3,407 research outputs found
The effects of vegetarian diets on bone health: a literature review
No full textIn these recent years many people are adopting a vegetarian type diet due to the numerous positive health effects of this regimen such as the reduction of the incidence of many chronic disorders like diabetes, hypertension, obesity and cancer. However this diet is quite restrictive and so it could be possible to have a deficiency in some specific nutrients, increasing the risk of osteoporosis and fractures. Although there are conflicting results on the effects of the vegetarian diet on bone health and fracture incidence, it is always recommendable in vegetarian people to have an adequate intake of calcium and vitamin D, through an increased intake of supplements, natural and fortified foods, an adequate intake of protein, fruit, vegetables, as well as vitamin B12. The aim of this literature review is to revise the actual knowledge of the effect of some nutrients and vegetarian diets on bone health. Copyright © 2022 Falchetti, Cavati, Valenti, Mingiano, Cosso, Gennari, Chiodini and Merlotti
Criticalities in applying the Neyman’s optimality in business surveys : a comparison of selected allocation methods
No full textIn finite population sampling, when dealing with negligible sampling fractions (budget
constraints) or when data quality is not satisfactory (e.g. frame lists, auxiliary information,
etc.), a rethinking of Tchuprow’s (1924) optimality concept (later extended by Neyman, 1934)
in stratified sampling is needed. In fact, the need of stratum representativeness from one side
and the optimum allocation from the other are often in conflict. Furthermore, the choice of a
sampling design which is rigorously respectful of the statistical theory is a difficult task in
practice, especially when knowledge barriers and operational constraints are present.
Sometimes a purposive design is the only possibility. This work aims at finding an optimal
allocation method from a population of enterprises. This task is carried out through a
simulation approach which compares different methodologies. We consider, among others,
and together with the popular optimal allocation and its multivariate extension (Bethel’s
algorithm -1989), the ‘Optimum Robust Allocation with Uniform Stratum Threshold –
AORSU’ (Chiodini P.M., Manzi G., Verrecchia F.; 2008) and the ‘dynamic allocation’
(Buisson, 2009). These methods are suitable both for domain analyses and for the
improvement of the estimates, obtained through a proxy of the stratum variability. In general,
AORSU is useful when an ex-ante allocation is possible. On the other hand the dynamic
allocation (i.e. ex-post) is becoming more and more of interest especially when no
information about stratum variability is available. The method relies on an in itinere adjustment process (i.e. an allocation based upon an estimate of the sampling variance of the first sampling data from the strata). For the latter method, even though a number of practical
solutions for the survey list are available (see, e.g., Chiodini P.M., Facchinetti, Manzi G., Nai Ruscone M., Verrecchia F, 2008), the substitution of sampling units to be interviewed, which is routinely performed, is the real practical drawback, especially when organizational problems, related to target shifting, arise. The solution to this is generally not trivial.
Simulations will be carried out on different databases (ASIA - ISTAT; Italian Register of
enterprises - Chamber of Commerce of Milan, Italy
Criticalities in applying the Neyman’s optimality in business surveys : a comparison of selected allocation methods
No full textIn finite population sampling, when dealing with negligible sampling fractions (budget
constraints) or when data quality is not satisfactory (e.g. frame lists, auxiliary information,
etc.), a rethinking of Tchuprow’s (1924) optimality concept (later extended by Neyman, 1934)
in stratified sampling is needed. In fact, the need of stratum representativeness from one side
and the optimum allocation from the other are often in conflict. Furthermore, the choice of a
sampling design which is rigorously respectful of the statistical theory is a difficult task in
practice, especially when knowledge barriers and operational constraints are present.
