University of Turku

About: University of Turku is a education organization based out in Turku, Finland. It is known for research contribution in the topics: Population & Galaxy. The organization has 16296 authors who have published 45124 publications receiving 1505428 citations. The organization is also known as: Turun yliopisto & Åbo universitet.

What determines the citation frequency of ecological papers

Abstract: Citation frequencies of scientific articles are increasingly used for academic evaluation in various disciplines, including ecology. However, the factors affecting citation rates have not been extensively studied. Here, we examine the association between the citation frequency of ecological articles and various characteristics of journals, articles and authors. Our analysis shows that the annual citation rates of ecological papers are affected by the direction of the study outcome with respect to the hypothesis tested (supportive versus unsupportive evidence), by article length, by the number of authors, and by their country and university of affiliation. These results cast doubt on the validity of using citation counts as an objective and unbiased tool for academic evaluation in ecology.

Phenotypic characterization of regulatory T cells in the human decidua

Abstract: Pregnancy is a unique situation for the maternal immune system. We have studied and identified a CD4+CD25+ regulatory T (Treg) cell population isolated from the human decidua. This mucosal surface in the uterus is in direct contact with semiallogenic fetal cells. We observed that about 14% of the decidual CD4+ T cells have the CD4+CD25+ phenotype. The decidual CD4+CD25+ T cells expressed high frequency of intracellular CTLA-4 (CTLA-4i). The majority of CD4+CD25+CTLA-4i+ cells were also positive for GITR and OX40, typical markers for human Treg cells. The frequency of CD4+CD25+ T cells in the peripheral blood from pregnant women was found to be increased during the first and second trimester of gestation when compared to nonpregnant controls. Being an important molecule for Treg cells, the role of CTLA-4 in the regulation of indoleamine 2,3-dioxygenase (IDO) expression was also examined. The stimulation with CTLA-4Ig did not increase IDO mRNA expression in CD14+ cells from pregnant women, while IFN-gamma was observed to up-regulate IDO expression. The presence of Treg cells in the human decidua suggests that these cells are important in protecting the fetus from alloreactive immune responses at the maternal-fetal interface.

A consistent terminology for quantifying species diversity? Yes, it does exist

Abstract: The prevailing terminological confusion around the concept ‘diversity’ has hampered accurate communication and caused diversity issues to appear unnecessarily complicated. In fact, a consistent terminology for phenomena related to (species) diversity is already available. When this terminology is adhered to, diversity emerges as an easily understood concept. It is important to differentiate between diversity itself and a diversity index: an index of something is just a surrogate for the thing itself. The conceptual problem of defining diversity also has to be separated from the practical problem of deciding how to adequately quantify diversity for a community of interest. In practice, diversity can be quantified for any dataset where units of observation (such as individuals) have been classified into types (such as species). All that needs to be known is what proportion of the observed units belong to a type of mean abundance. Diversity equals the inverse of this mean, and it quantifies the effective number of the types of interest. In ecology, interest often (but not always) focuses on species diversity. If the dataset consists of (or gets divided into) subunits, then the total effective number of species (gamma diversity) can be partitioned into the effective number of compositionally distinct subunits (beta diversity) and the mean effective number of species per such subunit (alpha diversity). Species richness is related to species diversity, but they are not the same thing; richness does not take the proportional abundances into account and is therefore the actual—rather than the effective—number of types. Most of the phenomena that have been called ‘beta diversity’ in the past do not quantify an effective number of types, so they should be referred to by names other than ‘diversity’ (for example, species turnover or differentiation).

Matrix metalloproteinases in tumor invasion.

Abstract: Controlled degradation of extracellular matrix (ECM) is essential for the growth, invasion, and metastasis of malignant tumors, and for tumor-induced angiogenesis. Matrix metalloproteinases (MMPs) are a family of zinc-dependent neutral endopeptidases collectively capable of degrading essentially all ECM components and they apparently play an important role in all these aspects of tumor development. Furthermore, recent evidence suggests that MMPs also play a role in tumor cell survival. In this review, we discuss the current concept concerning the role of MMPs and their inhibitors in tumor invasion, as a basis for prognosis and targeted therapeutic intervention in cancer.

Attraction of kestrels to vole scent marks visible in ultraviolet light

Abstract: IN northern Europe, broad four-year oscillations in small rodent and raptor populations are synchronous over hundreds of square kilometers1–6. Crashes in vole populations can induce wide emigration (> 1,000 km) of their predators7 –9, but almost nothing is known about how predators rapidly detect areas of vole abundance. Here we report on laboratory and field experiments on voles (Microtus agrestis) and kestrels (Falco tinnunculus). Voles mark their runaways with urine and faeces, which are visible in ultraviolet light. Wild kestrels brought into captivity were able to detect vole scent marks in ultraviolet light but not in visible light. In the field, kestrels hunted preferentially near experimental nest-boxes where artificial trails were treated with vole urine and faeces. We suggest that kestrels flying over an area can see and use vole scent marks to assess vole numbers. This ability would enable kestrels to 'screen' large areas in a relatively short time. Our results provide a novel explanation for how raptors detect patches of high vole densities without prior knowledge of local food resources.