586 research outputs found
Computing Matveev's complexity via crystallization theory: the boundary case
The notion of Gem-Matveev complexity has been introduced within
crystallization theory, as a combinatorial method to estimate Matveev's
complexity of closed 3-manifolds; it yielded upper bounds for interesting
classes of such manifolds. In this paper we extend the definition to the case
of non-empty boundary and prove that for each compact irreducible and
boundary-irreducible 3-manifold it coincides with the modified Heegaard
complexity introduced by Cattabriga, Mulazzani and Vesnin. Moreover, via
Gem-Matveev complexity, we obtain an estimation of Matveev's complexity for all
Seifert 3-manifolds with base and two exceptional fibers and,
therefore, for all torus knot complements.Comment: 27 pages, 14 figure
Analysis of navigation pattern in the sport of rowing
The effect of weather and environmental conditions on sports has been extensively studied over the last few years (Pezzoli et al., 2010). Based upon the studies of Lobozewicz (1981) and of Kay and Vamplew (2002), Pezzoli and Cristofori (2008) have studied the impact of some specific environmental parameters over different sports using a particular impact index divided into five classes. This analysis clearly shows that most of the outdoor sport activities are strongly influenced by the variation of meteorological parameters. However the impact of meteorological conditions on outdoor sport activities has not yet been extensively studied. The aim of this research is to show that an accurate assessment of wind and wave parameters enables decisive improvements in both training and race strategy planning. Furthermore this analysis provide a very innovative working method for the applied sport research. The work has been based on in-situ measurements of both environmental and performance parameters (wind direction, wind velocity, boat speed and stroke rate) made over different classes and in different race conditions during the 2009 FISA World Championship (Poznan, Poland). In particular a detailed environmental analysis was performed by measuring the wind direction, the wind speed and by evaluating the significant wave height and the wave peak period for each class during the semi-final phase and the final phase. It should be noted that, since wind is a key parameter affecting not only the boat speed but also the race strategy, the assessment of the wind velocity and of the wind direction has been made in connection with the boat movement. The comparison between coupled wind-wave data, boat speed and stroke rate evidently demonstrates that only crews that managed the adaption to changing in the environmental conditions from semi-final to final phase of the race, were able to get better results. References Kay, J., & Vamplew, W. (2002) Weather beaten: sport in the British climate. London: Ed. Mainstream Publishing. Lobozewicz, T. (1981) Meteorology in sport. Frankfurt: Ed. Sportverlag. Pezzoli, A,, Moncalero, M., Boscolo, A., Cristofori, E., Giacometto, F., Gastaldi, S., & Vercelli, G. (2010) The meteo-hydrological analysis and the sport performance: which are the connections? The case of the XXI Winter Olympic Games, Vancouver 2010, Journal of Sports Medicine and Physical Fitness, 50: 19-20. Pezzoli, A., & Cristofori, E. (2008) Analisi, previsioni e misure meteorologiche applicate agli sport equestri, in: 10th Congress "New findings in equine practices, Druento: Centro Internazionale del Cavallo Ed., p.38-4
Forests attenuate temperature and air pollution discomfort in montane tourist areas
Forests deliver many ecosystem services, from provisioning to regulating and cultural services. We aimed at demonstrating microclimatic regulation and pollutant removal as especially relevant ecosystem services when considering the tourism vocation of the Alpine regions. A study was realized along an altitudinal gradient (900–1600 m a.s.l.) in Trentino, northern Italy, an area with high touristic presence (ca. 9.3 million overnight stays in summer 2021). Nitrogen dioxide (NO2 , µg m−3 ), ozone (O3 , µg m−3 ) concentrations, air temperature (T, ◦C), and relative humidity (RH, %) were simultaneously measured in three open-field sites (OF) and below-canopy Norway spruce forest stands (FO) during the period 23 May–7 August 2013. The temperature–humidity index (THI) was calculated. We found a distinct mitigating effect of forest on T, with lower maximum (−30.6%) and higher minimum values (+6.3%) in FO than in OF. THI supported a higher comfort sensation in FO than in OF, especially in the central part of the day. NO2 concentrations did not differ between OF and FO; ozone concentrations were lower in FO than OF. This study confirms the role of forests in providing several ecosystem services beneficial for forest users, especially relevant for promoting nature-based tourism in the Alpine regio
