Stationary Observer Research Articles

Device concept for organization of monitoring network

State observation networks of the state of environment include a complex of stationary, route and sub torch observation posts. Stationary observation posts are a fairly expensive structure that used equipment of a certain accuracy. Modern technological development allows to create devices of small dimensions with a unified output interface, having a measurement error comparable to the error of equipment used in stationary observation posts or less. Therefore, this paper proposes the concept of creating a device, which, in particular, may be converted into an atmospheric air monitoring device. Currently, environmental and emission control issues remain relevant. The purpose of the study, the facet of which is revealed in this work, is to organize a monitoring network for the analysis of atmospheric air pollution. The work contains a list of priorities for the organization of the device, its main functions. The result is a structural diagram of the central component of the device, called “Heart” and an additional component - “Expansion Board”, that describes the main necessary nodes for the operating of the device. The working element of the instrument is sensors of substances with different operating principle. In addition, there are described a way to ensure nonvolatile device and organization of a unite interface of data transmission within it. A short list of tasks for which the proposed device is directed is presented.

Day and night continuous high-resolution shallow-water depth detection with single-photon underwater lidar.

Single-photon lidar has emerged as a strong technology for bathymetric measurements. However, its heightened sensitivity additionally makes it susceptible to solar radiation noise, particularly in the green light wavelength where solar radiation is strong, posing challenges for its daytime operation. To address this issue, a single-photon underwater lidar system is proposed and demonstrated. This scheme has these features. 1) Underwater applications not only mitigate the impact of the air-water interface on laser transmission but also significantly attenuate solar radiation reaching the lidar due to the absorption and scattering properties of water. 2) The telescope is designed with a small aperture and narrow field of view to significantly suppress solar radiation. 3) A combination of a narrowband laser and narrowband filter technique is effectively employed to minimize residual solar radiation, thus enabling continuous bathymetric observation capabilities during both day and night. 4) After acquiring the backscattered signal from the bottom, a water depth extraction algorithm utilizing bi-Gaussian fitting is proposed. To demonstrate the robustness of the lidar and the effectiveness of the algorithm, the underwater single-photon lidar system is deployed on a ship to conduct cruise surveys of two bays in the nearshore area, as well as a full-day stationary observation experiment. The lidar measurements are highly consistent with the synchronized sonar observations. The full-day stationary observation experiment showcased its capability to deliver continuous measurements throughout the day and night. These results demonstrate the potential of the system in various applications, including high-precision underwater terrain mapping, obstacle avoidance for underwater platforms, and underwater target imaging.

Total light bending in non-asymptotically flat black hole spacetimes

The gravitational deflection of light is a critical test of modified theories of gravity. A few years ago, Gibbons and Werner introduced a definition of the deflection angle based on the Gauss–Bonnet theorem. In more recent years, Arakida proposed a related idea for defining the deflection angle in non-asymptotically flat spacetimes. We revisit this idea and use it to compute the angular difference in the Kottler geometry and a non-asymptotically flat solution in Horndeski gravity. Our analytic and numerical calculations show that a triangular array of laser beams can be designed so that the proposed definition of the deflection angle is sensitive to different sources of curvature. Moreover, we find that near the photon sphere, the deflection angle in the Horndeski solution is similar to its Schwarzschild counterpart, and we confirm that the shadows seen by a static observer are identical.

Malignant Neoplasms of the Reproductive Organs as a Cause of Death of the Young Population in the Russian Federation

Relevance. The demographic situation in the Russian Federation over the past decades has been characterized by negative dynamics, while the two key indicators, the ratio of which affects this, are birth and death rates. Of particular interest in this case are malignant neoplasms (MNs) of the organs of the reproductive system, which can both affect the decline in fertility, especially when it comes to the age group under 40, and make a significant contribution to the structure of the population mortality. Аim. Analyze the changes in mortality rates from cancer of the reproductive organs among the population aged 15 to 39 years, their dynamics and structure in the Russian Federation for 2011–2020. Materials and methods. To calculate the indicators, an analysis was carried out of the data of the forms of the federal state static observation on the distribution of the deceased by sex, age groups and causes of death by Rosstat (FSN-C51) and statistical information on the age and sex composition of the population of the territories of the Russian Federation. Results. The highest «crude» mortality rates were noted in the Siberian and Far Eastern Federal Districts (5.04 (95% CI = 4.49–5.58) and 5.00 (95% CI = 4.09–5.90) per 100 thousand of the population, respectively), the smallest – n the regions of the North Caucasus Federal District (2.58 (95% CI = 2.06 - 3.11) per 100 thousand of the population). Significant gender differences were also identified. Female mortality from malignancies of the reproductive organs was significantly higher (the "crude” mortality rate among women was found to be 7.57 (95% CI = 7.22–7.92) versus 0.72 (95% CI = 0.61–0.82) among men per 100 thousand) due to the dominance of oncological lesions of the cervix and mammary gland at an earlier age. Conclusion. The identified features of the manifestations of mortality from cancer of the reproductive organs for various territories and population groups can serve as a rationale for strengthening the existing preventive measures, such as vaccination against HPV, as well as for developing new strategies aimed at improving the demographic situation.

