Characterizing ontogenetic habitat shifts in marine fishes: advancing nascent methods for marine spatial management.

Niche requirements and habitat resource partitioning by conspecific fishes of different sizes are significant knowledge gaps in the species distribution modelling domain. Management actions and operations are typically concentrated on static habitats, or specific areas of interest, without considering movement patterns of species associated with ontogenetic shifts in habitat usage. Generalized Additive Models were used to model the body length-habitat relationships of six fish species. These models were used to identify subsets of environmental parameters that drive and explain the continuous length-habitat relationships for each of the study species, which vary in their degree of ecological and/or commercial importance. Continuous predictive maps of the length distributions for each of the six study species across approx. 200 km(2) of the study area were created from these models. The spatial patterns in habitat partitioning by individuals of different body lengths for all six study species provide strong evidence for ontogenetic shifts. This highlights the importance of considering ontogenetic processes for marine spatial management. Importantly, predictive hotspot maps were created that identify potential areas that accumulate individuals of similar life stages of multiple species (e.g. multispecies nursery areas). In circumstances where limited resources are available for monitoring and management of fish resources, predictive modelling is a valuable tool for studying previously overlooked processes such as ontogenetic habitat shifts. Predictive modelling provides crucial information that elucidates spatial patterns in community composition across mosaics of benthic habitats. This novel technique can contribute to the spatial management of coastal fish and fisheries by identifying areas that are important for different life history stages of multiple fish species

Совершенствование ценообразования на предприятии

Выпускная квалификационная работа 105 с., 7 рис., 29 табл., 22 источника. Цель работы - экономическое обоснование оптимальной цены на продукцию. В процессе исследования проводились статистические исследования. В результате исследования была разработана оптимальная цена на продукцию. Основные технологические и управленческие характеристики: организационная структура является линейной, списочная численность предприятия - 150 человек.Final qualifying work 105 p., 7 Fig., 29 tab., 22 source. Purpose - the economic rationale for the optimal prices for the products. During the study, carried out statistical studies. The study developed the optimal price for the products. Basic technological and managerial characteristics: organizational structure is linear, the headcount of the enterprise - 150 people

Tracing the history and biogeography of the Australian blindsnake radiation

International audienceAim We investigated the biogeographical history of Australian blindsnakes ( Ramphotyphlops ) with reference to Australia's palaeoclimatic history over the past 20 Myr, particularly the development of an extensive arid zone over this period. Terrestrial vertebrate lineages dating back to the Miocene or earlier are predicted to display some or all of the following patterns: (1) for taxa including mesic, arid and monsoonal representatives, a mesic distribution should be phylogenetically ancestral; (2) mesic and monsoon tropical lineages should have diverged before the onset of aridification (with arid lineages appearing later); and (3) refuges may have allowed local persistence and diversification of lineages in the monsoon tropical and mesic zones since the mid‐Miocene. Location Continental Australia. Methods We compiled a molecular data set comprising one mitochondrial and three nuclear genes for 107 individuals belonging to 28 blindsnake species. Phylogenetic relationships were reconstructed using maximum likelihood and Bayesian inference with RA x ML and MrBayes , respectively. Divergence times were assessed using multidivtime . Ancestral habitat states (arid and non arid) were reconstructed using the maximum likelihood method implemented in Mesquite . Results The age of the Australian Ramphotyphlops radiation was estimated at 21.9 Ma (95% credibility interval: 30.2–15.1 Ma). Mesic and monsoon tropical lineages are older than the onset of aridification, with mesic distribution appearing as ancestral on phylogenies. After the onset of aridification, lineages persisted and diversified in mesic, tropical and/or rocky refugia. Arid lineages diversified more recently (< 5 Ma). Main conclusions Australian blindsnakes join several other Australian squamate lineages with tropical‐mesic origins that successfully adapted to the expansion of aridity since the mid‐Miocene ( c . 17 Ma) and now show evidence of multiple relatively recent evolutionary radiations across Australia. We further demonstrate that localized refugia permitted persistence and diversification of mesic taxa, with arid lineages diversifying much later (< 5 Ma) when the arid zone was well established