Let S(RG) be a normed Sylow p-subgroup in a group ring RG of an abelian group G with p-component Gp and a p-basic subgroup B over a commutative unitary ring R with prime characteristic p. The first central result is that 1 + I(RG; Bp) + I(R(p i )G; G) is basic in S(RG) and B[1 + I(RG; Bp) + I(R(p i )G; G)] is p-basic in V (RG), and [1 + I(RG; Bp) + I(R(p i )G; G)]Gp/Gp is basic in S(RG)/Gp and [1 + I(RG; Bp) + I(R(p i )G; G)]G/G is p-basic in V (RG)/G, provided in both cases G/Gp is p-divisible and R is such that its maximal perfect subring R p i has no nilpotents whenever i is natural. The second major result is that B(1 + I(RG; Bp)) is p-basic in V (RG) and (1 + I(RG; Bp))G/G is p-basic in V (RG)/G, provided G/Gp is p-divisible and R is perfect. In particular, under these circumstances, S(RG) and S(RG)/Gp are both starred or algebraically compact groups. The last results offer a new perspective on the long-standing classical conjecture which says that S(RG)/Gp is totally projective. The present facts improve the results concerning this topic due to Nachev (Houston J. Math., 1996) and others obtained by us in (C. R. Acad. Bulg. Sci., 1995) and (Czechoslovak Math. J., 2002).
Suppose ${F}$ is a perfect field of ${\mathop {\mathrm char}F=p\ne 0}$ and ${G}$ is an arbitrary abelian multiplicative group with a ${p}$-basic subgroup ${B}$ and ${p}$-component ${G_p}$. Let ${FG}$ be the group algebra with normed group of all units ${V(FG)}$ and its Sylow ${p}$-subgroup ${S(FG)}$, and let ${I_p(FG;B)}$ be the nilradical of the relative augmentation ideal ${I(FG;B)}$ of ${FG}$ with respect to ${B}$. The main results that motivate this article are that ${1+I_p(FG;B)}$ is basic in ${S(FG)}$, and ${B(1+I_p(FG;B))}$ is ${p}$-basic in ${V(FG)}$ provided ${G}$ is ${p}$-mixed. These achievements extend in some way a result of N. Nachev (1996) in Houston J. Math. when ${G}$ is $p$-primary. Thus the problem of obtaining a ($p$-)basic subgroup in ${FG}$ is completely resolved provided that the field $F$ is perfect. Moreover, it is shown that ${G_p(1+I_p(FG;B))/G_p}$ is basic in ${S(FG)/ G_p}$, and $G(1+I_p(FG; B))/G$ is basic in ${V(FG)/G}$ provided ${G}$ is ${p}$-mixed. As consequences, ${S(FG)}$ and ${S(FG)/G_p}$ are both starred or divisible groups. All of the listed assertions enlarge in a new aspect affirmations established by us in Czechoslovak Math. J. (2002), Math. Bohemica (2004) and Math. Slovaca (2005) as well.
A vocabulary resulting from the cooperation of the groups of REALITER network that collects the basic terminology mostly used in texts about Genomics. It contains equivalents in English, Peninsular and Latinamerican Spanish, French, Italian, Galician, Portuguese and Catalan.
Although it is well known that bats commonly forage in riparian areas, which provide water resources and insect concentrations, the role that the physical structure of riparian areas plays in influencing local bat communities is less certain. In 2000–2002, we used acoustic monitoring to determine bat species presence at 338 riparian sites in northwestern Georgia, USA. We used a 2-dimensional nonmetric multidimensional scaling (NMDS) ordination to assess how separations among species were partially associated with riparian conditions. Our NMDS analysis found some degree of habitat partitioning among bat species occurring in northwestern Georgia and was dictated in part by riparian condition. Myotis grisescens and M. septentrionalis were associated with low-elevation lotic waterways, whereas M. lucifugus, Lasiurus borealis, and Eptesicus fuscus were associated with high-elevation lentic waterways with sparse canopy cover. However, riparian conditions had weak relations with NMDS axes, possibly resulting in coincidental associations in some cases. Regression tree analysis indicated that higher bat species richness was associated with apparently uncommon small, high-elevation waterways with sparse canopy cover as well as larger streams and rivers that had wetlands adjacent to them. Including high-elevation waterways with existing management recommendations for endangered M. grisescens foraging areas (large, low-elevation streams and rivers) will be the most effective conservation strategy to benefit the most bat species in northwestern Georgia and probably elsewhere in the southern Appalachians.
