Identities in twisted Brauer monoids

We show that it is co-NP-hard to check whether a given semigroup identity holds in the twisted Brauer monoid $\mathcal{B}^\tau_n$ with $n\ge5$.Comment: 20 pages, 5 figures. In v2, several typos and inaccuracies are corrected, and a few suggestions by the anonymous referee are implemente

ИССЛЕДОВАНИЕ ТОЧНОСТИ МЕТОДА ГРАДИЕНТНОГО БУСТИНГА СО СЛУЧАЙНЫМИ ПОВОРОТАМИ

Gradient boosting method with random rotations is considered, where before training each base learner random rotation is applied to the feature space. The accuracy metric of the given method is estimated for a broad range of generated problems of binary classification. Obtained results are evaluated and recommendations given for application of this method.В статье рассматривается метод градиентного бустинга с осуществлением случайных поворотов признакового пространства на каждом шаге обучения алгоритма. Исследуется качество данного метода на различных модельных задачах бинарной классификации. Полученные результаты анализируются и даются рекомендации по применению указанного метода

Anomerisation von beta-D-Glucopyranosiden unter Glycosylierungsbedingungen

Unlängst wurde nachgewiesen, daß bei der Polykondensation von tritylierten 1,2–0–(1–Cyano)ethyliden-Zuckerderivaten in Anwesenheit von Tritylethern als Terminator unter Einfluß von Triphenylmethaniumperchlorat das sich bildende polymere Produkt 0–Tritylgruppen enthält, was uns die Möglichkeit zur Synthese von Polysaccharid-Blöcken eröffnete. Zur Verbesserung der Syntheseverfahren für Polysaccharide mit Blockstruktur muß man den Erhaltungsgrad der Tritylethern im ursprünglichen Polykondensationsprodukt bewerten. Zur Lösung dieser Frage wurde von uns eine Polykondensation des Tritylether des 1,2–0–(1–Cyano)ethyliden-Derivats der D–Mannose (I) in Anwesenheit von 0,1 äqu. trityliertem Glucosid (II) als Terminator und 0,1 äqu. TrClO4 durchgeführt und danach das Polykondensationsprodukt ohne seine Abscheidung 5 mal hinsichtlich des ursprünglichen Terminators (II) durch den Cyanoethylidenderivat-Überschuß der D–Galaktose (III) behandelt. Dies mußte zu einem Einbau des beta-D-Galaktopyranose-Restes in die Polysaccharid-Kette führen, wobei man nach dem Galaktose-Glucose-Verhältnis im Endprodukt den 0–Tritylgruppen-Gehalt im ursprünglichen Polykondensationsprodukt, mit 6-Phthalimidohexyl–beta-D-glucopyranosid-Rest am Kettenende, bewerten können sollte

Functional Sensory-Motor Performance Following Long Term Space Flight: The First Results of "Field Test" Experiment

