The influence of landslide shape and continental shelf on landslide generated tsunamis along a plane beach

This work proposes an advancement in analytical modelling of landslide tsunamis propagating along a plane beach. It is divided into two parts. In the first one, the analytical two-horizontal-dimension model of Sammarco and Renzi (2008) for tsunamis generated by a Gaussian-shaped landslide on a plane beach is revised and extended to realistic landslide shapes. The influence of finiteness and shape of the slide on the propagating waves is investigated and discussed. In the second part, a new model of landslide tsunamis propagating along a semi-plane beach is devised to analyse the role of the continental platform in attenuating the wave amplitude along the shoreline. With these parameters taken into account, the fit with available experimental data is enhanced and the model completed

Validation of a microwave radar system for the monitoring of locomotor activity in mice

BACKGROUND: The general or spontaneous motor activity of animals is a useful parameter in chronobiology. Modified motion detectors can be used to monitor locomotor activity rhythms. We modified a commercial microwave-based detection device and validated the device by recording circadian and ultradian rhythms. METHODS: Movements were detected by microwave radar based on the Doppler effect. The equipment was designed to detect and record simultaneously 12 animals in separate cages. Radars were positioned at the bottom of aluminium bulkheads. Animal cages were positioned above the bulkheads. The radars were connected to a computer through a digital I/O board. RESULTS: The apparatus was evaluated by several tests. The first test showed the ability of the apparatus to detect the exact frequency of the standard moving object. The second test demonstrated the stability over time of the sensitivity of the radars. The third was performed by simultaneous observations of video-recording of a mouse and radar signals. We found that the radars are particularly sensitive to activities that involve a displacement of the whole body, as compared to movement of only a part of the body. In the fourth test, we recorded the locomotor activity of Balb/c mice. The results were in agreement with published studies. CONCLUSION: Radar detectors can provide automatic monitoring of an animal's locomotor activity in its home cage without perturbing the pattern of its normal behaviour or initiating the spurt of exploration occasioned by transfer to a novel environment. Recording inside breeding cages enables long-term studies with uninterrupted monitoring. The use of electromagnetic waves allows contactless detection and freedom from interference of external stimuli

Circadian and ultradian rhythms in locomotory activity of inbred strains of mice

In this study we recorded locomotor activity of two inbred of mice (B6 and C) in two photoperiod conditions (LD 12:12 and DD) to characterize behavioural parameters of the endogenous rhythms of locomotor activity with particular attention to the ultradian rhythms. Literature reveals discordant data for these parameters, both for animals belonging to the same strain and to those in the same laboratory or monitored in the same conditions. Our results show that C strain has a shorter and unstable endogenous circadian period, while B6 strain has a longer and stable endogenous rhythm. In our study, B6 showed a longer and stable period than C, so we can confirm the presence of a genetic component underlying this trait. Ultradian rhythms are expressed independently of either the photoperiod or the circadian rhythm. There are no strain-dependent differences in the periods of 12, 8 and 4 h. The situation was different for the length of the ultradian period in the range 1-8 h and for the weighted power in the ranges 480-300 and 300-100 min, for which there were differences between photoperiods and strains

Recent advances on the mechanisms regulating cholangiocyte proliferation and the significance of the neuroendocrine regulation of cholangiocyte pathophysiology

Cholangiocytes are epithelial cells lining the biliary epithelium. Cholangiocytes play several key roles in the modification of ductal bile and are also the target cells in chronic cholestatic liver diseases (i.e., cholangiopathies) such as PSC, PBC, polycystic liver disease (PCLD) and cholangiocarcinoma (CCA). During these pathologies, cholangiocytes (which in normal condition are in a quiescent state) begin to proliferate acquiring phenotypes of neuroendocrine cells, and start secreting different cytokines, growth factors, neuropeptides, and hormones to modulate cholangiocytes proliferation and interaction with the surrounding environment, trying to reestablish the balance between proliferation/loss of cholangiocytes for the maintenance of biliary homeostasis. The purpose of this review is to summarize the recent findings on the mechanisms regulating cholangiocyte proliferation and the significance of the neuroendocrine regulation of cholangiocyte pathophysiology. To clarify the mechanisms of action of these factors we will provide new potential strategies for the management of chronic liver diseases

An infra-red beam device for the study of the motor activity rhythms on groundwater mysidacea

