Tracer Applications of Noble Gas Radionuclides in the Geosciences

The noble gas radionuclides, including 81Kr (half-life = 229,000 yr), 85Kr (11 yr), and 39Ar (269 yr), possess nearly ideal chemical and physical properties for studies of earth and environmental processes. Recent advances in Atom Trap Trace Analysis (ATTA), a laser-based atom counting method, have enabled routine measurements of the radiokrypton isotopes, as well as the demonstration of the ability to measure 39Ar in environmental samples. Here we provide an overview of the ATTA technique, and a survey of recent progress made in several laboratories worldwide. We review the application of noble gas radionuclides in the geosciences and discuss how ATTA can help advance these fields, specifically determination of groundwater residence times using 81Kr, 85Kr, and 39Ar; dating old glacial ice using 81Kr; and an 39Ar survey of the main water masses of the oceans, to study circulation pathways and estimate mean residence times. Other scientific questions involving deeper circulation of fluids in the Earth's crust and mantle also are within the scope of future applications. We conclude that the geoscience community would greatly benefit from an ATTA facility dedicated to this field, with instrumentation for routine measurements, as well as for research on further development of ATTA methods

Occurrence of Leaf-Cutting and Grass-Cutting Ants of the Genus Atta (Hymenoptera: Formicidae) in Geographic Regions of Brazil

Leaf-cutting ants are widely distributed in Brazil, particularly species of the genus Atta. We therefore described the occurrence of leaf-cutting and grass-cutting ant species of the genus Atta. Five routes comprising some of the main highways in the South, Southeast, Center-West, and North of Brazil were sampled, in addition to ants received from other 82 municipalities, composing 300 municipalities sampled. This is the first comprehensive study of Atta in Brazil. The following species were found: A. laevigata, A. capiguara, A. sexdens rubropilosa, A. sexdens piriventris, A. sexdens sexdens and A. cephalotes. Atta laevigata and A. capiguara were the species present in the largest number of the Brazilian municipalities sampled. Atta laevigata assumed the position of species of greatest occurrence in the Brazilian territory. Atta sexdens piriventris was only recorded in the southern region of Brazil. Atta bisphaerica presented lower expansion than A. capiguara. Atta cephalotes and Atta opaciceps are species of very restricted occurrence. Southeastern region was characterized by the occurrence of A. capiguara and A. laevigata. Atta laevigata exhibited a generalized pattern of occurrence in the Center-West and North. Our study contributes to a better understanding of the so far unknown occurrence of leaf-cutting and grass-cutting ants within Brazil

A New Method of Measuring 81Kr and 85Kr Abundances in Environmental Samples

We demonstrate a new method for determining the 81Kr/Kr ratio in environmental samples based upon two measurements: the 85Kr/81Kr ratio measured by Atom Trap Trace Analysis (ATTA) and the 85Kr/Kr ratio measured by Low-Level Counting (LLC). This method can be used to determine the mean residence time of groundwater in the range of 10^5 - 10^6 a. It requires a sample of 100 micro-l STP of Kr extracted from approximately two tons of water. With modern atmospheric Kr samples, we demonstrate that the ratios measured by ATTA and LLC are directly proportional to each other within the measurement error of +/- 10%; we calibrate the 81Kr/Kr ratio of modern air measured using this method; and we show that the 81Kr/Kr ratios of samples extracted from air before and after the development of the nuclear industry are identical within the measurement error

Optimalisasi Usaha Kelompok Pemuda Pengrajin Anyaman Paku Atta Dalam Upaya Pemasaran Produk Secara Online

Industri Anyaman Atta menempati posisi yang paling tinggi dalam data potensi perindustrian dan perdagangan Kabupaten Karangasem tahun 2017. Industri Anyaman Atta mempunyai unit usaha sebanyak 3.569 dengan jumlah penyerapan tenaga kerja sebanyak 5.838 orang. Namun pemasaran secara langsung untuk menembus pasar nasional dan internasional masih belum tercapai karena para pengrajin belum bias memanfaatkan memanfaatkan pemasaran secara online sesuai dengan perkembangan zaman sekarang.   Mitra dalam program Iptek bagi Masyarakat ini adalah Kelompok Pemuda Pengrajin Anyaman Atta Eka Genta. Kelompok Pengrajin ini berkedudukan di Banjar Desa, Desa Bungaya, Kecamatan Bebandem, Kabupaten Karangasem. Tujuan pelaksanaan pengabdian masyarakat ini adalah untuk memberikan pelatihan dan pemahaman marketing online   produk anyaman paku atta melalui media social seperti facebook dan Instagram. Metode pengabdian yang digunakan adalah metode ceramah, workshop, praktik. Hasil dari pengabdian masyarakat ini berupa media sosial online berupa facebook, Instagram dari para anggota pemuda pengrajin anyaman paku atta dan adanya peningkatan  omzet penjualan dan pelanggan dari masing-masing pengrajin

