Non-adiabacity and large flucutations in a many particle Landau Zener problem

We consider the behavior of an interacting many particle system under slow external driving -- a many body generalization of the Landau-Zener paradigm. We find that a conspiracy of interactions and driving leads to physics profoundly different from that of the single particle limit: for practically all values of the driving rate the particle distributions in Hilbert space are very broad, a phenomenon caused by a strong amplification of quantum fluctuations in the driving process. These fluctuations are 'non-adiabatic' in that even at very slow driving it is exceedingly difficult to push the center of the distribution towards the limit of full ground state occupancy. We obtain these results by a number of complementary theoretical approaches, including diagrammatic perturbation theory, semiclassical analysis, and exact diagonalization.Comment: 25 pages, 16 figure

Photo-induced halide redistribution in organic-inorganic perovskite films.

Organic-inorganic perovskites such as CH3NH3PbI3 are promising materials for a variety of optoelectronic applications, with certified power conversion efficiencies in solar cells already exceeding 21%. Nevertheless, state-of-the-art films still contain performance-limiting non-radiative recombination sites and exhibit a range of complex dynamic phenomena under illumination that remain poorly understood. Here we use a unique combination of confocal photoluminescence (PL) microscopy and chemical imaging to correlate the local changes in photophysics with composition in CH3NH3PbI3 films under illumination. We demonstrate that the photo-induced 'brightening' of the perovskite PL can be attributed to an order-of-magnitude reduction in trap state density. By imaging the same regions with time-of-flight secondary-ion-mass spectrometry, we correlate this photobrightening with a net migration of iodine. Our work provides visual evidence for photo-induced halide migration in triiodide perovskites and reveals the complex interplay between charge carrier populations, electronic traps and mobile halides that collectively impact optoelectronic performance

The first dozen years of the history of ITEP Theoretical Physics Laboratory

The theoretical investigations at ITEP in the years 1945-1958 are reviewed. There are exposed the most important theoretical results, obtained in the following branches of physics: 1) the theory of nuclear reactors on thermal neutrons; 2) the hydrogen bomb project ("Tube" in USSR and "Classical Super" in USA); 3) radiation theory; ~4) low temperature physics; 5) quantum electrodynamics and quantum field theories; 6) parity violation in weak interactions, the theory of $\beta$-decay and other weak processes; 7) strong interaction and nuclear physics. To the review are added the English translations of few papers, originally published in Russian, but unknown (or almost unknown) to Western readers.Comment: 55 pages, 5 fig

Lattice strain causes non-radiative losses in halide perovskites

Halide perovskites are found to exhibit strain patterns over large areas, which influences the lifetimes of charge carriers.EPSR

Aspergillus fumigatus and aspergillosis: From basics to clinics

The airborne fungus Aspergillus fumigatus poses a serious health threat to humans by causing numerous invasive infections and a notable mortality in humans, especially in immunocompromised patients. Mould-active azoles are the frontline therapeutics employed to treat aspergillosis. The global emergence of azole-resistant A. fumigatus isolates in clinic and environment, however, notoriously limits the therapeutic options of mould-active antifungals and potentially can be attributed to a mortality rate reaching up to 100 %. Although specific mutations in CYP51A are the main cause of azole resistance, there is a new wave of azole-resistant isolates with wild-type CYP51A genotype challenging the efficacy of the current diagnostic tools. Therefore, applications of whole-genome sequencing are increasingly gaining popularity to overcome such challenges. Prominent echinocandin tolerance, as well as liver and kidney toxicity posed by amphotericin B, necessitate a continuous quest for novel antifungal drugs to combat emerging azole-resistant A. fumigatus isolates. Animal models and the tools used for genetic engineering require further refinement to facilitate a better understanding about the resistance mechanisms, virulence, and immune reactions orchestrated against A. fumigatus. This review paper comprehensively discusses the current clinical challenges caused by A. fumigatus and provides insights on how to address them.AA, RGR, and DSP were supported by NIH AI 109025. MH was supported by NIH UL1TR001442. AC was supported by the Fundação para a Ciência e a Tecnologia (FCT) (CEECIND/03628/2017 and PTDC/MED GEN/28778/2017). Additional support was provided by FCT (UIDB/50026/2020 and UIDP/50026/2020), the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) (NORTE-01-0145-FEDER-000013 and NORTE-01-0145-FEDER-000023), the European Union's Horizon 2020 Research and Innovation programme under grant agreement no. 847507, and the “la Caixa” Foundation (ID 100010434) and FCT under the agreement LCF/PR/HP17/52190003. DJA was supported by CF Trust Strategic Research Centre TrIFIC (SRC015), Wellcome Trust Collaborative Award 219551/Z/19/Z and the NIHR Centre for Antimicrobial Optimisation.S

