Search results

Filter

Filetype

Your search for "*" yielded 525356 hits

Accelerator Mass Spectrometry

In this overview the technique of accelerator mass spectrometry (AMS) and its use are described. AMS is a highly sensitive method of counting atoms. It is used to detect very low concentrations of natural isotopic abundances (typically in the range between 10(-12) and 10(-16)) of both radionuclides and stable nuclides. The main advantages of AMS compared to conventional radiometric methods are the

Bomb-pulse dating of human material – modelling the influence of diet

The atmospheric testing of nuclear weapons during the 1950s and early 1960s produced large amounts of radiocarbon. This 14C bomb pulse provides useful age information in numerous scientific fields, e.g. in geosciences and environmental sciences. Bomb-pulse dating can also be used to date human material (e.g. in forensics and medical science). Bombpulse dating relies on precise measurements of the

Early changes in 2-deoxy-2-[18F]fluoro-D-glucose metabolism in squamous-cell carcinoma during chemotherapy in vivo and in vitro.

AIM: The aim of this study was to investigate early changes in uptake of 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG) in vivo and in vitro in a squamous-cell carcinoma (SCC) cell line originating from a human head and neck SCC during cytotoxic therapy with respect to metabolism in tumor cells and in surrounding stromal tissue. MATERIALS AND METHODS: In 60 nude mice with xenografted SCC, 50 animals were

Comparing spectrum estimators in speaker verification under additive noise degradation

Different short-term spectrum estimators for speaker verification under additive noise are considered. Conventionally, mel-frequency cepstral coefficients (MFCCs) are computed from discrete Fourier transform (DFT) spectra of windowed speech frames. Recently, linear prediction (LP) and its temporally weighted variants have been substituted as the spectrum analysis method in speech and speaker recog

Wool and Society : Manufacturing Policy, Economic Thought and Local Production in 18th-century Iceland

This is a study of wool in Icelandic history in a broad context, whereby wool production serves as a channel to central aspects of 18th-century society. The objective is to explore ideas about Iceland’s economy that were current in the 18th century in the light of developments in Denmark at the time, to place these ideas in the context of the recent introduction of workshopmanufacturing to Iceland

Late-Onset Hypogonadism and Mortality in Aging Men

Context: Late-onset hypogonadism (LOH) has recently been defined as a syndrome in middle-aged and elderly men reporting sexual symptoms in the presence of low T. The natural history of LOH, especially its relationship to mortality, is currently unknown. Objective: The aim of this study was to clarify the associations between LOH, low T, and sexual symptoms with mortality in men. Design, Setting, a

Like-charge attraction in a slit system: pressure components for the primitive model and molecular solvent simulations

We have recently reported Monte Carlo simulations for a system of two infinite like-charged plates in a dipolar fluid solvent (Pegado et al 2008 J. Chem. Phys. at press). The pressure as a function of plate separation qualitatively reproduces the ion-ion correlation attraction picture seen in primitive model studies, where the solvent only enters the picture implicitly through its dielectric const

Towards More Coherent and Sustainable Biomass Policy: Examining European biomass-to-energy planning

Popular Abstract in Swedish Mot en sammanhållen och hållbar biomassapolitik: En studie av europeisk biomassa-för-energi-planering Biomassa används för många ändamål. När den används som biobränsle för att producera energi utgör den en förnybar energikälla med många fördelar, bl. a. i form av minskade utsläpp av växthusgaser och en ökad trygghet i energiförsörjningen. Men biomassa är även en råvaCoordination of policies embracing biomass use has been called for in order to speed up progress towards the European Union renewable energy and climate change goals. Policy coordination and coherence is also required if the many complex and diverse issues constraining sustainable bioenergy development are to be addressed. To contribute to meeting such needs this doctoral thesis provides insights

Novel evaluation method of neutron reflectivity data applied to stimulus-responsive polymer brushes

Neutron reflectivity (NR) measurements have been performed on stimulus-responsive polymer brushes containing N-isopropylacrylamide (NIPAAM) at different temperatures and contrasts using two different brush samples of roughly the same grafting density and layer thickness. The NR data were analyzed using a novel method employing polymer density profiles predicted from lattice mean-field theory augme

Large spinel grains in a CM chondrite (Acfer 331): Implications for reconstructions of ancient meteorite fluxes

By dissolving 30400kg of marine limestone in HCl and HF acid, our group has previously recovered common relict chromite grains (approximately 63250m) from ordinary chondritic micrometeorites that fell on ancient sea floors, up to 500Myr old. Here, we evaluate if CM group carbonaceous chondritic material, which makes up an important fraction of the micrometeorite flux today, contains analogous grai

Rättens transcendens. Om skälighet inom avtalsrätten och relevansen av Rawls rättviseteori

Följande kapitel kommer att behandla avtalsrättens centrala generalklausul som gör det möjligt att jämka eller ogiltigförklara oskäliga avtalsvillkor. Paragrafen är omstridd och har tilldragit sig intresse då den öppnar upp för rättstillämparens skönsmässiga avgöranden – det inte finns några riktlinjer för vad som kan betecknas som oskäligt utöver den domstolspraxis som utvecklats. Det kan därmed

Proteomic Changes during B Cell Maturation: 2D-DIGE Approach

B cells play a pivotal role in adaptive immune system, since they maintain a delicate balance between recognition and clearance of foreign pathogens and tolerance to self. During maturation, B cells progress through a series of developmental stages defined by specific phenotypic surface markers and the rearrangement and expression of immunoglobulin (Ig) genes. To get insight into B cell proteome d

Neolithic Diversities : Perspectives from a conference in Lund, Sweden

Papers from a conference in Lund, Sweden. The title of the conference was "What's new in the Neolithic". The book brings together the latest research on the Neolithic of northern Europe. In the study of the distant human past, certain events and periods have come to represent decisive passages from one human state to another. From a global perspective, the characteristic feature of the last ten t

Distinct phases of free α-synuclein - A Monte Carlo study.

The α-synuclein protein (αS), implicated in Parkinson's disease (PD), shows conformational versatility. It aggregates into β-sheet-rich fibrils, occurs in helical membrane-bound forms, is disordered as a free monomer, and has recently been suggested to have a folded helical tetramer as its main physiological form. Here we use implicit solvent all-atom Monte Carlo (MC) methods to explore the confor

Evidence for a weakening relationship between interannual temperature variability and northern vegetation activity.

Satellite-derived Normalized Difference Vegetation Index (NDVI), a proxy of vegetation productivity, is known to be correlated with temperature in northern ecosystems. This relationship, however, may change over time following alternations in other environmental factors. Here we show that above 30°N, the strength of the relationship between the interannual variability of growing season NDVI and te

Cenomanian-Campanian (Late Cretaceous) mid-palaeolatitude sharks of Cretalamna appendiculata type

The type species of the extinct lamniform genus Cretalamna, C. appendiculata, has been assigned a 50 Ma range (Albian-Ypresian) by a majority of previous authors. Analysis of a partly articulated dentition of a Cretalamna from the Smoky Hill Chalk, Kansas, USA (LACM 128126) and isolated teeth of the genus from Cenomanian to Campanian strata of Western Australia, France, Sweden, and the Western Int