Airborne pollen in Alpine sites
Airborne pollen is usually monitored at urban centers, where most people live, to provide information on types and amount of allergenic pollen. Thus, very few aerobiological data are available for remote, mountainous sites. This study aims to characterize the biological quality of the air in an alpine valley in Trentino (North Italy), a region highly interested by the presence of tourists (e.g., 9.3 million overnight stays registered during June - September 2021). Materials and Methods An aerobiological study was carried out during late spring and summer in 2020 and 2021 in Val di Rabbi, an alpine valley located in the Trentino sector of Stelvio National Park. Gravitational Sigma2 samplers were selected for the survey, for their reliability and efficiency (VDI_2119 2013) and easy handling at remote sites (Gottardini et al. 2021), and installed at 2 m above ground level in 5 sites located at altitudes ranging from 700 to 2000 m a.s.l. Sampling surfaces, treated with an adhesive medium, were analyzed by optical microscopy (OM; 400×; Leitz Diaplan) for pollen identification and count (weekly samples); the average daily sedimentation rate (P cm–2 d–1 ) was calculated for the June-August period. In 2021, an active Hirst-type sampler was concurrently installed in one of the five sites (daily samples). Samples were processed and analyzed following conventional techniques and standardized protocols (UNI EN 16868:2019). Results and Discussion In the two study periods, the number of identified pollen taxa ranged from 25 at the highest elevation site (2000 m a.s.l.) to 39 at the lowest elevation (700 m a.s.l.). The proportion of arboreal pollen slightly decreased with the altitude, from 51% to 42%. The three most abundant pollen taxa were pine (Pinus), grasses (Poaceae) and neetle (Urticaceae), even if in different proportion at each site. The only grass and nettle allergenic pollen represented on average the 52% of the total pollen. The pollen season peak for grasses showed a delay of about 4 days every 100 m of elevation (Figure 1). 47 pollen taxa were identified, by active sampling, 10 more than by the passive one. The most abundant pollen taxa detected by active sampling were pine, grasses, and nettle, as for passive sampling, with the last two representing even the 71% of the total. The pollen season peak for grasses was on 22nd June, coherently with the passive sampling results at the same site. Conclusions Our mountain aerobiological study reveals the presence of allergenic pollen even at high altitude, with noteworthy shifts in the pollen season. The surveyed data can be further exploited for studying the plant biodiversity in remote areas, as well as to provide useful information for allergic tourist and hikers. Moreover, passive sampling proved to be a feasible solution for aerobiological studies in remote or orographically complex areas, typically excluded in routine air quality monitoring. References Gottardini et al. (2021). AAQR, Vol. 21, https://doi.org/10.4209/aaqr.210010 VDI_2119 (2013). Ambient air measurements. Sampling of atmospheric particles > 2.5 μm on an acceptor surface using the Sigma-2 passive sampler. Characterization by optical microscopy and calculation of number settling rate and mass concentration. ICS: 13.040.01. Beuth Verlag, Berlin. Germany. Acknowledgements The study was partially financed by Provincia Autonoma di Trento (IT). We are grateful to Mattia Precazzini and Gabriele Canella for the support in field work, and to Maria Cristina Viola for the microscope pollen analysis
Airborne pollen: a potential warning alert for tickborne encephalitis risk
