Population Transfer Research Articles

Tailoring light-induced charge transfer and intersystem crossing in FeCO using time-dependent spin-orbit configuration interaction.

Real-time (RT) electronic structure methods provide a natural framework for describing light-matter interactions in arbitrary time-dependent electromagnetic fields (EMF). Optically induced excited state transitions are of particular interest, which require tuned EMF to drive population transfer to and from the specific state(s) of interest. Intersystem crossing, or spin-flip, may be driven through shaped EMF or laser pulses. These transitions can result in long-lived "spin-trapped" excited states, which are especially useful for materials requiring charge separation or protracted excited state lifetimes. Time-dependent configuration interaction (TDCI) is unique among RT methods in that it may be implemented in a basis of eigenstates, allowing for rapid propagation of the time-dependent Schrödinger equation. The recent spin-orbit TDCI (TD-SOCI) enables a real-time description of spin-flip dynamics in an arbitrary EMF and, therefore, provides an ideal framework for rational pulse design. The present study explores the mechanism of multiple spin-flip pathways for a model transition metal complex, FeCO, using shaped pulses designed to drive controlled intersystem crossing and charge transfer. These results show that extremely tunable excited state dynamics can be achieved by considering the dipole transition matrix elements between the states of interest.

Exchanging Holiness for Harmony, Bringing Pontus to Patria: The Refugee Panagia on the Move

Abstract İsmet Pasha’s visit to Athens in 1931 was a highlight of the diplomatic revolution between Turkey and Greece in the early 1930s. Thanks to press coverage of the visit, the Turkish public had the opportunity to observe Greece’s social landscape as shaken by the refugee issue for the first time since the Greco-Turkish war and population exchange. Whether Greek refugees could return to their former homelands was the focal point of the visit. A month later, the Turkish government granted Greek exchangees the freedom to travel. Prior to this decision, the cabinet had handled authorization requests individually and issued special permits as a palliative solution. The case of the appeal made by an exchangee monk for a mission to unearth hidden relics at Sumela Monastery is especially intriguing. This article focuses on the story of this mission and the historical context that facilitated its realization.

On a Coupled Time-Varying Beverton–Holt Model with Two Habitats Subject to Harvesting, Repopulation, and Mixed Migratory Flows of Populations

Two time-varying Beverton–Holt models are investigated in which the population of the same species evolves jointly in two coupled habitats which can be subject to population exchanges. Both habitats can have different parameterizations concerning their intrinsic growth rates and their environment carrying capacities due to different environmental conditions. Mutual fluxes of populations in-between both habitats are possible together with harvesting actions. In one of the models harvesting acts on juvenile individuals. In the other proposed model, harvesting takes place on the adult populations after the reproduction cycle they have performed has ended. The second investigated model, contrarily to the first one, relies on an “a posteriori” harvesting action to the reproductive stage which is able to modify the stocks of population. The considered harvesting can also be negative to describe repopulation actions. The equilibrium points in steady-state and their stability properties as well as the extinction conditions and the boundedness, oscillation issues, and positivity of the solutions are also investigated.

Before the War: Orthodox Christians in Anatolia, 1880s–1914

Abstract Orthodox Christians in Anatolia engaged in a widespread effort to establish churches, schools, and cultural associations in the late Ottoman period. This effort lasted roughly from the 1880s until the Great War, marking these few decades in the late 19th and early 20th centuries as a period of intense institutionalization. This article historicizes the Orthodox Christian presence in Anatolia by exploring the moment of emergence of modern institutions, which would later provide our most direct and visual knowledge (real or remembered) of Orthodox Christian communities in the Ottoman Empire. Focusing on a diverse range of local, imperial and international actors in provincial space in western Anatolia, the study delineates the contexts and processes of institutionalization. It shows a modern community in the making, and demonstrates how Orthodox Christians consolidated themselves before being forced to leave as a result of the Greek-Turkish War of 1919–22 and the ensuing population exchange.

An Evaluation of Suitable Habitats for Amur Tigers (Panthera tigris altaica) in Northeastern China Based on the Random Forest Model.

