377 research outputs found
Orthorhombic phase of LaBiNiO studied by first principles
The aim of presented first principles study of LaBiNiO
is to investigate electronic structure of orthorhombic phase Pbnm. The
calculations show that metallicity and magnetism of the system are strongly
related with hybridization between Ni 3d and O 2p. To improve the quality of
the electronic structure description of the system, especially the treatment of
correlation for the Ni 3d, we employ GGA, LDA, and GGA+U, LDA+U. The LSDA
results give good agreement with experiment. Thus, the screening effects
originating from the hybridized 3d and O 2p electrons are sufficiently strong
that they reduce the electronic correlations in the
LaBiNiO, making it a weakly correlated metal.Comment: 4 pages, 3 figures; The European Conference Physics of Magnetism
2017, submitted to Acta Physica Polonica
Impact of Perceived Peer Attitudes and Social Network Diversity on Violent Extremist Intentions
Perceived peer attitudes often influence young adult men’s violent attitudes and intentions, whereas the structure of peer networks can moderate this relationship. For example, people with more diverse social networks are less likely to adopt their close peers’ violent attitudes and behaviors. Despite that, there is currently limited research examining the role of structural features of peer networks in the relationship between perceived peer attitudes and violent extremist attitudes or intentions. Consequently, the current study sought to address this gap in research and answer the following questions: (1) To what extent are perceived peer attitudes, personal attitudes, and violent extremist intentions related to each other? (2) To what extent does the relationship between perceived peer attitudes and violent extremist intentions differ at different levels of social network diversity? The study sample consisted of 340 young adult men (i.e., 18-29 years old). Data collection took place via Amazon Mturk, an online-based crowdsourcing platform. Participants first indicated a social group with which they most strongly identify and listed their five closest male peers from the same group. Next, participants reported their violent extremist attitudes, intentions, and their perceptions of their peers’ opinions. Overall, perceived peer attitudes were positively and significantly associated with violent extremist intentions through their relationship with personal attitudes. The mediating effect, however, was partial: personal attitudes did not fully account for the total association. Furthermore, social network diversity moderated the relationship between personal and perceived peer attitudes: participants with more diverse social networks were less likely to hold beliefs similar to their perceived peer attitudes. In general, study findings were in line with past research on the impact of perceived peer attitudes and social network structure on violent outcomes. Thus, future studies should explore the potential role of other aspects of peer networks in the development of violent extremist attitudes and intentions. Regarding its policy implications, the study highlights the need for social-ecological approaches to counter violent extremism, offering young adult men opportunities for community involvement and growth of social ties
Electronic structure and thermodynamic properties of RNi_{5}Sn (R = La, Ce, Pr, Nd) compounds
The electronic structure, pressure and temperature dependence of thermodynamic properties of RNi5Sn (R = La, Ce, Pr, Nd) compounds are calculated by ab initio full potential local orbital minimum-base(ver. 9 and ver. 14) method. These compounds crystallize in the hexagonal crystal structure (space group P6c/mmc, No. 194). The band calculations were performed in the scalar-relativistic mode for the exchange correlation potentials in the form: of the Perdew-Burke-Ernzerhof general gradient approximation. In this work we present the band structures of LaNi5Sn, CeNi5Sn, NdNi5Sn and PrNi5Sn compounds. The thermodynamic properties (bulk modulus, Debye temperature) are calculated in the Debye-Grüneisen model using the equation of states in the form of Birch-Murnaghan, Poirier-Tarantola and Vinet. Our results have shown that values of thermodynamic properties depend on the method of calculations
Long-term changes in fish community structure revealed by gillnet monitoring in a shallow, lowland reservoir
Background. Fish communities can support or hinder water quality management. Sulejów Reservoir, which is situated
on the Pilica River in Central Poland, serves as a strategic reserve of drinking water for the Łódź Agglomeration.
Precise knowledge of the long-term dynamics of the structure of the fish community, what was the aim of this study,
is important for proper management to slow the eutrophication of the reservoir and prevent toxic algal blooms.
Materials and methods. To determine fish species composition, multimesh gill nets with mesh sizes ranging
from 11 to 80 mm were used. From 1993 to 2015, gillnetting was conducted 1–2 times per month from June
through November in two representative parts of the reservoir, and principal component analysis (PCA) was
applied to explore the temporal variation in fish community structure expressed as the relative contribution of
each species to the total fish biomass.
Results. Dominance fluctuated among four species in the fish community: common bream, Abramis brama
(Linnaeus, 1758); roach, Rutilus rutilus (Linnaeus, 1758); white bream, Blicca bjoerkna (Linnaeus, 1758); and
pike-perch, Sander lucioperca (Linnaeus, 1758). PCA revealed three principal components with eigenvalues
larger than one that explained 73.3% of the observed variance in the temporal changes in fish community
composition. A negative correlation was found between pike-perch biomass and roach biomass (r = 0.82), while
a positive correlation was observed between the biomass of pike-perch and that of common bream (r = 0.73).
Consequently, there was a highly negative correlation between the biomasses of common bream and roach
(r = 0.80). Furthermore, an interesting temporal pattern was observed; from 1993 to 2000, the fish community
was dominated by common bream and pike-perch but then shifted towards domination by roach and white bream,
despite declining phosphorous and carbon concentrations. Recently, this trend has been reversed, and a more
balanced fish community structure has been established.
Conclusion. Fish community succession, which is usually reported to be a one-directional process in reservoirs,
i.e., from a riverine fish or percid-dominated to a cyprinid (bream)-dominated state, was more ambiguous in
Sulejów Reservoir. This was likely a consequence of both restoration issues related to decreasing nutrient loads
and the influence of zebra mussel, Dreissena polymorpha invasion on the trophic relations in the reservoir
Anatomical analysis of preangular mandibular notch in humans
The authors have analysed in detail the mandibular preangular notch on the
basis of 273 human cadaver mandibles. They have revealed that the pregonial
notch is present in almost 90% of cases and that it is generally asymmetric and
elliptical in shape. The depth and length of the anterior part of the notch is
greater in males. Moreover, the preangular notch depth is greater on the right
side (regardless of sex). Knowledge of the preangular notch anatomy can be
useful for surgeons during reconstructive and plastic procedures on the mandibular
shaft
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