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Search Results: 1 - 10 of 149901 matches for " Pentti H?ltt? "
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Intracratonic Palaeoproterozoic granitoids in northern Finland: prolonged and episodic crustal melting events revealed by Nd isotopes and U-Pb ages on zircon
Niina Ahtonen,Pentti Hltt,Hannu Huhma
Bulletin of the Geological Society of Finland , 2007,
Abstract: Zircons from twelve Palaeoproterozoic granitoids from the Central Lapland Granitoid Complex (CLGC) and from the Hetta Complex (HC) in northern Finland were dated using the NORDSIM ion microprobe. In addition, U-Pb age determinations on zircons from two samples were made using TIMS. Results reveal a wide range of U-Pb ages from 2.13Ga to 1.76 Ga. The oldest samples include the porphyritic, weakly deformed Nilip granite, which has an ion probe concordia age of 2126±5 Ma, compatible with the previously published TIMS age of 2136±5 Ma. The Tohmo granodiorite provided a slightly younger ion microprobe age of 2105±4 Ma. The age of these two granitoids overlaps the depositional age of Karelian cratonic metasediments, suggesting that they represent an unusual tectonic setting for granitoid magmatism in the Fennoscandian Shield. The Ruoppapalo granodiorite, which is also porphyritic and weakly deformed, yielded an ion probe zircon concordia age of 1905±5 Ma, in accord with the conventional TIMS result. The strongly deformed Molkok ng s granite has an ion probe concordia age of 1855±13 Ma, which is within error limits the same as the TIMS age, 1843±23 Ma. The Pernu monzogranite has a concordia age of 1813±6 Ma. All other granitoids in the CLGC, including those of appinitic affinity, as well as a leucosome from the Kappera migmatite in the Hetta Complex, are dated at 1.79 – 1.76 Ga, although many granitoids have older inherited zircons. The abundance of deformed granitoids of this age show that intensive ductile deformation, metamorphism and melting occurred at around 1.79 – 1.76 Ga in the northern Fennoscandian Shield, coeval with post-collisional magmatism in the southern part of the Shield. Most granitoids in the Central Lapland Granitoid Complex have strongly negative εNd values (1.8 Ga), ranging from -8 to -5. It is evident that they have a major Archaean component in their source, indicating derivation from Archaean crust during crustal reworking in an intracratonic tectonic setting.
U-Pb zircon geochronology of selected Archaean migmatites in eastern Finland
Asko K?pyaho,Pentti Hltt,Martin J. Whitehouse
Bulletin of the Geological Society of Finland , 2007,
Abstract: U-Pb SIMS data on eight samples (four mesosome-leucosome pairs) from migmatites in gneiss complexes are presented from the western part of the Archaean Karelian craton, eastern Finland. Most zircon grains in the mesosomes yield ages between 2.84 Ga and 2.79 Ga, with cores of 2.94 Ga in one sample. Age data imply that migmatite mesosome protoliths were generated at broadly the same time as metamorphosed volcanic rocks in the adjacent Kuhmo-Suomussalmi-Tipasj rvi greenstone belt, suggesting that at least some of the mesosomes may represent migmatised equivalents of the greenstone belt rocks. Two separate events of metamorphic zircon growth are recognised from different samples: the first occurred between 2.84 Ga and 2.81 Ga, and the second between 2.73 Ga and 2.70 Ga. The latter event is considered to have led up to a prolonged period of partial melting, as is suggested by the zircons dated from the leucosomes. Scattered age data, inheritance and the large number of discordant data prevented establishing accurate leucosome generation ages.Consequently, the age data are considered to support the previously proposed hypothesis that the Archaean Karelian craton was formed after accumulation of separate tectonic entities having variable ages.