Local Strain Heterogeneity Influences the Optoelectronic Properties of Halide Perovskites

Halide perovskites are promising semiconductors for optoelectronics, yet thin films show substantial microscale heterogeneity. Understanding the origins of these variations is essential for mitigating parasitic losses such as non-radiative decay. Here, we probe the structural and chemical origins of the heterogeneity by utilizing scanning X-ray diffraction beamlines at two different synchrotrons combined with high-resolution transmission electron microscopy to spatially characterize the crystallographic properties of individual micrometer-sized perovskite grains in high-quality films. We reveal new levels of heterogeneity on the ten-micrometer scale (super-grains) and even ten-nanometer scale (sub-grain domains). By directly correlating these properties with their corresponding local time-resolved photoluminescence properties, we find that regions showing the greatest luminescence losses correspond to strained regions, which arise from enhanced defect concentrations. Our work reveals remarkably complex heterogeneity across multiple length scales, shedding new light on the defect tolerance of perovskites

Transcriptional and Proteomic Analysis of the Aspergillus fumigatus ΔprtT Protease-Deficient Mutant

Aspergillus fumigatus is the most common opportunistic mold pathogen of humans, infecting immunocompromised patients. The fungus invades the lungs and other organs, causing severe damage. Penetration of the pulmonary epithelium is a key step in the infectious process. A. fumigatus produces extracellular proteases to degrade the host structural barriers. The A. fumigatus transcription factor PrtT controls the expression of multiple secreted proteases. PrtT shows similarity to the fungal Gal4-type Zn(2)-Cys(6) DNA-binding domain of several transcription factors. In this work, we further investigate the function of this transcription factor by performing a transcriptional and a proteomic analysis of the ΔprtT mutant. Unexpectedly, microarray analysis revealed that in addition to the expected decrease in protease expression, expression of genes involved in iron uptake and ergosterol synthesis was dramatically decreased in the ΔprtT mutant. A second finding of interest is that deletion of prtT resulted in the upregulation of four secondary metabolite clusters, including genes for the biosynthesis of toxic pseurotin A. Proteomic analysis identified reduced levels of three secreted proteases (ALP1 protease, TppA, AFUA_2G01250) and increased levels of three secreted polysaccharide-degrading enzymes in the ΔprtT mutant possibly in response to its inability to derive sufficient nourishment from protein breakdown. This report highlights the complexity of gene regulation by PrtT, and suggests a potential novel link between the regulation of protease secretion and the control of iron uptake, ergosterol biosynthesis and secondary metabolite production in A. fumigatus