Simulated Radio and Neutrino Imaging of a Microquasar

Microquasar stellar systems emit electromagnetic radiation and high-energy particles. Thanks to their location within our own galaxy, they can be observed in high detail. Still, many of their inner workings remain elusive; hence, simulations, as the link between observations and theory, are highly useful. In this paper, both high-energy particle and synchrotron radio emissions from simulated microquasar jets are calculated using special relativistic imaging. A finite ray speed imaging algorithm is employed on hydrodynamic simulation data, producing synthetic images seen from a stationary observer. A hydrodynamical model is integrated in the above emission models. Synthetic spectra and maps are then produced that can be compared to observations from detector arrays. As an application, the model synthetically observes microquasars during an episodic ejection at two different spatio-temporal scales: one on the neutrino emission region scale and the other on the synchrotron radio emission scale. The results are compared to the sensitivity of existing detectors.

Tree Storey Structure and Condition Dynamics in Middle-Taiga Native Spruce Forests of the Northern Ural Foothills

The paper focuses on the dynamic processes occurring in indigenous spruce phytocenoses developing on the territory of one of the large reserves of spontaneous dark coniferous taiga in the European North – the Pechoro-Ilychsky Reserve. The aim of the study was to assess the size structure dynamics of the forest stands and the undergrowth, as well as changes in their vital status in naturally developing spruce stands of the green moss and long-stem moss groups of forest types in the foothills of the Northern Urals (the basin of the upper reaches of the Pechora River). The spruce stands, mixed in composition and complex in structure, form a cyclic uneven-aged type of structure. For the middle taiga indigenous spruce forests, based on the assessment of inequality in the woody plants’ sizes distribution, the results of the long-term structure monitoring of the forest stands and the undergrowth on four permanent sample plots were analysed. In forest stands of different types, a similar dynamics of tree differentiation by trunk volume and undergrowth by trunk height was observed. There is a significant accumulation of small woody plants individuals, with a smooth, evenly fading distribution of their numbers in the direction of size increase. Under the canopy of forest stands there is a continuous regrowth process. According to the data of stationary observations of the vitality and damage degree of trees and undergrowth of spruce forests, based on a visual assessment of a woody plant state according to the characteristics of the crown, a slightly weakened condition of both the upper tree layers of the phytocenosis and the lower – undergrowth was revealed. Spruce stands are at the stage of initial weakening or are already weakened, the undergrowth is predominantly healthy.

THE FAUNA OF AQUATIC HEMIPTERA (HETEROPTERA) IN CHARYN NATURE PARK

The material for this research resulted from the authors’ work during 2018–2020 at the Charyn Nature Park in different floodplain reservoirs of the Charyn and Temirlik Rivers, Almaty region, Kazakhstan. Their study of the fauna and ecology of Hemiptera followed the methods of route surveys and stationary observations. The simplest way to collect is to catch aquatic Hemiptera using aquatic entomological nets and account for potential water bugs. Corixidae has 21 species, while other families have one or two species. Their density comprised Gerridae (8–10), Corixidae (16–20), Naucoridae (3–5), Notonecta (8–9), and Ranatra (3–5) specimens/m2, respectively. The mass species found included Ilyocoris cimicoides, Noton ecta glauca, Nepa cinerea, and Gerris costae. During the autumn survey, an observation revealed that the previously studied reservoirs have decreased in size, and some have even dried up. In the coastal part of the reservoirs, water scorpions (Nepa cinerea) were crawling along the bottom of the pool. Water backswimmers (Notonectidae) and toad bugs (Naucoridae) moved to deeper pond areas. Representatives of the Corixidae family were zoophytophages (21 species), with the remaining species being zoophages (12 species). Under the Charyn Nature Park conditions, most species were mono or univoltine (21 species), bivoltine (five species), and poly or multivoltine (seven species). The fauna of the Charyn State National Nature Park (SNNP) has the main characteristic of species of Hemiptera with Western Asia (40%), Trans-Palearctic (21%), Western Palearctic (18%), and Trans-Eurasian (12%) ranges. All the recognized species have a wide selection of hunting objects, feeding on aquatic invertebrates, including regulating the numbers of blood-sucking mosquito larvae (Culicidae).