Amur tigers are at the top of the food chain and play an important role in maintaining the health of forest ecosystems. Scientific and detailed assessment of the habitat quality of Amur tigers in China is the key to maintaining the forest ecosystem and also addressing the urgent need to protect and restore the wild population of Amur tigers in China. This study used the random forest method to predict the potential habitat of Amur tigers in Heilongjiang and Jilin provinces using animal occurrence sites and a variety of environmental variables. Random forests are a combination of tree predictors such that each tree depends on the values of a random vector sampled independently and with the same distribution for all trees in the forest. The generalization error for forests converges to a limit as the number of trees in the forest becomes large. The generalization error of a forest of tree classifiers depends on the strength of the individual trees in the forest and the correlation between them. The results showed that the AUC value of the test set was 0.955. The true skill statistic (TSS) value is 0.5924, indicating that the model had good prediction accuracy. Using the optimal threshold determined by the Youden index as the cutoff value, we found that the suitable habitat for Amur tigers in the field was approximately 107,600 km2, accounting for 16.3% of the total study areas. It was mainly distributed in the Sino-Russian border areas in the south of the Laoyeling Mountains at the junction of Jilin and Heilongjiang provinces, the Sino-Russian border areas of Hulin-Raohe in the eastern part of the Wanda Mountains, and the Lesser Khingan Mountain forest region. The habitat suitability of the Greater Khingan Mountain and the plain areas connecting Harbin and Changchun was relatively low. Prey potential richness was the most critical factor driving the distribution of Amur tigers. Compared with their prey, the potential habitats for Amur tigers in Heilongjiang and Jilin provinces were small in total areas, sporadically distributed, and had low continuity and a lack of connectivity between patches. This indicates that some factors may restrict the diffusion of the Amur tiger, whereas the diffusion of ungulates is less restricted. The Amur tigers in this area face a serious threat of habitat fragmentation, suggesting that habitat protection, restoration, and ecological corridor construction should be strengthened to increase population dispersal and exchange. We provide a reference for future population conservation, habitat restoration, construction of ecological migration corridors, and population exchange of Amur tigers.

Low Genetic Diversity of the Only Clade of the Tick Rhipicephalus microplus in the Neotropics.

This study addresses the variability of the mitochondrial cytochrome oxidase subunit I (COI) and 16S rDNA (16S), and nuclear internal transcriber spacer ITS2 (ITS2) genes in a set of field-collected samples of the cattle tick, Rhipicephalus microplus (Canestrini, 1888), and in geo-referenced sequences obtained from GenBank. Since the tick is currently considered to be a complex of cryptic taxa in several regions of the world, the main aims of the study are (i) to provide evidence of the clades of the tick present in the Neotropics, (ii) to explore if there is an effect of climate traits on the divergence rates of the target genes, and (iii) to check for a relationship between geographical and genetic distance among populations (the closest, the most similar, meaning for slow spread). We included published sequences of Rhipicephalus annulatus (Nearctic, Afrotropical, and Mediterranean) and R. microplus (Afrotropical, Indomalayan) to fully characterize the Neotropical populations (total: 74 16S, 44 COI, and 49 ITS2 sequences included in the analysis). Only the clade A of R. microplus spread in the Nearctic-Neotropics. Both the K and Lambda's statistics, two measures of phylogenetic signal, support low divergence rates of the tested genes in populations of R. microplus in the Neotropics. These tests demonstrate that genetic diversity of the continental populations does not correlate either with the geographic distance among samples or with environmental variables. The low variability of these genes may be due to a combination of factors like (i) the recent introduction of the tick in the Neotropics, (ii) a large, effective, and fast exchange of populations, and (iii) a low effect of climate on the evolution rates of the target genes. These results have implications for the ecological studies and control of cattle tick infestations.

Adiabatic Manipulation of a System Interacting with a Spin Bath

The Stimulated Raman Adiabatic Passage, a very efficient technique for manipulating a quantum system based on the adiabatic theorem, is analyzed in the case where the manipulated physical system is interacting with a spin bath. The exploitation of the rotating wave approximation allows for the identification of a constant of motion, which simplifies both the analytical and the numerical treatment, which allows for evaluating the total unitary evolution of the system and bath. The efficiency of the population transfer process is investigated in several regimes, including the weak and strong coupling with the environment and the off-resonance. The formation of appropriate Zeno subspaces explains the lowering of the efficiency in the strong damping regime.

