a médio e a longo prazo da aplicação continuada de fertilizantes que contenham diferentes formas de N em sua formulação, em estudo conduzido na Embrapa Arroz e Feijão, em Santo Antônio de Goiás-GO, comparou-se a ureia com nitrato de amônio e cálcio (CAN) aplicados nas culturas de milho e feijão- comum (irrigado) cultivados em sucessão.Evento online