Search results for "Nobel"

Effects of climate change and land use intensification on regional biological soil crust cover and composition in southern Africa

2022

Biological soil crusts (biocrusts) form a regular and relevant feature in drylands, as they stabilize the soil, fix nutrients, and influence water cycling. However, biocrust forming organisms have been shown to be dramatically vulnerable to climate and land use change occurring in these regions. In this study, we used Normalized Difference Vegetation Index (NDVI) data of biocrust-dominated pixels (NDVIbiocrust) obtained from hyperspectral and LANDSAT-7 data to analyse biocrust development over time and to forecast future NDVIbiocrust development under different climate change and livestock density scenarios in southern Africa. We validated these results by analysing the occurrence and compo…

Los pasados políticos de Grass / Ridruejo

2006

Ode laica per Chibok e Leah

2019

The volume contains two short poems by Nigerian Nobel Laureate Wole Soyinka ("No, He Said!", dedicated to Nelson Mandela, from the Author's 1988 classic collection "Mandela's Earth and Other Poems", and the recent "Mandela Comes to Leah", written purposely for this volume), along with the most recent long poem in five parts "A Humanist Ode to Chibok, Leah", published in English for the first time in 2019. The poem, and indeed the entire volume, denounces all forms of fundamentalism and fanaticism as opposed to secular humanism. Soyinka pays tribute to the girls abducted in Chibok and 15 year-old Leah Sharibu, one of the 108 girls abducted from Dapchi in 2018, comparing her firm refusal to r…

Bush, camino del Nobel

2003

Precision Measurement of the First Ionization Potential of Nobelium

2018

One of the most important atomic properties governing an element's chemical behavior is the energy required to remove its least-bound electron, referred to as the first ionization potential. For the heaviest elements, this fundamental quantity is strongly influenced by relativistic effects which lead to unique chemical properties. Laser spectroscopy on an atom-at-a-time scale was developed and applied to probe the optical spectrum of neutral nobelium near the ionization threshold. The first ionization potential of nobelium is determined here with a very high precision from the convergence of measured Rydberg series to be 6.626 21±0.000 05  eV. This work provides a stringent benchmark for st…

First Ionization Potentials of Fm, Md, No, and Lr

2018

We report the first ionization potentials (IP1) of the heavy actinides, fermium (Fm, atomic number Z = 100), mendelevium (Md, Z = 101), nobelium (No, Z = 102), and lawrencium (Lr, Z = 103), determined using a method based on a surface ionization process coupled to an online mass separation technique in an atom-at-a-time regime. The measured IP1 values agree well with those predicted by state-of-the-art relativistic calculations performed alongside the present measurements. Similar to the well-established behavior for the lanthanides, the IP1 values of the heavy actinides up to No increase with filling up the 5f orbital, while that of Lr is the lowest among the actinides. These results clear…

Stability and synthesis of superheavy elements: Fighting the battle against fission – example of $^{254}$No

2016

International audience; Superheavy nuclei exist solely due to quantum shell effects,which create a pocket in the potential-energy surface of the nucleus, thusproviding a barrier against spontaneous fission. Determining the height ofthe fission barrier and its angular-momentum dependence is important toquantify the role that microscopic shell corrections play in enhancing andextending the limits of nuclear stability. In this talk, the first measurement ofa fission barrier in the very heavy nucleus 254No will be presented.

Probing Sizes and Shapes of Nobelium Isotopes by Laser Spectroscopy

2018

Until recently, ground-state nuclear moments of the heaviest nuclei could only be inferred from nuclear spectroscopy, where model assumptions are required. Laser spectroscopy in combination with modern atomic structure calculations is now able to probe these moments directly, in a comprehensive and nuclear-model-independent way. Here we report on unique access to the differential mean-square charge radii of ^{252,253,254}No, and therefore to changes in nuclear size and shape. State-of-the-art nuclear density functional calculations describe well the changes in nuclear charge radii in the region of the heavy actinides, indicating an appreciable central depression in the deformed proton densi…

Latvijas Zinātņu akadēmijas, Latvijas Universitātes Astronomijas institūta populārzinātnisks gadalaiku izdevums

2012

Contents: JĀNIS IKAUNIEKS – 100: N.Cimahoviča. Subjacent Was Venture ; I.P. Articles on Jānis Ikaunieks and Articles by Jānis Ikaunieks in Zvaigžņotā debess ; “ZVAIGŽŅOTĀ DEBESS” FORTY YEARS AGO: A.Balklavs. Ball Lightning and Solar Activity (abridged) ; Streamer with the USSR State Emblem on Mars (TASS materials) ; NEWS: I.Eglītis. Asteroid Baldone – Christmas Gift for Latvia ; I.Eglītis. LUAI Astrophysics Observatory Discovers First Trojan Asteroid ; V.Kalniņš. Exceeding Speed of Light in CERN Experiment from the Theory of Relativity Viewpoint ; O.Dumbrājs. Higgs Boson ; NOBEL PRIZE WINNERS: D.Docenko. Nobel Prize in Physics for Discovery of Accelerating Expansion of Universe ; SPACE RESE…

Zvaigžņotā Debess: 2006/07, Ziema

2006

Latvijas Zinātnes padome, Latvijas Universitāte