Population-level analysis of migratory phenology using genomic data in a migratory songbird

2022 Spring.Includes bibliographical references.The timing of spring migration for Nearctic-Neotropical birds is key for maximizing access to seasonal resources, such as food or territory on the breeding grounds, while minimizing risk of exposure to winter conditions. Many factors, including sex, weather, energetic condition, and food availability influence migration timing. However, the methods for disentangling within and between population drivers of migratory timing have historically been limited by challenges associated with identifying the breeding location of migrants passing through stop-over sites. For example, spring phenology hypotheses predict that the timing of migration will be driven by the date of spring onset at the breeding grounds, but spring onset often co-varies with distance to breeding site, making it difficult to disentangle the relative roles of each. Here, we utilize genomic data to identify the breeding ground of origin for over one thousand Common Yellowthroats (Geothlypas trichas) collected at key migratory stopover points to test the relative roles of sex, migration distance, and date of spring onset in driving migratory timing. We found different relationships for analyses at the species and population level. We conclude that while sex, estimated migration distance, genetic population, and breeding ground phenology are all highly significant predictors of migratory timing across the species, the relative importance each factor differs among genetically distinct populations and from the species-level pattern. Our results highlight the importance of including population-level differences when attempting to understand the multitude of factors that regulate migratory timing

Identification of Belowground Woody Structures Using Molecular Biomarkers

Within the last two decades substantial progress has been made in understanding seed bank dynamics and the contribution of the soil seed bank to a post-disturbance plant community. There has been relatively little progress, however, in understanding perennial bud bank dynamics and the contribution of the soil bud bank to secondary succession. This lack of information is due primarily to the inability to reliably identify roots, rhizomes, and lignotubers that lie dormant beneath the soil surface. This scientific investigation, therefore, addressed the issue of identification of belowground woody structures. The first objective was to develop a methodology that utilizes molecular tools to reliably identify woody plant species from subsoil tissue samples. The second objective was to create a key in which molecular markers serve as criteria for identification and differentiation of selected tree and shrub species common to the mountains of northeast Oregon and southeast Washington. Application of restricted fragment length polymorphism (RFLP) analysis on polymerase chain reaction (PCR)-amplified rbcL gene products proved to be a reliable method to identify and differentiate 15 plants to the genus level. Two restriction enzymes, DPN II and Hha I, cut (or do not cut) the PCR-rbcL product into one to six fragments. Fragment number and length are used to develop an identification key. Plants not analyzed in this key may share the same banding patterns , resulting in a false-positive identification of unknowns. Future research needs and management implications are discussed

Magnetization Dynamics in the Lanthanide Metal Gadolinium

In this thesis we investigate the rare-earth metal Gd aiming to gain more insight into the complex interplay of physical processes leading to optically induced ultrafast magnetization dynamics. Using X-ray magnetic circular dichroism (XMCD) we study the magnetization dynamics in Gd over a wide range of time scales and pump laser fluences, while using photoemission spectroscopy (PES) we focus on the first 100 fs of the dynamics showing an increase in exchange splitting of the 5d6s bulk bands. Moreover, we analyze oscillations in the kinetic energy of the photoemitted electrons for negative pump-probe delays in our PES data. Using XMCD in reflection we find a two-step demagnetization on sub-ps and tens of ps time scales with a remagnetization on a hundred ps time scale for various pump laser fluences. An extended version of the microscopic three-temperature model (M3TM) captures the dynamics of the whole data set and suggests Elliott-Yafet-type spin-flip scattering to play a dominant role in the 100 fs to ns magnetization dynamics in Gd. On the fast time scale the demagnetization magnitude depends exponentially on the pump laser fluence implying that a complete demagnetization on that time scale in pure Gd is not physically possible. Results for varying pump photon energies indicate an influence of the initial hot electron distribution on the following dynamics, where lower pump photon energies cause a weaker demagnetization in the early sub-ps dynamics. Our PES study reveals new results particularly in the first 100 fs, where the majority-spin bulk band reacts directly to laser excitation and is not delayed as found in literature. Shifts in the minority- and majority-spin bulk band binding energies lead to a surprising increase in exchange splitting of the 5d6s valence bands in Gd for a few dozen fs after laser excitation indicating an increase in magnetization. Concurrently, the majority-spin bulk and surface states shift in opposing directions despite the same spin polarization. We find optically induced spin transfer (OISTR) between the surface and bulk states in Gd likely to account for this phenomenon. At negative pump-probe delays we observe oscillations in the kinetic energy of photoemitted electrons, a phenomenon explained in literature by ponderomotive acceleration by a transient grating formed by the interference of the incoming and reflected pump laser pulse. We observe a strong enhancement of the oscillation amplitudes on Gd in accordance with the model. We find similar oscillations on W and model parameters show the expected pump photon energy dependence. However, we see different amplitudes for electrons emitted out of different states in W with only slightly different kinetic energy, an unexpected result since photoemitted, free electrons subject to the same potential should experience the same force

Mega-Regionalism in Trade from a Sectoral Perspective. The Case of the Automotive Industry in the Regional Comprehensive Economic Partnership

Theoretical background: The Regional Comprehensive Economic Partnership (RCEP) is the largest mega-regional trade agreement ever signed, accounting for more than 30% of the global population, exports, and gross domestic product (GDP). It is also the largest automotive market worldwide, with significant potential both in terms of automotive manufacturing and sales.Purpose of the article: The paper’s main objective is to characterize China-RCEP automotive trade in the years 2012–2021 with reference to key provisions and implications of the aforementioned mega-regional trade agreement for the automotive industry. In the empirical part of the paper, the authors attempt to verify the hypothesis that trade liberalization under RCEP may contribute to the expansion of the regional automotive industry in terms of trade volume, as well as fragmentation of value and supply chains.Research methods: The authors conducted an analysis of intra-industry trade disaggregated into 54 six-digit HS tariff codes using the Grubel–Lloyd and Balassa indexes, accompanied by cross sectional analysis and studies of sectoral reports and literature in the field of mega-regionalism in trade.Main findings: The hypothesis formulated in the introduction of the paper was verified positively –the authors provided an added value to previous empirical studies on RCEP, in the form of a perspective of the automotive industry and in-depth analysis of sectoral trends for the last ten years. The potential for further fragmentation of value and supply chains inside the region was identified, including the possibility of relocation of manufacturing and assembly activities to lower the cost of RCEP Member States to strengthen comparative advantages over extra-regional counterparts (EU, USMCA). The authors pointed at the prospective rising attractiveness of RCEP in automotive manufacturers’ location decisions worldwide, considering both costs, retreat from global-oriented manufacturing and export strategies, investment security, sustainable development, as well as geopolitical trends in respect of newly established tariff and non-tariff barriers