1,922 research outputs found
Exploring the link between the corporate governance and efficiency of Italian water utilities
The present paper analyzes the linkage between the corporate governance of Italian water utilities (ownership, board size and board composition) and their ef fi ciency measured through data envelopment analysis (DEA). Using a general panel data regression model, we found that board size negatively affects the ef fi ciency of water utilities. Moreover, the presence of directors with political af fi liations or who are/were members of local or national go- vernment negatively affects ef fi ciency, and the presence of directors with a degree on the board has a slight negative effect on productivity. Conversely, other variables (ownership, gender diversity and average age of board members) were found not to affect the ef fi ciency of Italian water utilities. The existence of economies of scale was also confirmed .Este artÃculo analiza la relación entre el gobierno corporativo de los servicios del agua italianos (propiedad, tamaño y composición del consejo) y su e fi ciencia medida a través del análisis envolvente de datos (AED). Usando un modelo general de regresión de datos de panel averiguamos que el tamaño del consejo afecta negativamente la e fi ciencia de los servicios del agua. Además, la presencia de directores con a fi liaciones polÃticas o que son o fueron miembros del gobierno local o nacional afecta negativamente a la e fi ciencia, y la presencia de directores con una carrera universitaria en el consejo tiene un efecto ligeramente negativo sobre la productividad. Inversamente, otras variables (propiedad, diversidad de género y edad media de los miembros del consejo) no afectan a la e fi ciencia de los servicios del agua italianos. La existencia de economÃas de escala también fue con fi rmada
Effects of hip abductor strengthening on musculoskeletal loading in hip dysplasia patients after total hip replacement
Hip dysplasia patients after total hip replacement show worse functional performance compared to primary osteoarthritis patients, and unfortunately there is no research on muscle and joint loads that would help understand rehabilitation effects, motor dysfunctions and failure events. We tested the hypothesis that a higher functional improvement in hip dysplasia patients who received hip abductor strengthening after hip replacement, would result in different gait function and musculoskeletal loads during walking compared to patients who performed standard rehabilitation only. In vivo gait analysis and musculoskeletal modeling were used to analyze the differences in gait parameters and hip and muscle forces during walking between the two groups of patients. We found that, in a functional scenario of very mild abnormalities, the patients who performed muscle strengthening expressed a more physiological force pattern and a generally greater force in the operated limb, although statistically significant in limited portions of the gait cycle, and likely related to a higher gait speed. We conclude that in a low-demand task, the abductor strengthening program does not have a marked effect on hip loads, and further studies on hip dysplasia patients would help clarify the effect of muscle strengthening on loads
New spatial mechanisms for the kinematic analysis of the tibiotalar joint
In virtually unloaded conditions, the tibiotalar (ankle) joint behaves as a single degree-of-freedom system, and two fibres within the calcaneal-fibular and tibio-calcaneal ligaments remain nearly isometric throughout the flexion arc. A relevant theoretical model also showed that three articular surfaces and two ligaments act together as a mechanism to control the passive kinematics. Two equivalent spatial parallel mechanisms were formulated, with ligament fibres assumed isometric and articulating surfaces assumed rigid, either as three sphere-plane contacts, or as a single spherical pair. Predicted and measured motion in three specimens compared fairly well. Important enhancement of this previous work is here presented, with more accurate experimental data, more anatomical model surfaces, and a more robust mathematical model
Functional Evaluation of a Shock Absorbing Insole During Military Training in a Group of Soldiers: A Pilot Study
Abstract
Objective
Soldiers' lower limbs and feet are frequently affected by overload- and overuse-related injuries. In order to prevent or limit the incidence of these injuries, the use of foot orthoses is often recommended. The aim of this study is to assess the effects of shock-absorbing insoles on in-shoe plantar pressure magnitude and distribution in a group of professional infantry soldiers wearing military boots during standard indoor military training.