Bats appear regularly among the mammalian prey species of the barn owl. However, from numerous studies of owl pellets, bats are rarely represented in the prey of the barn owl and usually make up less than 1% of the prey individuals. Prey remains of the barn owl from the fortress Dömitz, south-east of Mecklenburg-Western Pomerania (Germany) were collected and analysed. A total of 2931 identifiable fragments from at least 1100 vertebrate individuals were discovered and identified. The analysis of the pellets over a four year period shows that, aside from the typical spectrum of mammalian prey (voles 34.9%, shrews 24.6 % and mice 13.8%), a relatively large proportion of prey individuals (26.6 %) were bats. From the pellet sample from 2002, Natterer’s bat Myotis nattereri were clearly the dominant prey with 79 individuals (30.2 %) followed by the common vole Microtus arvalis with 74 individuals (28.2 %). This high frequency of bats from the 2002 sample led to a total percentage of bats of almost 39 % and bats were clearly dominant over other potential prey groups. The frequency of bats in all samples is much higher than in all other known studies of barn owl pellet samples in a comparable volume. Our results show that Tyto alba is an opportunistic but no selective hunter of bats.
A sample of chigger mites from bat hosts collected in the Balearic Islands (Western Mediterranean Sea) is found to include two species. These are the first records of bat-infesting chiggers identified to species in Spain. Chiggers collected from Pipistrellus kuhlii (Kuhl) in Menorca are identified as Oudemansidium komareki (Daniel et Dusbábek, 1959); this species, which was known from Austria, Bulgaria, Romania, Slovakia, Moldova, Crimea, and Azerbaijan, is recorded for the first time in Spain. Chiggers collected from Plecotus austriacus (Fischer) in Formentera are identified as Trombicula knighti Radford, 1954, which was insufficiently described from a bat in Yemen and known only from its type locality. We transfer this species to the genus Trisetica Traub et Evans, 1950 and provide its re-description based on paratypes and the material from the Balearic Islands. The species Sasatrombicula (Rudnicula) balcanica Kolebinova, 1966 is synonymised with T. knighti. One species closely related to T. knighti, Trisetica aethiopica (Hirst, 1926), which was recorded in Ghana, Uganda, South Sudan, and Madagascar, is re-described on the basis of its syntype deposited in the Natural History Museum, London, UK. This specimen is designated as lectotype.
A single-machine batch scheduling problem is investigated. Each job has a positive processing time and due-date. Setup times are assumed to be identical for all batches. All batch sizes cannot exceed a common upper bound. As in many practical situations, jobs have to be subject to flexible precedence constraints. The aim of this paper is to find an optimal batch sequence. The sequence is to minimize the maximal completion time and maximize the minimum value of desirability of the fuzzy precedence. However, there usually exists no batch sequence optimizing both objectives at a time. Therefore, we seek some non-dominated batch sequences after the definition of non-dominated batch sequence. Based on an iterative Procedure HL proposed by Cheng et al., an efficient algorithm is presented to find some non-dominated batch sequences.
Carpathian forests represent unique and well-preserved ecosystems in relatively intensively managed forests of Europe. Habitat use, foraging assemblages and activity patterns of a bat community were investigated in semi-natural beech-oak forest by monitoring echolocation calls and mist-netting at three localities during the summers of 2003 and 2004. Six different forest habitat types were studied: oak forest, beech forest, stream, road, forest edge and open area within the forest. Bats were detected in all habitats. Sixteen species were found. Habitats were used differently by the individual species. The highest species diversity was observed in the forest interior. The first peak of flight activity was after sunset which then declined and was relatively even through the night until the second peak before sunrise, which was recorded in the forest interior, open area and on the road. The highest flight activity was recorded at the forest edge, forest stream and in open area. Recorded activity was 3× lower in the oak forest interior compared to the forest edge, but if the extent of the forests is considered, forest interior is the most important foraging habitat. Consequently future forest management should consider the needs of this endangered group of animals.
The species composition and relative density of bats were compared in forests of various sizes occurring as “islands” in the agricultural landscape of central Poland. The following island categories were distinguished: very small (0.3–0.7 km2), small (1.0–1.5 km2), medium (2.0–3.5km2) and large (approx. 18 km2). Bats flying over lanes were caught at 34 mist net stations in 13 islands at the end of June and beginning of July (period I) and again at the end of July and beginning of August (period II). Twelve species of bats were recorded (Plecotus auritus, Eptesicus serotinus and Barbastella barbastellus were the dominant species), and the number of species in specific categories of islands ranged from 8–9, except in the very small islands, where only 4 species were confirmed. Species diversity rose with the size of the islands. Nyctalus leisleri and Myotis mystacinus were caught only in the large island. The frequency of B. barbastellus and Nyctalus noctula clearly increased with island size as opposed to E. serotinus and P. auritus. The relative density (mean numbers of individuals caught at one location on one night) during period I increased with island size from very small (1.8) to large (8.1), while during period II, the highest values were achieved in the medium-sized islands (13.4). The mean number of species for one location and night rose in a similar manner. Forest fragmentation to very small units of less than 1 km2 in size negatively influences bat ensembles.