Wyniki wyszukiwania - Biblioteka Nauki

1

Accuracy assessment study of UNB3M neutral atmosphere model for global tropospheric delay mitigation

100%

Farah A.

Artificial Satellites : Journal of Planetary Geodesy

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2015

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tom Vol. 50, No. 4

201--215

EN

Tropospheric delay is the second major source of error after the ionospheric delay for satellite navigation systems. The transmitted signal could face a delay caused by the troposphere of over 2m at zenith and 20m at lower satellite elevation angles of 10 degrees and below. Positioning errors of 10m or greater can result from the inaccurate mitigation of the tropospheric delay. Many techniques are available for tropospheric delay mitigation consisting of surface meteorological models and global empirical models. Surface meteorological models need surface meteorological data to give high accuracy mitigation while the global empirical models need not. Several hybrid neutral atmosphere delay models have been developed by (University of New Brunswick, Canada) UNB researchers over the past decade or so. The most widely applicable current version is UNB3m, which uses the Saastamoinen zenith delays, Niell mapping functions, and a look-up table with annual mean and amplitude for temperature, pressure, and water vapour pressure varying with respect to latitude and height. This paper presents an assessment study of the behaviour of the UNB3m model compared with highly accurate IGS-tropospheric estimation for three different (latitude/height) IGS stations. The study was performed over four nonconsecutive weeks on different seasons over one year (October 2014 to July 2015). It can be concluded that using UNB3m model gives tropospheric delay correction accuracy of 0.050m in average for low latitude regions in all seasons. The model's accuracy is about 0.075m for medium latitude regions, while its highest accuracy is about 0.014m for high latitude regions.

2

GNSS-WARP software for real-time precise point positioning

88%

Hadaś T.

Artificial Satellites : Journal of Planetary Geodesy

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2015

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tom Vol. 50, No. 2

59--76

EN

On April 1, 2013 IGS launched the real-time service providing products for Precise Point Positioning (PPP). The availability of real-time makes PPP a very powerful technique to process GNSS signals in real-time and opens a new PPP applications opportunities. There are still, however, some limitations of PPP, especially in the kinematic mode. A significant change in satellite geometry is required to efficiently de-correlate troposphere delay, receiver clock offset, and receiver height. In order to challenge PPP limitations, the GNSS-WARP (Wroclaw Algorithms for Real-time Positioning) software has been developed from scratch at Wroclaw University of Environmental and Life Science in Poland. This paper presents the GNSS-WARP software itself and some results of GNSS data analysis using PPP and PPP-RTK (Real-Time Kinematic) technique. The results of static and kinematic processing in GPS only and GPS + GLONASS mode with final and real-time products are presented. Software performance validation in postprocessing mode confirmed that the software can be considered as a state-ofthe-art software and used for further studies on PPP algorithm development. The real-time positioning test made it possible to assess the quality of real-time coordinates, which is a few millimeters for North, East, Up in static mode, a below decimeter in kinematic mode. The accuracy and precision of height estimates in kinematic mode were improved by constraining the solution with an external, near real-time troposphere model. The software also allows estimation of real-time ZTD, however, the obtained precision of 11.2 mm means that further improvements in the software, real-time products or processing strategy are required.

3

Observed vertical distribution of tropospheric carbon monoxide during 2012 over Iraq

75%

Abdulfattah I. S. , Rajab J. M. , Al-Salihi A. M. , Suliman A. , Lim H. S.

Przegląd Naukowy. Inżynieria i Kształtowanie Środowiska

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2020

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tom 29

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nr 2[88]

4

Opóźnienie troposferyczne GNSS i jego zastosowanie do badań stanu atmosfery

75%

Kruczyk M.

