4,135 research outputs found
The faunistic diversity of cave-dwelling spiders (Arachnida, Araneae) of Greece
Until today, from Greek caves a total of 109 species of spiders belonging to 25 families are known. One species, the linyphiid Porrhomma convexum (Westring, 1861) was recorded here for the first time in Greece. The 109 species are distributed in caves of different geographic territories as follows: Thrace â 8 species, Macedonia â 18, Epirus â 1, Thessaly â 6, Central Greece â 3, Attiki-Saronic Islands â 24, Peloponnese â 15, Evoia-Vories Sporades â 1, Eastern Aegean Islands â 5, Cyclades â 3, Dodecanese â 6, Ionian Islands â 23, Crete â 47. The largest fraction of troglobite species were encountered mainly in the territories of Crete â 15 species (5 of which are anophthalmic), the Ionian Islands â 4, Thrace â 2 (both anophthalmic), the Attiki-Saronic Islands â 2 (both anophthalmic), the Peloponnese â 2 (one anophthalmic), and Macedonia, Thessaly, and the Cyclades â each with 2 species. The richness of the troglobitic spidersin these regions strengthens the assumption that they were major centres of speciation and evolution for the species of this group. According to their current distribution, the established 109 species can be classified into 12 zoogeograpical categories, grouped into 4 complexes (widely distributed, European, Mediterranean, endemics). The largest number of species belong to the endemic complex (53.2 %) and are also the most characteristic and reflect the local character of the cave-dwelling spiders
South African Grain Farmers in Dire Straits: Scenarios for Sustainable Farming
Traditionally, the South African farmer has always been an entrepreneur, running his/her farming activities as a business to support lifestyle, provide a future for the children (as successors to the family farm or by providing education for a career) and to provide for comfortable retirement one day. However, a number of climatic- and economic environmental issues has resulted in severe constraints to farmers as entrepreneurs, creating a situation where farming are on the brink of collapse and maize farmers are struggling to survive. The production years 2005/6 and 2006/7 are critical. This paper focuses specifically on the summer grain production areas in South Africa where, in addition to the main crop maize, they also plant crops such as sunflower, peanuts, dry beans, sorghum and grazing for livestock). The objective of this paper is to report on the viability of possible scenarios that could assist the farming entrepreneur to sustain his/her farming activities beyond the following two years. A number of specific constraints impact on the grain farmer, namely the overproduction of almost all grain types, the free market system of pricing grain internationally, the Rand/Dollar exchange rate, the capital investment trap and the current government assistance policy, to name but a few. All of these constraints have resulted in a situation where it is no longer viable for farmers to produce the main crop (in excess of 80% of farming activities) namely maize. This situation calls for drastic intervention in entrepreneurial decision-making, and farmers must consider other viable options to service debt and to maintain a positive cash-flow. The analyses show that, ultimately (and most unfortunately), no favourable solution is at hand. From the possible scenarios evaluated in the paper, it is evident that maize farmers should discontinue production of maize on a large scale for the immediate future until the market environment improves. The farming community is faced with a situation of minimising losses and not with any real positive solution pertaining to the scenarios evaluated. The final conclusion is that current economic situations for maize production are unfavourable and the resulting recommendation is that farmers should not plant maize in the 2005/6 production year, that they should ride out the market and then revisit the production decision for the production year 2006/7.Crop Production/Industries,
Managing international students attendance with consideration of completion and satisfaction
Internationalization is one of the many expectations of TEC, as per the TEC Strategy (2007). This includes having a noticeable level of students from overseas, is covered in our instituteâs business plan and is reported our annual report (2008). Servicing these students is guided by the Code of Practice for the Pastoral care of International Students (2003), amongst other things. This paper reports our experiences when the institution tightened up attendance habits of international students for their visa requirements. At the end of the year we revisited our actions, looked at attendance statistics and also considered data about related matters of completion and student satisfaction. We noticed several students attending less than 80% required for their visas, relationship between attendance and module pass rates and nothing specific re student satisfaction. There were some idiosyncrasies with student satisfaction measurement worthwhile noting. We also experienced several problems with our information systems, such as functionality shortcomings for our growing population sub-groups and mismatch between these systems. Further study might include experiences with relevant information systems elsewhere in the institution and rest of the sector. More formal research can and should now be planned, including the use of our pilot use of an online attendance system from 2008. We believe our insights and process would be useful to others even though it does not sit in the framework of ICT teaching contents proposed by Simon (2007) and used by Simon et at (2008) when profiling NACCQ conference papers 2000-2007
The mincut graph of a graph
In this paper we introduce an intersection graph of a graph , with vertex
set the minimum edge-cuts of . We find the minimum cut-set graphs of some
well-known families of graphs and show that every graph is a minimum cut-set
graph, henceforth called a \emph{mincut graph}. Furthermore, we show that
non-isomorphic graphs can have isomorphic mincut graphs and ask the question
whether there are sufficient conditions for two graphs to have isomorphic
mincut graphs. We introduce the -intersection number of a graph , the
smallest number of elements we need in in order to have a family of subsets, such that for each subset. Finally we
investigate the effect of certain graph operations on the mincut graphs of some
families of graphs
Biotopical distribution and seasonal activity of model species of the family Gnaphosidae (Araneae) in Zemen gorge (SW Bulgaria)
A faunistic study was carried out for three years in Zemen gorge (1984-1986). With the help of Barber-traps 675 gnaphosid spiders were caught in 4 localities, each with 2 habitats, meadow and forest. 23 species were found in total and their biotopical distribution was recorded. The investigated habitats are faunistically similar, mainly in qualitative respect. In addition data about the phenology of the most frequent species are presented. The males are most abundant in spring and summer and disappear in VIII, the females are most numerous after VII and can be found till the end of IX, whereas the juveniles can be found till the end of X. The species abundance reaches its peak in V-VI
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