Sometimes a purposive design is the only possibility. This work aims at finding an optimal
allocation method from a population of enterprises. This task is carried out through a
simulation approach which compares different methodologies. We consider, among others,
and together with the popular optimal allocation and its multivariate extension (Bethel’s
algorithm -1989), the ‘Optimum Robust Allocation with Uniform Stratum Threshold –
AORSU’ (Chiodini P.M., Manzi G., Verrecchia F.; 2008) and the ‘dynamic allocation’
(Buisson, 2009). These methods are suitable both for domain analyses and for the
improvement of the estimates, obtained through a proxy of the stratum variability. In general,
AORSU is useful when an ex-ante allocation is possible. On the other hand the dynamic
allocation (i.e. ex-post) is becoming more and more of interest especially when no
information about stratum variability is available. The method relies on an in itinere adjustment process (i.e. an allocation based upon an estimate of the sampling variance of the first sampling data from the strata). For the latter method, even though a number of practical
solutions for the survey list are available (see, e.g., Chiodini P.M., Facchinetti, Manzi G., Nai Ruscone M., Verrecchia F, 2008), the substitution of sampling units to be interviewed, which is routinely performed, is the real practical drawback, especially when organizational problems, related to target shifting, arise. The solution to this is generally not trivial.
Simulations will be carried out on different databases (ASIA - ISTAT; Italian Register of
enterprises - Chamber of Commerce of Milan, Italy
Persistence of somatostatinergic tone in acromegaly
No full textIt is a matter of debate whether hypothalamic somatostatin (SRIH) secretion in acromegaly is preserved and still regulated by the physiological feedback mechanisms of growth hormone (GH) and insulin-like growth factor I. To gather further information on this, the reproducibility of plasma GH changes induced by growth hormone-releasing hormone (GHRH) administration was evaluated in 15 acromegalic patients. There was a highly significant correlation between the peak/basal ratio (P/B) GH response in the 15 patients administered GHRH on two separate occasions (r = 0.99, p < 0.001). The test was performed also before and after the administration of drugs able to inhibit or stimulate hypothalamic SRIH release, by activating (pyridostigmine) or inhibiting (pirenzepine) cholinergic pathways, respectively. The GHRH-induced GH response (P/B = 2, range 1.1-26.1) was increased significantly by pyridostigmine pretreatment in 30 patients (P/B = 2.6, range 1.3-34.8; p = 0.0045). In nine out of 30 patients an increase of greater than 2 SD of within-subject GHRH variability was observed in response to GHRH plus pyridostigmine when compared to GHRH alone. An inverse correlation (r = -0.37, p < 0.05) was observed between GH response to GHRH alone and after pyridostigmine pretreatment. On the contrary, no change of GHRH-induced GH response was observed in 12 patients after pirenzepine pretreatment (P/B = 1.9, range 1.1-5 and P/B = 2, range 1.3-6 without and after pirenzepine pretreatment, respectively). These data suggest that in acromegaly the somatostatinergic tone does not seem to fluctuate, and that it can be inhibited often by cholinergic pathway activation but not increased further by cholinergic suppression
Criticalities in applying the Neyman's optimality in business surveys : a comparison of selected allocation methods
No full textIn finite population sampling, when dealing with negligible sampling fractions (budget constraints) or when data quality is not
satisfactory (e.g. frame lists, auxiliary information, etc.), a rethinking of Tchuprow’s (1924) optimality concept (later extended by Neyman, 1934) in stratified sampling is needed. In fact, the need of stratum representativeness from one side and the optimum allocation from the other
are often in conflict. Furthermore, the choice of a sampling design which is rigorously respectful of the statistical theory is a difficult task in practice, especially when knowledge barriers and operational constraints are present. Sometimes a purposive design is the only possibility.
