Critique of proposed limit to space--time measurement, based on Wigner's clocks and mirrors

Based on a relation between inertial time intervals and the Riemannian curvature, we show that space--time uncertainty derived by Ng and van Dam implies absurd uncertainties of the Riemannian curvature.Comment: 5 pages, LaTex, field "Author:" correcte

Növényi jellegek és alkalmazásuk növényökológiai kutatásokban I.: Történeti áttekintés, jelleg típusok, módszertan és adatbázisok = Plant functional traits and their application in ecological research I.: History, traits, methodologies and databases

Abstract: The importance of studies based on plant functional traits is indicated by the huge number of papers (more than 5000) published in the last 15 years in this topic. In community ecology the recent trend of studying organisms on the functional- rather than on the taxonomic level is quite significant. In this review we attempted to summarise the applicability of functional plant traits commonly used in ecological studies. We discussed the levels of functional categorisation, described the different plant strategies based on functional traits and emphasised the usage of standardised measurements. The most outstanding trait databases are introduced here, showing their availability, content and specialities. This review is intended as an introduction to the topic and can later be completed by papers elaborating on how plant functional traits are used in theoretical and applied plant ecology. Keywords: functional ecology, growth-form, LEDA, life-form, plant strategies, SLA, TRY | Összefoglalás: A növényi funkcionális jellegek kutatásának aktualitását mi sem jelzi jobban, mint az a több mint 5000 publikáció, mely az utóbbi 15 évben megjelent a témában. A közösségi ökológia számára ma már nélkülözhetetlen a fajok szintjén túlmutató funkcionális csoportok alkalmazása, ahol a növényeket taxonómiai minőségük helyett funkcionális jellegeik alapján vizsgálják. Jelen dolgozatban bemutatjuk a növényökológiában leggyakrabban alkalmazott növényi jellegeket, típusaikat valamint az általuk meghatározott növényi stratégiákat. Szót ejtünk a jellegek egységes mérésének módszertanáról, illetve bemutatjuk a legfontosabb jellegadatbázisokat, és azok alkalmazási lehetőségeit. Jelen dolgozatot a téma bevezetésének szánjuk, amit később olyan írások követhetnek, amelyek részletesen foglalkoznak a funkcionális jellegek gyakorlatban történő alkalmazásának lehetőségeivel. Kulcsszavak: életforma, fajlagos levélfelület, funkcionális ökológia, LEDA, növekedési forma, növényi stratégiák, TR

Applications of Commutator-Type Operators to pp-Groups

For a p-group G admitting an automorphism $\phi$ of order $p^n$ with exactly $p^m$ fixed points such that $\phi^{p^{n-1}}$ has exactly $p^k$ fixed points, we prove that G has a fully-invariant subgroup of m-bounded nilpotency class with $(p,n,m,k)$-bounded index in G. We also establish its analogue for Lie p-rings. The proofs make use of the theory of commutator-type operators.Comment: 11 page

Different sensing mechanisms in single wire and mat carbon nanotubes chemical sensors

Chemical sensing properties of single wire and mat form sensor structures fabricated from the same carbon nanotube (CNT) materials have been compared. Sensing properties of CNT sensors were evaluated upon electrical response in the presence of five vapours as acetone, acetic acid, ethanol, toluene, and water. Diverse behaviour of single wire CNT sensors was found, while the mat structures showed similar response for all the applied vapours. This indicates that the sensing mechanism of random CNT networks cannot be interpreted as a simple summation of the constituting individual CNT effects, but is associated to another robust phenomenon, localized presumably at CNT-CNT junctions, must be supposed.Comment: 12 pages, 5 figures,Applied Physics A: Materials Science and Processing 201

The Urban Political Ecology of Post-industrial Scottish Towns: Examining Greengairs and Ravenscraig

Urban ecological politics is shaped by both moments of concerted action and more silent perceptions and responses. Instead of only being evident in situations of organised protest, the politics of urban ecology is also manifested, in material and symbolic terms, in the daily life of the residents. The fragmentation of urban political ecology turns out to be an important element in the affirmation of post-political forms of urban governance. Those issues were the object of fieldwork research carried out in Greengairs and Ravenscraig, two towns in North Lanarkshire, near Glasgow, with the goal of unravelling the understanding and the coping mechanisms of environmentally deprived residents. The towns are permeated by a widespread, often dissimulated, political ecology that is nonetheless always present. Empirical results demonstrate that a more comprehensive handling of the political ecology of the urban is crucial in order to halt the sources of marginalisation and ecological degradation

Factors affecting reproductive success in three entomophilous orchid species in Hungary

The reproductive success of orchids is traditionally estimated by determining the fruit-set of individuals. Here, we investigated both the fruit and the seed production of three orchid species and the factors that may affect individual fruit-set, like pollination strategy, individual traits or the annual amount of precipitation. The species [Dactylorhiza sambucina (L.) Soó, Dactylorhiza majalis (Rchb.) P. F. Hunt & Summerhayes and Platanthera bifolia (L.) L. C. M. Richard] were studied in three consecutive years (2010–2012) in the Bükk Mountains, Hungary. All three species were proved to be non-autogamous by a bagging experiment. Data analyses showed significant differences between seed numbers but not between fruit-sets of species. There was no statistical difference in individual reproductive success between wet and dry years, however, the effect of the annual amount of precipitation is significant on the population level. Comparison of published fruit-set data revealed accordance with our results in P. bifolia, but not in D. sambucina and D. majalis. We assume that the surprisingly high fruit-set values of the two Dactylorhiza species may be due to the fact that the pollination crisis reported from Western European countries is not an actual problem in the Bükk Mountains, Hungary

Small amplitude quasi-breathers and oscillons

Quasi-breathers (QB) are time-periodic solutions with weak spatial localization introduced in G. Fodor et al. in Phys. Rev. D. 74, 124003 (2006). QB's provide a simple description of oscillons (very long-living spatially localized time dependent solutions). The small amplitude limit of QB's is worked out in a large class of scalar theories with a general self-interaction potential, in $D$ spatial dimensions. It is shown that the problem of small amplitude QB's is reduced to a universal elliptic partial differential equation. It is also found that there is the critical dimension, $D_{crit}=4$, above which no small amplitude QB's exist. The QB's obtained this way are shown to provide very good initial data for oscillons. Thus these QB's provide the solution of the complicated, nonlinear time dependent problem of small amplitude oscillons in scalar theories.Comment: 24 pages, 19 figure