Crystal Chemistry and Geochronology of Thorium-Rich Monazite from Kovela Granitic Complex, Southern Finland  [PDF]
Thair Al-Ani, Pentti Hltt, Sari Gr?nholm, Lassi Pakkanen, Nadhir Al-Ansari
Natural Resources (NR) , 2019, DOI: 10.4236/nr.2019.106016
Abstract: Abundant porphyritic granites, including Grt-bearing and Bt-bearing porphyritic granites, and porphyritic potash-feldspar granite (trondhjemite-granitic composition) are widely distributed within the Kovela granitic complex Southern Finland, which associated with monazite-bearing dikes (strong trondhjemite composition). The investigated monazite-bearing dikes are dominated by a quartz + K-feldspar + plagioclase + biotite + garnet + monazite assemblage. The monazite forms complexly zoned subhedral to euhedral crystals variable in size (100 - 1500 μm in diameter) characterized by high Th content. The chemical zoning characterised as: 1) concentric, 2) patchy, and 3) intergrowth-like. Textural evidence suggests that these accessory minerals crystallized at an early magmatic stage, as they are commonly associated with clusters of the observed variations in their chemical composition are largely explained by the huttonite exchange \"\", and subordinately by the cheralite exchange \"\" with proportions of huttonite (ThSiO4) and cheralite [CaTh(PO4)2] up to 20.4% and 9.8%, respectively. Textural evidence suggests that these monazites and associated Th-rich minerals (huttonite/thorite) crystallized at an early magmatic stage, rather than metamorphic origin. The total lanthanide and actinide contents in monazite and host dikes are strongly correlated. Mineral compositions applied to calculate P-T crystallization conditions using different approaches reveal a temperature range of 700
A resposta das politécnicas finlandesas aos desafios das políticas de inova??o e de desenvolvimento regional
Lyytinen, Anu;Hltt, Seppo;
Caderno CRH , 2011, DOI: 10.1590/S0103-49792011000300002
Abstract: this paper presents an analysis of the recent development of a part of the higher education in finland. its objective is to analyse how finnish polytechnic school reacted to the new requirements to become responsive to regional needs and how they build up the necessary abilities to this regional engagement. the central theoretical framework are the institutional changing elements described by burton clark (1998) on his analysis about entrepreneurial universities. in particular the article focus on the channels and interfaces that those institutions have established with other players in the region.
Psychosocial group intervention to enhance self-management skills of people with dementia and their caregivers: study protocol for a randomized controlled trial
Laakkonen Marja-Liisa,Hltt? Eeva H,Savikko Niina,Strandberg Timo E
Trials , 2012, DOI: 10.1186/1745-6215-13-133
Abstract: Background After diagnosis of a dementing illness, patients and their spouses have many concerns related to the disease and their future. This often leads to poor psychological well-being and reduced health-related quality of life (HRQoL) of the family. Support for self-management skills has been proven to be an effective method to improve prognosis of asthma, heart failure and osteoarthritis. However, self-management interventions have not been studied in dementia. Therefore, our aim was to examine, in an objective-oriented group intervention, the efficacy of self-management support program (SMP) on the HRQoL of dementia patients and their spousal caregivers as well as on the sense of competence and psychological well-being of caregivers. Methods During the years 2011 to 12, 160 dementia patients and their spouses will be recruited from memory clinics and randomized into two arms: 80 patients for group-based SMP sessions including topics selected by the participants, 80 patients will serve as controls in usual community care. Sessions may include topics on dementia, community services, active lifestyle and prevention for cognitive decline, spousal relationship, future planning and emotional well-being. The patients and spouses will have their separate group sessions (ten participants per group) once a week for eight weeks. Main outcome measures will be patients’ HRQoL (15D) and spousal caregivers’ HRQoL (RAND-36), and sense of competence (SCQ). Secondary measures will be caregivers’ psychological well-being (GHQ-12) and coping resources, patients’ depression, cognition and signs of frailty. Data concerning admissions to institutional care and the use and costs of health and social services will be collected during a two-year follow-up. Discussion This is a ‘proof-of-concept’ study to explore the efficacy of group support for self-management skills among dementia families. It will also provide data on cost-effectiveness of the intervention. Trial registration ACTRN12611001173987
Peptidome Analysis of Cerebrospinal Fluid by LC-MALDI MS
Mikko Hltt, Henrik Zetterberg, Ekaterina Mirgorodskaya, Niklas Mattsson, Kaj Blennow, Johan Gobom
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0042555
Abstract: We report on the analysis of endogenous peptides in cerebrospinal fluid (CSF) by mass spectrometry. A method was developed for preparation of peptide extracts from CSF. Analysis of the extracts by offline LC-MALDI MS resulted in the detection of 3,000–4,000 peptide-like features. Out of these, 730 peptides were identified by MS/MS. The majority of these peptides have not been previously reported in CSF. The identified peptides were found to originate from 104 proteins, of which several have been reported to be involved in different disorders of the central nervous system. These results support the notion that CSF peptidomics may be viable complement to proteomics in the search of biomarkers of CNS disorders.
