MDPI -artikkelit


Uusimmat julkaisut

  • Annila, Arto (Multidisciplinary Digital Publishing Institute, 2016)
    Rotation of galaxies is examined by the general principle of least action. This law of nature describes a system in its surroundings, here specifically a galaxy in the surrounding Universe. According to this holistic theory the gravitational potential due to all matter in the expanding Universe relates to the universal curvature which, in turn, manifests itself as the universal acceleration. Then the orbital velocities from the central bulge to distant perimeters are understood to balance both the galactic and universal acceleration. Since the galactic acceleration decreases with distance from the galaxy’s center to its luminous edge, the orbital velocities of ever more distant stars and gas clouds tend toward a value that tallies the universal acceleration. This tiny term has been acknowledged earlier by including it as a parameter in the modified gravitational law, but here the tiny acceleration is understood to result from the gravitational potential that spans across the expanding Universe. This resolution of the galaxy rotation problem is compared with observations and contrasted with models of dark matter. Also, other astronomical observations that have been interpreted as evidence for dark matter are discussed in light of the least-action principle.
  • Mozumder, Mohammad Mojibul Hoque; Uddin, Mohammad Muslem; Schneider, Petra; Islam, Mohammad Mahmudul; Shamsuzzaman, Md. Mostafa (Multidisciplinary Digital Publishing Institute, 2018)
    Recreational fishing trips constitute a significant part of the tourism business in many countries. Linking fisheries to tourism can be both a response to the need to create innovative tourism products and the need to find new sources of income for fisheries to make them more profitable and sustainable. This leads to the question of whether Bangladesh can be developed as a Fisheries-Based Ecotourism (FbE) destination. Though several types of research have been done concerning the prospects of ecotourism in Bangladesh, the feasibility of FbE specifically remains under-studied. Based on a literature review and stakeholder interviews, this study explores the concept of FbE in a Bangladeshi context and its potential impacts on socio-economic community life as well as on the environment. This paper makes the case that the diversified topography of Bangladesh—including the riverine flat alluvial plains, hills and valleys, deciduous and evergreen forests, lakes, seashores, and beaches—is ripe with potential for FbE development. With its focus on the prospects and challenges of FbE development in Bangladesh, this paper could provide a useful reference point for future discourse on these sorts of cultural and economic strategies.
  • Muratore-Ginanneschi, Paolo; Schwieger, Kay (Multidisciplinary Digital Publishing Institute, 2017)
    We present a stylized model of controlled equilibration of a small system in a fluctuating environment. We derive the optimal control equations steering in finite-time the system between two equilibrium states. The corresponding thermodynamic transition is optimal in the sense that it occurs at minimum entropy if the set of admissible controls is restricted by certain bounds on the time derivatives of the protocols. We apply our equations to the engineered equilibration of an optical trap considered in a recent proof of principle experiment. We also analyze an elementary model of nucleation previously considered by Landauer to discuss the thermodynamic cost of one bit of information erasure. We expect our model to be a useful benchmark for experiment design as it exhibits the same integrability properties of well-known models of optimal mass transport by a compressible velocity field.
  • Heiskanen, Eva; Hyvönen, Kaarina; Laakso, Senja; Laitila, Päivi; Matschoss, Kaisa; Mikkonen, Irmeli (Multidisciplinary Digital Publishing Institute, 2017)
    Experimentation is critical for the deployment of low-carbon technologies. New solutions need to be selected and adapted to their contexts of use, and users need to learn new skills. Society as a whole needs to create new modes of production, consumption and governance. We investigated how local pilot projects, demonstrations and trials of low-carbon technologies promote learning in Finnish society, where the government has made a commitment to a culture of experimentation. We drew on a database of 100 pilot projects and experiments and 15 detailed case studies. We identified several types of learning, beyond the formal evaluation of “what works where and when”: pilot projects served to inspire, to create commitment and to develop networks. We also investigated how lessons learned are transferred to other sites and into societal knowledge. We contribute by conceptualizing different forms of learning and transfer—particularly situated and embodied forms—alongside more techno-scientific ones. While highlighting this form of learning, we also note that it is not particularly strong in acknowledging challenges faced in experimentation. We argue that there is scope for more systematic evaluation, alongside more situated forms of learning and sharing. We also pinpoint tensions between these two forms of learning that need to be addressed.