Prace Naukowe Politechniki Warszawskiej. Geodezja

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2013

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tom z. 54

3--150

EN

Work provides various empirical evidences on need for close cooperation of satellite geodesy and meteorology (and numerical weather prediction). Standard GNSS tropospheric delay products (IGS. EPN) show some inconsistencies, smaller after 2006 but still present (demonstrated by neat statistical analysis). Zenith Tropospheric Delay (ZTD) from GNSS solution (network or PPP) can be separated into hydrostatic part (it is a function of surface atmospheric pressure) and 'wet' part which can be transformed into IPW. Integrated Precipitable Water (or Integrated water Vapour - IWV) - column water vapour in atmosphere is highly interesting parameter of atmosphere. Amount of water vapour (here acquired by geodetic method) is crucial in thermodynamics of atmosphere (e.g. precipitation) and climate processes. Different GNSS solutions (with special case of EPN reprocessing) were verified by aerological techniques. radiosoundings and sun photometer CIMEL. It turns out that crucial problem in this comparisons is station collocation: bias and RMS depends on distance and station height. Permanent GPS station has been set up at Central Geophysical Observatory PAS (Belsk) in years 2009-2012, to carry out calibration campaign: GPS vs. sunphotometer CIMEL CF-318. IPW coming from two versions of GPS solutions (network and PPP) demonstrate deficiencies of IPW comma from sunpotometer technique. Differences were modeled by seasonal and semiannual signal, clearly CIMEL measurements are subject of systematic bias - no-linear function of atmospheric temperature. The same procedure were tried for polar stations, especially at Hornsund (Svalbard). Vertical profiles of atmospheric parameters from numerical weather prediction models can be utilized in the same way as radiosounding. Input fields (so called analysis) and first prognosis steps of model COSMO (in two versions of 14 km and 2.8 km resolution) - basic synoptic tool of Polish Institute of Meteorology and Water Management in Warsaw - were used to obtain both IPW and ZTD. Many factors were taken into account to work out optimal procedure: interpolation of data from model grid for GNSS station, corrections of height (crucial), vertical integration procedure etc. There is only slight degradation of data quality for first prognosis steps and we can get time series of IPW and ZTD with 3 h resolution Two disparate procedures for obtaining ZTD were tried: hydrostatic (only wet part from integration) and complete integration of refractivity profile in vertical direction. The second method gives in comparison with EPN combined solution quite different results for 14 ion resolution model (3 %bias), and 2.8 km resolution (0,5%bias). Use of surface meteorological data retrieved from numerical model for IPW calculation is also presented. Global model GFS (NCEP) was used only for IPW comparisons: results comparable to regional model COSMO. Topospheric delay from numerical weather model can be used in GNSS position solutions (PPP method). Horizontal coordinates estimated in PPP mode with use of COSMO model ZTD are comparable to coordinates obtained when ZTD is estimated. Vertical coordinates show greater scattering but less big outliers in case of ZTD from numerical weather model. Next topic is to analyze parameters of GNSS solutions most affecting ZTD solution: reference system shows more significance than orbits (ultra rapid or final). In the end this work demonstrates that IPW (column water) coming from satellite geodesy solutions reveals features of meteorological parameter: seasonal dependence, weather pattern changes etc. Most important application of long series od IPW of uniform quality is climatology. Work suggests how to search for climatological signal in IPW series.

5

Analysis of tropospheric NO2 over Iraq using OMI satellite measurements

75%

Rajab J. M. , Hassan A. S. , Kadhum J. H. , Al-Salihi A. M. , San Lim H.

Przegląd Naukowy. Inżynieria i Kształtowanie Środowiska

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2020

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tom 29

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nr 1[87]

6

On the lower atmosphere effect nature in GPS and SLR measurements in polar regions

75%

Zablotskyj F.

Archiwum Fotogrametrii, Kartografii i Teledetekcji

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2001

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tom Vol. 11

2-51--2-56

EN

The paper studies some determination peculiarities of atmospheric propagation delay by the microwave- and laser distance measurements in polar regions. On the basis of the average monthly and separate (one-time) aerological sounding data at a number of Antarctic and Arctic stations the distribution analysis of the main meteorological parameters as well as of refractivity both in space and in time is adduced. Zenith atmospheric delay for microwave- and laser range was estimated by the data of these stations. A small effect of moist component (zenith wet delay) in the Central Antarctica is noted. The values of dry and wet components of the zenith tropospheric delay obtained by radiosonde data and Saastamoinen and Hopfield’s analytical models are cited.

PL

W pracy przedstawiono niektóre osobliwości wyznaczenia pochłaniania atmosfery przy pomiarach laserowych i w paśmie radiowym. Na podstawie średnio-miesięcznych danych z radiosond na kilku antarktycznych i arktycznych stacjach przeprowadzono analizy rozkładu głównych parametrów meteorologicznych, współczynnika refrakcji i dokonano oceny pochłaniania atmosfery dla zakresów optycznego i radiowego . Wartości suchej i wilgotnej składowej zenitalnej pochłaniania troposfery, otrzymano drogą całkowania i przez zastosowanie modeli analitycznych Saastamoinena i Hopfielda.

7

Natural and artificial radionuclides in the tropospheric and lower stratospheric air over Poland

75%

Kownacka L.