The circulation of tick-borne encephalitis virus (TBEv) depends on population dynamics of host tick and rodents, which in turn depend on nutrient resources. Tree seeds are the main food for rodents, and their fluctuating production is strongly correlated to pollen abundance. Our study aims to fill the gap and investigate whether airborne pollen is directly associated to recorded TBEv human cases in the Alpine biogeographical region. Materials and Methods We focused our study within the province of Trento (northern Italy, 6,000km2, 500,000 inhabitants). The territory is included in the Alpine biogeographical region (EEA Report No 1/2002) and the main forest tree species growing within a 5-km radius from the pollen sampler are represented by hop-hornbeam (Ostrya carpinifolia Scop.), beech (Fagus sylvatica L.), spruce (Picea abies L.), pine (Pinus sylvestris L. and P. nigra J. F. Arnold), downy oak (Quercus pubescens Willd.), manna ash (Fraxinus ornus L.), and hazel (Corylus avellana L.). Airborne pollen concentration has been monitored since 1989 at Fondazione Edmund Mach, in San Michele all’Adige (Latitude 46.19 N, Longitude 11.13 E, 220 m a.s.l.), while TBEv human cases have been recorded since 1992 by the local Public Health Agency. Airborne pollen was sampled by a Hirst-type trap, processed, and analyzed following conventional techniques and standardized protocols (UNI EN 16868:2019). First, we statistically investigated the association between the annual total pollen concentration of the dominant arboreal plant taxa and the annual number of TBEv human cases (1989-2020) with different time lags by univariate linear models. Consequently, we built a full model by considering all significant covariates, we computed all possible sub-models and finally we selected the best (the one with the lowest Akaike’s Information Criterion score). Results and Discussion We found a significant positive association between pollen abundances for beech (p=0.04), oak p=0.012), hop hornbeam (p=0.013) and TBEv human cases with a two-year lag (Figure 1). All other lags and taxa resulted in non-significant relationships. Subsequently, we identified the best model, which considered only hop-hornbeam and oak pollen quantities, both with positive coefficients, consistently with the univariate analysis. Conclusions To the best of our knowledge, this is the first attempt at quantifying the potential relationship between airborne pollen abundances of tree species and TBEv infections, based on a three-decade time series of data. If validated at a larger spatial scale, pollen data might therefore be used to realize an early warning system for the risk of TBEv transmission, two years in advance. Moreover, as pollen monitoring is routinely performed worldwide at multiple sites and provides quantitative measures, the association between pollen abundances and TBEv infections could be replicated in different biogeographical regions
Editorial: Recent advances in hazelnut (Corylus spp.)
The European hazelnut (Corylus avellana L.) of the genus Corylus is a major species of interest for nutritional use, and its nuts are widely used worldwide in the chocolate, confectionery, and bakery industries. Other Corylus species, including C. americana, C. heterophylla, and C. colurna, are of local interest for commercial uses and provide important genetic resources for breeding. The global production of hazelnut has increased since the beginning of the last century, especially in the last 10 years in
response to the demands of the confectionery industry, which processes about 90% of the harvested nuts. Cultivation of this nut has expanded in several traditional countries as well as in new areas, including Chile, South Africa, and Australia. Therefore, this Research Topic devoted to European hazelnut and its related species has been designed with the aim of assembling an effective-knowledge platform based on recent research carried out in the Corylus spp. sector. The Research Topic brings together some of the latest research outputs in hazelnut cultivation, genetic resources, and post-harvest processing, thanks to the excellent response to the call which resulted in the publication of 25 original articles. We found the edition and selection of articles for this book very inspiring and rewarding. We also
thank the editorial staff and reviewers for their efforts and help during the process. The scientific contributions are briefly discussed below, grouped into seven sections according to the main topics proposed during the Research Topic launch.info:eu-repo/semantics/publishedVersio
PolliniTrentino: informazione pollini in digitale per migliorare la qualità di vita dei cittadini allergici: relazione finale
