4,075 research outputs found
The seed sector in Latvia
In each issue, European Seed shines the spotlight on one of the many national seed associations in Europe that are so crucial in representing the local seed sector at both the national and international levels, along sharing the sector's concerns with the government. Although seed and seed trade associations are present in many countries throughout the continent there is no such association in Latvia, so European Seed decided to look at several other factors that shape the seed sector environment in this country. Interviewing Roberts Stafeckis, Director of the Institute of Agricultural Resources and Economics (AREI)
Cationic Group 3 Alkyl Complexes with Isopropyl-Substituted Triazacyclononane-amide Ligands: Synthesis, Structure, and Thermal Decomposition Processes
Yttrium and lanthanum dialkyl complexes with the isopropyl-substituted triazacyclononane-amide monoanionic ligands [iPr2TACN-(B)-NtBu] (B = (CH2)2, L1; SiMe2, L2) are described. For Y, these were obtained by reaction of Y(CH2SiMe3)2(THF)2 with HL, whereas for La in situ peralkylation of LaBr3(THF)4 preceded reaction with HL. In C6D5Br solvent, reaction of LMR2 with [PhNMe2H][B(C6F5)4] results in rapid decomposition involving loss of propene from the ligand. This decomposition is prevented (Y) or retarded (La) in THF solvent. For yttrium, salts of the cations [LYR(THF)]+ were isolated and structurally characterized. ES-MS of these cations revealed facile desolvation. At increased nozzle voltages, fragmentation is observed with initial loss of SiMe4, followed by loss of propene. Thus decomposition is likely to involve initial cyclometalation of a ligand iPr group, followed by propene extrusion. Decomposition of [L2LaR(THF)x]+ in THF solution yields the dinuclear dication {[tBuN(Me2Si)N(C2H4)2N(C2H4)NiPr]2La2(THF)2}2+, which was structurally characterized. Kinetic data of the decomposition suggest that the process involves initial THF dissociation.
Assessment of facial function and quality of life in patients with peripheral facial palsy
Facial palsy can have a large impact on the patients’ daily life. A patient may experience difficulties not only in the facial region, for example when eating or when closing the eyes, but also in psycho-social functioning. To measure the impact of facial palsy several assessment instruments for grading facial function and quality of life are available. In this thesis these instruments and outcomes when using these instruments were analysed. Part I of this thesis focused on the measurement instruments themselves. Instruments that assess facial function are often used without prior training. However, it was found that a period of training is required for the correct application of these instruments. Furthermore, three commonly used instruments to assess quality of life for patients with facial palsy are not suitable to evaluate changes on an individual level. They can be applied to evaluate changes on a group level. In part II factors impacting on quality of life of patients with facial palsy were studied. A systematic review with meta-analysis showed that facial function severity only partly explained quality of life. Other factors such as age, anxiety, depression, bilateral facial palsy and several personality traits also impact on quality of life. The factors should be taken into account when assessing quality of life in patients suffering from facial palsy
Fluorescence overlay antigen mapping of the epodermal basement membrane zone with reference to the different diagnosis of bullous pemphogoid and epidermolysis bullosa acquisita
Radiocarbon dating in near-Eastern contexts:Confusion and quality control
Near-Eastern archaeology has long remained oblivious to radiocarbon dating as unique historical calendars brought about a perception that C-14 dating is superfluous. Circular chronological reasoning may occur as a result. There is now strong C-14 evidence that the early part of Egyptian history seems older than age assessments currently in vogue among scholars. It is vital to apply systematic and high-quality C-14 dating to each and every excavation in the Near East to measure time with the same yardstick. Such a strategy will enable chronological comparison of different areas at an excavation site and also between sites and regions, independent of cultural deliberations. This is essential for proper interpretation of archaeological layers and association with data from other fields. Radiocarbon (C-14) is the most common radiometric dating tool applied in archaeology, geosciences, and environmental research. Stringent quality control is required to build up a reliable C-14 chronology for the historical periods in Near-Eastern contexts. Important aspects of quality control involve regular laboratory intercomparisons, transparent duplicate and triplicate analysis of selected samples, conventional versus accelerator mass spectrometry (AMS) (i.e. sample size), sample selection and association. Finally, bones may provide short-lived dates in important stratigraphic archaeological contexts
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