Number Of Darts Research Articles

THE BEHAVIOR OF YOUNG SALMON (SALMO SALAR L.) IN THE RIVER LIZHMA (LAKE ONEGO) IN THE SUMMER SEASON

It was found that each age group of young salmon has its own daily foraging activity pattern, mainly regulated by illumination. At the latitude of the Lizhma River (62°22ʹ40ʺ N, 34°29ʹ57ʺ E), which drains to Lake Onego, the foraging activity duration in June and July is 16 h ± 30 min. In twilight hours and in the dark (below 200 lx) it was absent in all age groups. Young-of-the-year (0+) maintained a constant level of foraging activity during the day, making about 900 darts at food. Parr aged 1+ and 2+ foraged the most actively in the morning (18,000 lx), after which the activity declined until 15 h (70,000 lx)and remained low until 19 h (21,000 lx). Then it increased slightly until dusk. The number of darts at food was about 350 per day. For 3+ parr, the activity was the lowest in the morning hours, gradually growing afterwards to reach a peak at around 15 hours, after which a gradual decline was observed. During the day they make about 300 darts at food. The foraging intensity for 0+ fish averages 63 darts per hour. Fish aged 1+ make less than 30 darts/h; 2+ make about 40 darts/h; 3+ salmon make about 25 darts/h. Foraging activity can be reduced by dense clouds and competition. Young fish aged 0+ and 1+ cannot compete with larger parr and other predators for fodder-rich sites. 2+ and 3+ parr occupy the most advantageous feeding microsites, where they perform up to 88 % of all daily darts for food in less than 50 % active time, and thus satisfy their daily nutritive demand. As a result, 2+ and 3+ parr would be more often seen inactive in “shelter” microsites compared to 0+ and 1+ individuals.

Enumeration of hypermaps of a given genus

This paper addresses the enumeration of rooted and unrooted hypermaps of a given genus. For rooted hypermaps the enumeration method consists of considering the more general family of multirooted hypermaps, in which darts other than the root dart are distinguished. We give functional equations for the generating series counting multirooted hypermaps of a given genus by number of darts, vertices, edges, faces and the degrees of the vertices containing the distinguished darts. We solve these equations to get parametric expressions of the generating functions of rooted hypermaps of low genus. We also count unrooted hypermaps of given genus by number of darts, vertices, hyperedges and faces.

Counting hypermaps by Egorychev’s method

The aim of this paper is to find explicit formulae for the number of rooted hypermaps with a given number of darts on an orientable surface of genus \(g\le 3\). Such formulae were obtained earlier for \(g=0\) and \(g=1\) by Walsh and Arques respectively. We first employ the Egorychev’s method of counting combinatorial sums to obtain a new version of the Arques formula for genus \(g=1\). Then we apply the same approach to get new results for genus \(g=2,3\). We could do it due to recent results by Giorgetti, Walsh, and Kazarian, Zograf who derived two different, but equivalent, forms of the generating functions for the number of hypermaps of genus two and three.

Evaluation of Modified Techniques for Immobilization of Wild Ring-Tailed Lemurs (Lemur catta)

Wild ring-tailed lemurs (Lemur catta) can be anesthetized with Telazol via blow dart, but improved techniques are needed so that each lemur is reliably induced with a single dart. Medetomidine-butorphanol (MB) is a good supplemental protocol to be administered once the lemurs are captured, but other protocols may provide longer periods of sedation and immobility. One possible way of increasing the efficacy of each dart is to increase the time it is retained in the leg. In this investigation, a "double-sleeve" technique was used to try to increase the time of dart retention. This technique used a standard silicone sleeve on the needle, along with a second sleeve at the needle hub. Induction values were compared between lemurs darted with double-sleeve needles and those induced with needles that each had a single silicone sleeve. Once the lemurs were induced, supplementation with MB (0.04 mg/kg and 0.2 mg/kg) was compared with supplementation with ketamine-medetomidine (KM) (10 mg/ kg and 0.04 mg/kg). Twenty-three lemurs were darted with Telazol by using single-sleeve needles, and 24 were darted with double-sleeve needles. The number of darts per lemur and number of escapes were not different between animals darted with a single sleeve compared with a double-sleeve; thus, there were no significant improvements in induction success with the double-sleeve technique. Adequate sedation and muscle relaxation were achieved with both MB and KM; however, lemurs that received MB were more relaxed and needed fewer additional supplements that those that received KM. Single-sleeve dart needles are recommended for Telazol induction of ring-tailed lemurs via blow dart and MB is preferable to KM for supplemental sedation and muscle relaxation.

Enumeration of unrooted hypermaps of a given genus

In this paper we derive an enumeration formula for the number of hypermaps of a given genus g and given number of darts n in terms of the numbers of rooted hypermaps of genus γ ≤ g with m darts, where m | n . Explicit expressions for the number of rooted hypermaps of genus g with n darts were derived by Walsh [T.R.S. Walsh, Hypermaps versus bipartite maps, J. Combin. Theory B 18 (2) (1975) 155–163] for g = 0 , and by Arquès [D. Arquès, Hypercartes pointées sur le tore: Décompositions et dénombrements, J. Combin. Theory B 43 (1987) 275–286] for g = 1 . We apply our general counting formula to derive explicit expressions for the number of unrooted spherical hypermaps and for the number of unrooted toroidal hypermaps with given number of darts. We note that in this paper isomorphism classes of hypermaps of genus g ≥ 0 are distinguished up to the action of orientation-preserving hypermap isomorphisms. The enumeration results can be expressed in terms of Fuchsian groups.

Enumeration of unrooted hypermaps

Abstract In this paper we derive an enumeration formula for the number of hypermaps of given genus g and given number of darts n in terms of the numbers of rooted hypermaps of genus γ ⩽ g with m darts, where m | n . Explicit expressions for the number of rooted hypermaps of genus g with n darts were derived by Walsh (1975) for g = 0 , and by Arques (1987) for g = 1 . We apply our general counting formula to derive explicit expressions for the number of unrooted spherical hypermaps and for the number of unrooted toroidal hypermaps with given number of darts. The enumeration results can be expressed in terms of Fuchsian groups.