BACKGROUND: Dengue haemorrhagic fever (DHF) is a disease found in most tropical and subtropical regions of the world, including Indonesia. One of the problems of vector control programs is insecticides resistance to Aedes spp.
AIM: The objective of this study is to determine the effectiveness of an alternative larvacide using papaya leaves (Carica papaya L).
METHODS: To obtain an ethanolic extract of C. papaya leaf (EECP), the dried of C. papaya leaf was macerated with ethanol 70%. Phytochemical compounds were screened qualitatively. Twenty-five larvae were entered into each cup that had been mixed with five concentrations of EECP i.e., EECPI (100-), EECPII (150-), EECPIII (200-), EECPIV (250), EECPV (300 ppm), 1% of Temephos (T), and water (A). Alkaloid carpain, saponin, flavonoid, tannin, glycosides and triterpenoid/steroid were traced in EECP. The mortality of larvae at 180, 360, 1440 and 2880 minutes were observed. The lethal concentration (LC50) and lethal time (LT50) were measured. Probit analysis was used to determine the concentration of killing larvae.
RESULTS: The mortality of larvae was found at 360 minutes only in EECPV. Then after 1440 minutes, all extracts shown the increasing of larvae mortality. LC50 and LT50 values were 215,96 ppm and 2,369 minutes of each.
CONCLUSION: EECP has larvicidal activity to Aedes spp.
The heart is a very vital organ. There are two main states in the heartbeat cycle, systole and diastole. The heartbeat system studied in this paper was taken from a study of Thanom and Loh in 2011. This paper is aimed to analyze the stability of the heartbeat system using Lyapunov’s Direct Method. This method requires a Lyapunov function. To construct the Lyapunov function, the Gradient Variable Method will be used. In this research, the Lyapunov function constructed
V
(
x
)
=
x
1
2
+
x
2
2
,
V
˙
(
x
)
>
0
is obtained. This means
V
˙
(
x
)
is said to be a positive definite and the equilibrium point (0,0) of the heartbeat system is unstable.
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