6,401 research outputs found
KLUN+ peculiar velocity survey
The enhanced Kinematics of the Local Universe (KLUN+) galaxy sample is a
collection of galaxies suitable for Tully-Fisher (TF) or Faber-Jackson (FJ)
distance estimation. Here we extract a subsample of 6229 KLUN+ galaxies closer
than 80 Mpc/h, and calculate their distances and peculiar velocities with the
Iterative Normalized Distance method. Within this method we can derive an
analytical formula, independent from the density inhomogeneities, for
correcting the selection biases. The radial peculiar velocities can then be
derived from the redshifts and the corrected distances. The velocities are
smoothed, and the smoothed velocity field is used as a correction term at the
next derivation of normalized distances. This iterative procedure is repeated
until converging values are reached. Here we present the resulting map of the
radial peculiar velocity field at the < 80 Mpc/h environment. The infall
patterns towards the main galaxy clusters are clearly visible. The color
version of the map, other figures, and animations are provided on the project
web site
Revisiting the optical depth of spiral galaxies using the Tully-Fisher B relation
Aims. We attempt to determine the optical depth of spiral galaxy disks by a
statistical study of new Tully-Fisher data from the ongoing KLUN+ survey, and
to clarify the difference between the true and apparent behavior of optical
depth. Methods. By utilizing so-called normalized distances, a subsample of the
data is identified to be as free from selection effects as possible. For these
galaxies, a set of apparent quantities are calculated for face-on positions
using the Tully-Fisher diameter and magnitude relations. These values are
compared with direct observations to determine the mean value of the parameter
C describing the optical depth. Results. The present study suggests that spiral
galaxy disks are relatively optically thin tauB = 0.1, at least in the
outermost regions, while they appear in general to be optically thick tauB > 1
when the apparent magnitude and average surface brightness are studied
statistically.Comment: 9 pages, 13 figures, accepted for publication in Astronomy &
Astrophysic
Kinematics of the local universe IX. The Perseus-Pisces supercluster and the Tolman-Bondi model
We study the mass distribution and the infall pattern of the Perseus-Pisces
(PP) supercluster. First we calculate the mass of the central part of PP, a
sphere with a radius of 15/h Mpc centered at (l,b)=(140.2\deg ,-22.0\deg),
d=50/h Mpc, using the virial and other estimators. We get M_{PP} = 4 -- 7 /h
10^{15} M_{sun}, giving mass-to-light ratio 200 -- 600 h M_{sun} / L_{sun}, and
overdensity \delta \approx 4.
The radially averaged smoothed density distribution around the PP is inputted
to the Tolman-Bondi (TB) equations, calculated for different cosmologies:
\Omega_0 = [0.1,1], \Omega_{\Lambda} = 1-\Omega_0 or 0. As a result we get the
infall velocities towards the PP center. Comparing the TB results to the
peculiar velocities measured for the Kinematics of the Local Universe (KLUN)
Tully-Fisher data set we get the best fit for the conditions \Omega_0 = 0.2 --
0.4 and v_{inf} < 100 km/s for the Local Group infall towards the center of PP.
The applicability of the TB method in a complex environment, such as PP, is
tested on an N-body simulation.Comment: in press (A&A
Voidaanko metsien biologisen monimuotoisuuden väheneminen pysäyttää vuoteen 2020 mennessä? Huomioita metsälakiesityksestä
Tieteen tori: Metsälakiuudistu
Designing and building Si bolometers for diagnostics and spectroscopy of magnetically trapped hydrogen gas
In this thesis we will be discussing the theory behind low-temperature bolometers
for measurements of atomic hydrogen, as well as the possibility of building such
bolometers from affordable commercially available silicon wafers, based on previous
research into the low-temperature properties of doped silicon.