Aneuploidy in oocytes from women of advanced maternal age: analysis of the causal meiotic errors and impact on embryo development.

In oocytes of advanced maternal age (AMA) women, what are the mechanisms leading to aneuploidy and what is the association of aneuploidy with embryo development? Known chromosome segregation errors such as precocious separation of sister chromatids explained 90.4% of abnormal chromosome copy numbers in polar bodies (PBs), underlying impaired embryo development. Meiotic chromosomal aneuploidies in oocytes correlate with AMA (>35 years) and can affect over half of oocytes in this age group. This underlies the rationale for PB biopsy as a form of early preimplantation genetic testing for aneuploidy (PGT-A), as performed in the 'ESHRE STudy into the Evaluation of oocyte Euploidy by Microarray analysis' (ESTEEM) randomized controlled trial (RCT). So far, chromosome analysis of oocytes and PBs has shown that precocious separation of sister chromatids (PSSC), Meiosis II (MII) non-disjunction (ND), and reverse segregation (RS) are the main mechanisms leading to aneuploidy in oocytes. Data were sourced from the ESTEEM study, a multicentre RCT from seven European centres to assess the clinical utility of PGT-A on PBs using array comparative genomic hybridization (aCGH) in patients of AMA (36-40 years). This included data on the chromosome complement in PB pairs (PGT-A group), and on embryo morphology in a subset of embryos, up to Day 6 post-insemination, from both the intervention (PB biopsy and PGT-A) and control groups. ESTEEM recruited 396 AMA patients: 205 in the intervention group and 191 in the control group. Complete genetic data from 693 PB pairs were analysed. Additionally, the morphology from 1034 embryos generated from fertilized oocytes (two pronuclei) in the PB biopsy group and 1082 in the control group were used for statistical analysis. Overall, 461/693 PB pairs showed abnormal segregation in 1162/10 810 chromosomes. The main observed abnormal segregations were compatible with PSSC in Meiosis I (MI) (n = 568/1162; 48.9%), ND of chromatids in MII or RS (n = 417/1162; 35.9%), and less frequently ND in MI (n = 65/1162; 5.6%). For 112 chromosomes (112/1162; 9.6%), we observed a chromosome copy number in the first PB (PB1) and second PB (PB2) that is not explained by any of the known mechanisms causing aneuploidy in oocytes. We observed that embryos in the PGT-A arm of the RCT did not have a significantly different morphology between 2 and 6 days post-insemination compared to the control group, indicating that PB biopsy did not affect embryo quality. Following age-adjusted multilevel mixed-effect ordinal logistic regression models performed for each embryo evaluation day, aneuploidy was associated with a decrease in embryo quality on Day 3 (adjusted odds ratio (aOR) 0.62, 95% CI 0.43-0.90), Day 4 (aOR 0.15, 95% CI 0.06-0.39), and Day 5 (aOR 0.28, 95% CI 0.14-0.58). RS cannot be distinguished from normal segregation or MII ND using aCGH. The observed segregations were based on the detected copy number of PB1 and PB2 only and were not confirmed by the analysis of embryos. The embryo morphology assessment was static and single observer. Our finding of frequent unexplained chromosome copy numbers in PBs indicates that our knowledge of the mechanisms causing aneuploidy in oocytes is incomplete. It challenges the dogma that aneuploidy in oocytes is exclusively caused by mis-segregation of chromosomes during MI and MII. Data were mined from a study funded by ESHRE. Illumina provided microarrays and other consumables necessary for aCGH testing of PBs. None of the authors have competing interests. Data were mined from the ESTEEM study (ClinicalTrials.gov Identifier NCT01532284).

