The knowledge of snowpack distribution at a catchment scale is important to predict the snowmelt runoff. The objective of this study is to select and quantify the most important factors governing the snowpack distribution, with special interest in the role of different canopy structure. We applied a simple distributed sampling design with measurement of snow depth and snow water equivalent (SWE) at a catchment scale. We selected eleven predictors related to character of specific localities (such as elevation, slope orientation and leaf area index) and to winter meteorological conditions (such as irradiance, sum of positive air temperature and sum of new snow depth). The forest canopy structure was described using parameters calculated from hemispherical photographs. A degree-day approach was used to calculate melt factors. Principal component analysis, cluster analysis and Spearman rank correlation were applied to reduce the number of predictors and to analyze measured data. The SWE in forest sites was by 40% lower than in open areas, but this value depended on the canopy structure. The snow ablation in large openings was on average almost two times faster compared to forest sites. The snow ablation in the forest was by 18% faster after forest defoliation (due to the bark beetle). The results from multivariate analyses showed that the leaf area index was a better predictor to explain the SWE distribution during accumulation period, while irradiance was better predictor during snowmelt period. Despite some uncertainty, parameters derived from hemispherical photographs may replace measured incoming solar radiation if this meteorological variable is not available.
The paper compares Carnap’s and Hempel’s Standard Conception of Scientific Theories with Newton’s method of theory construction as applied in his Principia. It is shown that the latter is built, contrary to Carnap’s and Hempel’s views, by a cyclical method., Příspěvek porovnává Carnapovu a Hempelovu standardní koncepci vědeckých teorií s Newtonovou metodou konstrukce teorie, jak je aplikován v jeho Principii. To je ukazováno že latter je postaven, na rozdíl od Carnap je a Hempel pohledy, cyklickou metodou., and Igor Hanzel
The paper, as a continuation of the paper Hanzel (2009), provides a methodological generalization of Newton’s method of theory construction as applied in Book I and Book III of his Principia. It reconstructs also the method of measures applied in those books. Finally, it shows how the term ''harmonic law'' changes its meaning in the Principia., Příspěvek, jako pokračování článku Hanzel (2009), poskytuje metodologickou zobecnění Newtonovy metody teorie konstrukce, jak je aplikováno v knize I a knize III jeho Principia. Rekonstruuje také metodu opatření uplatňovanou v těchto knihách. Nakonec ukazuje, jak pojem ,,harmonické právo'' mění svůj význam v Principii., and Igor Hanzel
In this paper, we present Carnap’s modal logic C, which is one of the first attempts to use the concept of possible world (that of state description in the Carnapian original terminology) in shaping the semantics for modalities. Some older technical results, which concern the logic C, are summarized, namely two different kinds of axiomatization of C, one unusual characterization of C as the only set of formulae having one special property, and semantical and syntactical relations of C to S5. The fact that C is not closed under the universal substitution is shortly discussed. Finally, the predicate version of C, which is not axiomatizable, is defined., V tomto příspěvku prezentujeme Carnapovu modální logiku C, která je jedním z prvních pokusů o využití konceptu možného světa (státního popisu v karnapské původní terminologii) při formování sémantiky modalit. Jsou shrnuty některé starší technické výsledky, které se týkají logiky C, a to dva různé druhy axiomatizace C, jedna neobvyklá charakterizace C jako jediná množina vzorců s jednou speciální vlastností a sémantické a syntaktické vztahy C až S5. Krátce je diskutována skutečnost, že C není uzavřena pod univerzální substitucí. Nakonec je definována predikátová verze C, která není axiomatizovatelná., and Vít Punčochář
First I present a puzzle involving two opaque objects and a shadow cast on the ground. After I offer a solution to this puzzle by identifying which of the objects is causally responsible for the shadow, I argue that this case poses a counterexample to David Lewis’s latest counterfactual account of causation, known as his in-fluence theory. Along the way, I discuss preemption, overdetermina-tion, absence causation, and trumping preemption.