Nukleonika

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2001

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tom Vol. 46, nr 4

175-177

EN

The high altitude aircraft sampling of aerosols have been carried out at four to seven levels up to 15 km over Poland from 1973 to 1998, and 117 vertical concentration profiles of natural radionuclides and fission products were determined. It was found that the atmospheric concentrations of 226Ra increased after large volcanic eruptions. The vertical concentrations profile of 226Ra had a characteristic quasi-parabolic distribution, with the highest concentrations near the ground level and in the stratosphere. Concentrations of 210Pb had a more homogeneous vertical distribution, due to the quiescent ascent of its gaseous 222Rn precursor from the ground. Vertical concentrations of fission products revealed different types of profiles. After nuclear explosions, the highest concentrations were observed in the stratosphere. The Chernobyl accident reversed the aerial vertical profiles; the main source was near the ground level, but part of the radioactive debris entered also the lower stratosphere. Because of resuspension, the stratospheric residence time of radiocesium from the Chernobyl accident was about three times longer than that of the fallout from nuclear explosions. The resuspension effects and the atmospheric mass transport in the boundary layers are also responsible for the increased concentrations of radiocesium at 1 km altitude observed since 1987 in the situations of atmospheric mass advection from the highly contaminated Chernobyl region.

8

Vertical distributions of beryllium-7 and lead-210 in the tropospheric and lower stratospheric air

75%

Kownacka L.

Nukleonika

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2002

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tom Vol. 47, nr 2

79-82

EN

Vertical distributions of 7Be and 210Pb were observed in the troposphere and lower stratosphere over Poland at several altitudes between 0 and 15 km in the period 1987-1998. These two natural radionuclides are formed from gases in the atmosphere by nuclear processes. They are associated with similar size distributions aerosol particles and are removed from the atmosphere with similar efficiencies by scavenging processes of washout and deposition, however, they have various types of sources in the atmosphere. Vertical profiles of 7Be (cosmogenic origin), characterized by small concentrations near the ground level, increase in the tropospheric levels and at 15 km altitude the concentrations are the highest. The highest concentrations of 210Pb (terrestrial origin) are observed near the ground level, the lowest are below the tropopause, and in the stratosphere the concentration increases slightly. The dependence of the vertical distributions of both radionuclides in the situation of various levels of tropopause are discussed in this work.

9

Powstawanie i zanikanie ozonu w atmosferze

75%

Protczak A.

Chemistry-Didactics-Ecology-Metrology

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2004

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tom R. 9, NR 1-2

39--42

PL

Ozon wpływa na stan równowagi termicznej i strukturę dynamiczną atmosfery. Ozon stratosferyczny tworzy warstwę ozonową, która pełni rolę filtra osłaniającego Ziemię przed promieniowaniem nadfioletowym. Natomiast ozon troposferyczny jest składnikiem smogu wielkomiejskiego, który powoduje podrażnienia dróg oddechowych, a także ma właściwości korodujące. Wpływ procesów antropogennych na warstwę ozonu jest zagadnieniem skomplikowanym ze względu na szereg powiązań pomiędzy procesami chemicznymi, radiacyjnymi oraz procesami transportu masy między stratosferą a troposferą.

EN

Ozone effects the state of thermal eguilibrium and dynamical structure of the atmosphere. The stratospheric ozone forms the ozone layer, which shields the Earth from the ulraviolet radiation. Instead the tropospheric ozone is a component of an urban smog, which causes the irritation of respiratory system and has also a corrosive properties. The effect of the anthropogenic processes on the ozone layer is the complicated problem for the sake of connection between chemical and radiation processes, and processes of mass transport between the stratosphere and troposphere.

10

Metrologia GNSS

63%

Hadaś T. , Bosy J. , Kapłon J. , Rohm W. , Sierny J. , Wilgan K.

Geodeta : magazyn geoinformacyjny

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2014

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tom nr 1

44--48

11

Investigation of the 16-year and 18-year ZTD Time Series Derived from GPS Data Processing

63%

Bałdysz Z. , Nykiel G. , Figurski M. , Szafranek K. , Kroszczyński K.

Acta Geophysica

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2015

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tom Vol. 63, no. 4

1103--1125

EN

The GPS system can play an important role in activities related to the monitoring of climate. Long time series, coherent strategy, and very high quality of tropospheric parameter Zenith Tropospheric Delay (ZTD) estimated on the basis of GPS data analysis allows to investigate its usefulness for climate research as a direct GPS product. This paper presents results of analysis of 16-year time series derived from EUREF Permanent Network (EPN) reprocessing performed by the Military University of Technology. For 58 stations Lomb-Scargle periodograms were performed in order to obtain information about the oscillations in ZTD time series. Seasonal components and linear trend were estimated using Least Square Estimation (LSE) and Mann-Kendall trend test was used to confirm the presence of a linear trend designated by LSE method. In order to verify the impact of the length of time series on trend value, comparison between 16 and 18 years were performed.

