3,617 research outputs found
Gamification and Coding to Engage Primary School Students in Learning Mathematics: A Case Study
This paper describes a pilot educational project made in a Primary School in Italy (Scuola Primaria Alessandro Manzoni at Mulazzano, Milan) implemented in 2016 and 2017. The project was born from a specific request: the school aimed at improving the results achieved by students aged 7 during the National Tests for Mathematics since they registered performances lower than the National Average. In this context, we supported teachers providing information tools and methods to improve performances. Our aim was to develop new game-oriented approaches to problem-solving, mixing our different experiences and competences (organization design, information technologies, psychology). We provided a broader spectrum of parameters tools and keys to understand how to achieve an inclusive approach personalized on students, involving them and their teachers in the project. This cooperative approach allowed us to collect interesting observations about learning styles, pointing out the negative impact that standardized processes and instruments can have on self-esteem and consequently on the performance of pupils. We argue that addressing pupils in considering mathematics as continuous research and development can increase their performances in National Tests execution. Children free to realize their own experiments and observations dramatically improve their involvement and curiosity about Mathematics
Putative Microbial Population Shifts Attributable to Nasal Administration of Streptococcus salivarius 24SMBc and Streptococcus oralis 89a
Changes in bacterial composition of nasal microbiota may alter the host\u2019s susceptibility to several infectious and allergic diseases such as chronic rhinosinusitis and allergic rhinitis. The aim of this study was to evaluate the effects of 1-week administration of a probiotic product, composed by a combination of Streptococcus salivarius 24SMBc and Streptococcus oralis 89a, on the nostril microbiota. Differences in the nasal microbiota composition were investigated by using a next-generation sequencing approach. A strong and significant decrease in Staphylococcus aureus abundance was detected immediately after the bacterial administration. Moreover, comparing the microbial networks of nostril microbiota before and 1 month after the end of treatment, we detected an increase in the total number of both bacterial nodes and microbial correlations, with particular regard to the beneficial ones. Furthermore, a less abundance of microbial genera commonly associated to potential harmful bacteria has been observed. These results suggest a potential ability of S. salivarius 24SMBc and S. oralis 89a to regulate and reorganize the nasal microbiota composition, possibly favoring those microorganisms that may be able to limit the overgrowth of potential pathogens
Modulation of opportunistic species Corynebacterium diphtheriae, Haemophilus parainfluenzae, Moraxella catarrhalis, Prevotella denticola, Prevotella melaninogenica, Rothia dentocariosa, Staphylococcus aureus and Streptococcus pseudopneumoniae by intranasal administration of Streptococcus salivarius 24SMBc and Streptococcus oralis 89a combination in healthy subjects
\u2013 OBJECTIVE: Probiotics S. salivarius 24SMBc and S. oralis 89a comprised in the nasal spray Rinogermina are known to exert inhibition of harmful pathogens and ameliorate the outcome of patients with chronic upper airways infections. In this study, for the first time, the effect of this formulation on the modulation of the microflora of healthy subjects was evaluated, with particular interest on pathobionts and pathogens present. PATIENTS AND METHODS: Metagenomic identification and quantification of bacterial abundances in healthy subjects were carried out by means of Ion Torrent Personal Machine. In particular, nasal swabs were sampled one, two and four weeks after seven days of treatment with Rinogermina. RESULTS: The modulation of the abundance of pathobionts and pathogenic species (i.e., Corynebacterium diphtheriae, Haemophilus parainfluenzae, Moraxella catarrhalis, Prevotella denticola, Prevotella melaninogenica, Rothia dentocariosa, Staphylococcus aureus and Streptococcus pseudopneumoniae) was characterized and a significant temporary decrease in their presence was identified. CONCLUSIONS: The beneficial effects of S. salivarius 24SMBc and S. oralis 89a nasal intake was assessed but seemed to be restricted in specific temporal windows. Thus it would be interesting to evaluate also this positive impact of longer administration of this probiotic formulation
Dynamical charge density fluctuations pervading the phase diagram of a Cu-based high-Tc superconductor
Charge density waves are a common occurrence in all families of high critical
temperature superconducting cuprates. Although consistently observed in the
underdoped region of the phase diagram and at relatively low temperatures, it
is still unclear to what extent they influence the unusual properties of these
systems. Using resonant x-ray scattering we carefully determined the
temperature dependence of charge density modulations in
(Y,Nd)BaCuO for three doping levels. We discovered
short-range dynamical charge density fluctuations besides the previously known
quasi-critical charge density waves. They persist up to well above the
pseudogap temperature T*, are characterized by energies of few meV and pervade
a large area of the phase diagram, so that they can play a key role in shaping
the peculiar normal-state properties of cuprates.Comment: 34 pages, 4 figures, 11 supplementary figure
Automotive leathers – evaluating the performance limits (part II)
Content:
Consumers perceive leather as a durable and natural product. To support this positive image, car manufacturers have set demanding performance profiles addressing wear, emissions and sustainable
manufacture. Poor performance of auto leather becomes visible as the polymeric finishing coat wears off or cracks over time. Therefore ageing property is seen as a representative key performance parameter and is determined by checking how flexible and strong a polymer coating remains after leather has been exposed to light, heat and humidity for a given time. Ageing of leather is complex to determine and depends on various parameters and requires a full system approach .
