Search results for "Zen"

An Indication of Anisotropy in Arrival Directions of Ultra-high-energy Cosmic Rays through Comparison to the Flux Pattern of Extragalactic Gamma-Ray …

2018

A new analysis of the dataset from the Pierre Auger Observatory provides evidence for anisotropy in the arrival directions of ultra-high-energy cosmic rays on an intermediate angular scale, which is indicative of excess arrivals from strong, nearby sources. The data consist of 5514 events above 20 EeV with zenith angles up to 80 deg recorded before 2017 April 30. Sky models have been created for two distinct populations of extragalactic gamma-ray emitters: active galactic nuclei from the second catalog of hard Fermi-LAT sources (2FHL) and starburst galaxies from a sample that was examined with Fermi-LAT. Flux-limited samples, which include all types of galaxies from the Swift-BAT and 2MASS …

All-particle cosmic ray energy spectrum measured with 26 IceTop stations

2012

Astroparticle physics 44, 40 - 58 (2013). doi:10.1016/j.astropartphys.2013.01.016

Medicīna (Latvijas Universitātes Raksti; 812 sēj.)  

2016

Formatīvās vērtēšanas paņēmieni ķīmijā pamatskolā

2016

Formatīvās vērtēšanas paņēmieni ķīmijā pamatskolā. Darba autore Tālberga M., darba vadītāja Mg. ķīm. Gaile I. Bakalaura darbs, 44 lappuses, 26 attēli, 3 tabulas, 23 literatūras avoti, 14 pielikumi. Latviešu valodā. Darba mērķis ir izpētīt formatīvās vērtēšanas pieejas, lai uzlabotu skolēnu mācīšanās procesu. Darbā ir literatūras un avotu apskats par vērtēšanu, formatīvo vērtēšanu un formatīvās vērtēšanas pieeju izvēli pamatskolā. Darba pētnieciskajā daļā izstrādātas un aprobētas mācību stundas tematā „Gaiss un tā kvalitāte’’. Veikta stundu analīze. Izstrādāts un aprobēts noslēguma darbs. Veikta skolēnu anketēšana, lai noskaidrotu viedokli par mācību procesu ķīmijas priekšmetā, tematā „Gaiss…

Jelgavas Zinātniskās bibliotēkas ārējās komunikācijas izpēte un pilnveide

2016

Nepieciešamība pēc efektīvas ārējās komunikācijas publisko bibliotēku pakalpojumu popularizēšanā pieaug. Bibliotēkām jāpievēršas veiksmīgas komunikācijas veidošanā, lai tās būtu konkurētspējīgas un saglabātu savu vērtību mūsdienu mainīgajā sabiedrībā. Pētījuma mērķis ir izpētīt Jelgavas Zinātniskās bibliotēkas ārējo komunikāciju un izvirzīt ieteikumus tās pilnveidei, balstoties uz bibliotēkas lietotāju, nelietotāju un ekspertu viedokļiem. Pētījuma teorētisko bāzi veido pragmatisms, Gruniga un Hanta četri sabiedrisko attiecību modeļi un Ekoloģiskais komunikācijas procesa modelis. Darbā izmantotās datu ieguves metodes – anketēšana, mediju monitorings un ekspertu intervijas. Pēc pētījuma rezul…

Measurement-based J(NO2) sensitivity in a cloudless atmosphere under low aerosol loading and high solar zenith angle conditions

2000

Abstract The comparison between measured and simulated photodissociation frequencies of NO 2 , J( NO 2 ) , in a cloudless atmosphere in a recent paper by Fruh et al., 2000 (Journal of Geophysical Research 105, 9843–9857) revealed an overestimation of J(NO2) near ground level by model calculations compared with measurements and an underestimation in the upper part of the aerosol layer. A possible reason for the disagreement is the changing sun position during the vertical ascent. To resolve this problem we carried out a sensitivity study varying the solar zenith angle of 74° by 1.4° (which corresponds to the change of sun position during the vertical flight patterns). This results in a consi…

2018

Abstract. Detailed measurements of radiation, atmospheric and aerosol properties were carried out in summer 2013 during the Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region (ADRIMED) campaign in the framework of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx) experiment. This study focusses on the characterization of infrared (IR) optical properties and direct radiative effects of mineral dust, based on three vertical profiles of atmospheric and aerosol properties and IR broadband and narrowband radiation from airborne measurements, made in conjunction with radiosonde and ground-based observations at Lampedusa, in the central Mediterranean. Satell…

Exploring the Validity of the Long-Term Data Record V4 Database for Land Surface Monitoring

2016

A new version of the long-term data record (LTDR)—Version 4—has been released recently by NASA. This database includes daily information for all advanced very high resolution radiometer channels, as well as ancillary data, from July 1981 up to present. This dataset is the longest available record of remotely sensed data useful for land surface monitoring, since it allows the daily estimation of vegetation indices, as well as the estimation of land surface temperature (LST). Here, we analyze the fitness of this database for land surface monitoring, especially as regards long-term trends and their validity. To that end, we estimated normalized difference vegetation index (NDVI), LST, as well …

Heating rate profiles and radiative forcing due to a dust storm in the Western Mediterranean using satellite observations

2017

Abstract We analyze the vertically-resolved radiative impact due to a dust storm in the Western Mediterranean. The dust plume travels around 3–5 km altitude and the aerosol optical depth derived by MODIS at 550 nm ranges from 0.33 to 0.52 at the overpass time (13:05 UT). The aerosol radiative forcing (ARF), forcing efficiency (FE) and heating rate profile (AHR) are determined throughout the dust trajectory in shortwave (SW) and longwave (LW) ranges. To do this, we integrate different satellite observations (CALIPSO and MODIS) and detailed radiative transfer modeling. The combined (SW + LW) effect of the dust event induces a net cooling in the studied region. On average, the FE at 22.4° sola…

Simulation of Future Geostationary Ocean Color Images

2012

The objective of this work is to simulate global images that would be provided by a theoretical ocean color sensor on a geostationary orbit at longitude 0, in order to assess the range of radiance value data reaching the sensor throughout the day for 20 spectral bands similar to those of the Ocean and Land Color Imager (OLCI). The secondary objective is to assess the illumination and viewing geometries that result in sunglint. For this purpose, we combined a radiative transfer model for ocean waters (Hydrolight) and a radiative transfer model for atmosphere (MODTRAN) to construct the simulated radiance images at the sea surface and at the Top-Of-Atmosphere (TOA). Bio-optical data from GlobC…