The ovarian ecophysiology of mature female camels under extremely arid conditions was studied by investigating 288 nonpregnant genital tracts. The proportions of females with inactive ovaries were 31.25%, 25%, and 50% during the winter, the spring, and the summer, respectively. The mean number of active follicular structures per ovary and the proportion of females with active ovaries were significantly higher (P < 0.05) during the winter (0.75 ± 0.36, 68.75%) and spring (0.7 ± 0.41, 75%) than during the summer (0.33 ± 0.28, 50%). Furthermore, the proportion of active ovaries that presented active corpora lutea was also significantly higher (P < 0.05) during the spring season (45.83%). These physiological ovarian changes significantly influenced the ovarian weight and mass. The proportion of females with active ovaries was significantly correlated with the body condition score (BCS, P < 0.05). The results of this work indicate that the ovarian activity of Sahrawi female camels that live in extremely arid conditions in Algeria is high during the cold and rainy months (December–February) and moderately high in the spring (March–May), but drops significantly in the summer without stopping entirely. The favorable reproductive period for female camels corresponds to optimal seasonal food availability in pasture and a marked improvement in BCS.
We present a novel control method achieving stable multiple-degrees-of-freedom electroacoustic resonators. Such broadband absorbers, composed of a feedback-controlled electrodynamic loudspeaker, have many practical applications to real-world acoustic engineering problems, such as low-frequency industrial noise reduction in the range of [20 - 200 Hz]. The proposed control architecture combines a conventional microphone-based feedback control loop and a current-driven direct acoustic impedance control scheme, proven to perform optimally in recently reported acoustic impedance synthesis methods. This paper presents a methodology for designing the transfer function to be implemented in the controller, after specifying a target multiple-degree-of-freedom acoustic resonator impedance. Numerical simulations presents the expected acoustic performances, confirmed by experimental assessments in an impedance tube.
In this paper, the dynamics of a dc-ac resonant self-oscillating LC series inverter is analyzed from the point of view of piecewise smooth dynamical systems. Our system is defined by two symmetric configurations and its bifurcation analysis can be given in a one dimensional param- eter space, thus finding a non smooth transition between two strongly different dynamics. The oscillating regime, which is the one useful for applications and involves a repetitive switching action between those configurations, is given whenever their open loop equilibrium is a fo- cus. Otherwise, the only attractors are equilibrium points of node type whose stable manifolds preclude the appearance of oscillations.
This paper deals with new capturing technologies to safeguard and transmit endangered intangible cultural heritage including Corsican multipart singing technique. The described work, part of the European FP7 i-Treasures project, aims at increasing our knowledge on rare singing techniques. This paper includes (i) a presentation of our light hyper-helmet with 5 non-invasive sensors (microphone, camera, ultrasound sensor, piezoelectric sensor, electroglottograph), (ii) the data acquisition process and software modules for visualization and data analysis, (iii) a case study on acoustic analysis of voice quality for the UNESCO labelled traditional Cantu in Paghjella. We have identified specific features for this singing style, such as changes in vocal quality, especially concerning the energy in the speaking and singing formant frequency region, a nasal vibration that seems to occur during singing, as well as laryngeal mechanism characteristics. These capturing and analysis technologies will contribute to define relevant features for a future educational platform.
Most commonly, element based prediction techniques, such as the Finite Element Method and the Boundary Element Method are used to solve steady state dynamic problems. These procedures divide the problem domain or its boundary into a large number of small elements in which the dynamic fields are described using simple, most often polynomial, shape functions. When frequency increases and the wavelengths shorten, the mesh needs to be refined to obtain accurate solutions, due to interpolation and pollution errors. The sizes of the system matrices, and consequently the computational load, increase accordingly. From a certain frequency on, the models become computationally too demanding, such that the element based techniques are limited for solution at lower frequencies. The Wave Based Method is also a deterministic numerical prediction technique to solve steady-state dynamic problems, developed to overcome some of these frequency limitations imposed by the use of small elements and simple interpolation functions. The method belongs to the family of indirect Trefftz approaches and uses a weighted sum of so-called wave functions, which are exact solutions of the governing partial differential equations, to approximate the dynamic field variables. Contrarily to element based techniques, the problem domain is subdivided into a small number of large, convex subdomains. By minimising the errors on boundary and interface conditions, a system of equations is obtained which can be solved for the unknown contribution factors of each wave function. As a result, the system of equations is smaller and a higher convergence rate and lower computational loads are obtained as compared to conventional prediction techniques. On the other hand, the method shows its full efficiency for moderately complex geometries. Various enhancements have been made to the method through the years, in order to extend the applicability of the Wave Based Method. This paper aims to give an overview of the current state of the art of the Wave Based Method, its modelling procedure, application areas and extensions to the method such as hybrid and multi-level approaches.
The paper aims to present a research, recently ended, that has been carried out inside the European Program "Culture 2000" between Italian, French and Polish partners, under the co-ordination of the Polytechnic of Turin. The project springs from the belief, shared by all research units, that the architecture and the landscape in rural areas constitute fundamental and inimitable components of the culture and the identity of locations in all Countries participating in the project. The project, entitled "Rural architecture and landscape between tradition and innovation" had the following main objectives: - to identify the common elements and the technical and cultural diversities that characterise the rural building heritage of every country and the problems related to its sustainable rehabilitation, with a view to developing common strategies for counteracting the risks of abandonment of rural territories and the unchecked reuse of the building legacy; - to develop strategies that aim for sustainable rehabilitation and valorisation of the rural building heritage, by studying the methods for rehabilitating the landscape and the man-made structures, while respecting the existing buildings, local cultures, and the economic circumstances of each country, and aiming also for widespread sharing of such objectives; - to identify and advance the methodological structures and technical procedures to support the rehabilitation activity, applicable to the various countries. The main results of the project are: - the publication of a book and the edition of a web site, in order to set up a data bank that can be progressively implemented. - the dissemination of a "best practices code," not purely technical but also with a cultural and economic framework for the sustainable rehabilitation and valorisation of the landscape and rural architecture. - an itinerant exhibition that has been set up in each of the participating countries and it is available to be eventually shown at other locations
