Following the excited state relaxation dynamics of indole and 5-hydroxyindole using time-resolved photoelectron spectroscopy

Time-resolved photoelectron spectroscopy was used to obtain new information about the dynamics of electronic relaxation in gas-phase indole and 5-hydroxyindole following UV excitation with femtosecond laser pulses centred at 249 nm and 273 nm. Our analysis of the data was supported by ab initio calculations at the coupled cluster and complete-active-space self-consistent-field levels. The optically bright 1La and 1Lb electronic states of 1\u3c0\u3c0* character and spectroscopically dark and dissociative 1\u3c0\u3c3* states were all found to play a role in the overall relaxation process. In both molecules we conclude that the initially excited 1La state decays non-adiabatically on a sub 100 fs timescale via two competing pathways, populating either the subsequently long-lived 1Lb state or the 1\u3c0\u3c3* state localised along the N-H coordinate, which exhibits a lifetime on the order of 1 ps. In the case of 5-hydroxyindole, we conclude that the 1\u3c0\u3c3* state localised along the O-H coordinate plays little or no role in the relaxation dynamics at the two excitation wavelengths studied.Peer reviewed: YesNRC publication: Ye

Unexpected changes in the oxic/anoxic interface in the Black Sea

THE Black Sea is the largest anoxic marine basin in the world today1. Below the layer of oxygenated surface water, hydrogen sulphide builds up to concentrations as high as 425 μM in the deep water down to a maximum depth of 2,200 m (ref. 2). The hydrographic regime is characterized by low-salinity surface water of river origin overlying high-salinity deep water of Mediterranean origin1,3. A steep pycnocline, centred at about 50 m is the primary physical barrier to mixing and is the origin of the stability of the anoxic (oxygen/hydrogen sulphide) interface. Here we report new observations, however, that indicate dramatic changes in the oceanographic characteristics of the anoxic interface of the Black Sea over decadal or shorter timescales. The anoxic, sulphide-containing interface has moved up in the water column since the last US cruises in 1969 and 1975. In addition, a suboxic zone overlays the sulphide-containing deep water. The expected overlap of oxygen and sulphide was not present. We believe that these observations result from horizontal mixing or flushing events that inject denser, saltier water into the relevant part of the water column. It is possible that man-made reduction in freshwater inflow into the Black Sea could cause these changes, although natural variability cannot be discounted. © 1989 Nature Publishing Group

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Pacemaker implantation through pericardial reflections under fluoroscopic guidance: a novel approach for patients with limited venous access

Excited state intramolecular proton transfer (ESIPT) in salicylideneaniline (SA) and selected derivatives substituted in para-position of the anilino group has been investigated by femtosecond time-resolved photoelectron spectroscopy (TRPES) and time-dependent density functional theory (TDDFT). The planarity of the molecule was found to be a key parameter to describe ESIPT

Semantic analysis with inference: high spots of the football match = СемантичеСкий анализ С логичеСким выводом: оСтрые моменты футбольного матча

The paper describes a new version of the semantic analyzer SemETAP. Our approach is based on the assumption that the depth of understanding is growing with the number of inferences we can draw from the text. The salient features of SemETAP include: 1) intensive use of both linguistic and background knowledge. The former is incorporated in the Combinatorial Dictionary and the Grammar, and the latter is stored in the Ontology and Repository of Individuals. 2) Words and concepts of the ontology may be supplied with explicit decompositions for inference purposes. 3) Two levels of semantic structure are distinguished. Basic semantic structure (BSemS) interprets the text in terms of ontological elements. Enhanced semantic structure (EnSemS) extends BSemS by means of a series of inferences. 4) A new logical formalism Etalog is developed in which all inference rules are written. Semantic analysis with inference allows us to extract implicit information. The analyzer is tested on the task of interpreting high spots of the football match

