325 research outputs found
The Next Frontier: Blockchain In The Music Industry
This Research Paper takes a look at how Blockchain technology can potentially change the music industry as we know it
Theory of Room Temperature Ferromagnet V(TCNE)_x (1.5 < x < 2): Role of Hidden Flat Bands
Theoretical studies on the possible origin of room temperature ferromagnetism
(ferromagnetic once crystallized) in the molecular transition metal complex,
V(TCNE)_x (1.5<x<2) have been carried out. For this family, there have been no
definite understanding of crystal structure so far because of sample quality,
though the effective valence of V is known to be close to +2. Proposing a new
crystal structure for the stoichiometric case of x=2, where the valence of each
TCNE molecule is -1 and resistivity shows insulating behavior, exchange
interaction among d-electrons on adjacent V atoms has been estimated based on
the cluster with 3 vanadium atoms and one TCNE molecule. It turns out that
Hund's coupling among d orbitals within the same V atoms and antiferromagnetic
coupling between d oribitals and LUMO of TCNE (bridging V atoms) due to
hybridization result in overall ferromagnetism (to be precise, ferrimagnetism).
This view based on localized electrons is supplemented by the band picture,
which indicates the existence of a flat band expected to lead to ferromagnetism
as well consistent with the localized view. The off-stoichiometric cases (x<2),
which still show ferromagnetism but semiconducting transport properties, have
been analyzed as due to Anderson localization.Comment: Accepted for publication in J. Phys. Soc. Jpn. Vol.79 (2010), No. 3
(March issue), in press; 6 pages, 8 figure
Endogenous cycles, activity patterns and energy expenditure of an intertidal fish is modified by artificial light pollution at night (ALAN)
The increase of global light emissions in recent years has highlighted the need for urgent evaluation of their impacts on the behaviour, ecology and physiology of organisms. Numerous species exhibit daily cycles or strong scototaxic behaviours that could potentially be influenced if natural lighting conditions or cycles are disrupted. Artificial Light Pollution at Night (ALAN) stands for situations where artificial light alters natural light-dark cycles, as well as light intensities and wavelengths. ALAN is increasingly recognized as a potential threat to biodiversity, mainly because a growing number of studies are demonstrating its influence on animal behaviour, migration, reproduction and biological interactions. Most of these studies have focused on terrestrial organisms and ecosystems with studies on the effects of ALAN on marine ecosystems being more occasional. However, with the increasing human use and development of the coastal zone, organisms that inhabit shallow coastal or intertidal systems could be at increasing risk from ALAN. In this study we measured the levels of artificial light intensity in the field and used these levels to conduct experimental trials to determine the impact of ALAN on an intertidal fish. Specifically, we measured ALAN effects on physiological performance (oxygen consumption) and behaviour (activity patterns) of “Baunco” the rockfish Girella laevifrons, one of the most abundant and ecologically important intertidal fish in the Southeastern Pacific littoral. Our results indicated that individuals exposed to ALAN exhibited increased oxygen consumption and activity when compared with control animals. Moreover, those fish exposed to ALAN stopped displaying the natural (circatidal and circadian) activity cycles that were observed in control fish throughout the experiment. These changes in physiological function and behaviour could have serious implications for the long-term sustainability of fish populations and indirect impacts on intertidal communities in areas affected by ALAN
Strategies to reduce antimicrobials in livestock and aquaculture, and their impact under field conditions: a structured scoping literature review
Arts-based approach to describe the perceptions of spiders by local people
People's perceptions of spiders can vary from disgust to fascination, which has a substantial impact on the value People's perceptions of spiders can range from disgust to fascination, and these perceptions significantly impact how they value the conservation of Aranea. This study employed an arts-based methodology to explore the perspectives of 123 respondents from Talenceras, Bohol, Philippines, towards spiders. Data collection involved spider drawings and interviews with participants. The findings unveiled people's diverse relationships with spiders, including their role in controlling problematic insect populations. While humans appreciate spiders for their pest control abilities, they also view them as a source of entertainment, particularly in the context of spider derbies, which pose a significant threat to female spiders. Demographic data indicated a growing number of young people engaging in spider-related entertainment without realizing they might encounter pregnant female spiders. Some individuals fear spiders due to concerns about their potential toxicity, leading them to avoid contact with these arachnids. Negative perspectives toward spiders, mainly if people are unable to distinguish between spider species, could hinder conservation efforts. This study emphasizes the importance of taking proactive measures to address these spider-related issues and protect biodiversity
Numerical Study of a Mixed Ising Ferrimagnetic System
We present a study of a classical ferrimagnetic model on a square lattice in
which the two interpenetrating square sublattices have spins one-half and one.
This model is relevant for understanding bimetallic molecular ferrimagnets that
are currently being synthesized by several experimental groups. We perform
exact ground-state calculations for the model and employ Monte Carlo and
numerical transfer-matrix techniques to obtain the finite-temperature phase
diagram for both the transition and compensation temperatures. When only
nearest-neighbor interactions are included, our nonperturbative results
indicate no compensation point or tricritical point at finite temperature,
which contradicts earlier results obtained with mean-field analysis.Comment: Figures can be obtained by request to [email protected] or
[email protected]
Warpage Behavior of 7075 Aluminum Alloy Extrusions
Extruded I sections of 7075-T6 aluminum were machined into four different sections shapes: L, short depth L, T, and short depth 7. The furnace was preheated to 416 degrees C (780 degrees F) and the samples were placed inside. The temperature was raised to 471 degrees C (880 degrees F) and then the samples were quenched in either a 30% polyalkylene Glycol solution or water, both at 15 degrees C (59 degrees F). Points on the distorted samples were recorded before and after the solution treatment; the difference between the measurements indicated the extent of warpage
Magnetic Behavior of a Mixed Ising Ferrimagnetic Model in an Oscillating Magnetic Field
The magnetic behavior of a mixed Ising ferrimagnetic system on a square
lattice, in which the two interpenetrating square sublattices have spins +- 1/2
and spins +-1,0, in the presence of an oscillating magnetic field has been
studied with Monte Carlo techniques. The model includes nearest and
next-nearest neighbor interactions, a crystal field and the oscillating
external field. By studying the hysteretic response of this model to an
oscillating field we found that it qualitatively reproduces the increasing of
the coercive field at the compensation temperature observed in real
ferrimagnets, a crucial feature for magneto-optical applications. This behavior
is basically independent of the frequency of the field and the size of the
system. The magnetic response of the system is related to a dynamical
transition from a paramagnetic to a ferromagnetic phase and to the different
temperature dependence of the relaxation times of both sublattices.Comment: 10 figures. To be published in Phys.Rev
Nueva especie de lagartija del norte de Chile, Liolaemus molinai (Reptilia: Liolaeminae)
- …