Analysing the Development Implications of Technological Innovations from China to SSA economies: A Conceptual Framework

China’s relationship with Africa has grown enormously, especially in the last two decades. From trade to foreign direct investment and official development assistance to migration, there are many myths surrounding the relationship between China and Africa, some of which are being dispelled through research. However, the academic community is still at an early stage in researching this evolving relationship and its impact on Africa economies. A significant gap remains in the literature in the area of technology transfer from China to African economies and developing countries in general. This paper seeks to present a literature review on various issues on technology, developing a conceptual framework that will guide future research in analysing the impact of technology transfer from China on recipient developing countries as well as informing policy

Are Chinese Technologies A Mode Of Entry For Firms In Developing Countries? The Case of Furniture Manufacturing in Kenya

Kenya has started to rely significantly on technologies developed in developing countries particularly China rather than those from advanced countries such as the United Kingdom, Germany and Japan. Using data from furniture manufacturing firms in Kenya, the paper compares the investment cost and the scale characteristics of the technologies (machines and equipment) from China with those from advanced countries and Kenya. By examining the characteristics of the firms that have invested in technologies from various sources, the paper concludes that the technologies from China and Kenya have lessened entry barrier (specifically high capital cost) for new firms, compared to advanced country technologies. Chinese technology appears to serve as an entry mode more than the Kenyan technology. In terms of barriers to entry, therefore Chinese and Kenyan technologies appear to be more appropriate for Kenya (and more generally developing countries) than advanced country technolog

Дослідження коливань скребкових канатних робочих органів конвеєрів для транспортування насипних вантажів

Denna studie undersökte hur en tillämpning av myrarten Atta Colombicas trafikregler påverkade trafikflödet på en dubbelriktad väg med två körfält där en del av ett körfält var avstängt. Detta gjordes genom att utveckla ett simulationsprogram, en algoritm baserad på Atta Colombicas trafikregler samt en algoritm baserad på svenska trafikregler. Algoritmerna jämfördes med avseende på trafikflöde och fordons genomsnittliga resetid. Simuleringen samlade kvantitativ data om trafikflödet och genomsnittliga resetider från båda algoritmer. Resultaten visade att algoritmen baserad på svenska trafikregler presterade bättre i alla testfall. Slutsatsen att Atta Colombicas trafikregler inte ökar flödet jämfört med svenska trafikregler drogs.

Counting individual 41Ca atoms with a magneto-optical trap

Atom Trap Trace Analysis (ATTA), a novel method based upon laser trapping and cooling, is used to count individual atoms of 41Ca present in biomedical samples with isotopic abundance levels between 10^-8 and 10^-10. ATTA is calibrated against Resonance Ionization Mass Spectrometry, demonstrating a good agreement between the two methods. The present ATTA system has a counting efficiency of 2x10^-7. Within one hour of observation time, its 3-sigma detection limit on the isotopic abundance of 41Ca reaches 4.5x10^-10

Demonstration of a Dual Atom Trap Trace Analysis Setup for 39Ar and 85Kr

Atom Trap Trace Analysis (ATTA) detects rare isotopes within a huge background of abundant ones by exploiting specific optical transition frequencies of the desired atoms. ATTA utilizes the high number of photon-scattering processes in a magneto-optical trap for a distinct capture of the desired isotope alone. The Heidelberg ATTA collaboration successfully employed this technique on the environmental tracer 39Ar. This thesis demonstrates the first setup of a dual ATTA (D-ATTA) experiment for the two radio-isotopes 39Ar and 85Kr. The measurement of both tracers within a short time span enables a more thorough study of an environmental sample. In the course of 24 h, count rates of 1420(40) a/h for 85Kr and 1.8(3) a/h for 39Ar were obtained with a sample volume of 60 µL and 600 µL, respectively. These results demonstrate the feasibility of radio-isotope dating of both tracers within short times in the same apparatus and sample. Improvements to the vacuum system enabled a count rate of 140 a/h for 1 µL krypton gas which corresponds to a 10 L water sample. Additionally, this thesis presents 39Ar detection in a new dating facility. This second apparatus was built up to increase sample throughput and evolve the machine to a more modular and robust design