In a first step different type of crusts (wet-blue, wet-white) were prepared and finished with a standard polyurethane coating. It turned out that the selection of the right fat liquors and tanning agents as well as the presence of vegetable tannins play an important role. On top of this the effective use of proper protective chemicals like anti-oxidants is needed.
In a second approach the polymer coating itself was studied and optimized with regard to aged flexing and abrasion. Parameters like polymer type, crosslinking, application technology, coating thickness and impact of additives were investigated and tested when applied on the best crust leathers selected from part 1 of this work. Results show that not only is the right selection of polymers critical but also so is the way the coat is being applied . Furthermore coating thickness greatly defines wear (abrasion), lightfastness and ageing properties. Additives like dulling agents, levelers, feel agents, waxes ,fillers although needed can weaken the integrity of the polymer matrix and consequently reduce physical and chemical fastness properties. This may also apply to a certain extent to protective additives such as anti-oxidants and UV stabilizers, but when used properly their advantages outweigh the potential disadvantages. As to application, special emphasis is given to transfer coating technology which can provide advantages in application and quality consistency but also with regards to fastness properties such as wear and ageing.
Take-Away:
- crust leather has a critical impact on performance of finishing coat of automotive leathers and requires careful selction of products and use of protective chemical
- polymer selection and use of protective chemical play an important role for achieving good aged flexing performance
- type of application of finishing coat on auto leather further determines the performance of coatin
Probiotics Streptococcus salivarius 24SMB and Streptococcus oralis 89a interfere with biofilm formation of pathogens of the upper respiratory tract
Background: Infections of the ears, paranasal sinuses, nose and throat are very common and represent a serious issue for the healthcare system. Bacterial biofilms have been linked to upper respiratory tract infections and antibiotic resistance, raising serious concerns regarding the therapeutic management of such infections. In this context, novel strategies able to fight biofilms may be therapeutically beneficial and offer a valid alternative to conventional antimicrobials. Biofilms consist of mixed microbial communities, which interact with other species in the surroundings and communicate through signaling molecules. These interactions may result in antagonistic effects, which can be exploited in the fight against infections in a sort of "bacteria therapy". Streptococcus salivarius and Streptococcus oralis are α-hemolytic streptococci isolated from the human pharynx of healthy individuals. Several studies on otitis-prone children demonstrated that their intranasal administration is safe and well tolerated and is able to reduce the risk of acute otitis media. The aim of this research is to assess S. salivarius 24SMB and S. oralis 89a for the ability to interfere with biofilm of typical upper respiratory tract pathogens. Methods: To investigate if soluble substances secreted by the two streptococci could inhibit biofilm development of the selected pathogenic strains, co-cultures were performed with the use of transwell inserts. Mixed-species biofilms were also produced, in order to evaluate if the inhibition of biofilm formation might require direct contact. Biofilm production was investigated by means of a spectrophotometric assay and by confocal laser scanning microscopy. Results: We observed that S. salivarius 24SMB and S. oralis 89a are able to inhibit the biofilm formation capacity of selected pathogens and even to disperse their pre-formed biofilms. Diffusible molecules secreted by the two streptococci and lowered pH of the medium revealed to be implied in the mechanisms of anti-biofilm activity. Conclusions: S. salivarius 24SMB and S. oralis 89a possess desirable characteristics as probiotic for the treatment and prevention of infections of the upper airways. However, the nature of the inhibition appear to be multifactorial and additional studies are required to get further insights
Comparative evaluation of synergy of combinations of \u3b2-lactams with fluoroquinolones or macrolides in Streptococcus pneumoniae
OBJECTIVES: Streptococcus pneumoniae has shown a great ability to develop
efficacious mechanisms of resistance to the main drugs for the treatment of
pneumonia, such as \u3b2-lactams, macrolides and fluoroquinolones. The present study
aimed to compare the antipneumococcal activity of combinations of respiratory
fluoroquinolones with cephalosporins (either parenteral or oral) or protected
penicillin versus the standard combinations (i.e. a macrolide with a protected
penicillin or cephalosporin) against 100 isolates with different susceptibilities
to macrolides and/or penicillin.
METHODS: Chequerboard assays for all isolates and time-kill curves for nine
isolates with different patterns of susceptibility were performed. Synergy
between antibiotics at serum peak concentrations was also determined.
RESULTS: The combination of levofloxacin with ceftriaxone produced the highest
rate of synergy (54/100), mainly against macrolide-resistant strains (22/30).