12

Research on GNSS positioning and applications in Poland in 2019–2022

63%

Paziewski J. , Hadas T. , Rohm W. , Wielgosz P.

Advances in Geodesy and Geoinformation

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2023

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tom Vol. 72, no. 2

art. no. e43, 2023

EN

This paper reviews the key studies concerning GNSS positioning and applications conducted at leading Polish research institutions from 2019 until 2022. The review also constitutes a contribution to the national report of Poland for the International Union of Geodesy and Geodynamics (IUGG) presented at the 28th General Assembly of IUGG held in 2023 in Berlin, Germany. In particular, we discuss the advances in theory and applications of relative and absolute positioning, troposphere and ionosphere sounding, smartphone and low-cost GNSS data processing, and other specific studies such as those on satellite antenna calibration and clock stability. In light of these recent advances by the Polish scientific community, continuous progress in GNSS theory and processing algorithms is thought to be maintained in the future, and GNSS applications are expected to continue to proliferate.

13

Positioning and applications

63%

Rogowski J. B. , Wielgosz P.

Geodesy and Cartography

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2015

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tom Vol. 64, no. 2

243--259

EN

The paper presents national report of Poland for IAG on positioning and applications. The selected research presented was carried out at leading Polish research institutions and concern precise multi-GNSS satellite positioning - relative and absolute - and also GNSS-based ionosphere and troposphere modelling and studies. The research resulted in noticeable advancements in these subjects confirmed by the development of new algorithms and methods. New and improved methods of precise GNSS positioning were developed, and also GNSS metrology was studied. New advanced troposphere models were presented and tested. In particular, these models allowed testing IPW variability on regional and global scales. Also, new regional ionosphere monitoring web-based services were developed and launched.

14

Methane flux from sediment into near-bottom water in the coastal area of the Puck Bay (Southern Baltic)

63%

Reindl A. R. , Bolalek J.

Oceanological and Hydrobiological Studies

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2012

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tom 41

|

nr 3

15

Oznaczanie ozonu - urządzenia wzbudzające tlen

63%

Ćwikła-Bundyra W.

Laboratorium - Przegląd Ogólnopolski

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2012

|

tom nr 3-4

40--42

PL

Ozon powstaje w otoczeniu urządzeń energetycznych, w których dochodzi do wzbudzenia lub dysocjacji cząsteczek tlen, np. w sąsiedztwie dużych stacji generatorowych, w otoczeniu pracujących lamp kwarcowych, lamp emitujących promienie gamma, światłokopiarek, w czasie procesów spawania w palniku plazmowym. Długotrwała ekspozycja na jego oddziaływanie może doprowadzić do zagrożenia zdrowia.

EN

Ozone is formed in the vicinity of power equipment, in which there is excitation or dissociation of oxygen molecules, eg. in the vicinity of large generator station, surrounded by working quartz lamps, lamps which emit gamma rays, printing-frames, during the welding process in a plasma torch. Prolonged exposure to its effects may lead to health risks.

16

Examination of different models of troposphere delays in SBAS positioning in aerial navigation

63%

Krasuski K. , Kirschenstein M.

Zeszyty Naukowe. Transport / Politechnika Śląska

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2023

|

tom z. 118

123--137

EN

This paper presents the results of a study on the use of different tropospheric correction models in SBAS positioning for air navigation. The paper, in particular, determines the influence of the Saastamoinen troposphere and RTCAMOPS models on the determination of aircraft coordinates and mean coordinate errors in the SBAS positioning method. The study uses real kinematic data from a GPS navigation system recorded by an onboard GNSS satellite receiver as well as SBAS corrections. In the experiment, the authors include SBAS corrections from EGNOS and SDCM augmentation systems. The navigation calculations were performed using RTKLIB v.2.4.3 and Scilab 6.1.1 software. Based on the conducted research, it was found that the difference in aircraft coordinates using different troposphere models can reach up to ±2.14 m. Furthermore, the use of the RTCA-MOPS troposphere model improved the values of mean coordinate errors from 5 to 9% for the GPS+EGNOS solution and from 7 to 12% for the GPS+SDCM solution, respectively. The obtained computational findings confirm the validity of using the RTCA-MOPS troposphere model for SBAS positioning in aerial navigation.