ПРОБЛЕМЫ ФОРМИРОВАНИЯ ИННОВАЦИОННОГО ПАРКА СЕЛЬСКОХОЗЯЙСТВЕННЫХ ТРАКТОРОВ РОССИИ

Formation of tractors park and its perspective development are carried out on the basis of realization and improvement of the scientifically based types range constructed on a traction classification sign which conforms to requirements of agricultural production when performing two main conditions: full meeting the requirements for various standard sizes of tractors applicable to conditions of the corresponding zones of Russia and continuous reproduction and development of tractor fleet, both by quantity of efficient machinery and its structure. The developed types range practically runs the gamut of organizational and economic and climatic conditions, and also all range of forms of the organizations using machinery, beginning from individual consumers, small and large rent and contract collectives and finishing large-scale enterprises and their associations. Federal Service of State Statistics (Rosstat) information about a steady tendency of fleet reduction was used for studying of regularities of development of tractor fleet. This information was added by analytical synthesis of data about the annual brand purchases in the Russian market of agricultural tractors. The developed database shows a share of the tractors in fleets of agricultural organizations, which are used over depreciation term, and also minimum necessary number of new machines introduction for formation of volume of tractors with limit age and the total quantity of tractors necessary for minimization of set of expenses. It was established that it is possible to estimate visually the developed quantitative and age structure of tractors fleet and to predict its development on prospect by worked out database representing set of annual tractors brand lines purchasing.Формирование парка тракторов и его перспективное развитие осуществляются на основе реализации и совершенствования научно обоснованного типажа, построенного по тяговому классификационному признаку, который соответствует требованиям сельхозпроизводства при выполнении двух основных условий: полное обеспечение потребности в различных типоразмерах тракторов применительно условиям соответствующих зон России и постоянное воспроизводство и развитие тракторного парка, как по количеству работоспособной техники, так и по его структуре. Разработанный типаж охватывает практически весь диапазон организационно-хозяйственных и климатических условий, а также весь спектр форм организаций, использующих технику, начиная от индивидуальных потребителей, мелких и крупных арендных и подрядных коллективов и кончая крупными хозяйствами и их объединениями. Для изучения закономерностей развития тракторного парка информацию Росстат об устойчивой тенденции сокращения парка дополнили путем аналитического обобщения данных о годовых помарочных закупках на российском рынке сельскохозяйственных тракторов. Показали, что разработанная база данных отражает долю тракторов в парке СХО, используемых сверх срока амортизации, а также минимально необходимое количество введения новых машин для формирования объема тракторов предельного возраста и общего количества тракторов, необходимого для минимизации совокупности затрат. Установили, что наглядно оценить сложившуюся количественно-возрастную структуру парка тракторов и прогнозировать ее развитие на перспективу возможно при помощи разработанной базы данных, представляющей собой совокупность годовых помарочных закупочных линеек тракторов

ПРОБЛЕМЫ ФОРМИРОВАНИЯ ИННОВАЦИОННОГО ПАРКА СЕЛЬСКОХОЗЯЙСТВЕННЫХ ТРАКТОРОВ РОССИИ

In the market of agricultural tractors of Russia in 2013 were 900 domestic models, or 3.4 percent. There were produced 7655 tractors, 6707 from which were foreign models. It was revealed that purchasing power of the agricultural organizations appears at profitability not less than 20 percent. Because this indicator is 5.2-11.7 percent lower, agricultural enterprises are not able to turn over their fleets. The authors have presented the forecast of development of tractor fleet till 2020 taking into account the solution of national tasks, including import substitution and dynamics of the annual purchases providing its realization. Methodology of development of the State program of food import substitution based on tractor fleet revival as conditions of self-sustainability of Russia was proposed. A role of tractor fleet as multiplier in development of the mechanized agricultural production was revealed. The first-priority problem is working out of tractors of economic category.На рынке сельскохозяйственных тракторов России в 2013 г. отечественные модели составили 0,9 тыс.ед., или 3,4 процента. Было произведено 7655 тракторов, 6707 из которых представлены иностранными моделями. Выявили, что покупательная способность сельскохозяйственных организаций появляется при рентабельности не менее 20 процентов. Так как этот показатель на 5,2-11,7 процента ниже, сельхозпредприятия не способны полноценно обновлять парк. Представили прогноз развития тракторного парка до 2020 г. с учетом решения национальных задач, включая импортозамещение и динамику годовых закупок, обеспечивающих его реализацию. Предложили Методологию разработки Государственной программы продовольственного импортозамещения на основе возрождения тракторного парка как условия самодостаточности России. Выявили роль тракторного парка как мультипликатора в развитии механизированного сельхозпроизводства. В качестве первоочередной представили задачу разработки тракторов экономической категории