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Objective Administration of FGF21 to mice reduces body weight and increases body temperature. The increase in body temperature is generally interpreted as hyperthermia, i.e. a condition secondary to the increase in energy expenditure (heat production). Here, we examine an alternative hypothesis: that FGF21 has a direct pyrexic effect, i.e. FGF21 increases body temperature independently of any effect on energy expenditure. Methods We studied the effects of FGF21 treatment on body temperature and energy expenditure in high-fat-diet-fed and chow-fed mice exposed acutely to various ambient temperatures, in high-fat diet-fed mice housed at 30 °C (i.e. at thermoneutrality), and in mice lacking uncoupling protein 1 (UCP1). Results In every model studied, FGF21 increased body temperature, but energy expenditure was increased only in some models. The effect of FGF21 on body temperature was more (not less, as expected in hyperthermia) pronounced at lower ambient temperatures. Effects on body temperature and energy expenditure were temporally distinct (daytime versus nighttime). FGF21 enhanced UCP1 protein content in brown adipose tissue (BAT); there was no measurable UCP1 protein in inguinal brite/beige adipose tissue. FGF21 increased energy expenditure through adrenergic stimulation of BAT. In mice lacking UCP1, FGF21 did not increase energy expenditure but increased body temperature by reducing heat loss, e.g. a reduced tail surface temperature. Conclusion The effect of FGF21 on body temperature is independent of UCP1 and can be achieved in the absence of any change in energy expenditure. Since elevated body temperature is a primary effect of FGF21 and can be achieved without increasing energy expenditure, only limited body weight-lowering effects of FGF21 may be expected., Graphical abstract Image 1, Highlights • FGF21 increases body temperature independently of energy expenditure changes. • FGF21-induced increase in body temperature is independent of UCP1. • FGF21-induced (short-term) increase in energy expenditure is fully UCP1-dependent. • FGF21 increases UCP1 content in brown, but not in brite/beige adipose tissue. • FGF21 can increase body temperature by decreasing heat loss.

Excursion tourism as a mode of travelling to closer destinations has had a long tradition and a cognitive character. Excursions belong to the specific forms of tourism trends and as such, can be viewed in terms of their significant impact on tourist trade within the Serbian tourism market. The demand for this type of tourist travel is constant, thereby highlighting its economic importance. Themed excursions of children in protected areas are developing an interest in nature and are building environmental practices. Thus, children are introduced to the ways of environmental protection, fostering a positive attitude towards the values of preserved natural environment as an opportunity to raise environmental awareness of future generations.

The phenomenon of mass tourism development in recent years has undergone certain transformations, in particular, with the appearance of small forms of tourism, having significant prospects for development in the future. Although mass tourism development has represented, for a long time, a successful example of the concept of development of various tourist destinations around the world, in time, it was getting more exposed to criticism. Numerous authors and tourism scholars emphasize negative impact of mass tourism, whereas World Tourism Organization's forecast is in favor of reducing the mass as opposed to small forms of tourism. The small forms of tourism are primarily characterized by individual tours or traveling within small groups, usually consisting of educated, experienced and responsible participants with greater purchasing power when compared to typical tourists, participants of mass tourism. This case study entails prospects for the development of small forms of tourism in Surčin, the youngest of seventeen Belgrade municipalities. Due to its favorable traffic and tourist position, natural resources, cultural heritage and built infrastructure, in recent years, Surčin has become more attractive for individuals and small groups of tourists, positioning itself as a tourist destination for excursions in the market capital. This paper investigated the possibilities for tourism development of small forms of tourism based on the natural environment, cultural heritage, events; adventure, sport and recreation; authentic offer and local tradition as well as the parts of a short city break tour and cruising programs in the area of the Surčin municipality.

The global economic crisis, the decline of standard and climatic factors influence the allocation of tourism trends at the global level. Certain types of tourist movements start up and develop; they have been present, but not sufficiently studied by authors. They also include a short trip or visit to a particular destination. Considering their characteristics, they do not require a lot of money and they make an increasingly important segment of the tourism market. Therefore, the importance of same-day trips should not be neglected on today's tourism market. Although in practice this part of the tourist offers and demand has not often been attached enough importance, same day trip can achieve a very significant inflow of funds and encourage the development of many potential tourist destinations. For all the reasons mentioned above, and because of its importance, the organization of same day-trips should be the fundamental basis and essential focus for tourism development. Taking into consideration that inbound tourist agencies show special interest for same-day trips, we have tried to give a starting point for further research in this part of the tourism market.