The Population Exchange and Politics in the Historiography of Turkey and Greece

Abstract This is a historiographical essay about the impact of the population exchange on the political sphere in Greece and Turkey. Notwithstanding the asymmetry in the literature produced in the two countries—excessive in Greece and limited in Turkey—there have been two seminal narratives regarding the impact of the exchange on interwar politics. In regard to Greece, the political cleavage between refugees and locals is shown as the basic factor shaping politics. In regard to Turkey, the exodus of the Christian bourgeoisie is seen as a major factor behind the authoritarianism of the interwar regime. Nevertheless, recent research on local communities that specifically explores refugee and exchangee agency in local and regional politics and studies the place of refugees and exchangees in state demographic projects goes beyond the limitations of macro perspectives, qualifying the prevailing theses on the impact of the exchange on politics in both countries.

The Refugee Sports Clubs in Greece as Carriers of Asia Minor Memory (1922–40)

Abstract After the exodus from their homelands and the population exchange between Turkey and Greece, Greek Orthodox refugees from Asia Minor formed hundreds of associations in Greece’s refugee settlements. These associations served the purposes of recovery and cultural expression, with many among them also functioning as carriers and promoters of the memory of their members’ places of origin. Among these associations were hundreds of sports clubs that young refugees joined. The mnemonic practices that members of these sports clubs pursued included the repeated use of texts, images, and rituals which referred mainly to the geography and history of Asia Minor. Based on the archives of refugee sports clubs from all over Greece, this article analyzes these mnemonic practices and places them in the general context of collective refugee memory.

A Gender Analysis of the Population Exchange Between Greece and Turkey

Abstract One hundred years after people were forcibly driven from their ancestral lands, this article traces the gender aspect of the Turkish-Greek population exchange from an ethnographic perspective. This aspect certainly differs with respect to the refugees’ place of origin, place of residence, social class, and the cultural capital they brought from their previous lives. The experiences were diverse, in some cases similar, and cut across religious boundaries. Based on memoirs, literary works, and oral history, this article draws a comparative picture of refugee lives before and after their displacement.

The Asymmetries of Displacement: The Spatial Aspects of the Greek-Turkish Population Exchange

Abstract The Greek-Turkish population exchange convention of 1923 had major effects on both countries in terms of politics, economy, society, and space. Some of the negative impacts were minimized over time. However, there are some long-term impacts, for instance on space, that are still observable in the cities we live in, even though a full century has passed since the exchange. This article focuses on both the local and broader spatial consequences of the population exchange from a comparative perspective.

Optimization and validation of universal response functions for interior spruce (Picea glauca, Picea engelmannii, and their hybrids)

Ecological models, including various forms of population transfer and response functions, have been widely employed to predict the performance of forest trees under future climate conditions. However, the accuracy of model predictions remains a challenge due to the lack of systematic model optimization and validation processes. In this study, we explored a series of candidate universal response functions (URFs) based on comprehensive provenance trials for interior spruce, a tree hybrid complex of great ecological and economic importance in British Columbia. We first developed URFs with various numbers of climate variables and their combinations, then evaluated and validated these models with conventional statistical methods. Although these models showed high predictive power and performed well in statistical validation, the map visualizations of these models varied substantially. Therefore, we further conducted a pixel-wise spatial validation based on site productivity data to identify the model with the best performance. Finally, we analyzed the impact of climate change on interior spruce based on the final model. Our results revealed that: 1) a minimum number of independent climate variables is required to generate a reliable and informative ecological model; 2) spatial validation is critical to ensure the credibility of ecological models; 3) among-population variation resulting from local adaptation is relatively weak, indicating a potential for modest productivity gains from selecting well-adapted populations for stand establishment; and 4) most of the current interior spruce habitat is projected to be vulnerable to anthropogenic climate change, largely due to temperature rise, with a major upslope shift predicted.

