Finger weeder for cabbage and lettuce cultures

Summer 2002 we compared finger weeder against net harrow and herbicides in cabbage. Field trial 2003 was dedicated to lettuce: we compared different intensities of finger weeding in two different lettuce cultivars

Exploring the dimensions of metapopulation persistence : a comparison of structural and temporal measures

The spatial arrangement of habitat patches in a metapopulation and the dispersal connections among them influence metapopulation persistence. Metapopulation persistence emerges from a dynamic process, namely the serial extinctions and recolonizations of local habitat patches, while measures of persistence are typically based solely on structural properties of the spatial network (e.g., spatial distance between sites). Persistence estimators based on static properties may be unable to capture the dynamic nature of persistence. Understanding the shape of the distribution of extinction times is a central goal in population ecology. Here, we examine the goodness of fit of the power law to patch persistence time distributions using data on a foundational metapopulation system-the Glanville fritillary butterfly in the angstrom land islands. Further, we address the relationship between structural measures of metapopulation persistence (i.e., metapopulation capacity) and our temporal distributional fits to patch persistence times based on a power law. Patch persistence time distributions were well fit by a power law for the majority of semi-independent networks. Power law fits to persistence time distributions were related to metapopulation capacity, linking structural and temporal measures of metapopulation persistence. Several environmental variables and measures of network topology were correlated with both measures of metapopulation persistence, though correlations tended to be stronger for the structural measure of metapopulation persistence (i.e., metapopulation capacity). Together, our findings suggest that persistence time distributions are useful dynamic properties of metapopulations, and provide evidence of a relationship between metapopulation structure and metapopulation dynamics.Peer reviewe

Parajuoksijoiden proteesit teknillisen mekaniikan näkökulmasta

Tiivistelmä. Tämän kandidaatintyön tarkoituksena on tarkastella proteeseja teknillisen mekaniikan näkökulmasta. Pääpaino on proteesien mekaanisilla ominaisuuksilla. Käsiteltäviä asioita työssä ovat juoksemiseen tarkoitetut proteesit, juoksemisen mekaniikka ja mallintaminen, proteeseja käyttävän juoksijan biomekaniikka ja proteesien mekaaniset ominaisuudet. Juoksemista voidaan mallintaa usealla eri tavalla, joten sen mallintamisesta käydään läpi vain yleisin mallintamistyyli eli jousi-massa -malli. Proteesien mekaaniset ominaisuudet eivät ole valmistajien toimesta julkisesti tarjolla. Näitä on kuitenkin selvitetty testaamalla proteeseja käytössä ja mittaamalla ulkoisia kuormituksia. Toinen vaihtoehto on selvittää proteesiin kohdistuvat voimat ja laskea niiden sisäisiä ja ulkoisia voimia. Proteesien ominaisuuksia voidaan selvittää myös esimerkiksi elementtimenetelmien avulla. Tärkein proteesien mekaaninen ominaisuus on niiden jäykkyys. Jäykkyyden on todettu vaikuttavan suoraan juoksunopeuteen. Tutkimusmetodi tässä kandidaatintyössä on kirjallisuuskatsaus. Tavoitteena työlle on selvittää proteesien ominaisuuksien ja juoksemisen mekaniikan olennaiset asiat. Samalla vertaillaan proteesia käyttävän urheilijan mekaniikkaa vammattoman urheilijan mekaniikkaan.Para-runners’ prostheses from engineering mechanics point of view. Abstract. The purpose of this bachelor’s thesis is to examine prostheses from engineering mechanics point of view. The focus is on the mechanical properties of prostheses. Issues covered in the work include prostheses intended for running, mechanics and modelling of running, bio-mechanics of runners using prostheses and mechanical properties of prostheses. Running can be modeled in several different ways and, thus, only the most common spring-mass model is reviewed. The mechanical properties of the prostheses are not publicly available by the manufacturers. However, these properties have been clarified by testing prostheses in use measuring external loads. Another option is to find out the forces acting on the prosthesis and calculate their internal and external forces. The properties of prostheses can also be determined using element methods. The most important information that has been studied about prostheses is their stiffness, which has been found to have a directly affect running speed. The research method in this bachelor’s thesis is a literature review and the goal of the work is to find out the essential issues of the properties of prostheses and mechanics of running. At the same time, the mechanics of an athlete using a prosthesis are compared with the mechanics of an uninjured athlete

Isomeric states close to doubly magic 132^{132}Sn studied with JYFLTRAP

The double Penning trap mass spectrometer JYFLTRAP has been employed to measure masses and excitation energies for $11/2^-$ isomers in $^{121}$Cd, $^{123}$Cd, $^{125}$Cd and $^{133}$Te, for $1/2^-$ isomers in $^{129}$In and $^{131}$In, and for $7^-$ isomers in $^{130}$Sn and $^{134}$Sb. These first direct mass measurements of the Cd and In isomers reveal deviations to the excitation energies based on results from beta-decay experiments and yield new information on neutron- and proton-hole states close to $^{132}$Sn. A new excitation energy of 144(4) keV has been determined for $^{123}$Cd$^m$. A good agreement with the precisely known excitation energies of $^{121}$Cd$^m$, $^{130}$Sn$^m$, and $^{134}$Sb$^m$ has been found.Comment: 10 pages, 6 figures, submitted to Phys. Rev.

Q_EC values of the Superallowed beta-Emitters 10-C, 34-Ar, 38-Ca and 46-V

The Q_EC values of the superallowed beta+ emitters 10-C, 34-Ar, 38-Ca and 46-V have been measured with a Penning-trap mass spectrometer to be 3648.12(8), 6061.83(8), 6612.12(7) and 7052.44(10) keV, respectively. All four values are substantially improved in precision over previous results.Comment: 9 pages, 7 figures, 5 table

Structure of 10N in 9C+p resonance scattering

The structure of exotic nucleus 10N was studied using 9C+p resonance scattering. Two L=0 resonances were found to be the lowest states in 10N. The ground state of 10N is unbound with respect to proton decay by 2.2(2) or 1.9(2) MeV depending on the 2- or 1- spin-parity assignment, and the first excited state is unbound by 2.8(2) MeV.Comment: 6 pages, 4 figures, 1 table, submitted to Phys. Lett.

Precision mass measurements of radioactive nuclei at JYFLTRAP

The Penning trap mass spectrometer JYFLTRAP was used to measure the atomic masses of radioactive nuclei with an uncertainty better than 10 keV. The atomic masses of the neutron-deficient nuclei around the N = Z line were measured to improve the understanding of the rp-process path and the SbSnTe cycle. Furthermore, the masses of the neutron-rich gallium (Z = 31) to palladium (Z = 46) nuclei have been measured. The physics impacts on the nuclear structure and the r-process paths are reviewed. A better understanding of the nuclear deformation is presented by studying the pairing energy around A = 100.Comment: 4 pages and 4 figures, RNB7 conf. pro

Laser Spectroscopy of Niobium Fission Fragments: First Use of Optical Pumping in an Ion Beam Cooler Buncher

A new method of optical pumping in an ion beam cooler buncher has been developed to selectively enhance ionic metastable state populations. The technique permits the study of elements previously inaccessible to laser spectroscopy and has been applied here to the study of Nb. Model independent mean-square charge radii and nuclear moments have been studied for $^{90,90 m,91,91 m,92,93,99,101,103}$Nb to cover the region of the N=50 shell closure and N≈60 sudden onset of deformation. The increase in mean-square charge radius is observed to be less than that for Y, with a substantial degree of β softness observed before and after N=60