A dataset of soil carbon flux in Xishuangbanna tropical rainforest ecosystem from 2003 to 2008

Long-term and large-scale carbon flux data supports research on key processes of the global carbon and water cycle. Soil is the largest carbon pool in the terrestrial ecosystem. Small variations in soil carbon can significantly impact the carbon budgets of terrestrial ecosystems. Tropical forest is a crucial carbon sink in the world. However, there have been some reports indicating a decrease in soli carbon levels, potentially approaching neutrality, as a result of soil carbon degradation caused by global changing. Thus, the long-term and continuous observation of soil carbon flux is of great significance for evaluating the role of soil carbon in the tropical carbon cycle. ChinaFLUX Observation and Research Network (ChinaFLUX) has not only conducted the observation and research on carbon flux by using vorticity correlation technology, but also carried out the long-term observation and research on surface CO2 flux by using the box method. In this dataset, we collected and sorted out the soil CO2 emission flux data and conventional meteorological data of Xishuangbanna tropical rain forest ecosystem from January 2003 to August 2008 according to the static box observation method and data quality control management of greenhouse gas emissions. The dataset consists of three types of files at daily, monthly and yearly scales, covering surface CO2 flux, pressure, atmospheric temperature, soil temperature (5 cm) and soil water content (5 cm). It is expected to provide essential data for estimating carbon balance and understanding carbon cycle processes at both tropical and global scales.

Influential factors of long-term and seasonal 137Cs change in agricultural and forested rivers: Temperature, water quality and an intense Typhoon Event

In this study, the effect of temperature, water quality, and the impact of an intense typhoon event on change in 137Cs concentration in the water of agricultural and forested rivers near the Fukushima Daiichi nuclear power plant (Japan) was evaluated using monthly stationary observations obtained under baseflow conditions 2.8–10.6 years after the nuclear accident in 2011. The dissolved 137Cs concentration fluctuated seasonally with water temperature in all rivers, and the increase in dissolved 137Cs concentration for unit increase in temperature was higher in forested rivers than in agricultural rivers. The relationship between water temperature and the apparent distribution coefficient of 137Cs well followed the van ’t Hoff equation in the two agricultural rivers, where the enthalpy of reaction was estimated as −15.6 and −19.6 kJ mol−1. The van ’t Hoff equation was not well followed for a forested river, where the suspended solids mainly comprised organic matter, suggesting that the dominant process determining dissolved 137Cs concentrations in forested rivers is not only water temperature effect on ion exchange, but rather the input of 137Cs and K+ (competing with 137Cs for exchange sites on mineral particles) into the water phase via litter leaching. Suspended solids concentrations in agricultural rivers correlated negatively with 137Cs concentrations in suspended solids, suggesting an increased proportion of coarse particles or the input of soils with low 137Cs concentration from decontaminated agricultural land. At some sites, 137Cs concentrations in dissolved form and in suspended solids were reduced sharply in association with the passage of Typhoon Hagibis in October 2019, suggesting that Typhoon Hagibis caused large-scale surface erosion that removed the source of 137Cs.

Mapping cherry blossom phenology using a semi-automatic observation system with street level photos

Floral phenology is a key indicator of climate change. However, constructing a local level spatiotemporal record of cherry blossom blooming events is challenging because of the limited coverage of traditional stationary observations. To address this issue, citizen-based observation programs and remote sensing applications have been implemented. However, these strategies have still been limited by insufficient spatial and temporal observation data. In this study, we introduced a novel semi-automatic observation system framework for cherry blossom blooming by combining geographically and temporally dispersed street-level imagery and deep-learning models. We developed a YOLOv4 model for cherry blossom detection from street-level photos obtained from Mapillary, one of the main social sensing data repositories. The detection model achieved an overall accuracy, recall, and precision of 86.7%, 70.3%, and 90.1%, respectively. By using observation coordinates and dates attached to Mapillary photos, we mapped the probability of cherry blossoms occurrence daily using a spatial grid of dimensions of 10 m × 10 m. With sufficient observations, the start, peak, and cessation of blooming were estimated using time series analysis. A case study conducted in 2022 at the main campus of Saitama University confirmed the potential for automatically mapping the presence of cherry blossoms and their blooming timing with local variations. Given that our approach solely relied on geotagged street-level photos that could be taken by anyone with no prior knowledge of cherry tree species identification, it is likely to be easier to build spatial and temporal blooming records than using conventional stationary or citizen-based observations. This approach can be applicable to other study areas, as well as observing other species phenology and understanding the response of local environments.