In Crohn's Disease, Anti-TNF-
Veera Hölttä,Taina Sipponen,Mia Westerholm-Ormio,Harri M. Salo
ISRN Gastroenterology , 2012, DOI: 10.5402/2012/505432
Evaluating Amyloid-β Oligomers in Cerebrospinal Fluid as a Biomarker for Alzheimer’s Disease
Mikko Hltt, Oskar Hansson, Ulf Andreasson, Joakim Hertze, Lennart Minthon, Katarina N?gga, Niels Andreasen, Henrik Zetterberg, Kaj Blennow
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0066381
Abstract: The current study evaluated amyloid-β oligomers (Aβo) in cerebrospinal fluid as a clinical biomarker for Alzheimer’s disease (AD). We developed a highly sensitive Aβo ELISA using the same N-terminal monoclonal antibody (82E1) for capture and detection. CSF samples from patients with AD, mild cognitive impairment (MCI), and healthy controls were examined. The assay was specific for oligomerized Aβ with a lower limit of quantification of 200 fg/ml, and the assay signal showed a tight correlation with synthetic Aβo levels. Three clinical materials of well characterized AD patients (n = 199) and cognitively healthy controls (n = 148) from different clinical centers were included, together with a clinical material of patients with MCI (n = 165). Aβo levels were elevated in the all three AD-control comparisons although with a large overlap and a separation from controls that was far from complete. Patients with MCI who later converted to AD had increased Aβo levels on a group level but several samples had undetectable levels. These results indicate that presence of high or measurable Aβo levels in CSF is clearly associated with AD, but the overlap is too large for the test to have any diagnostic potential on its own.
Some characterizations of specially multiplicative functions
Pentti Haukkanen
International Journal of Mathematics and Mathematical Sciences , 2003, DOI: 10.1155/s0161171203301139
Abstract: A multiplicative function f is said to be specially multiplicative if there is a completely multiplicative function fA such that f(m)f(n)=∑d|(m,n)f(mn/d2)fA(d) for all m and n. For example, the divisor functions and Ramanujan's τ-function are specially multiplicative functions. Some characterizations of specially multiplicative functions are given in the literature. In this paper, we provide some further characterizations of specially multiplicative functions.
Maintaining Access to print Materials – a Finnish Model
Pentti Vattulainen
Liber Quarterly : The Journal of European Research Libraries , 2005,
Abstract: Even though there are signs that the end of the hybrid library might well be in sight within a few years, we still have to manage and develop the hybrid library. Hybridism manifests itself in all sectors of the library profession, starting from library space and building planning, information provision on internet, virtual reference etc. In collection management one of the most challenging issues is how to manage the rising costs of hybrid collection development. The challenge is to provide access for every user to the document he or she needs and at same time to ensure at least an acceptable basic print collection in the library (Ceynova & Coners, 2003). Many tools have been developed to support local libraries in managing hybridism. Co-operation and specialisation of different types of libraries is naturally needed in this. Another direction is to provide centralised tools for managing reasonable service levels for users in terms of access to information. In Finland, library co-operation has been developed over many decades and specialisation in terms of collections and database constructions etc. have been essential in formulating national collections.
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