Efficiency of Xist-mediated silencing on autosomes is linked to chromosomal domain organisation

BACKGROUND: X chromosome inactivation, the mechanism used by mammals to equalise dosage of X-linked genes in XX females relative to XY males, is triggered by chromosome-wide localisation of a cis-acting non-coding RNA, Xist. The mechanism of Xist RNA spreading and Xist-dependent silencing is poorly understood. A large body of evidence indicates that silencing is more efficient on the X chromosome than on autosomes, leading to the idea that the X chromosome has acquired sequences that facilitate propagation of silencing. LINE-1 (L1) repeats are relatively enriched on the X chromosome and have been proposed as candidates for these sequences. To determine the requirements for efficient silencing we have analysed the relationship of chromosome features, including L1 repeats, and the extent of silencing in cell lines carrying inducible Xist transgenes located on one of three different autosomes. RESULTS: Our results show that the organisation of the chromosome into large gene-rich and L1-rich domains is a key determinant of silencing efficiency. Specifically genes located in large gene-rich domains with low L1 density are relatively resistant to Xist-mediated silencing whereas genes located in gene-poor domains with high L1 density are silenced more efficiently. These effects are observed shortly after induction of Xist RNA expression, suggesting that chromosomal domain organisation influences establishment rather than long-term maintenance of silencing. The X chromosome and some autosomes have only small gene-rich L1-depleted domains and we suggest that this could confer the capacity for relatively efficient chromosome-wide silencing. CONCLUSIONS: This study provides insight into the requirements for efficient Xist mediated silencing and specifically identifies organisation of the chromosome into gene-rich L1-depleted and gene-poor L1-dense domains as a major influence on the ability of Xist-mediated silencing to be propagated in a continuous manner in cis

Міжнародно-правові тенденції розвитку принципу раціонального використання природних ресурсів в екологічному праві України

The article analyzes some issues of further development of the principle of rational use of natural resources in the environmental law of Ukraine from the point of view of modern international legal trends. The ecological-legal thought has not yet developed a common understanding of the place of the ecosystem approach in environmental law, since it can be considered in at least two aspects: how the characteristic of the principle of rational use of natural resources and as an independent principle of environmental law are necessary. Therefore, the answer to this question can be obtained after a thorough and comprehensive scientific study of the essence of the ecosystem approach in the aspect of legal regulation of environmental relations. It is concluded that the further development of this principle is necessarily connected with its understanding and implementation in the aspect of the concept of sustainable development, according to which the compulsory balance between meeting the modern needs of all humanity and protecting the interests of future generations, including their need for safe and a healthy environment. This concept is based on the ecosystem approach, which is a strategy for integrated resource management, which ensures their conservation and sustainable use on an equitable basis. In other words, such extremely important characteristics as sustainability and complexity of the use of natural resources, will serve as the basis for understanding the principle of their rational use.В статье анализируются отдельные вопросы дальнейшего развития принципа рационального использования природных ресурсов в экологическом праве Украины с точки зрения современных международно-правовых тенденций. Делается вывод о том, что дальнейшее развитие этого принципа непременно связано с его пониманием и воплощением в аспекте концепции устойчивого развития, согласно которой на первый план выходит обязательность установления баланса между удовлетворением современных потребностей всего человечества и защитой интересов будущих поколений, включая их потребность в безопасной и здоровой окружающей среде, а также в аспекте ядра этой концепции – экосистемного подхода, который представляет собой стратегию комплексного управления ресурсами, обеспечивающую их сохранение и устойчивое использование на справедливой основе.Розглянуто окремі питання подальшого розвитку принципу раціонального використання природних ресурсів в екологічному праві України з точки зору сучасних міжнародно-правових тенденцій. Зроблено висновок, що подальший розвиток зазначеного принципу неодмінно пов’язаний з його розумінням та втіленням в аспекті концепції сталого розвитку, за якою на перший план виходить обов’язковість встановлення балансу між задоволенням сучасних потреб усього людства та захистом інтересів майбутніх поколінь, включаючи їх потребу в безпечному й здоровому довкіллі, а також в аспекті ядра цієї концепції – екосистемного підходу, що являє собою стратегію комплексного управління ресурсами, яка забезпечує їх збереження та стале використання на справедливій основі

