15 research outputs found
Geographical variation in the body size of adult female sperm whales (Physeter macrocephalus) – an example of McNab’s resource rule?
This study investigates possible regional variations in size composition of adult female sperm whales (Physeter macrocephalus) using data from 3302 pregnant individuals taken on Soviet whaling expeditions to the Southern Hemisphere 1961/62–1974/75. A general linear model (GLM) was used to take the covariates of expedition, latitude and ocean basin into account. The average body size decreased from south to north in each ocean basin, with the biggest decrease (about 200 cm) in the Indian Ocean; followed by the Pacific Ocean (about 110 cm), and the Atlantic Ocean (about 80 cm). Independent data confirm the small size of female/immature sperm whales in some tropical areas of the Indian and Pacific Oceans. The mechanism responsible for this geographic variation in sperm whale growth could reflect culturally transmitted differences in foraging behaviour between clans of female/immature sperm whales in response to differing availabilities of prey resources by geographical region – McNab’s resource rule. However there is little available information for such a mechanism to be readily identifiable. Although data for oceanic squids (sperm whale’s main source of food) are lacking, there is evidence that the individual sizes of neritic species are positively correlated with latitude. Hence feeding in equatorial regions may be energetically more demanding due to smaller individual prey size, with consequent effects on growth rate
Geographical variation in the body size of adult female sperm whales (Physeter macrocephalus) – an example of McNab’s resource rule?
This study investigates possible regional variations
in size composition of adult female sperm whales
(Physeter macrocephalus) using data from 3302 pregnant
individuals taken on Soviet whaling expeditions to the
Southern Hemisphere 1961/62–1974/75. A general linear
model (GLM) was used to take the covariates of expedition,
latitude and ocean basin into account. The average body
size decreased from south to north in each ocean basin,
with the biggest decrease (about 200 cm) in the Indian
Ocean; followed by the Pacific Ocean (about 110 cm),
and the Atlantic Ocean (about 80 cm). Independent data
confirm the small size of female/immature sperm whales
in some tropical areas of the Indian and Pacific Oceans.
The mechanism responsible for this geographic variation
in sperm whale growth could reflect culturally transmitted
differences in foraging behaviour between clans of
female/immature sperm whales in response to differing
availabilities of prey resources by geographical region –
McNab’s resource rule. However there is little available
information for such a mechanism to be readily identifiable.
Although data for oceanic squids (sperm whale’s
main source of food) are lacking, there is evidence that the individual sizes of neritic species are positively correlated
with latitude. Hence feeding in equatorial regions may be
energetically more demanding due to smaller individual
prey size, with consequent effects on growth rate.The National Research
Foundation, South Africa, under grant numbers 2047517
and 2053574.http://www.degruyter.com/view/j/mammam2018Mammal Research Institut
Catches of Humpback Whales in the Southern Ocean, 1947-1973
We review catches of humpback whales (Megaptera novaeangliae) in the Southern Ocean during the period following World War II, with an emphasis on Areas IV, V and VI (the principal regions of illegal Soviet whaling on this species). Where possible, we summarize legal and illegal Soviet catches by year, Area and factory fleet, and also include information on takes by other nations. Soviet humpback catches between 1947 and 1973 totaled 48702 and break down as follows: 649 (Area I), 1412 (Area II), 921 (Area III), 8779 (Area IV), 22569 (Area V) and 7195 (Area VI), with 7177 catches not assignable to area. In all, at least 72542 humpback whales were killed by all operations (Soviet plus other nations) after World War 2 in Areas IV (27201), V (38146) and VI (7195). More than a third of these (25474 whales, of which 25192 came from Areas V and VI) were taken in just two seasons, 1959/60 and 1960/61. The impact of these takes, and of those from Area IV in the late 1950\u27s, is evident in the sometimes dramatic declines in catches at shore stations in Australia, New Zealand and Norfolk Island. When compared to recent estimates of abundance, the large removals from Areas IV and V indicate that the populations in these regions remain well below pre-exploitation levels despite reported strong growth rates off eastern and western Australia. Populations in many areas of Oceania continue to be small, indicating that the catches from Area VI and eastern Area V had long-term impacts on recovery
Catches of Humpback Whales, \u3ci\u3eMegaptera novaeangliae\u3c/i\u3e, by the Soviet Union and Other Nations in the Southern Ocean, 1947–1973
The great whales of the Southern Ocean were extensively exploited by modern whaling methods, with the first catches made in the Falkland Islands Dependencies region of IWC Management Area II in 1904 (Tønnesson and Johnsen, 1982; Hart, 2006). Exploitation went through several phases. Populations of humpback whales, Megaptera novaeangliae, and blue whales, Balaenoptera musculus, around South Georgia crashed around the time of World War I, and further exploitation occurred in other regions into the 1930’s. There was a hiatus in whaling during World War II, but large-scale catches resumed in Antarctic waters after 1945
Anode overvoltages on the industrial carbon blocks
Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала
Transfer Processes in the Bath of High Amperage Aluminium Reduction Cell
Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала
Anode Processes Malfunctions Causes. An Overview
Одним из наиболее типичных видов технологических расстройств в анодах после их установки
в электролизер является неравномерное изменение рельефа подошвы анода и образование
на ней выступов, называемых в зарубежной технической литературе шипами, грибами,
деформациями, в российской – конусами. Конусы могут вызвать короткое замыкание анода
и катода, увеличить флуктуации тока, выход угольной пены, уровень шумов. Другой вид
технологических расстройств в анодах – образование в них трещин вследствие теплового удара
(термошока), который испытывает холодный анод при установке в расплав. Образовавшиеся
в результате растрескивания куски анода попадают в электролит, нарушая технологический
режим электролизера, увеличивая расход углерода и существенно осложняя обслуживание
электролизера. Одна из основных опасностей образования конусов и растрескивания анода –
значительное снижение выхода по току и технико-экономических показателей производства
алюминия. В настоящей статье представлен обзор исследований российских и зарубежных
экспериментаторов, посвященных изучению причин технологических расстройств в анодахOne of the most common anodes malfunctions appearing after its set up is uneven anode’s profile
relief modification and protrusion formation, called “spikes”, “mushrooms” “deformations”
and “cones”. Spikes can provide short circuits between anode and cathode, increase current
fluctuations, carbon dust volume and noise. Another kind of anodes malfunctions is cracking
due to thermal shock, which strikes “cold” anode during its setup. Pieces, formed as a result,
fall into bath, make a technological malfunction, increase carbon consumption and make cell
operating more difficult. One of the dangers of spikes formation is decrease of current efficiency
and aluminium production economical and technical indices. An overview of Russian and foreign
author’s anodes malfunctions causes researches are presented in the pape
Prediction of the Behavior of Sunflower Husk Ash after Its Processing by Various Torrefaction Methods
Biomass can be considered an alternative to coal in the production of heat and electricity. Many types of biomass are waste from agriculture and the food industry. This waste is cheap, readily available, and replenished annually. However, most agricultural and food industry wastes (sugar cane pulp, olive and sunflower oil production wastes, straw, etc.) have ash with a low melting point. This leads to a rapid growth of ash deposits on the heating surfaces of boilers; as a result, the actual efficiency of boilers in which waste from agriculture and the food industry is burned is 45–50%. Known biomass pre-treatment technologies that allow for the fuel characteristics of biowaste. For example, leaching of biowaste in water at a temperature of 80–240 °C makes it possible to drastically reduce the content of alkali metal compounds in the ash, the presence of which reduces the melting point of the ash. However, this biomass pre-treatment technology is complex and requires additional costs for drying the treated biomass. We proposed to use torrefaction for pre-treatment of biomass, which makes it possible to increase the heat of combustion of biomass, increase the hydrophobicity of biomass, and reduce the cost of grinding it. However, we are not aware of studies that have studied the effect of torrefaction on the chemical composition of ash from the point of view of solving the problem of preventing the formation of agglomerates and reducing the growth rate of ash deposits on the convective heating surfaces of boilers. In this paper, the characteristics of sunflower husk subjected to torrefaction in an environment of superheated steam at a temperature of 300 °C and in an environment of gaseous products at a temperature of 250 °C are studied. All experiments were conducted using fluidized bed technology. The resulting biochar has a calorific value of 14.8–23% higher than the initial husk. To assess the behavior of sunflower husk ash, predictive coefficients were calculated. Torrefaction of sunflower husks does not exclude the possibility of slagging of the furnace but reduces the likelihood of slagging by 2.31–7.27 times. According to calculations, the torrefaction of sunflower husks reduces the likelihood of ash deposits on the convective heating surfaces of the boiler by 2.1–12.2 times. According to its fuel characteristics, the husk, after torrefaction in an environment of superheated steam, approaches wood waste, i.e., can be burned separately without additives or mixtures with other fuels with refractory ash
63,65Cu NMR study of the magnetically ordered state of the multiferroic CuFeO2
Field-swept 63,65Cu NMR spectra under magnetic fields up to 8.3 T at a constant NMR frequency and temperatures T c axis, a nearly zero internal magnetic field at the Cu site in magnetic ordered state was observed. This is explained by the perfect cancellation of the internal fields produced by the 6 nearest neighbor Fe3+ (S = 5/2) ions, revealing the magnetic structure to be a collinear four-sublattice structure. On the other hand, when the magnetic field is applied along the ab plane, we observed a finite internal field at the Cu sites, which is due to the canting of the Fe moments. Strong change in the NMR signal intensity is observed around 7–8 T, corresponding to the magnetic phase transition from the collinear magnetic to ferroelectric incommensurate states. The ratio of the two magnetic phases significantly depends on the history of the change in the external magnetic field and the temperature of the sample. The details of history dependence of the ratio were discussed.</p