Antagonism was not observed for any tested combination apart from clarithromycin
with amoxicillin/clavulanic acid (22/100 isolates). Although the killing
activities of all antibiotics improved when they were tested in combination,
synergy was observed only for some combinations after 12 and/or 24 h. Serum
concentrations were effective in inhibiting the growth of the tested strains.
CONCLUSIONS: Combinations of levofloxacin with parenteral cephalosporins were the
most active among all the tested combinations, while antagonism occurred when
clarithromycin and amoxicillin/clavulanic acid were tested
Probiotics Streptococcus salivarius 24SMB and Streptococcus oralis 89a interfere with biofilm formation of pathogens of the upper respiratory tract
Background: Infections of the ears, paranasal sinuses, nose and throat are very common and represent a serious issue for the healthcare system. Bacterial biofilms have been linked to upper respiratory tract infections and antibiotic resistance, raising serious concerns regarding the therapeutic management of such infections. In this context, novel strategies able to fight biofilms may be therapeutically beneficial and offer a valid alternative to conventional antimicrobials. Biofilms consist of mixed microbial communities, which interact with other species in the surroundings and communicate through signaling molecules. These interactions may result in antagonistic effects, which can be exploited in the fight against infections in a sort of "bacteria therapy". Streptococcus salivarius and Streptococcus oralis are \u3b1-hemolytic streptococci isolated from the human pharynx of healthy individuals. Several studies on otitis-prone children demonstrated that their intranasal administration is safe and well tolerated and is able to reduce the risk of acute otitis media. The aim of this research is to assess S. salivarius 24SMB and S. oralis 89a for the ability to interfere with biofilm of typical upper respiratory tract pathogens. Methods: To investigate if soluble substances secreted by the two streptococci could inhibit biofilm development of the selected pathogenic strains, co-cultures were performed with the use of transwell inserts. Mixed-species biofilms were also produced, in order to evaluate if the inhibition of biofilm formation might require direct contact. Biofilm production was investigated by means of a spectrophotometric assay and by confocal laser scanning microscopy. Results: We observed that S. salivarius 24SMB and S. oralis 89a are able to inhibit the biofilm formation capacity of selected pathogens and even to disperse their pre-formed biofilms. Diffusible molecules secreted by the two streptococci and lowered pH of the medium revealed to be implied in the mechanisms of anti-biofilm activity. Conclusions: S. salivarius 24SMB and S. oralis 89a possess desirable characteristics as probiotic for the treatment and prevention of infections of the upper airways. However, the nature of the inhibition appear to be multifactorial and additional studies are required to get further insights
The role of clothing in thermal comfort: how people dress in a temperate and humid climate in Brazil
Abstract Thermal insulation from clothing is one of the most important input variables used to predict the thermal comfort of a building's occupants. This paper investigates the clothing pattern in buildings with different configurations located in a temperate and humid climate in Brazil. Occupants of two kinds of buildings (three offices and two university classrooms) assessed their thermal environment through 'right-here-right-now' questionnaires, while at the same time indoor climatic measurements were carried out in situ (air temperature and radiant temperature, air speed and humidity). A total of 5,036 votes from 1,161 occupants were collected. Results suggest that the clothing values adopted by occupants inside buildings were influenced by: 1) climate and seasons of the year; 2) different configurations and indoor thermal conditions; and 3) occupants' age and gender. Significant intergenerational and gender differences were found, which might be explained by differences in metabolic rates and fashion. The results also indicate that there is a great opportunity to exceed the clothing interval of the thermal comfort zones proposed by international standards such as ASHRAE 55 (2013) - 0.5 to 1.0 clo - and thereby save energy from cooling and heating systems, without compromising the occupants' indoor thermal comfort
New Records Of Bird Species From Ilha Grande, State Of Rio De Janeiro, Southeastern Brazil
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)We add 32 new records of species to the existing checklist of birds of the coastal island of Ilha Grande, state of Rio de Janeiro, Brazil. Notably, seven of these species are endemic to the Atlantic Forest. Sporophila falcirostris is globally Vulnerable and Haematopus palliatus is Near Threatened in Brazil. We also report the second record of Agelaioides badius from Rio de Janeiro state. We also compare our species list with lists of birds of Ilhabela and Anchieta islands. While some of the newly recorded species are probably non-resident to Ilha Grande or represent range expansions, most species occur in Rio de Janeiro throughout the year. Thus, our records may be a consequence of the surveying new sites on the island but also recent colonization. Our study increases the number of bird species known to occur on Ilha Grande from 222 to 254, which is one-third of the species reported from Rio de Janeiro state. We recorded 13 species threatened by extinction at regional, national or global levels. © 2016 Check List and Authors.126CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico305798/2014-6, FAPERJ, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de JaneiroE-26/102.837868/2012, FAPERJ, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de JaneiroUERJ, Universidade do Estado do Rio de JaneiroConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
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