Search

The paper provides synthetic indications regarding the measuring performances of procedures for using a robotic total station (RTS) in emergency situations, such as the survey of the structural conditions of buildings and the assessment of the safety level for rescue operations after the occurrence of an earthquake. Particular attention is paid to operative aspects that could impact on the performance of the system in this situation; specifically considered is the effect of the layout of the measurement setup and of the number of monitoring points, depending on the geometry of the site and of the considered buildings, because the criticality of emergency conditions imposes geometrical solutions which are far from having optimal solutions. The analysis is carried out with reference to two different buildings, which have different characteristics from the point of view of height and distance from the instrument, and that implies different geometrical constraints for the instrument during the acquisition of the monitoring points. The methodology allows the evaluation of the repeatability, reproducibility, and detection limit of a RTS, in field conditions, referring to a 1-year observation period, with reference to different quantities, like positions of the monitoring points and the inclination of walls and façades. In particular, the analysis of the geometrical characteristics of reduced configurations of the monitoring points has highlighted interesting aspects in view of defining a simplified procedure, which is also suitable for speeding up the acquisition of reliable data in emergency conditions.

A method for amplitude–phase calibration of tri-axial accelerometers in the low-frequency range (0 to 20 Hz) is proposed, based on a linear slide, used to excite all the axes of the accelerometer at the same time, and a laser Doppler vibrometer (LDV) as a reference. For the phase evaluation different methods, like cross-correlation analysis and cross-spectrum analysis, have also been used for validation purposes. The procedure includes many further validation actions in order to verify the correctness of modelling of the systems being tested, of the data processing and to reduce the calibration uncertainty. Results show that the phase is a critical aspect to consider in calibration, more than the amplitude, and the comparison with the theoretical model is useful to verify the hypotheses. Different behaviours result depending on the elements of the measurement chain and not only on the type of accelerometer.

A comparison among three methods for the calibration of tri-axial accelerometers, in particular MEMS, is presented in this paper, paying attention to the uncertainty assessment of each method. The first method is performed according to the ISO 16063 standards. Two innovative methods are analysed, both suitable for in-field application. The effects on the whole uncertainty of the following aspects have been evaluated: the test bench performances in realizing the reference motion, the vibration reference sensor, the geometrical parameters and the data processing techniques. The uncertainty contributions due to the offset and the transverse sensitivity are also studied, by calibrating two different types of accelerometers, a piezoelectric one and a capacitive one, to check their effect on the accuracy of the methods under comparison. The reproducibility of methods is demonstrated. Relative uncertainty of methods ranges from 3 to 5 %, depending on the complexity of the model and of the requested operations. The results appear promising for low-cost calibration of new tri-axial accelerometers of MEMS type.

Two alternative experimental procedures for the calibration of tri-axial accelerometers have been compared with traditional methods, performed according the procedures stated in the standard ISO 16063-21. Standard calibration is carried out by comparison with a laser Doppler vibrometer (LDV), used as a primary reference transducer. The main sensitivities have been investigated and, where applicable, also transverse ones. Many aspects have been evaluated: the hypotheses about transverse sensitivities, the simplicity of the procedure, the number of measurements needed, and the effect of typology of transducer, depending on electrical and geometrical contributions. Two different accelerometers have been tested, a piezo-electric accelerometer and a capacitive MEMS accelerometer. A low-frequency range of vibration has been investigated, 3 and 6 Hz, with amplitude of acceleration ranging from 2 to 20 ms−2. A satisfactory reproducibility of methods has been verified, with percentage differences less than 2.5 %. Anyway, pros and cons of each method are also discussed with reference to their possible use for easy and quick calibration of low-cost tri-axial accelerometers.

El hombre produce impactos acumulativos sobre los ecosistemas, siendo las especies exóticas invasoras uno de los más relevantes. Uno de los fines de la restauración ecológica es reparar los ecosistemas para que sean capaces de persistir en ambientes futuros. Este trabajo tiene como objetivo diseñar e implementar técnicas de manejo para la recuperación de ambientes invadidos por tamariscos Tamarix ramossisima en el sur de Córdoba (Argentina). Se realizó un ensayo de restauración consistente en el control de tamariscos (tala y aplicación de herbicida), selección y plantación de especies nativas y evaluación del banco de semillas germinable del bosque de tamarisco y del bosque nativo de referencia. Se delimitaron doce parcelas donde se aplicaron cuatro tratamientos: 1) testigo; 2) control de tamariscos; 3) control y plantación de especies nativas; y 4) control, plantación de especies nativas y trasplante de banco de semillas. Se monitoreó durante 20 meses las variables rebrote de tamarisco, riqueza de la comunidad, cobertura de las especies nativas, emergencia y supervivencia de las plántulas del banco de semillas. El 89 % de los individuos de tamarisco no rebrotaron. Las especies seleccionadas y plantadas fueron Lycium boerhaviifolium, Vachellia caven, Schinus fasciculatus, Celtis ehrembergiana y Atriplex undulata. El banco de semillas no aportó nuevos individuos de especies nativas. Se destaca la importancia de la revegetación con especies leñosas nativas luego del control de tamariscos como estrategia para incrementar la biodiversidad.

