490,771 research outputs found
Shipping Through Sea Ice: Impacts on Marine Habitats and Best Practices
As the result of Arctic climate change and an increase in shipping season length, there is a growing interest in Arctic shipping operations. Sea ice serves as an important habitat for marine mammals, therefore, shipping through sea ice could lead to increased negative interactions with ice-bound marine mammals. The following literature review discusses the impacts of icebreaking on marine mammals and habitats. These impacts include: avoidance of areas where icebreaking is occurring, behavioral and physiological impacts of increased anthropogenic noise, entrapment, habitat destruction and fragmentation, and oil spills
Evidence of strong stabilizing effects on the evolution of boreoeutherian (Mammalia) dental proportions.
The dentition is an extremely important organ in mammals with variation in timing and sequence of eruption, crown morphology, and tooth size enabling a range of behavioral, dietary, and functional adaptations across the class. Within this suite of variable mammalian dental phenotypes, relative sizes of teeth reflect variation in the underlying genetic and developmental mechanisms. Two ratios of postcanine tooth lengths capture the relative size of premolars to molars (premolar-molar module, PMM), and among the three molars (molar module component, MMC), and are known to be heritable, independent of body size, and to vary significantly across primates. Here, we explore how these dental traits vary across mammals more broadly, focusing on terrestrial taxa in the clade of Boreoeutheria (Euarchontoglires and Laurasiatheria). We measured the postcanine teeth of NÂ =Â 1,523 boreoeutherian mammals spanning six orders, 14 families, 36 genera, and 49 species to test hypotheses about associations between dental proportions and phylogenetic relatedness, diet, and life history in mammals. Boreoeutherian postcanine dental proportions sampled in this study carry conserved phylogenetic signal and are not associated with variation in diet. The incorporation of paleontological data provides further evidence that dental proportions may be slower to change than is dietary specialization. These results have implications for our understanding of dental variation and dietary adaptation in mammals
Parenteral vaccination of mammalian livestock with Newcastle disease virus-based vector vaccines offers optimal efficacy and safety
Newcastle disease virus (NDV) is an avian virus that is being evaluated as a vaccine vector for the delivery of foreign genes in mammals. The use of NDV as a vaccine vector in these species offers two major advantages. First, NDV is highly attenuated in mammals, rendering its use inherently safe. Second, mammals lack pre-existing NDV immunity, which minimizes the risk of vaccination failure. NDV-vector vaccines are generally administered to mammals via the respiratory route. We recently showed that intramuscular vaccination with NDV-based Rift Valley fever virus (RVFV) vaccines provides complete protection in mice and induces neutralizing antibodies in sheep and cattle, the main target species of RVFV. Here, we discuss the use of NDV as a vaccine vector for applications in mammalian livestock with an emphasis on the vaccination route. We also report the results of novel experiments that underscore our notion that vaccination via a parenteral route is more effective than immunization via the respiratory route
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Therapy of cancer by insect cells containing recombinant baculovirus encoding genes
Provided are compositions and methods of use for insect cells comprising baculovirus encoding non-surface expressed proteins and peptides. The claimed invention particularly relates to compositions comprising insect cells containing baculovirus that express cytokines. Such compositions may be administered by, for example, direct intratumoral injection into tumors in mammals, resulting in tumor reduction or recission. Another aspect of the claimed invention concerns methods of promoting resistance to the reoccurence of tumors in mammals who have undergone such tumor recission. In a specific aspect of the claimed invention, the mammals are human subjects presenting with various forms of cancer.Board of Regents, University of Texas Syste
Helminth fauna of Mt. Ontake. Part 2. Trematoda and Cestoda
I. Trematodes of mammals
1. Brachylaemus tokudai n. sp.
2. Acanthatrium ovatum Yamaguti, 1939
II. Cestodes of frogs
3. Baerietta montana n. sp.
4. Baerietta claviformis n. sp.
III. Cestodes of· birds
5. Choanotaenia barbara Meggitt, 1926
IV. Cestodes of mammals
6. Hymenolepis apodemi n. sp.</p
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Darwin and evolution: a set of activities based on the evolution of mammals
These activities, prepared for key stage 5 students (ages 16-18) and also suitable for key stage 4 (ages 14-16), show that physical appearance is not necessarily the best way to classify mammals. DNA structure is examined to show how similarities and differences between DNA sequences of mammals can be used to establish evolutionary relationships. Some real DNA sequences are compared to illustrate that the whale is surprisingly closely related to mammals such as the hippo, camel and cow, a relationship confirmed by fossil evidence. Finally, an analysis of haemoglobin sequences of primates shows the close relationship between humans and other great apes such as the chimpanzee
How large should whales be?
The evolution and distribution of species body sizes for terrestrial mammals
is well-explained by a macroevolutionary tradeoff between short-term selective
advantages and long-term extinction risks from increased species body size,
unfolding above the 2g minimum size induced by thermoregulation in air. Here,
we consider whether this same tradeoff, formalized as a constrained
convection-reaction-diffusion system, can also explain the sizes of fully
aquatic mammals, which have not previously been considered. By replacing the
terrestrial minimum with a pelagic one, at roughly 7000g, the terrestrial
mammal tradeoff model accurately predicts, with no tunable parameters, the
observed body masses of all extant cetacean species, including the 175,000,000g
Blue Whale. This strong agreement between theory and data suggests that a
universal macroevolutionary tradeoff governs body size evolution for all
mammals, regardless of their habitat. The dramatic sizes of cetaceans can thus
be attributed mainly to the increased convective heat loss is water, which
shifts the species size distribution upward and pushes its right tail into
ranges inaccessible to terrestrial mammals. Under this macroevolutionary
tradeoff, the largest expected species occurs where the rate at which
smaller-bodied species move up into large-bodied niches approximately equals
the rate at which extinction removes them.Comment: 7 pages, 3 figures, 2 data table
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