Methods
Twenty male professional soldiers of the Italian Army (age 35.1 ± 6.1 years; BMI 25.2 ± 2.3 kg/m2) were recruited for this study. Each subject underwent clinical examination to assess possible overuse-related diseases of the lower limb and trunk. Subjects with altered foot morphology according to the Foot Posture Index (FPI) were excluded from this study. Twelve subjects were considered eligible and therefore underwent an indoor training routine comprised of marching, running, jumping inside parallel bars and jumping from different heights. Soldiers repeated the training session twice wearing standard military boots along with two types of insoles: the standard prefabricated insole within the boots (STI), and a special shock-absorbing insole (SAI) featuring an elastic medial arch support. A 99-capacitive sensor insole system was used to record plantar pressure distribution in both feet. Analysis of in-shoe pressure parameters at rearfoot, midfoot and forefoot and in the total foot was performed via a custom-software application developed in MATLAB. Perceived foot comfort (VAS 0–15) was also assessed.
Results
Pressure parameters recorded during walking and running were considered suitable for statistical analysis. In the whole foot region, pressure parameters were 18–22% lower in military boots fitted with the SAI during walking and 14–18% lower during running. SAI resulted in better comfort (+25%) with respect to the prefabricated boot orthotics (median comfort: SAI = 15/15; STI = 12/15; p = 0.0039) both during walking and running.
Conclusions
Shock-absorbing insoles can be an effective solution when fitted inside military boots. The present functional evaluation shows that wearing a prefabricated shock-absorbing insole can provide a significant amelioration of perceived foot comfort and plantar pressure parameters. Further studies are now needed with a larger population and more demanding exercises
Massive Pericardial Effusion in a 14-Year-Old Girl with Mild Fatigue and Neck Pain
Pericardial effusion is rare in pediatric patients and is characterized by a variable clinical presentation. Mild symptoms may be present despite severe effusion. We here report the case of a patient with massive pericardial effusion with mild clinical presentation. Our case points out the need not to exclude this diagnosis in patients with mild general impairment. This clinical suspicion can be lifesaving
Elastic behavior and high pressure-induced phase transition in chabazite: new data from a sample from Nova Scotia
Recently, the high pressure (HP) behavior of a natural chabazite from Vallerano [1] (VALL), and on the synthetic
phases SAPO-34 [1] and ALPO-34 [2], was investigated in the frame of a wider project aimed at understanding
the role of the framework/extraframework content on the compressibility of CHA-type porous materials.
In this work, further structural information is obtained studying the response to HP of another natural chabazite
sample from Nova Scotia (Canada) (NS) (s.g. R-3mR [3]), characterized by a different chemical composition with
respect to VALL. The study was performed by means of in situ synchrotron X-ray powder diffraction (XRPD) and
silicone oil as non-penetrating P-transmitting medium. XRPD experiments were performed in DAC at the BM01
beamline at ESRF (Grenoble, France) with a fixed =0.7355 Ã…. Powder patterns were collected from Pambup to 8.6
GPa and upon decompression. All the features of the Pamb pattern and the unit cell parameters are well recovered
upon P release. Below 2.1 GPa, a and cell parameters slightly decrease and increase respectively with a resulting
volume reduction of 3.6 %. Above 2.1 GPa, a transition to a triclinic P-1 pseudo-rhombohedral phase is observed.
The rhombohedral to triclinic phase transition is accompanied by an abrupt decrease in the unit cell parameters and
in the unit cell volume ( V=-4.0%). Between 2.5 and 5.9 GPa, the triclinic/pseudo-rhombohedral cell parameters
decrease regularly and the unit cell volume variation ( V=-3.0%) indicates a lower compressibility with respect to
that observed before the transition. In the highest P regime (5.9-7.2 GPa), a further slope change, with an increase
in compressibility, is observed. As a whole, V between Pamb and 7.2 GPa is -12.6%. The elastic parameters,
calculated with a second order BM-EoS, are V0 = 826 (1) Ã…3, K0 = 54(3) GPa and V0 = 784(2) Ã…3, K0 = 91(5)
GPa, for the rhombohedral and triclinic phase, respectively.
Preliminary results from Rietveld refinements up to about 1 GPa, suggest that the deformation mechanism acting
in the low-P regime is a cooperative tilting of the tetrahedra belonging to the double 6-ring – resulting in a decrease
of its thickness – accompanied by a simultaneous di-trigonalization of the two 6-rings. A similar mechanism was
previously observed during compression of levyne [4].
The HP-induced cell volume contraction of NS (12.6 %) is higher than that of VALL (10.3%) in the same P range.
This is congruent with the lower content in large extraframework potassium cations of NS, which contribute to
sustain the porous structure in VALL
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