التوزيع الرأسي والعلاقات البينية للأكسجين والأملاح المغذية في الخليج العربي وخليج عمان في فصل الصيف

The distribution patterns of oxygen and nutrients (phosphate, nitrate, nitrite and ammonia) were studied along the Arabian shelf of the Arabian Gulf and the Gulf of Oman, including the Strait of Hormuz, during September, 1985 and 1986. Frequency distributions of oxygen and nutrients at different levels indicated the occurrence of a layer of minimum oxygen ( 12.0 (.tg at NO~3-N/1) at depths below 50 meters. The co-occurrence of low oxygen, low ammonia and high nitrate shows a probability of nitrification process at that relatively deep water. Means and standard deviations were calculated for the measured parameters. Different linear equations were found betwen some parameters; for which the constants were estimated whenever the total correlation coefficients were significant.يختص البحث بدراسة شاملة للأكسجين والأملاح المغذية في مياه المنطقة البحرية على الجانب العربي من الخليج العربي وخليج عمان . وقد تمت هذه الدراسة بواسطة سفينة مختبر البحار في ( سبتمبر- أكتوبر) لعامي1985 ، 1986 . ويقدم البحث التوزيع الرأسي للملوحة والأكسجين والأملاح المغذية ( الفوسفات ، النيترات ، النيتريت والأمونيا ) مع مناقشة تفصيلية لمستويات تلك الخواص بالأعماق المختلفة . وقد تبين من البحث أن الطبقة السطحية لكل من الخليج العربي وخليج عمان تحتوي على تركيزات من الأكسجين تتراوح بين 3 ، 4 مل / لتر بينما ينخفض التركيز إلى 1.2 مل /لتر في مياه القاع بالخليج العربي ويصل إلى حدة الأدنى في خليج عمان عند العمق بين 50 ، 200 متر . أما في حالات النيترات - على وجه الخصوص - والفوسفات فنجد أنه يحدث العكس . فتقل تركيزاتها بالمياه السطحية بينما تزيد كثيرا بالمياه القاعية . ويدل تغير الأكسجين والنيترات والأمونيا مع الأعماق على حدوث عملية النترتة التي تتأكسد بموجبها الأمونيا إلى نترات ويستهلك تبعا لذلك الاكسجين الذائب بمياه القاع . وقد تم حساب المتوسطات والانحراف المعياري لكل منها للمتغيرات التي درست وذلك فى كل عمق على حدة . وقد تم أيضا مناقشة الحسابات التي تمت لإيجاد العلاقات الرياضية بين كل متغيرين على حدة . وقد تميزت نتائج عام 1986 بوجود علاقات خطية واضحة وذات دلالة رياضية بين معظم الخواص التي درست وخاصة بين الأكسجين وكل من الفوسفات والنيترات مما يجعل دراسة تلك العلاقات بين الخواص الكيميائية من الأهمية من حيث إمكانية استخدامها في دراسات أخرى مثل دراسة انتاجية أو مصايد الخليج العربي وخليج عمان

Irrigation water requirements as affected by diverse climate conditions

Determination of crop water requirement is one of the key parameters for precise irrigation scheduling, especially under limited water resources, such as in Egypt. Hence, an accurate estimation of reference evapotranspiration (ETo) is a vital factor for agriculture production, therefore the objectives of the present study were to study the influence of climate change on different seasons and comparing of ETo estimations using Blany- Criddle (BC) and FAO-56 Penman-Monteith (PM) equations under present and future climatic conditions. Data on the present climate have been collected from Wadi El-Natrun meteorological station, Egypt from 1991 to 2020. While the future climate data have been chosen for the concerned RCPs scenarios: RCP2.6, RCP4.5, RCP6.0, and RCP8.5 in 2040, 2060, 2080, and 2100. The results revealed that all months’ reordered Tmean above 20 oC, except December, January, and February where they ranged between 17.68 and 19.44 oC.  The highest Tmean values were observed in July (32.3oC), August (31.9 oC), and June (31.8 oC), while February scored the lowest Tmean (17.7 oC).&nbsp

