Engineering students' actions in a mathematical modelling task: Mediating mathematical understanding in a computer algebra system

Many engineering subjects rely on the interpretation of symbolic, numeric and graphic representations. Engineering students have challenges pertaining to their mathematical understanding of their actions with a computer algebra system (CAS). We investigated how a mathematical modelling task could mediate varied levels of mathematical understanding. When engineering students are exposed to a CAS environment, they habitually engage in programming activities without considering the computerised outputs. The purpose of this paper was to ascertain South African engineering students’ actions that can mediate broader levels of mathematical understanding in a CAS by utilising the Pirie- Kieren model of growth in mathematical understanding. Thirteen participants agreed to engage collaboratively in a mathematical modelling task. The task was analysed by means of content analysis following a deductive research approach. The findings disclosed that engineering students interdepend on paper-and-pen, computerised and reflective actions in their growth of mathematical understanding. Engineering students can be assisted in mediated and folding-back actions in order to fluctuate back and forth on their way to a more sound mathematical understanding. Explicit planning and sequence of subtasks can support engineering students to merge new levels of mathematics understanding with past comprehensions. Thoroughly planned modelling tasks can mediate novel levels of mathematical understanding when engineering students learn with a CAS

Carabid beetle and spider assemblages along a forested urban–rural gradient in southern Finland

To investigate the effects of urbanization on carabid beetles (Carabidae) and ground dwelling spiders (Araneae) a study was completed along a 20 kmurban–rural forest gradient in the Helsinki–Espoo area of southern Finland. To study changes in assemblage structure, abundance and species richness, these taxa were collected in the year 2000 using pitfall traps, which had been placed in four forest sites within each of the urban, suburban and rural zones.We expected to find changes in the abundances and species richnesses in the two taxa across the urban–rural gradient, but did not find any. Our second and third hypotheses, stating that generalist species and small-bodied species should gain dominance along the gradient from rural to urban sites, were partly supported as carabid specialists were more characteristic of suburban and rural environments whereas generalists were more likely to be collected from rural areas compared to suburban or urban sites. Furthermore, medium to large-sized carabid individuals were more likely to be collected in the rural sites compared to urban forests. We found no evidence for significant changes in spider abundance or species richness across the urban–rural gradient in relation to body size or habitat specialization. We suggest that urbanization does not have significant effects on the total abundances and species richnesses in these two taxa. However, individual species responded differently to urbanization, and there were significant differences in the specialization and body sizes of carabids across the gradient

Plant functional type affects nitrogen dynamics in urban park soils similarly to boreal forest soils

Purpose Although plant functional type can modulate soils and their processes in natural, nitrogen (N)-limited ecosystems, little is known about their ability to influence soil N dynamics in urban ecosystems that have high excess N input. We investigated whether i) plant functional type effects on soil N dynamics in urban parks follow the same pattern as those in undisturbed natural/semi-natural forests, and ii) park age influences plant functional type effects on soil N dynamics under boreal climate. Methods We selected 13 urban parks of varying ages (young: 10 to 15, old: > 70 years), and 5 undisturbed natural/semi-natural forests (> 80 years) in southern Finland. In these parks and forests, we measured soil total N concentration, availability of inorganic N, nitrous oxide (N2O) flux and earthworm biomass under three plant functional types (evergreen tree, deciduous tree, lawn). Results Our results showed that plant functional type influenced N dynamics also in urban greenspace soils, which may relate to the clear effect of plant functional type on earthworm biomass. Evergreen trees tended to have the highest ability to foster N accumulation and reduce N2O emissions in urban parks. Moreover, with increasing park age, N accumulation increased under trees but decreased under lawns, further emphasising the role of vegetation in affecting soil N dynamics in urban greenspaces. Conclusions Our results show that, similar to natural/semi-natural forests, plant functional type, irrespective of park age, can influence soil N dynamics in urban parks.Peer reviewe

Carabid beetles of tropical dry forests display traits that cope with a harsh environment

The tropical dry forest (TDF) ecosystem is characterised by strong seasonality exasperated periodically by the El Nino/southern oscillation (ENSO). The environment produced by this event could constrain the survival of small organisms, such as insects. Carabid beetles were collected in a TDF in Armero, Colombia, during wet and dry seasons in both El Nino and non-El Nino periods. A series of traits linked to desiccation resistance were measured to characterise their adaptation to the TDF environment and to investigate changes experienced by carabid beetles during both episodes in quantitative (assemblage) and qualitative (traits) parameters. We found no difference in the presence of traits between El Nino and non-El Nino episodes, but carabid assemblages changed significantly in composition and assemblage structure between these episodes. During both periods, small-sized and nocturnal species dominated the assemblages, but in terms of number of individuals, medium and large-sized, and visual hunter species dominated. Calosoma alternans and Megacephala affinis were the most abundant species with high dispersal capacity. Carabid beetles exhibited morphological traits well-adapted to drought experienced in TDF, including when it is exasperated by ENSO. However, long-term studies can help to elucidate the real effects of ENSO and to confirm the adaptation of carabid beetles to cope with this extreme environment.Peer reviewe