High energy hadrons in EAS at mountain altitude

An extensive simulation has been carried out to estimate the physical interpretation of dynamical factors such as , in terms of high energy interaction features, concentrated in the present analysis on the average transverse momentum. It appears that the large enhancement observed for versus primary energy, suggesting in earliest analysis a significant rise of with energy, is only the result of the limited resolution of the detectors and remains in agreement with a wide range of models used in simulations.Comment: 13 pages, 6 PostScript figures, LaTeX Subm. to JPhys

Public procurement as a strategic instrument to meet sustainable policy goals: the experience of Rotterdam.

The Dutch government, in alignment with the Paris climate agreement, has expressed the ambition to reduce CO 2 emissions in the Netherlands by 49% in 2030 compared to 1990. As freight transport is recognized as a serious CO 2 emitter, this sector is confronted with a substantial part of the target. For cities, the reduction of the urban freight transport emissions is, next to the CO 2 reduction, also important to improve the air quality. Dutch municipalities take an active role in coordination, facilitation and acceleration of the emission reduction processes, not only via regulation but also by using their public procurement power. This paper describes the City of Rotterdam's experiences from the EU Horizon 2020 BuyZET project. This project was launched in November 2016 and includes the cities of Rotterdam, Oslo and Copenhagen. The project aims at understanding and optimising the impact of public procurement activities on transport patterns and emissions in cities as well as to find innovative and sustainable delivery solutions for goods and services-related transport in order to reduce emissions

Historical and recent aufeis in the Indigirka River basin (Russia)

A detailed spatial geodatabase of aufeis (or naled in Russian) within the Indigirka River watershed (305&thinsp;000&thinsp;km2), Russia, was compiled from historical Russian publications (year 1958), topographic maps (years 1970–1980s) and Landsat images (year 2013–2017). Identification of aufeis by late spring Landsat images was performed with a semi-automated approach according to Normalized Difference Snow Index (NDSI) and additional data. After this, a cross-reference index was set for each aufeis field to link and compare historical and satellite-based aufeis datasets. The aufeis coverage varies from 0.26&thinsp;% to 1.15&thinsp;% in different sub-basins within the Indigirka River watershed. The digitized historical archive (Cadastre, 1958) contains the coordinates and characteristics of 896 aufeis fields with a total area of 2064&thinsp;km2. The Landsat-based dataset included 1213 aufeis fields with a total area of 1287&thinsp;km2. Accordingly, the satellite-derived total aufeis area is 1.6 times less than the Cadastre (1958) dataset. However, more than 600 aufeis fields identified from Landsat images are missing in the Cadastre (1958) archive. It is therefore possible that the conditions for aufeis formation may have changed from the mid-20th century to the present. Most present and historical aufeis fields are located in the elevation band of 1000–1200&thinsp;m. About 60&thinsp;% of the total aufeis area is represented by just 10&thinsp;% of the largest aufeis fields. Interannual variability of aufeis area for the period of 2001–2016 was assessed for the Bolshaya Momskaya aufeis and for a group of large aufeis fields (11 aufeis fields with areas from 5 to 70&thinsp;km2) in the basin of the Syuryuktyakh River. The results of this analysis indicate a tendency towards an area decrease in the Bolshaya Momskaya aufeis in recent years, while no reduction in Syuryuktyakh River aufeis area was observed. The combined digital database of the aufeis is available at https://doi.org/10.1594/PANGAEA.891036.</p

X-ray film chamber with carbon target of Tien-Shan complex array

X-ray films were exposed inside the ionization calorimeter under 74g/sq cm of carbon and 5 cm of lead. The X-ray film chamber area is 35 sq. m. Moving X-ray films were used, 50% of the events, which succeeded to determine incidence time, were identified with corresponding extensive air showers (EAS). For such events the size spectrum of associated EAS was derived. Two methods of energy measurement using X-ray films and ionization calorimeter were compared. The energy transfer from selected hadron to electromagnetic component is illustrated. It is found that in cascades with high energy release into electromagnetic components the hadron component is practically absent