Background: The aim of our study was to evaluate in patients with acute ischemic stroke the relationship between immuno-inflammatory variables, clinical outcome and infarct site., Materials and Methods: We evaluated plasma levels of IL-1beta, TNF-alpha, IL-6 and IL-10, E-selectin, P-selectin, sICAM-1 ,sVCAM-1 vWF, TPA and PAI-1., Results: Patients with cardioembolic subtype showed significantly higher median plasma levels of TNF-alpha, IL-6, IL-1beta whereas the lacunar subtype showed significantly lower median plasma levels of TNF-alpha, IL-6 and IL-1beta., Conclusions: A significant association was noted between the severity of neurological deficit at admission, the diagnostic subtype and some inflammatory variables.

We report the case of a patient who, following a right thalamic haemorrhage, developed thalamic syndrome characterised by burning pain and hyperalgesia in the left side of the body. Three years later, following a further (contralateral ischaemic) stroke, she reported the complete disappearance of the pain and hyperalgesia. To our knowledge, this is the first described case of disappearance of thalamic syndrome following a second stroke, different in nature from and contralateral to the first. Various hypotheses, based on the nervous tracts and nuclei involved in pain processing, may be advanced to explain this occurrence.

Stroke is frequently followed by electrocardiographic (ECG) changes. The aim of the present study was to evaluate the global incidence of these changes after ischemic or hemorrhagic strokes, but it focused on cardiac arrhythmias. In ischemic strokes, these were correlated with the side of the lesion(s). The study was retrospective, and 450 patients (out of 971 examined) were entered in the study based on the following inclusion criteria: (1) "completed" stroke (352 ischemic and 98 hemorrhagic), (2) ECG on admission, and (3) at least 1 previous ECG. We also examined 71 patients with carotid or vertebro-basilar transient ischemic attacks (TIA). As controls, 71 patients suffering from nonvascular neurologic diseases were examined. The results were as follows: In stroke patients, new-onset ECG abnormalities were present in 75% of cases, and cardiac arrhythmias accounted for 28.7%. Cardiac arrhythmias were observed in 21.9% of ischemic strokes (26.8% of patients with right hemispheric lesion and 14.3% of those with left hemispheric lesion) and in 20.4% of hemorrhagic strokes, with the highest incidence in subarachnoid hemorrhage (37.5%). The mechanisms of genesis of cardiac arrhythmias occurring after stroke are still not well understood. Some evidence supports the hypothesis of a "cardiac cortical rhythm control site," probably lying within the middle cerebral artery territory. Vascular damage to this area could be followed by cardiac arrhythmias related to a disinhibition of the right insular cortex with resulting increased sympathetic tone. Our data seem to indicate that ischemic involvement of the right hemisphere induces a higher risk for cardiac arrhythmia occurrence than that of the left hemisphere.

Objectives: To evaluate the efficacy of gabapentin in the treatment of hemifacial spasm., Material and Methods: Twenty-three patients with hemifacial spasm not suitable for surgery or therapy with botulinum toxin were treated with gabapentin. The main efficacy parameter was the percentage of spasm reduction., Results: A clinically significant reduction of spasms was obtained by 16 patients., Conclusion: Gabapentin was effective and safe in reducing hemifacial spasm in 16 out 23 (69.6%) patients.

Auditory event-related potentials (AERPs) were recorded during an auditory oddball paradigm in 108 epileptics and in 32 healthy controls. P300 latency varied in relationship with age only in controls. Symptomatic epileptics had significantly prolonged P300 mean latency compared to those without detectable brain lesion(s) on MR scan. Moreover, these latter patients were compared on the basis of epilepsy duration, type of seizure, seizure frequency and antiepileptic treatment; the application of a multiple regression model showed a significant relationship between P300 latency prolongation and epilepsy duration, seizure frequency and polytherapy.

A series of 88 patients with completed stroke was selected in which heralding, early and late seizures were distinguished according to their onset. Relationships between CT scan and clinical EEG data are discussed with particular emphasis on possible mechanisms of seizures. Thus, small emboli or haemodynamic factors are stressed in the cases of heralding seizures, metabolic disturbances with cytotoxic effects in early seizures and chronic epileptic focus in late seizures.