17

Rola MgO i CaO w oczyszczaniu atmosfery ziemskiej z freonów

63%

Karski S. , Gołuchowska J. , Szynkowska M. , Witońska I.

Przemysł Chemiczny

|

2005

|

tom T. 84, nr 3

171-174

PL

Dokonano analizy zanieczyszczeń obecnych w troposferze ziemskiej oraz podano przyczynę absorpcji promieniowania przez obecne w troposferze tlenki wapnia i magnezu. Przedstawiono także najważniejsze mechanizmy przebiegu reakcji fotochemicznych związane z fotogenerowaniem chemicznie reaktywnej pary elektron– dziura oraz z powstawaniem na powierzchni tlenków aktywnych centrów reakcyjnych, którymi są jony niektórych metali przejściowych na niskim stopniu utlenienia.

EN

A review covering the troposphere as a natural photocatalytic reactor, photocatalytic reaction mechanisms, MgO and CaO as absorbers of 300–400-nm radiation, which give rise to mobile electron–mobile hole pairs and destroy freons by photoadsorption.

18

Designation of the troposphere radio refractivity for the area of the military aerodrome in Dęblin

63%

Kirschenstein M. , Krasuski K.

Journal of KONBiN

|

2019

|

tom Vol. 49, iss. 3

137--158

EN

The radio refractivity is one of major parameters in troposphere monitoring over a selected military aerodrome. The paper makes an in-depth analysis and description of the results of radio refractivity of the troposphere zone. The radio refractivity of the troposphere zone was estimated for the area of the military aerodrome EPDE in Dęblin, Poland. The radio refractivity of the troposphere zone was calculated using empirical troposphere models for the GNSS satellite technique as well as real meteorological data from the SYNOP message. In the paper, the authors demonstrate the results of wet, hydrostatic and total radio refractivity of the troposphere zone for EPDE military aerodrome. The SA and UNB3m models were applied in numerical computations of troposphere refractivity in an annual period.

PL

Refrakcyjność fal radiowych jest jednym z głównych parametrów monitorowania troposfery na wybranym lotnisku wojskowym. W artykule dokonano pogłębionej analizy i opisu wyników załamania radiowego w warstwie troposfery. Refrakcyjność radiową warstwy troposfery oszacowano dla obszaru lotniska wojskowego EPDE w Dęblinie. Refrakcyjność radiowa warstwy troposfery została obliczona przy użyciu empirycznych modeli troposfery dla techniki satelitarnej GNSS, a także rzeczywistych danych meteorologicznych z depeszy SYNOP. W artykule autorzy przedstawiają wyniki mokrej, hydrostatycznej i całkowitej refrakcji radiowej warstwy troposfery dla lotniska wojskowego EPDE. Modele SA i UNB3m zastosowano w obliczeniach numerycznych refrakcji troposfery w okresie rocznym.

19

Research on GNSS positioning and applications in Poland in 2015–2018

63%

Wielgosz P. , Hadaś T. , Kłos A. , Paziewski J.

|

20

Propagacja fal radiowych w naziemnych i satelitarnych systemach nawigacyjnych

51%

Januszewski J.

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

|

2012

|

tom nr 1

3-9

PL

Sygnały emitowane przez satelity systemów nawigacyjnych (SSN) i systemów wspomagających (SBAS) na swej drodze do odbiornika użytkownika napotykają dwie warstwy atmosfery ziemskiej - jonosferę i troposferę. Omówiono wpływ tych warstw na określanie pozycji użytkownika i jej dokładność oraz podano szczegółowe informacje o poprawkach dotyczących jonosfery, które są przekazywane w depeszy nawigacyjnej satelitów systemów GPS, GLO-NASS, Galileo, OZSS i SBAS. Scharakteryzowano też sposoby propagacji sygnałów emitowanych przez stacje naziemnych systemów radionawigacyjnych, takich jak system Loran C.

EN

The signals transmitted from the satellites of navigation systems (SNS) and augmentation systems (SBAS) on the way to the user's receiver propagate through the two Earth's atmosphere layers - ionosphere and troposphere. The influence of these layers on determination of the user's position and its accuracy and the detailed Information about corrections concerning ionosphere transmitted in the navigation message of GPS, GLONASS, Galileo, OZSS and SBAS satellites are presented in this paper. Additionally the ways of propagation of the signals transmitted from the stations of terrestrial radionavigation systems, as Loran C, are showed also.