  • Saarinen, Ninni; Vastaranta, Mikko; Näsi, Roope; Rosnell, Tomi; Hakala, Teemu; Honkavaara, Eija; Wulder, Michael A.; Luoma, Ville; Tommaselli, Antonio M. G.; Imai, Nilton N.; Ribeiro, Eduardo A. W.; Guimarães, Raul B.; Holopainen, Markus; Hyyppä, Juha (Multidisciplinary Digital Publishing Institute, 2018)
    Forests are the most diverse terrestrial ecosystems and their biological diversity includes trees, but also other plants, animals, and micro-organisms. One-third of the forested land is in boreal zone; therefore, changes in biological diversity in boreal forests can shape biodiversity, even at global scale. Several forest attributes, including size variability, amount of dead wood, and tree species richness, can be applied in assessing biodiversity of a forest ecosystem. Remote sensing offers complimentary tool for traditional field measurements in mapping and monitoring forest biodiversity. Recent development of small unmanned aerial vehicles (UAVs) enable the detailed characterization of forest ecosystems through providing data with high spatial but also temporal resolution at reasonable costs. The objective here is to deepen the knowledge about assessment of plot-level biodiversity indicators in boreal forests with hyperspectral imagery and photogrammetric point clouds from a UAV. We applied individual tree crown approach (ITC) and semi-individual tree crown approach (semi-ITC) in estimating plot-level biodiversity indicators. Structural metrics from the photogrammetric point clouds were used together with either spectral features or vegetation indices derived from hyperspectral imagery. Biodiversity indicators like the amount of dead wood and species richness were mainly underestimated with UAV-based hyperspectral imagery and photogrammetric point clouds. Indicators of structural variability (i.e., standard deviation in diameter-at-breast height and tree height) were the most accurately estimated biodiversity indicators with relative RMSE between 24.4% and 29.3% with semi-ITC. The largest relative errors occurred for predicting deciduous trees (especially aspen and alder), partly due to their small amount within the study area. Thus, especially the structural diversity was reliably predicted by integrating the three-dimensional and spectral datasets of UAV-based point clouds and hyperspectral imaging, and can therefore be further utilized in ecological studies, such as biodiversity monitoring.
  • Vuorio, Alpo; Laukkala, Tanja; Junttila, Ilkka; Bor, Robert; Budowle, Bruce; Pukkala, Eero; Navathe, Pooshan; Sajantila, Antti (Multidisciplinary Digital Publishing Institute, 2018)
    Pilot aircraft-assisted suicides (AAS) are rare, and there is limited understanding of copycat phenomenon among aviators. The aim of this study was to evaluate the possible effect the 11 September 2001, terrorist attacks had on pilot AASs in the U.S. Fatal aviation accidents in the National Transportation Safety Board (NTSB) database were searched using the following search words: “suicide”, “murder-suicide” and “homicide-suicide”. The timeline between 11 September 1996, and 11 September 2004, was analyzed. Only those accidents in which NTSB judged that the cause of the accident was suicide were included in the final analysis. The relative risk (RR) of the pilot AASs in all fatal accidents in the U.S. was calculated in order to compare the one, two, and three-year periods after the September 11 terrorist attacks with five years preceding the event. The RR of a fatal general aviation aircraft accident being due to pilot suicide was 3.68-fold (95% confidence interval 1.04–12.98) during the first year after 11 September 2001, but there was not a statistically significant increase in the later years. This study showed an association, albeit not determinate causal effect, of a very specific series of simultaneous terrorist murder-suicides with subsequent pilot AASs.
  • Odeh, Issam; Hussein, Tareq (Multidisciplinary Digital Publishing Institute, 2016)
    Knowledge of human activity patterns is needed in air pollution exposure and health risk assessment. However, human activity patterns have never been evaluated in the Eastern Mediterranean societies. Therefore, we investigated the activity pattern of 285 subjects (17–63 years) in Amman, Jordan during October to November, 2015. The subjects spent >80% of their time indoors during weekend days and >85% on workdays. They spent ~4.8% and ~5.7% in transportation during weekend days and workdays, respectively. Males had a different activity pattern than females on weekend days, but both genders had similar activity patterns on workdays. On workdays, males spent less time indoors than females. The activity pattern found in this study is a bit different than that for North Americans and Europeans, who spend more time indoors and in transit. The activity pattern found in this study was very different than that observed for Koreans, who spent about 59% and 67% indoors on workdays and weekend, respectively. The main outcomes of this survey can be utilized in human exposure studies. This study and the upcoming future studies have been encouraged and supported by the regional WHO office in Amman.