No abstract

The largest number of tropical cyclones (TCs) is generated in the northeastern Pacific Basin. These storms can produce extreme precipitation (EP) in northwestern Mexico, causing loss of life and environmental damage. It is important to understand the dynamics that cause the EP associated with TCs, since most human activity requires planning to adjust to the dynamics of local climate changes. Therefore, in this work the goal was to estimate the trends and return periods of the average annual daily extreme precipitation (AADEP; 95th percentile, P95) in the June-September season in the core North American monsoon. To do this, daily precipitation data from 1961 to 2000 from 48 climate computing (CLICOM) weather stations located in the core of the North American monsoon were used to determine AADEP:1. Non-parametric trends with Mann-Kendall tests and Sen's slope estimator. 2. Linear trends of annual averages of 95 (P95) and 99 (P99) percentiles with the least squares method. 3. Return periods with the Gumbel frequency distribution function. The results disclose a significant upward trend in the intensity of P95 increases in mountain stations, which may be related to a greater contribution of precipitation associated with TCs. The seasonal contribution of P95 in coastal stations and the total monsoon precipitation did not show statistical significance at α = 0.05. The return periods of P95 associated and not associated with TC's from 2005 to 2500 were calculated. Return periods of P99 have been rising since 2010 and will continue to 2500. For P95 events associated with TCs, the anomalies are expressed with synoptic conditions of simultaneous positive anomalies in the Pacific Decadal Oscillation (+PDO), negative anomalies in the

The e¡ect of plants and probiotics on the survival and immune response of Litopenaeus vannamei challenged with the white spot syndrome virus (WSSV) was evaluated. A probiotic mixture (PM), plant extract (PE) or powdered plants (PP) were added to feed with the attractant Dry Oil s . An experiment was conducted with ¢ve treatments in triplicate. Shrimp (weighing11.70 AE 2.5 g) were cultured in120 L plastic tanks and fed twice a day with commercial feed plus additives or with commercial feed plusWSSV. Animals were monitored for the occurrence of WSSVusing single-step and nested PCR. The PM and PP added to the commercial feed showed high survival, a decrease in WSSV prevalence in shrimp and an increase in the activity of lysosomal enzymes, N-acetyl-b-glucosaminidase and acid phosphatase. The total haemocyte count in shrimp treated with PM was signi¢cantly higher than that in the control group (treatment I) and in shrimp fed with PE. The results of the present work indicate that PP and PM are good candidates for use as feed additives against WSSV in shrimp cultures.

Meteorological drought is an atmospheric condition characterized by a deficiency in the amount of precipitation and increased evapotranspiration. We calculated the magnitudes of average annual seasonal trends (June to September) of the following drought indicators for 1970-2011: average temperature (T avg ), precipitation (Prec), potential evapotranspiration (PET), standardized precipitation evapotranspiration index (SPEI) on a 24-month scale (SPEI-24), and return periods (RP) of drought (SPEI-24). The indicators were calculated from records of daily T avg and Prec obtained from 38 CONAGUA (National Water Commission) weather stations located in the northern states of Sinaloa, Baja California Sur, Durango, Chihuahua, and Sonora. PET was calculated by the method of Thornthwaite; drought was calculated by the expression for SPEI-24 based on the calculation of deciles 1, 2, 3, 7, 8, and 9 of Prec; and the RP of SPEI-24 were calculated using the probability distribution function of Gumbel on time scales from 2 to 500 years. The nonparametric Mann-Kendall test was applied. The magnitude of change in the trends was estimated by Sen's method for slopes. SPEI-24 showed positive and negative trends (-0.066 to 0.082). The results have predicted that there will be severe droughts in 2021 and 2036 in the states of Baja California Sur and Sinaloa.