This work aims at finding an optimal allocation method from a population of enterprises. This task is carried out through a simulation approach which compares different methodologies. We consider, among others, and together with the popular optimal allocation and its multivariate extension (Bethel’s algorithm -1989), the “Optimum Robust Allocation with Uniform Stratum Threshold - AORSU” (Chiodini P.M.,
Manzi G., Verrecchia F.; 2008) and the “dynamic allocation” (Buisson, 2009). These methods are suitable both for domain analyses and for the improvement of the estimates, obtained through a proxy of the stratum variability. In general, AORSU is useful when an ex-ante allocation is possible. On the other hand the dynamic allocation (i.e. ex-post) is becoming more and more of interest especially when no information about
stratum variability is available. The method relies on an in itinere adjustment process (i.e. an allocation based upon an estimate of the sampling variance of the first sampling data from the strata
CO2/CH4 ratio in fumaroles a powerful tool to detect magma degassing episodes at quiescent volcanoes
No full textLong time series of fumarolic compositions at Campi Flegrei (Italy),
Mammoth Mountain (California), Panarea (Italy) and Nisyros (Greece) show rapid
increases, up to orders of magnitude, of the CO2/CH4 ratio systematically with the
occurrence of volcanic unrest periods. These easily detected anomalies originate with
the arrival of CH4-poor magmatic fluids in the shallower levels of the volcanoes. The
data suggest that volcanoes are characterized by magmatic activity at depth also in
periods of apparent quiescence. The activity is constituted by the pulsing release of large
amount of fluids which either cause unrest periods (seismicity and ground deformation)
or possibly could precede volcanic eruption. This type of volcanic activity can be
monitored trough the classical geophysical techniques together with the systematic
sampling and analysis of fumaroles.In press4.5. Degassamento naturaleJCR Journalreserve
Exact and Approximate Critical Values of Kolmogorov-Smirnov Test for Discrete Random Variables
No full textThere are several authors who have studied the problem of the application of Kolmogorov-
Smirnov test in the case of discrete random variables. Indeed, as defined by its author,
the Kolmogorov-Smirnov test is valid when the distribution function of the universe F(x)
is continuous, and when is not satisfied this assumption the test is no longer applicable
accurately. Kolmogorov and Noether showed that if the distribution of the universe is
discontinuous, the critical values are smaller than or equal to the corresponding values of
the continuous case. The objective of this paper is to present a procedure for determining
the exact critical values of Kolmogorov-Smirnov test for discrete random variables
Analysis of Sustainability Propensity of Bike-Sharing Customers Using Partially Ordered Sets Methodology
No full textThe propensity for sustainability actions and awareness among population might be driven by ad hoc policies. For example, in the transportation framework, the bike is (re)gaining popularity as a mean of transportation both convenient and environmental-prone,and consequently more and more cities around the world are developing bike-sharing systems in urban areas to let their citizens be more ‘green’. Satisfaction for bike-sharing systems could be influenced in general by how the service is managed and by users’ attitudes towards sustainability:if users’ participation in sustainability is high, then the level of satisfaction will increase and the service will result more successful. In this paper we analyze the connection between propensity and orientation towards sustainability and satisfaction for a particular bike-sharing system via Partially Ordered Sets based methodology
An experimental comparison of ROS-compatible stereo visual SLAM methods for planetary rovers
No full textTemperature and pressure gas geoindicators at the Solfatara fumaroles (Campi Flegrei)
No full textLong time series of fluid pressure and temperature within a hydrothermal system feeding the Solfatara fumaroles are investigated here, on the basis of the chemical equilibria within the CO2&ndash;H2O&ndash;H2&ndash;CO gas system. The Pisciarelli fumarole external to Solfatara crater shows an annual cycle of CO contents that indicates the occurrence of shallow secondary processes that mask the deep signals. In contrast, the Bocca Grande and Bocca Nova fumaroles located inside Solfatara crater do not show evidence of secondary processes, and their compositional variations are linked to the temperature&ndash;pressure changes within the hydrothermal system. The agreement between geochemical signals and the ground movements of the area (bradyseismic phenomena) suggests a direct relationship between the pressurization process and the ground uplift. Since 2007, the gas geoindicators have indicated pressurization of the system, which is most probably caused by the arrival of deep gases with high CO2 contents in the shallow parts of the hydrothermal system. This pressurization process causes critical conditions in the hydrothermal system, as highlighted by the increase in the fumarole temperature, the opening of new vents, and the localized seismic activity. If the pressurization process continues with time, it is not possible to rule out the occurrence of phreatic explosions.<br />
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