Research on rheological properties and phenomenological theory-based constitutive model of magnetorheological shear thickening fluids

This paper investigates the rheological properties of magnetorheological shear thickening fluid (MRSTF) and proposes a phenomenological theory-based constitutive model. Multiple samples with varying mass fractions and particle sizes were prepared. Then, the rheological properties were experimentally studied, including the effects of silicon particle size and concentration, carbonyl iron powder concentration and magnetic field on rheological properties. Next, the sedimentation stability experiment was also carried out by the static observation method. Finally, based on phenomenological theory, a constitutive model called the M-S model was derived through geometric transformation of shear stress curves. The results show that there is an inhibitory relationship between magnetorheological and shear thickening effect, and the correlation between composition and rheological properties was established, which can provide guidance for preparation of MRSTF with required properties. It also shows that the MRSTF under specific preparation scheme could effectively avoid sedimentation, and its performance is clearly superior to traditional materials in terms of sedimentation resistance and damping adjustment. The accuracy and universality of the proposed model are fully verified by fitting shear stress curves and calculating the goodness of fit values. All these investigations can offer an effective guidance for further study of MRSTF in controllable damping equipment development.

Multidimensional attributes expose Heider balance dynamics to measurements

Most of studied social interactions arise from dyadic relations. An exception is Heider Balance Theory that postulates the existence of triad dynamics, which however has been elusive to observe. Here, we discover a sufficient condition for the Heider dynamics observability: assigning the edge signs according to multiple opinions of connected agents. Using longitudinal records of university student mutual contacts and opinions, we create a coevolving network on which we introduce models of student interactions. These models account for: multiple topics of individual student opinions, influence of such opinions on dyadic relations, and influence of triadic relations on opinions. We show that the triadic influence is empirically measurable for static and dynamic observables when signs of edges are defined by multidimensional differences between opinions on all topics. Yet, when these signs are defined by a difference between opinions on each topic separately, the triadic interactions’ influence is indistinguishable from noise.

Stationary observers in Kerr-de Sitter spacetimes

In this paper, we present a study of basic classes of stationary observers orbiting in stationary and axially symmetric Kerr-de Sitter spacetimes. Along with proper definitions of these classes, we focus on their possible matching on particular circular orbits. Especially, we determine a number of such orbits in a given spacetime characterized by its rotational and cosmological parameters that leads to a comprehensive classification of the Kerr-de Sitter spacetimes. Studied profiles of orbital velocities of the observers and of forces keeping them on their orbits directly reflect complex structure of the Kerr-de Sitter spacetimes that is caused by a unique interplay of attraction and rotation of a central object and an ambient cosmic repulsion.

Analysis of the trend in the morbidity of the population of the Russian Federation considering the factors affecting the availability of general medical services

Introduction. The morbidity is one of the key indicators used to assess the level of public health and demonstrating the level of accessibility of medical care to the population and the effectiveness of primary health care. 
 The aim was to analyze the trend in the morbidity of the population in the Russian Federation, considering factors affecting the availability of general medical services, in the context of the subjects of the Russian Federation. 
 Material and methods. The study based on information from the federal static observation form No. 12 “Information on the number of diseases registered in patients living in the service area of a medical organization” for 2018–2021. 
 Results. In the Russian Federation from 2018 to 2021, general morbidity increased by 2.6%, while newly identified morbidity increased by 9.4%. The Ivanovo region had the largest rate of rise in general morbidity (24.9%), Stavropol Krai — the highest newly identified morbidity (34.7%). When assessing the influence of various factors on the level of morbidity using the method of stable regression, the level of provision of the population with doctors was revealed to have the greatest influence, which is confirmed by the presence of a strong direct dependence.
 Limitations. The data from the federal static observation form No. 12 “Information on the number of diseases registered in patients living in the service area of a medical mamnagement” for 2018–2021 for 85 subjects of the Russian Federation were examined to determine the morbidity of the population of the Russian Federation that is able-bodied and over the working age.
 Conclusion. The morbidity rate in the Russian Federation during the period under review tends to increase. It is an integral indicator of the availability of medical care and the detection of diseases, which influenced by a variety of factors, including the availability of primary care doctors, the strength of the medical managemorganization, the degree of hospitalization, the average number of visits to doctors.