The effect that extended-duration space flights may have on human space travelers, including exploration missions, is widely discussed at the present time. Specifically, there is an increasing amount of evidence showing that the physical capacity of cosmonauts is significantly reduced after long-duration space flights. It is evident that the most impaired functions are those that rely on gravity, particularly up right posture and gait. Because of the sensorimotor disturbances manifested in the neurology of the posture and gait space flight and postflight changes may also be observed in debilitating motion sickness. While the severity of particular symptoms varies, disturbances in spatial orientation and alterations in the accuracy of voluntary movements are persistently observed after long-duration space flights. At this time most of the currently available data are primarily descriptive and not yet suitable for predicting operational impacts of most sensorimotor decrements observed upon landing on planetary surfaces or asteroids. In particular there are no existing data on the recovery dynamics or functionality of neurological, cardiovascular or muscle performance making it difficult to model or simulate the cosmonauts' activity after landing and develop the appropriate countermeasure that will ensure the rapid and safe recovery of crewmembers immediately after landing in what could be hostile environments. However and as a starting position, the videos we have acquired during recent data collection following the long duration flights of cosmonauts and astronauts walking and performing other tasks shortly after return from space flight speak volumes about their level of deconditioning. A joint Russian-American team has developed a new study specifically to address the changes in crewmembers performance and the recovery of performance with the intent of filling the missing data gaps. The first (pilot) phase of this study includes recording body kinematics and quantifying the coordination and timing of relatively simple basic movements - transition from seated and prone positions to standing, walking, stepping over obstacles, tandem walking, muscle compliance, as well as characteristics of postural sway and orthostatic tolerance. Testing for changes in these parameters have been initiated in the medical tent at the landing site. The first set of experiments showed that during the first hour after landing, cosmonauts and astronauts were able to execute (although slower and with more effort than preflight) simple movements such as egress from a seated or prone position and also to remain standing for 3.5 minutes without exhibiting pronounced cardiovascular changes. More challenging tests, however, demonstrated a prominent reduction in coordination - the obstacle task, for example, was performed at much slower speed and with a marked overestimation of the obstacle height and tandem walking was greatly degraded suggesting significant changes in proprioception, brainstem and vestibular function. There is some speculation that the neural changes, either from the bottom-up or top down may be long lasting; requiring compensatory responses that will modify or mask the adverse responses we have observed. Furthermore, these compensatory responses may actually be beneficial, helping achieve a more rapid adaptation to both weightlessness and a return to earth

АНАТОЛИЙ ИВАНОВИЧ КИТОВ: ЛИЧНОСТЬ ЧЕРЕЗ ПРИЗМУ ДОКУМЕНТОВ

The paper for the first time discusses nine formal characteristics and certifications of the outstanding Russian scientist Anatoly Ivanovich Kitov related to the military and the first postwar years (1944–1950). Their analysis allows detecting the manifestations of the properties of the personality and character of the young combat officer, and then of a student of the military Academy, which later became the basis of his scientific achievements, but also determined the conflict with the administrative-command system.В статье впервые рассматриваются девять официальных характеристик и аттестаций выдающегося российского ученого Анатолия Ивановича Китова, относящихся к военным и первым послевоенным годам (1944–1950). Их анализ позволяет обнаружить проявления тех свойств личности и характера молодого офицера-фронтовика, а затем слушателя военной академии, которые впоследствии стали основой его научных достижений, но и предопределили конфликт с административно- командной системой

Does Banque de France control inflation and unemployment?

We re-estimate statistical properties and predictive power of a set of Phillips curves, which are expressed as linear and lagged relationships between the rates of inflation, unemployment, and change in labour force. For France, several relationships were estimated eight years ago. The change rate of labour force was used as a driving force of inflation and unemployment within the Phillips curve framework. The set of nested models starts with a simplistic version without autoregressive terms and one lagged term of explanatory variable. The lag is determined empirically together with all coefficients. The model is estimated using the Boundary Element Method (BEM) with the least squares method applied to the integral solutions of the differential equations. All models include one structural break might be associated with revisions to definitions and measurement procedures in the 1980s and 1990s as well as with the change in monetary policy in 1994-1995. For the GDP deflator, our original model provided a root mean squared forecast error (RMSFE) of 1.0% per year at a four-year horizon for the period between 1971 and 2004. The rate of CPI inflation is predicted with RMSFE=1.5% per year. For the naive (no change) forecast, RMSFE at the same time horizon is 2.95% and 3.3% per year, respectively. Our model outperforms the naive one by a factor of 2 to 3. The relationships for inflation were successfully tested for cointegration. We have formally estimated several vector error correction (VEC) models for two measures of inflation. At a four year horizon, the estimated VECMs provide significant statistical improvements on the results obtained by the BEM: RMSFE=0.8% per year for the GDP deflator and ~1.2% per year for CPI. For a two year horizon, the VECMs improve RMSFEs by a factor of 2, with the smallest RMSFE=0.5% per year for the GDP deflator.Comment: 25 pages, 12 figure