A novel strategy for eliminating antibiotic resistance genes during fertilization of dewatered sludge by earthworms: Vermicomposting practice using Chinese herbal residues derived from Lianhua Qingwen as a bulking material

Vermicomposting is a sustainable sludge recycling technology that utilizes an eco-friendly composting using earthworms and microorganisms. However, a high abundance of antibiotic resistance genes (ARGs) remains in dewatered sludge that is not satisfactorily eliminated by vermicomposting. Chinese herbs have played a major role in curing many diseases in East Asia, leading to a large amount of Chinese herbal residues (CHRs) are difficult to dispose of. The present study investigated the feasibility of CHRs on the ARGs reduction in dewatered sludge during vermicomposting. The CHRs derived from Lianhua Qingwen were added separately to sludge with weight ratios of 0%, 10%, 30%, and 50%; sludge was then vermicomposted for 30 days. The results showed that co-vermicomposting of sludge and CHRs is a feasible strategy. The CHR treatments significantly (P < 0.05) decreased antibiotic concentration and bacterial population by 23.64%–49.68% and 42.58%–93.07%, respectively, compared to counterpart. Compared to the control, the CHR addition lowered the absolute abundances of macrolide, tetracycline, and sulfonamide ARGs by 42.69%–85.15%, 22.03%–75.24%, and 23.59%–90.66%, respectively. In addition, sludge containing 30% CHRs showed significant (P < 0.05) elimination of intⅠ-1 and tnpA-4 genes with abundance reductions of 71.40% and 52.33%, respectively, relative to the control. This study suggests that the CHRs can effectively reduce ARGs content in sludge by decreasing the bacterial population and horizontal gene transfer capacity during vermicomposting.

Singlet Fission in Lycopene H-Aggregates.

A theory of singlet fission (SF) in carotenoid dimers is applied to explain the SF in lycopene H-aggregates observed after high-energy photoexcitation. The explanation proposed here is that a high energy, delocalized bright 1Bu+ state first relaxes and localizes onto a single lycopene monomer. The high-energy intramonomer state then undergoes internal conversion to the 11Bu- state. Once populated, the 11Bu- state allows exothermic bimolecular singlet fission, while its internal conversion to the 21Ag- state is symmetry forbidden. The simulation of SF predicts that the intramonomer triplet-pair state undergoes almost complete population transfer to the intermonomer singlet-pair state within 100 ps. Simultaneously, ZFS interactions begin to partially populate the intermonomer quintet triplet-pair state up to ca. 2 ns, after which hyperfine interactions thermally equilibrate the triplet-pair states, thus forming free single triplets within 50 ns.

Characterizing Conical Intersections in DNA/RNA Nucleobases with Multiconfigurational Wave Functions of Varying Active Space Size.

We characterize the photochemically relevant conical intersections between the lowest-lying accessible electronic excited states of the different DNA/RNA nucleobases using Cholesky decomposition-based complete active space self-consistent field (CASSCF) algorithms. We benchmark two different basis set contractions and several active spaces for each nucleobase and conical intersection type, measuring for the first time how active space size affects conical intersection topographies in these systems and the potential implications these may have toward their description of photoinduced phenomena. Our results show that conical intersection topographies are highly sensitive to the electron correlation included in the model: by changing the amount (and type) of correlated orbitals, conical intersection topographies vastly change, and the changes observed do not follow any converging pattern toward the topographies obtained with the largest and most correlated active spaces. Comparison across systems shows analogous topographies for almost all intersections mediating population transfer to the dark 1nO/Nπ* states, while no similarities are observed for the "ethylene-like" conical intersection ascribed to mediate the ultrafast decay component to the ground state in all DNA/RNA nucleobases. Basis set size seems to have a minor effect, appearing to be relevant only for purine-based derivatives. We rule out structural changes as a key factor in classifying the different conical intersections, which display almost identical geometries across active space and basis set change, and we highlight instead the importance of correctly describing the electronic states involved at these crossing points. Our work shows that careful active space selection is essential to accurately describe conical intersection topographies and therefore to adequately account for their active role in molecular photochemistry.

