FURTHER EVIDENCE OF RESISTANCE TO WARFARIN IN RATTAS RATTAS DIARDII

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Y.M. LAM

SUMMARY

Studies' were conducted in the laboratory to determine the efficacy of 0.025% warfarin against laboratory-bred warfarin-naive and wild-caught R. rattus diardii from a suspected warfarin-resistant population. A base-line for the susceptibility of warfarin-naive R. rattus diardii to 0.025% warfarin was determined. The median lethal feeding period (LFP50) for males and females was 1.78 (95% fiducial limits 0.85-2.63) and 1.84 (1.11-2.56)days respectively. The LFP95 for malesa nd females was 9.01 (5.52-30.00) and 6.41 (4.32-1489) days respectively. The pooled LFP50 and LFP95 for both sexes was 1.81 (1.25-2.35) and 7.59 (5.45-13.45) days respectively. The estimated LFP, indicated that a 14-day feeding on 0.025% warfarin is a suitable test for the detection of warfarin resistance. For the wild-caught males and females the LFP50 was 4.73 (3.16-6.11 ) and 7.56 (5.96-9.28) days respectivelyl. The LFP95 for wild-caugh males and females was 16.10 (11.23-36.3) and 19.03 (13.91-40.11) days. The pooled LFP50  and LFP95 for both sexes of wild-caught rats was 6.02 (4.92-7.10) and 18.91 (14.35-30.82) days respectively. A resistance factor (R) was calculated and the R values indicated that the wild-caught rats were 3.3 times less susceptible to 0.025% warfarin when compared with warfarin-naive rats. In conclusion, warfarin resistance has been confirmed in the wild populationo f R. rattus diardii studied.

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EFFECTS OF PACKINGHOUSE OPERATIONS ON SOME VEGETABLES PRIOR TO STORAGE IN COLD ROOMS OF HUMIFRESH REFRIGERATION SYSTEM

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MOHD. SALLEH PUNAN, LAM P.F. and AB. AZIZ IBRAHIM

SUMMARY

The suitability of packinghouse operations on vegetables namely mustard, long beans, cabbage, Chinese cabbage and tomatoes prior to storage in cold rooms of the Humifresh refrigeration system were tested. Packing houso eperations such assorting, trimming, wiping with moist cloth, washing drip drying after washing, and precooling were tried and found to be very useful for some vegetables in reducing deterioration durings storage. With proper packinghouse operations the above vegetables could be kept for 1, 2, 8, 3 and 2 weeks respectively where about 70% (w/w) produce were still acceptable or human consumption. Losses were mainly due to water evaporation, physiological damage, wilting, yellowing, chilling injury, bacterial soft rot and anthracnose.

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THE EFFECTS OF TEMPERATURE ON ADULT SURVIVAL,OVPOSITION AND THE INTRINSIC RATE OF INCREASE OF PLUTELLA XYLOSTELLA (L)

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SIVAPRAGASAM A. and K.L. HEONG

SUMMARY

Laboratory studies were conducted to determine the effects of temperatures on the adult survival, oviposition and intrinsic rate of increase , rm, of Plutella xylostella (L), Results showed that temperature had significant effects on adult survival and oviposition rates and generation time. Based on the intrinsic rate of increase (rm) obtained the temperature most favourable for Plutella populations was found to be around 30°C. The relationship between longevity and temperature was found to fit a logistic equation whilst relationships of oviposition rate and rm, with temperature were found to fit polynormial equations.

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WATER TURN OVER IN JERSEYA ND CROSSBREDS OF JERSEY X LOCAL INDIAN DAIRY CATTLE IN SHADE

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MOHAMAD AZIZDOLLAH

SUMMAR

An experiment was conducted to determine water turn over in purebred Jersey and Jersey crosses (Jersey x Local Indian Dairy cattle: Jersey-LID) heifen kept under the shade to study their adaptation to Malaysian climate. Tritiated water was injected intramusculary to determine the water turnover. Water turnover of purebred Jersey (263 ml/kg0.82/day) was significantly higher (P<0.05) than Jersey-LID crosses(222 ml/kg0.82/day)while the half life of former (5.71days) was shorter( p<0.01)t han the later (6.77 days). Dry matter intake, however was not significantly different (P>0.05) between Jersey (5.50 kg,/day) and Jersey-LID (5.88 kg/day). The results of the experiment indicate that the purebred Jersey kept under the shade had higher heat load than its crossbred (Jersey-LID). However, the purebred Jersey was capable of maintaining its heat balance.

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ANTHER CULTURE OF RICE HYBRIDS 1854 AND 1856

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CHUA BENG KHOON, CHEN YOK HWA and OTHMAN OMAR

SUMMARY

Progenies of rice Hybrid 1854 were successfully raised through anther culture technique. A 27.42% callus induction rate and 10.67'% plant regeneration frequency were obtained from anthers of Hybrid 1854 cultured on various media. Anthers of Hybrid 1856 produced less callus and no plant regeneration as compared with Hybrid 1854 under same cultural conditions. High incidence of albino plants were also found among generated Hybrid 1854 plants. The induced plants were first transplanted and grown in the glasshouse. H2 and H3 lines of these plants were subsequently planted in the field. Some of the agronomic characters of Hybrid 1854 lines were reported and discussed.

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