Additionally experiments conducted over the summer of 2020 to find a proper silicon
material for such bolometers will be presented along with sensitivity comparison to
previously used sensor
Local and regional ecological morphology of dung beetle assemblages across four biogeographic regions
Aim Niche partitioning within species assemblages is thought to influence species packing and/or total niche space occupied. The evolution of dung beetles (Scarabaeinae) is likely to have been strongly influenced by inter-specific competition, leading to niche partitioning. We consider whether local-scale processes leave a signature in regional patterns of functional diversity in dung beetle assemblages, and investigate the correlation between total exploited ecomorphological space and density of species packing with increased species richness. We test whether ecomorphological space occupied by local assemblages reflects that of their regional species pool, and the extent to which ecomorphological space is convergent or divergent within functional groups across regional pools. Location Neotropics, Africa, Australia and Madagascar. Methods Dung beetle assemblages were collected in a standardized manner from four biogeographic regions. Ecomorphological similarity among the assemblages was assessed by multivariate analysis of 19 linear measurements for 300 species and three functional nesting types (roller, tunneller or dweller), firstly on a local level within the Neotropics and Afrotropics, and then between the regional species pools. Results Key body measurements, in particular the hind tibia, separated rollers and tunnellers into largely non-overlapping entities along the first three axes of the shape analysis. Three Neotropical assemblages, which vary widely in species numbers, each harboured a similar amount of morphometric variation, resulting in increasingly dense species packing with greater species richness. Similar findings were obtained in two South African assemblages. Assemblages in the four biogeographic regions showed largely similar distributions of ecomorphological variation, including the separation of rollers and tunnellers, despite their distant phylogenetic relationships. Ecomorphological similarity among regions was particularly high in tunnellers, whilst the rollers exhibited greater regional differentiation. Main conclusions Local assemblages evidently represent the full diversity of functional groups available in the regional pool, even in species-poor assemblages. There is a strong trend towards convergence in morphology separating tunnellers and rollers in phylogenetically independent lineages. The ecomorphological similarity of regional assemblages suggests that morphological convergence is the result of common selective forces active within the assemblages themselves. This lends support to the widely hypothesized effect of inter-specific interactions and niche partitioning in determining assemblage composition and lineage evolution in the Scarabaeinae. © 2011 Blackwell Publishing Ltd
Identifying key notions of corporate responsibility : The perspectives of qualified Finnish corporate executives in Latin American countries and of Latin American employees living in Finland
The aim of this thesis is to study corporate social responsibility from the perspective of corporate leaders and employees in the context of Latin American countries. The main theories in this thesis are based on the work of Karl Polanyi, Esa Pohjanheimo, Jouko Kuisma, Teuvo Teivainen, Geert Hofstede, Ivan Kolstad, Eduard Freeman, and Milton Friedman. Various articles, corporate websites, courses, and events on corporate social responsibility are utilized in this research. The methodology of this thesis is semi-structured interviews carried out in person or by phone in English and Finnish.
The corporate leaders are represented by three executive leaders who all have extensive living experience in various corporate, cultural, and geographical perspectives in several Latin American countries. The industries captured in this research are 1) the mining industry (Outokumpu) in Chile, 2) the paper and pulp (renewable materials) industries (Stora Enso) in Uruguay and Brazil, and 3) the forestry industry (Enso) in Brazil. The employee perspective is represented by three Venezuelan employees, three Bolivian employees, and one Honduran employee living and working in Finland across various Finnish companies. Seven common key notions of corporate social responsibility (CSR) are found in the interviews both of the executive leaders as well as the employees. Four of the key notions are mutual. The mutual CSR notions among the leadership figures and the employees include i) the experienced level of hierarchy and power distance between employees and supervisors, ii) the level (or lack of) of environmental CSR, iii) the experienced power of the state and the government, and iv) the level of corruption in Latin American countries. The top three shared CSR notions among the executive leaders are related to cultural similarities between Nordic and Latin American countries. All seven shared notions of CSR among the executive leadership figures include 1) similarities between the experienced levels of infrastructure among the Nordic and Latin American countries, 2) similarities in historical and cultural practices between the Nordic and Latin American countries, 3) CSR supporting the collective and individual rights of indigenous populations, 4) erosion of natural resources in Latin America, 5) benefits of local empowerment, 6) the power of the media in Latin American countries, and 7) the level of corruption in Latin American countries. The strongest CSR notions among the employees include 1) excellence of the Finnish healthcare and welfare system, 2) CSR as a profit-seeking activity, 4) differences in social benefits (pension, health insurance, taxation) between Latin America and Finland, 5) a lack of democracy and the power of the government in Latin American countries, 6) the level of corruption in Latin American countries, and 7) a lack of environmental CSR in Latin American countries. The results of the study can be applied from the perspectives of Bolivia and Venezuela from the employee side and from the perspectives of Chile, Uruguay, and Brazil from the executive leaders’ side. The results give us an understanding of the key dimensions of CSR aspects in these specific countries, limited by the roles and context of the interviews. Variance between the countries (and industries) among the executive leaders and the employees exist, but the results are combined into a regional study representing various Latin American countries or the Latin American (LAM) region as a whole
Exact asymptotic analysis for metapopulation dynamics on correlated dynamic landscapes
We compute the mean patch occupancy for a stochastic, spatially explicit patch-occupancy metapopulation model on a dynamic, correlated landscape, using a mathematically exact perturbation expansion about a mean-field limit that applies when dispersal range is large. Stochasticity in the metapopulation and landscape dynamics gives negative contributions to patch occupancy, the former being more important at high occupancy and the latter at low occupancy. Positive landscape correlations always benefit the metapopulation, but are only significant when the correlation length is comparable to, or smaller than, the dispersal range. Our analytical results allow us to consider the importance of spatial kernels in all generality. We find that the shape of the landscape correlation function is typically unimportant, and that the variance is overwhelmingly the most important property of the colonisation kernel. However, short-range singularities in either the colonisation kernel or landscape correlations can give rise to qualitatively different behaviour
Interaction between habitat quality and an Allee-like effect in metapopulations
We construct a stochastic patch occupancy metapopulation model that incorporates variation in habitat quality and an Allee-like effect. Using some basic results from stochastic ordering, we investigate the effect of habitat degradation on the persistence of the metapopulation. In particular, we show that for a metapopulation with Allee-like effect habitat degradation can cause a dramatic decrease in the level of persistence while in the absence of an Allee-like effect this decrease is more gradual
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