Neo-spaces for urban livability? Urbanites' versatile mental images of green roofs in the Helsinki metropolitan area, Finland

Within the context of enhancing sustainable and livable urban environments, one aim is to establish multifunctional green infrastructure (GI). We argue that in order to successfully plan and manage the development of GI, an inclusive and future-oriented stance concerning the needs and expectations of urbanites is required. By using green roofs as an example, the aim of this paper was to offer insights into how people envisage novel GI in urban environments and to reveal the scope of meanings and values people attach to these kinds of green infrastructure. We present results based on 149 stories collected with the method of empathy-based stories. Respondents were asked to use their imagination to produce mental images of not-yet-existing green roofs in different urban situations. Our results reflect a rich set of dimensions of green roofs that the respondents vividly imagined. Green roofs may contribute to the livability of urban areas in multiple ways, such as strengthening social cohesion, providing space for everyday renewal and restoration, offering interesting sceneries and multisensory experiences, softening the hard cityscape, showing ephemeral events and making experiences of "height" possible, as well as increasing the "contact with nature" experiences for residents, e.g. through biodiverse nature in the middle of built environments. Furthermore, the need for local, customized solutions that offer different benefits and experiences was expressed. Using both qualitative and quantitative analyses, we idealized four green roof meta-types for understanding the diverse expectations people may have for green roofs in urban area: Urban farm, Oasis, Urban hill and Meadow. Based on our results we suggest that comprehensive experiences and needs of people should be taken into account when designing urban green roofs or urban green in general not only, e.g. visual pleasure. Also, site- and user-specific solutions should be considered instead of generally applied ones. Our results offer tools for, e.g. urban planners to understand the value of diverse green roof solutions to the user. (C) 2016 The Authors. Published by Elsevier Ltd.Peer reviewe

The influence of a Mediterranean Diet with and without Red Wine on the Haemostatic and Inflammatory Parameters of Subjects with the Metabolic Syndrome

This 8 week study examined whether a Mediterranean diet supplemented with red wine, had an acute impact onsubjects diagnosed with the metabolic syndrome. Twelve non-smoking subjects with diagnostic criteria of themetabolic syndrome on minimal medication, consumed a Mediterranean-like diet for 4 weeks respectively withoutand with red wine. The amount of red wine consumed was 250 ml (26 grams of alcohol) per day for male and 180ml (19 grams) per day for female participants. A nutrigenetic profile for cardiovascular risk factors was performedon each participant. Fasting blood specimens were taken at baseline, after the diet and after the diet with wineinterventions for platelet function, procoagulants FVII and FVIII, von Willebrand’s factor, fibrinogen, tissueplasminogen activator, plasminogen activator inhibitor-1, highly sensitive C-reactive protein and oxygen radicalabsorbance capacity (ORAC). After both periods of diet without wine and with wine, ORAC increased significantlycompared to baseline levels. Except for platelet H2O2 fluxes and FVII concentration, none of the haemostatic orinflammatory parameters changed significantly after the intervention periods compared with baseline levels.Genetic risk factors for cardiovascular disease were identified in all study participants and the potential genotypiceffects relevant to this study were generally in agreement with expected phenotypic response following the dietaryintervention. Our conclusions are that the period of intervention was too short for substantial changes inhaemostatic or in inflammatory parameters in subjects who already manifest some changes in their cardiovascularsystem and who showed diverse genetic profiles underlying increased cardiovascular risk

Quantifying Long-Term Urban Grassland Dynamics: Biotic Homogenization and Extinction Debts

Sustainable urban nature conservation calls for a rethinking of conventional approaches. Traditionally, conservationists have not incorporated the history of the landscape in management strategies. This study shows that extant vegetation patterns are correlated to past landscapes indicating potential extinction debts. We calculated urban landscape measures for seven time periods (1938–2019) and correlated it to three vegetation sampling events (1995, 2012, 2019) using GLM models. We also tested whether urban vegetation was homogenizing. Our results indicated that urban vegetation in our study area is not currently homogenizing but that indigenous forb species richness is declining significantly. Furthermore, long-term studies are essential as the time lags identified for different vegetation sampling periods changed as well as the drivers best predicting these changes. Understanding these dynamics are critical to ensuring sustainable conservation of urban vegetation for future citizens