First report of Erysiphe corylacearum causing powdery mildew on Corylus avellana in Spain
In the Mediterranean basin area, powdery mildew disease on hazelnut is commonly caused by Phyllactinia guttata. The disease occurs in late summer-autumn causing limited damage or economic impact. In April 2021, an unusual outbreak of the disease was observed on lower leaves of hazelnuts (cvs, Negret and San Giovanni) leading to rapid leaf desiccation in two commercial orchards (Camà de la Serra and Mas de la Coma), both located at La Selva del Camp, Tarragona, in north-eastern Spain. Unlike P. guttata, roundish spots of white mycelium appeared on the adaxial side of the leaves (Figure 1). Fruit was also infected and damaged.info:eu-repo/semantics/publishedVersio
The late flowering of invasive species contributes to the increase of Artemisia allergenic pollen in autumn: an analysis of 25 years of aerobiological data (1995–2019) in Trentino-Alto Adige (Northern Italy)
Artemisia pollen is an important aeroallergen in late summer, especially in central and eastern Europe where distinct anemophilous Artemisia spp. produce high amounts of pollen grains. The study aims at: (i) analyzing the temporal pattern of and changes in the Artemisia spp. pollen season; (ii) identifying the Artemisia species responsible for the local airborne pollen load.
Daily pollen concentration of Artemisia spp. was analyzed at two sites (BZ and SM) in Trentino-Alto Adige, North Italy, from 1995 to 2019.
The analysis of airborne Artemisia pollen concentrations evidences the presence of a bimodal curve, with two peaks, in August and September, respectively. The magnitude of peak concentrations varies across the studied time span for both sites: the maximum concentration at the September peak increases significantly for both the BZ (p < 0.05) and SM (p < 0.001) site. The first peak in the pollen calendar is attributable to native Artemisia species, with A. vulgaris as the most abundant; the second peak is mostly represented by the invasive species A. annua and A. verlotiorum (in constant proportion along the years), which are causing a considerable increase in pollen concentration in the late pollen season in recent years.. The spread of these species can affect human health, increasing the length and severity of allergenic pollen exposure in autumn, as well as plant biodiversity in both natural and cultivated areas, with negative impacts on, e.g., Natura 2000 protected sites and crops
Experimental Investigation of a Novel Formulation of a Cyanoacrylate-Based Adhesive for Self-Healing Concrete Technologies
The selection of an appropriate healing agent is critical to the success of vascular and mini-vascular networks. In self-healing concrete technology, commercially available cyanoacrylate (CA) adhesives have been shown to produce good strength recoveries; however, their rapid curing rate and short shelf-life make them unsuitable for site application. The aim of this study was to develop a modified cyanoacrylate (n-CA) with an extended shelf-life suitable for incorporation in a self-healing system. A series of n-CAs were formed from a commercial Ethyl Cyanoacrylate adhesive mixed with acrylic acid (AA) and nitro-anthraquinone (nAq) in varying ratios. When encapsulated within 3D printed mini-vascular networks (MVNs), the n-CAs remained dormant in liquid form for up to 5 days. The contact angle between the n-CAs and the cement mortar substrate, as measured via the sessile drop technique, decreased significantly with increasing AA content. The mechanical properties (bond strength) and the polymerization hardening of the n-CAs were evaluated over a curing period of 7–21 days, via a series of pull-off tests using cement mortar cubes. The 4:1:02 (CA:AA:nAq) n-CA formulation showed a significant increase in bond strength from 14 to 21 days, with a ceiling value of 2.6 MPa, while the 2:1 (CA:AA) n-CA formulation exhibited a good bond strength after 21 days (1 MPa). Nuclear Magnetic Resonance (NMR) conducted on the n-CAs suggested the formation of several new polymeric species, whilst differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) on the pre- and post-printed MVN material confirmed no significant changes in chemistry with no evidence of polymer degradation. Considered together, the experimental results show the potential for different n-CA formulations to act efficiently as a healing agent
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