ItL’attività motoria o locomotoria è un parametro utile per comprendere il funzionamento degli orologi biologici. Gli animali cavernicoli rappresentano un eccellente modello per gli studi cronobiologici oltre che per comprendere l’evoluzione e l’adattamento alla vita sotterranea.Le ricerche in ambito cronobiologico richiedono spesso monitoraggi molto lunghi per i quali è necessario ricorrere all’utilizzo di sistemi automatici. L’obbiettivo primario del presente lavoro consiste nel testare, con animali vivi, il prototipo di un apparato elettronico ad infrarossi appositamente costruito per il monitoraggio dell’attività motoria di animali acquatici di piccole dimensioni. La specie utilizzata in questa ricerca è un misidaceo, Spelaeomysis bottazzii Caroli 1924, proveniente dalla Grotta di San Isidoro (Nardò – LE, Pu/507). La registrazione dell’attività motoria ha riguardato animali mantenuti singolarmente in celle di coltura da 30 ml (5x3x2 cm). L’attività motoria è stata rilevata con un sistema di 9 barriere a luce infrorossa (ciascuna barriera composta da una sorgente e un sensore alle sue estremità). I sensori erano collegati ad un circuito elettronico che inviava i segnali ad un personal computer che a sua volta li archiviava. È stata eseguita un’analisi qualitativa dell’attività motoria dei singoli animali, rappresentandola graficamente per mezzo di attogrammi. Inoltre è stata eseguita un’ analisi quantitativa esplorativa di questi primi dati sull’attività motoria dei misidacei. A tal fine tutte le serie temporali sono state analizzate applicando la trasformata discreta di Fourier (DFT). Sono state eseguite registrazioni per un totale di 20 giorni, 24 ore su 24 (12 gg il primo animale, 4 gg il secondo ed il terzo animale). Durante tale periodo non sono stati riportati problemi di eccessivo surriscaldamento dell’acqua, la componente elettronica (in particolare quella optoelettronica) si è rivelata altamente sensibile e non ha mostrato segni di usura dovuti alle condizioni di utilizzo. Gli animali sono rimasti vivi sino alla conclusione dell’esperimento. L’ispezione visiva degli attogrammi ha evidenziato una continua e costante rilevazione dell’attività locomotoria dei misidacei. L’analisi cronobiologia si è concentrata sul calcolo della lunghezza del periodo circadiano in free-running, trovando un periodo medio di 24,7 h. La DFT ha rilevato la presenza di un picco a circa 24 h in tutte le registrazioni esaminate, evidenziando inoltre una bassa potenza spettrale.Oltre al ritmo circadiano, in tutte le registrazioni ricorrevano ritmi ultradiani nell’attività motoria. Nonostante le repliche sperimentali non siano sufficienti a giustificare conclusioni circa i ritmi dell’attività motoria di Speleomysis bottazzii, i ritmi individuati e la loro differente intensità, testimoniano di un incoraggiante funzionamento dell’apparato progettato.EnLocomotor activity and cave animals represent excellent models for study of biological clocks. An infrared-based detection device for recording motor activity has been tested on the stigobitic Spelaeomysis bottazzii Caroli, 1924 (Crustacea: Mysidacea). The individual activity of mysidaceans was monitored in continuous darkness. Data were analyzed by a DFT and chi-square periodogram. The apparatus was able to read rhythms of activity, in particular a lower circadian rhythm and some ultradian ones

A second-order theory for wave energy converters with curved geometry

A second-order theory for wave energy converters with curved geometr

The development of postural strategies in children: a factorial design study

BACKGROUND: The present study investigates balance control mechanisms, their variations with the absence of visual input, and their development in children from 7 to 11 years old, in order to provide insights on the development of balance control in the pediatric population. METHODS: Posturographic data were recorded during 60 s trials administered on a sample population of 148 primary school children while stepping and then quietly standing on a force plate in two different vision conditions: eyes closed and eyes open. The extraction of posturographic parameters on the quiet standing phase of the experiment was preceded by the implementation of an algorithm to identify the settling time after stepping on the force plate. The effect of different conditions on posturographic parameters was tested with a two-way ANOVA (Age × Vision), and the corresponding eyes-closed/eyes-open (Romberg) Ratios underwent a one-way ANOVA. RESULTS: Several posturographic measures were found to be sensitive to testing condition (eyes closed vs. eyes open) and some of them to age and anthropometric parameters. The latter relationship did not explain all the data variability with age. An evident modification of postural strategy was observed between 7 and 11 years old children. CONCLUSION: Simple measures extracted from posturographic signals resulted sensitive to vision and age: data acquired from force plate made it possible to confirm the hypothesis of the development of postural strategies in children as a more mature selection and re-weighting of proprioceptive inputs to postural control in absence of visual input

Pressures and impacts on structure, functioning and services in marine, terrestrial, and transitional ecosystems

Goal of the special issue - Given this premise, the special issue will gather theoretical, methodological, and applied papers focusing on the assessment of pressures and impacts on structure, functioning and services in marine, terrestrial, and transitional ecosystem

Spatial and temporal variations of nutrients and chlorophyll a in a Mediterranean coastal lagoon: Varano lagoon, Italy

The purpose of this paper is to assess the present status of a Mediterranean lagoon (Varano lagoon, Italy), basing on nutrient and chlorophyll a data. A water sampling in Varano lagoon was performed at 7 fixed stations from February 2004 to July 2005, collecting surface water samples to analyse ammonia, nitrite, nitrate, soluble reactive phosphorus (SRP) and soluble reactive silica (SRSi), chlorophyll a (chl a) and total suspended solids (TSS). Spatial and temporal distributions of chemical and biological parameters in Varano lagoon were examined to accomplish the goal of this study. Statistical tests were used to investigate the correlations between analysed variables and to characterize, from a spatial and temporal point of view, the lagoon in relation to each variable. Ammonia and nitrate did not showed good correlation (P<0.05). SRP was not correlated with any nutrient (only with Chl a, P<0.05). The seasonal distribution show a random pattern for soluble reactive phosphorus with relatively low mean concentrations (0.16 ± 0.03 µM) and a well-defined seasonal pattern for nitrate, with the highest mean value (34.44 ± 10.18 µM) recorded in the wet season (February 2004) and a high spatial variability. The most homogeneous chl a values were observed in both autumn and winter seasons with averages of about 1-1.5 µg . L-1; in contrast, higher mean values (5.50 µg . L-1 ) were recorded in July 2005. The ratio between the dissolved inorganic nitrogen species and SRP (N/P) in Varano lagoon was constantly high and it varied seasonally from about 300:1 during rainy seasons to 60-90:1 during dry seasons. High values of the N/P ratio in autumn and winter were accompanied by an increase in total N implying an input of nitrogen to the system probably associated with rainfall. The high fluctuation in the various chemical parameters in the lagoon during the rainy season suggested that this is the period of large variability, in which environmental processes as marine waters, freshwaters and wastewaters represent inputs that determine the spatial behaviour of the system