Knowledge-based approach to Winograd Schema Challenge

We propose a method to resolve anaphoric pronouns in the framework of Winograd Schema Challenge (WSC) by means of SemETAP –a knowledge-based semantic analyzer. WSC is a modern version of the famous Turing test. Its objective is to check a machine’s ability to exhibit intelligent behavior indistinguishable from that of a human. In contrast to other approaches to WSC, which are based on machine learning, our method uses explicit knowledge. An important advantage of this approach is that it gives an opportunity to provide an explanation of the result understandable for humans. SemETAP interprets the text using both linguistic and extralinguistic (background) knowledge. The former is stored in the grammar and the dictionary of the ETAP-4 system, and the latter is provided by the SemETAP ontology, inference rules and the repository of individuals. We show how this knowledge is used for resolving WSC. At the moment, the performanceof the algorithm is not high –54%. This is due to the incompleteness of the background knowledge supplied to the system. It is shown, however, that if the background knowledge is complete and accurate enough, the WSC test is resolved well and it is easily understandable why the system arrived at a particular conclusion.---Аннотация---Предлагается метод разрешения анафоры в рамках теста WinogradSchemaChallenge(WSC) с помощью семантического анализатора SemETAP, основанного на знаниях. Тест WSCпредставляет собой современный вариант теста Тьюринга и предназначен для проверки того, в какой степени компьютер владеет фоновыми знаниями и некоторыми мыслительными операциями, свойственными человеку. В отличие от других подходов к WSC, использующих машинное обучение, наш метод основан на эксплицитных знаниях. Важное преимущество такого подхода состоит в том, что он позволяет дать обоснование полученного результата, понятное человеку. Для интерпретации текста SemETAPиспользует как лингвистические, так и внелингвистические (фоновые) знания. Лингвистические знания собраны в словарях и грамматике системы ETAP-4, а фоновые знания –в онтологии, массиве правил вывода и в базе индивидов. Мы показываем, какиезнания и как используются для WSC-теста. Проведенная оценка алгоритма показала невысокий результат –54%. Этообъясняетсянедостаточнополнымифоновымизнаниями, вложеннымивсистему. Тем не менее, показано, что,если фоновые знания системы достаточно детальны, WSC-тест дает хороший результат, обоснование которого легко понимается человеком

Knowledge-based approach to Winograd Schema Challenge

We propose a method to resolve anaphoric pronouns in the framework of Winograd Schema Challenge (WSC) by means of SemETAP –a knowledge-based semantic analyzer. WSC is a modern version of the famous Turing test. Its objective is to check a machine’s ability to exhibit intelligent behavior indistinguishable from that of a human. In contrast to other approaches to WSC, which are based on machine learning, our method uses explicit knowledge. An important advantage of this approach is that it gives an opportunity to provide an explanation of the result understandable for humans. SemETAP interprets the text using both linguistic and extralinguistic (background) knowledge. The former is stored in the grammar and the dictionary of the ETAP-4 system, and the latter is provided by the SemETAP ontology, inference rules and the repository of individuals. We show how this knowledge is used for resolving WSC. At the moment, the performanceof the algorithm is not high –54%. This is due to the incompleteness of the background knowledge supplied to the system. It is shown, however, that if the background knowledge is complete and accurate enough, the WSC test is resolved well and it is easily understandable why the system arrived at a particular conclusion.---Аннотация---Предлагается метод разрешения анафоры в рамках теста WinogradSchemaChallenge(WSC) с помощью семантического анализатора SemETAP, основанного на знаниях. Тест WSCпредставляет собой современный вариант теста Тьюринга и предназначен для проверки того, в какой степени компьютер владеет фоновыми знаниями и некоторыми мыслительными операциями, свойственными человеку. В отличие от других подходов к WSC, использующих машинное обучение, наш метод основан на эксплицитных знаниях. Важное преимущество такого подхода состоит в том, что он позволяет дать обоснование полученного результата, понятное человеку. Для интерпретации текста SemETAPиспользует как лингвистические, так и внелингвистические (фоновые) знания. Лингвистические знания собраны в словарях и грамматике системы ETAP-4, а фоновые знания –в онтологии, массиве правил вывода и в базе индивидов. Мы показываем, какиезнания и как используются для WSC-теста. Проведенная оценка алгоритма показала невысокий результат –54%. Этообъясняетсянедостаточнополнымифоновымизнаниями, вложеннымивсистему. Тем не менее, показано, что,если фоновые знания системы достаточно детальны, WSC-тест дает хороший результат, обоснование которого легко понимается человеком