196,609 research outputs found
Isoprene and Rubber. XIX. The Molecular Size of Rubber and Balata
No full textAbstract
It was shown in the preceding work that a very dilute solution of balata in an organic solvent contains macromolecules in solution and not micelles. The same is true of rubber. On the basis of these findings it is possible to calculate the molecular weight of rubber and balata from viscosity measurements by means of the formula developed in a previous work: M=η8p/c. Km. The supposition is made that the molecules of rubber and balata have the form of threads and double threads, respectively. Also it is necessary to determine the constant KKm, and this may be calculated in the case of low molecular products, where the average molecular weight can be determined as well as the viscosity of the solutions. Such semi-colloidal decomposition products were obtained by heating rubber or gutta-percha in either tetralin or xylene. As shown by the following table the four samples thus obtained gave the constant: 0.3×10−3,5</jats:p
Silica-scaled chrysophytes from the bog-lake Balata-to, SW Hungary
No full textTwenty-six species of silica-scaled chrysophytes representing the genera Chrysosphaerella (1 species), Mallomonas (19 species) and Synura (6 species) are reported based on transmission electron microscopy from the springtime flora of the slightly acidic bog-lake Balata-to, a Nature Reserve, situated in Southwest Hungary. Ten of them (Mallomonas alata, M. clavus, M. insignis, M. mangofera, M. oviformis, M. papillosa, M. pillula, M. scalaris, M. transsylvanica and Synura multidentata) are new records for Hungary. Furthermore, two species, M. pillula and M. scalaris are for the first time found in the Carpathian Basin and M. alara f. hualvensis is a new record for the flora of Europe. Dispersal problems are discussed
Isolation and Characterization of Microsatellite Markers for Mimusops balata (Sapotaceae) and Cross-Amplification in Other Mimusops Species
No full textMimusops balata (Sapotaceae) is an endemic tree species from La Réunion and Mauritius. Like many species growing in lowland forests in La Réunion, it has suffered from human disturbances. We developed twelve microsatellite markers for M. balata and tested cross-amplification in five other Mimusops species to have powerful tools for genetic diversity studies. Genotyping peaks were of very low quality for two loci and were consequently abandoned for the genetic diversity analyses. Ten microsatellite loci were tested on 34 individuals of M. balata from two natural populations. The number of alleles per locus ranged from one to seven. The observed and expected heterozygosity levels varied from 0.000 to 0.823, and from 0.000 to 0.812 respectively. Two loci deviated from the Hardy-Weinberg equilibrium. The presence of null alleles was detected for one of these two loci. Nine to ten loci cross-amplified reliably in Mauritian species, for the other three species, four to six loci show successful amplifications. These polymorphic microsatellite markers are now available for population genetic investigations in Mimusops species aiming to establish accurate guidelines for conservation managers
Sustainability certification and hospitality management. An enquiry on the Sardinian coastal hotels’ approach and criticalities towards the EU Ecolabel Certification
No full textThe purpose of this research is to highlight and analyse the main difficulties and critical points experienced by Sardinian coastal hotel managers and their staff when the possibility to obtain an EU
Ecolabel certification is presented to them.
The paper aims to identify some of the main factors that determine the decision of continuing the certification process or to abandon it.
The study uses data collected through a set of interviews carried out with hotel owners and managers. The selected hotels took part in a certification support programme set up by the regional agency for coastal preservation (Conservatoria delle Coste) in late 2013. At the end of the process, out of 30 hotels, five obtained the EU Ecolabel Certification.
The interviews were carried out in presence during the visit of a specialised consultant, which also collected the data related to the main features/critical points of the hotel. The data was used as an
input to measure the distance in terms of points as awarded by the EU Ecolabel score datasheet. The results of this preliminary analysis is then elaborated with statistical methods in order to
determine which are the main critical points and weaknesses experienced by the hotel managers and the rationality underlying the choice of facultative criteria.
Motivation and actual awareness of the benefits of a certification scheme are also analysed.The study evidences that, although structural variables as size and complexity of the hotel physical
structure are important, motivation of management and owners seems to be the main factor to influence the certification process success. Recently built hotels or less complex buildings may have
on average far less difficulties in achieving the Ecolabel certificate while larger hotels require important investments in order to meet the criteria. Such investments are sometimes often not seen
as easily redeemable by the hotel management. This fact, which is also influenced by a low capability of exploiting the certification in terms of visibility and appeal to new customers, reduces the
motivation of the hotel owners to embark in a process deemed expensive, complicated and not useful. On the other side, when the investments are clearly connected to the reduction of costs (e.g. energy saving investments) they are perceived as useful and redeemable, making easier for the company to decide in their favour.
The study is based on very detailed data and on a sample that is representative both geographically and qualitatively of the hotel sector of Sardinia. The current shift of the visitors’ preferences towards
more sustainable destinations as experienced by tourism operators and evidenced by researchers, brings under light the subject of viable certification schemes and the need to create a managing culture that integrates environmental strategies and market results
Spatial and temporal variability of Mediterranean macroalgal coralligenous assemblages in relation to habitat and substrate inclination
No full text
Traditional Products and Longevity in Sardinia. A Preliminary Study for a Certification Strategy
No full textStudies carried out by medical researchers and demographers have discovered the existence of areas of the world, the so-called Blue Zones, which
show a very high concentration of long-lived people, the first one being the Sardinian Blue Zone, identified by a team of researchers led by M. Poulain and
G.M. Pes and located in the Nuoro and Ogliastra provinces. The same areas are also home to several traditional products that not only are very popular, as they also showcase some characteristics that may be linked to longevity. In order to successfully market these products, whose diffusion is limited by several
factors and with the aim to preserve the products’ quality and authenticity, a study on the possibility of creating quality brands that could enhance the diffusion of the local products of Ogliastra and valorise the positive effects they have on health, must be carried out. After a revision of the state of the art, the paper analyses the results of an enquiry carried out on pupils of the primary and junior high schools in Ogliastra and their families, aimed at assessing the persistence (and thus the level of perceived authenticity) of traditional products within the households of Ogliastra. Moreover, the paper focuses on the efforts made until now to create a certification system for local products of Ogliastra with a critical approach, aimed at evidencing the main challenges and providing a framework for a harmonisation of the subject that could provide a base for a regional strategy of development
The Gray Zone: relationships between habitat loss and marine diversity and their applications in conservation
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