Irrigation Water Requirements as Affected by Diverse Climate Conditions

Determination of crop water requirement is one of the key parameters for precise irrigation scheduling, especially under limited water resources, such as in Egypt. Hence, an accurate estimation of reference evapotranspiration (ETo) is a vital factor for agriculture production, therefore the objectives of the present study were to study the influence of climate change on different seasons and comparing of ETo estimations using Blany- Criddle (BC) and FAO-56 Penman-Monteith (PM) equations under present and future climatic conditions. Data on the present climate have been collected from Wadi El-Natrun meteorological station, Egypt from 1991 to 2020. While the future climate data have been chosen for the concerned RCPs scenarios: RCP2.6, RCP4.5, RCP6.0, and RCP8.5 in 2040, 2060, 2080, and 2100. The results revealed that all months' reordered Tmean above 20 oC, except December, January, and February where they ranged between 17.68 and 19.44 oC.  The highest Tmean values were observed in July (32.3oC), August (31.9 oC), and June (31.8 oC), while February scored the lowest Tmean (17.7 oC).&nbsp

Simultano spektrofotometrijsko određivanje valsartana i hidroklorotiazida metodom H-točke standardne adicije i djelomičnom regresijom najmanjih kvadrata

Simultaneous determination of valsartan and hydrochlorothiazide by the H-point standard additions method (HPSAM) and partial least squares (PLS) calibration is described. Absorbances at a pair of wavelengths, 216 and 228 nm, were monitored with the addition of standard solutions of valsartan. Results of applying HPSAM showed that valsartan and hydrochlorothiazide can be determined simultaneously at concentration ratios varying from 20:1 to 1:15 in a mixed sample. The proposed PLS method does not require chemical separation and spectral graphical procedures for quantitative resolution of mixtures containing the titled compounds. The calibration model was based on absorption spectra in the 200-350 nm range for 25 different mixtures of valsartan and hydrochlorothiazide. Calibration matrices contained 0.5-3 µg mL-1 of both valsartan and hydrochlorothiazide. The standard error of prediction (SEP) for valsartan and hydrochlorothiazide was 0.020 and 0.038, respectively. Both proposed methods were successfully applied to the determination of valsartan and hydrochlorothiazide in several synthetic and real matrix samples.U radu je opisano simultano određivanje valsartana i hidroklorotiazida metodom H-točke standardne adicije (HPSAM) i djelomičnom kalibracijom najmanjih kvadrata (PLS). Praćene su apsorbancije na dvije valne duljine, 216 i 228 nm, nakon dodatka standardne otopine valsartana. Rezultati primjene HPSAM pokazali su da se valsartan i hidroklorotiazid dadu odrediti simultano ako je omjer njihovih koncentracija u smjesi od 20:1 do 1:15. Za potpunu rezoluciju smjesa navedenih ljekovitih tvari preporučena PLS metoda ne treba niti kemijsko odjeljivanje niti grafičku obradu. Kalibracija se temelji na apsorpciji pri valnim duljinama 200–350 nm provedenoj na 25 različitih smjesa valsartana i hidroklorotiazida. Koncentracije valsartana i hidroklorotiazida u kalibracijskim matricama bile su 0.5–3 µg mL–1. Očekivane standardne greške (SEP) za valsartan i hidroklorotiazid iznosile su 0,020, odnosno 0,038 µg mL–1. Obje predložene metode uspješno su primijenjene za određivanje valsartana i hidroklorotiazida u nekoliko sintetskih i realnih uzoraka

Inheritance of Schistosoma mansoni infection incompatibility in Biomphalaria alexandrina snails

In this study, we looked at the inheritance of susceptibility and resistance to Schistosoma mansoni infection in the first generation of crossbred Biomphalaria alexandrina snails. Our ultimate goal is to use such information to develop a biological method of controlling schistosomiasis. We infected laboratory-bred snails with S. mansoni miracidia and examined cercarial shedding to determine susceptibility and resistance. Five parental groups were used: Group I contained 30 susceptible snails, Group II contained 30 resistant snails, Group III contained 15 susceptible and 15 resistant snails, Group IV contained 27 susceptible and three resistant snails and Group V contained three susceptible and 27 resistant snails. The percentage of resistant snails in the resulting progeny varied according to the ratio of susceptible and resistant parents per group; they are 7%, 100%, 68%, 45% and 97% from Groups I, II, III, IV and V, respectively. On increasing the percentage of resistant parent snails, the percentage of resistant progeny increased, while cercarial production in their susceptible progeny decreased