Optimal and robust control of population transfer in asymmetric quantum-dot molecules

We present an optimal and robust quantum control method for efficient population transfer in asymmetric double quantum-dot molecules. We derive a long-duration control scheme that allows for highly efficient population transfer by accurately controlling the amplitude of a narrow-bandwidth pulse. To overcome fluctuations in control field parameters, we employ a frequency-domain quantum optimal control theory method to optimize the spectral phase of a single pulse with broad bandwidth while preserving the spectral amplitude. It is shown that this spectral-phase-only optimization approach can successfully identify robust and optimal control fields, leading to efficient population transfer to the target state while concurrently suppressing population transfer to undesired states. The method demonstrates resilience to fluctuations in control field parameters, making it a promising approach for reliable and efficient population transfer in practical applications.

Multi-scale molecular dynamics simulations of enhanced energy transfer in organic molecules under strong coupling

Exciton transport can be enhanced in the strong coupling regime where excitons hybridize with confined light modes to form polaritons. Because polaritons have group velocity, their propagation should be ballistic and long-ranged. However, experiments indicate that organic polaritons propagate in a diffusive manner and more slowly than their group velocity. Here, we resolve this controversy by means of molecular dynamics simulations of Rhodamine molecules in a Fabry-Pérot cavity. Our results suggest that polariton propagation is limited by the cavity lifetime and appears diffusive due to reversible population transfers between polaritonic states that propagate ballistically at their group velocity, and dark states that are stationary. Furthermore, because long-lived dark states transiently trap the excitation, propagation is observed on timescales beyond the intrinsic polariton lifetime. These insights not only help to better understand and interpret experimental observations, but also pave the way towards rational design of molecule-cavity systems for coherent exciton transport.

Complete population transfer between next-adjacent energy levels of a transmon qudit

The utilization of qudits in quantum systems has led to significant advantages in quantum computation and information processing. Therefore, qudits have gained increased attention in recent research for their precise and efficient operations. In this work, we demonstrate the complete population transfer between the next-adjacent energy levels of a transmon qudit using the Pythagorean coupling method and energy level mapping. We achieve a |0〉 to |2〉 transfer with a process fidelity of 97.76% in the subspace spanned by |0〉 to |2〉. Moreover, the transfer operation is achieved within a remarkably fast timescale, as short as 20 ns. This study may present a promising avenue for enhancing the operation flexibility and efficiency of qudits in future implementations.

Gender and Forced Displacement at the International Criminal Court

Abstract International criminal courts and tribunals have missed opportunities to recognize gendered experiences, including when addressing crimes without a clearly sexual component. The International Criminal Court (ICC) has an opportunity to take a different approach when considering the crime against humanity of deportation in its Bangladesh/Myanmar proceedings. While the prevalence of sexual and other gendered violence, including rape and killings, in Myanmar and perpetrated against the Rohingya is well-documented, and will likely form an important aspect of investigations, there is also scope to explore the gendered nature of displacement. This article reviews the intersection of international criminal law with broader critiques of international law concerned with displacement. It then investigates how ICC Chambers could take a gender-competent approach towards the elements of the crime against humanity of deportation and forcible transfer of population in the Bangladesh/Myanmar proceedings, including when examining the concepts of expulsion and coercion, lawful presence and the purpose of the forcible displacement. It proposes a contextual approach to that analysis, informed by gender-inclusive expert evidence, gender-competent investigation practices and thoughtful integration of victims’ representations

Coupled Cluster Simulation of Impulsive Stimulated X-ray Raman Scattering.

Time-dependent equation-of-motion coupled cluster (TD-EOM-CC) is used to simulate impulsive stimulated X-ray Raman scattering (ISXRS) of ultrashort laser pulses by neon, carbon monoxide, pyrrole, and p-aminophenol. The TD-EOM-CC equations are expressed in the basis of field-free EOM-CC states, where the calculation of the core-excited states is simplified through the use of the core-valence separation (CVS) approximation. The transfer of electronic population from the ground state to the core- and valence-excited states is calculated for different numbers of included core- and valence-excited states, as well as for electric field pulses with different polarizations and carrier frequencies. The results indicate that Gaussian pulses can transfer significant electronic populations to the valence states through the Raman process. The sensitivity of this population transfer to the model parameters is analyzed. The time-dependent electronic density for p-aminophenol is also showcased, supporting the interpretation that ISXRS involves localized core excitations and can be used to rapidly generate valence wavepackets.