The impact of feed cost on U.S. poultry production: implications for the impact of increased ethanol production

Crop Production/Industries, Livestock Production/Industries,

Mechanism of adhesion and detachment at the anterior end of Merizocotyle icopae (Monogenea: Monocotylidae) including ultrastructure of the anterior adhesive matrix

The anterior adhesive mechanism was studied for Merizocotyle icopae (Monogenea: Monocotylidae). Adult anterior apertures can open and close. In addition, duct endings terminating within the apertures are everted or retracted depending on the stage of attachment. Adhesive in adults is synthesized from all 3 secretory types (rod-shaped, small and large spheroidal bodies) found within anterior apertures. All exit together and undergo mixing to produce the adhesive matrix, a process that depletes duct contents. A greater number of ducts carrying rod-shaped bodies is depleted than ducts containing spheroidal bodies which changes the ratio of secretory types present on detachment. Detachment involves elongation of duct endings and secretion of additional matrix as the worm pulls away from the substrate. The change in secretory type ratio putatively modifies the properties of the secreted matrix enabling detachment. Only after detachment do ducts refill. During attachment, individual secretory bodies undergo morphological changes. The larval and adult adhesive matrix differs. Anterior adhesive in oncomiracidia does not show fibres with banding whereas banded fibres comprise a large part of adult adhesive. The data suggest that this is the result of adult spheroidal secretions modifying the way in which the adult adhesive matrix forms.B. W. Cribb, W. D. Armstrong and I. D. Whittingto

The only known cyclopygid–‘atheloptic’ trilobite fauna from North America: the upper Ordovician fauna of the Pyle Mountain Argillite and its palaeoenvironmental significance

The trilobite fauna of the upper Ordovician (middle Katian) Pyle Mountain Argillite comprises a mixture of abundant mesopelagic cyclopygids and other pelagic taxa and a benthic fauna dominated by trilobites lacking eyes. Such faunas were widespread in deep water environments around Gondwana and terranes derived from that continent throughout Ordovician time but this is the only known record of such a fauna from North America and thus from Laurentia. It probably reflects a major sea level rise (the ‘Linearis drowning events’) as does the development of coeval cyclopygid-dominated deep water trilobite faunas in terranes that were marginal to Laurentia and are now preserved in Ireland and Scotland. The Pyle Mountain Argillite trilobite fauna occurs with a deep water Foliomena brachiopod fauna and comprises 22 species. Pelagic trilobites (mostly cyclopygids) constitute 36% of the preserved sclerites, and 45% of the fauna is the remains of trilobites lacking eyes, including one new species, Dindymene whittingtoni sp. nov. Three species of cyclopygid are present, belonging in Cyclopyge, Symphysops and Microparia (Heterocyclopyge). Cyclopygids are widely thought to have been stratified in the water column in life and thus their taxonomic diversity reflects the relative depths of the sea-beds on which their remains accumulated. A tabulation of middle and upper Katian cyclopygid-bearing faunas from several palaeoplates and terranes arranged on the basis of increasing numbers of cyclopygid genera allows an assessment of the relative depth ranges of the associated benthic taxa. The Pyle Mountain Argillite fauna lies towards the deeper end of this depth spectrum

THE ATTITUDE–BEHAVIOR DICHOTOMY IN THE TIME OF COVID-19: AN EXPLORATION USING GENERALIZED STRUCTURAL EQUATION MODELING

The COVID-19 pandemic brought the need to quickly deploy non-pharmaceutical measures like facemasks to reduce transmission rates into sharp focus. Factors influencing this behavior are examined through the classic attitude–behavior lens of Fishbein and Ajzen [Belief, Attitude, Intention, and Behavior: An Introduction to Theory and Research. Reading, MA: Addison-Wesley] cast in the language of property rights and social norms. Behavior is operationalized as wearing a facemask (or not) and attitude in terms of supporting a mandatory mask mandate. This yields targetable segments of the population as they are referred to in a marketing context: wearing/supporting, wearing/not supporting, not wearing/supporting, not wearing/not supporting [Kim, D, RT Carson, D Whittington and WM Hanemann (2022). Support for regulation versus compliance: Face masks during COVID-19. Public Health in Practice, 5, 100324]. Membership in each segment is predicted using a generalized structural equation modelling (GSEM) approach focused on three broad factors. The first includes political and demographic variables, which represent exogenous taste parameters. The second is a set of knowledge variables characterizing the COVID-19 information a person possesses. These are potentially influenceable by health officials. The third relates to risk cast in the form of knowing someone who had tested positive for COVID-19, been hospitalized or died from it. The GSEM results paint a rich picture of how our factor sets interact with the four targetable segments of the population in a critical situation where high but not perfect compliance is needed

Seahorse Brood Pouch Transcriptome Reveals Common Genes Associated with Vertebrate Pregnancy

Viviparity (live birth) has evolved more than 150 times in vertebrates, and represents an excellent model system for studying the evolution of complex traits. There are at least 23 independent origins of viviparity in fishes, with syngnathid fishes (seahorses and pipefish) unique in exhibiting male pregnancy. Male seahorses and pipefish have evolved specialized brooding pouches that provide protection, gas exchange, osmoregulation, and limited nutrient provisioning to developing embryos. Pouch structures differ widely across the Syngnathidae, offering an ideal opportunity to study the evolution of reproductive complexity. However, the physiological and genetic changes facilitating male pregnancy are largely unknown. We used transcriptome profiling to examine pouch gene expression at successive gestational stages in a syngnathid with the most complex brood pouch morphology, the seahorse Hippocampus abdominalis. Using a unique time-calibrated RNA-seq data set including brood pouch at key stages of embryonic development, we identified transcriptional changes associated with brood pouch remodeling, nutrient and waste transport, gas exchange, osmoregulation, and immunological protection of developing embryos at conception, development and parturition. Key seahorse transcripts share homology with genes of reproductive function in pregnant mammals, reptiles, and other live-bearing fish, suggesting a common toolkit of genes regulating pregnancy in divergent evolutionary lineage