The Many Flaws of the Lorentz Transformation

The Lorentz transformation (LT) is one of the most revered set of relationships in modern physics. Overlooked in this broad assessment are a number of clear inconsistencies in its predictions, however, as will be discussed herein. For example, it makes three predictions which are not consistent with one another: Lorentz-FitzGerald length contraction (FLC), time dilation (TD) and light-speed equality for observers in relative motion to one another. Einstein’s light-speed postulate (LSP) is shown to be unviable by considering a case in which a light source passes by a stationary observer at the same time that it emits a light pulse in the same direction. It is found that, in contradiction to the LSP, that the classical velocity (Galilean) transformation (GVT) is applicable when two observers in relative motion deduce the speed of a light wave from their different perspectives. The LT also stands in violation of the Law of Causality because it fails to recognize that inertial clocks can never change their rate spontaneously; thus its two clocks must always measure elapsed times in the same ratio (Q), contrary to the LT prediction of space-time mixing. The Newton-Voigt transformation (NVT) is consistent with the Law of Causality because it assumes space and time do not mix. It is nonetheless also consistent with the relativistic velocity transformation (RVT) and also with Einstein’s mass-energy equivalence relation E=mc2. The ratio Q of clock rates for two inertial rest frames S and S’ is required input for the NVT. Experimental data obey the Universal Time-dilation Law (UTDL) which states that the measured time Δt obtained by an inertial clock for a given event is inversely proportional to γ(v)= (1-v2c-2)-0.5, where v is the speed of the clock relative to a specific rest frame referred to as the objective rest frame ORS. The Uniform Scaling method employs Q as a conversion factor between the units of time in the two rest frames. It is found that the conversion factors

Application of K-Nearest Neighbor Classification for Static Webcams Visibility Observation

Visibility observations and accurate forecasts are essential in meteorology, requiring a dense network of observation stations. This paper investigates image processing techniques for object detection and visibility determination using static cameras. It proposes a comprehensive method that includes image preprocessing, landmark identification, and visibility estimation, mirroring the observation process of professional meteorological observers. This study validates the visibility observation procedure using the k-nearest neighbors machine learning method across six locations, including four in the Czech Republic, one in the USA, and one in Germany. By comparing our results with professional observations, the paper demonstrates the suitability of the proposed method for operational application, particularly in foggy and low visibility conditions. This versatile method holds potential for adoption by meteorological services worldwide.

Engineering Challenges of Stationary Wireless Smart Ocean Observation Systems

Engineering Challenges of Stationary Wireless Smart Ocean Observation Systems

Influence of chemical modifications on dynamic rheological behaviour, thermal techno-functionalities, morpho-structural characteristics and prebiotic activity of banana starches

Banana starch is explored for its use in food and pharmaceutical applications. In this study, in order to improve the techno-functional properties of native banana starch (NS), different chemical modifications namely acid thinning (AT), oxidation (OX), sodium-trimetaphosphate method (STMP), cross linking phosphorylation (CLP), hydroxypropylation (HYP) were employed. Among the modified starches, amylose content was higher in CLP starch and the least was observed in AT. Resistant starch (RS) of HYP (65.38 %) and CLP starches (62.76 %) were significantly higher than other modified starches. Lesser amylose, higher water solubility and lower swelling of AT starch resulted in inferior paste clarity and inability to make a firm gel. Non-Newtonian behaviour of starch gels were observed from static viscosity observations. The dynamic rheological behaviour of the starch gels affirmed the higher gel strength of STMP (0.46) and CLP (0.56) starches. Imperfection and exo-corrosion in starch morphology was observed through SEM and influence of chemicals on the starch structure was elucidated through FTIR and XRD analyses. Except AT starch, modified starches with higher RS resulted in lowering glycemic index (57–69 %). STMP starches recorded highest prebiotic activity score of 0.88. Chemical modifications enable to enhance the functionalities of banana starch and offers potential industrial uses.

Dynamic and static properties of quantum Hall and harmonic oscillator systems on the non-commutative plane

We study two quantum mechanical systems on the noncommutative plane using a representation independent approach. First, in the context of the Landau problem, we obtain an explicit expression for the gauge transformation that connects the Landau and the symmetric gauge in noncommutative space. This lead us to conclude that the usual form of the symmetric gauge A⃗=−β2Ŷ,β2X̂, in which the constant β is interpreted as the magnetic field, is not true in noncommutative space. We also be able to establish a precise definition of β as a function of the magnetic field, for which the equivalence between the symmetric and Landau gauges is held in noncommutative plane. Using the symmetric gauge, we obtain results for the spectrum of the quantum Hall system, its transverse conductivity in the presence of an electric field, and other static observables. These results amend the literature on quantum Hall effect in the noncommutative plane in which the incorrect form of the symmetric gauge, in noncommutative space, is assumed. We also study the non-equilibrium dynamics of simple observables for this system. On the other hand, we study the dynamics of the harmonic oscillator in non-commutative space and show that, in general, it exhibits quasi-periodic behavior, in striking contrast with its commutative version. The study of dynamics reveals itself as a most powerful tool to characterize and understand the effects of non-commutativity.