Showing papers by "Cairo University published in 1971"
TL;DR: In this article, the spectral properties of 18 phenyl carbamoylarylhydrazidic chlorides derived from coupling of diazotized anilines to α-chloroacetoacetanilide have been investigated.
119 citations
68 citations
TL;DR: In this article, the kinetics of anodic oxidation of Ti are studied in H 2 SO 4, HNO 3 HCl and H 3 PO 4 solutions of varying concentration, and the potential/log (cd) relations are constructed at constant time of polarization, and at constant Q, where Q is the charge passed.
52 citations
TL;DR: Azotobacter and nitrogen-fixing clostridia are ubiquitous soil inhabitants in Egypt, Iraq and probably in all of the Near East and they occur in high numbers except where barrenness, NaCl accumulation or other depressing factors exist.
Abstract: Azotobacter and nitrogen-fixing clostridia are ubiquitous soil inhabitants in Egypt, Iraq and probably in all of the Near East. They occur in high numbers except where barrenness, NaCl accumulation or other depressing factors exist. The soil environment has proved favourable for their development since their response to supplementation with energy materials is quite marked. The organisms are resistant to drought, but optimal activity of Azotobacter is around 60% W.H.C. while that of clostridia is at 100%. Azotobacter as well as clostridia show optimal activity around 30°C, higher temperatures favour clostridia while lower ones favour Azotobacter. Gains of soil nitrogen are linked to the growth of Azotobacter rather than to that of Clostridium. The amounts of nitrogen gained and fixation efficiency are affected by the nature of the substrate, being greatest in clay, then in sand and calcareous soils and least in liquid media. Phosphate is essential, favouring nitrogen fixation firstly by satisfying the high phosphate requirement of Azotobacter and secondly by increasing the rate of decomposition of otherwise unavailable material. Gains of combined nitrogen and fixation efficiency are also affected by the type of organic matter added. A wide C/N ratio and susceptibility to decomposition are specially beneficial properties. Plant residues enrich the soil with nitrogen, partly by enhancing nitrogen fixation and partly by causing immobilization of mineral nitrogen which would otherwise be leached out of the soil by irrigation.
51 citations
TL;DR: In this paper, the variation of elastic constants of MgO with temperature has been measured from 4.2 to 300 K, in units of 1010 N/m2, with a limiting value of θ 0 = 948 K for the Debye characteristic temperature.
Abstract: The variation of elastic constants of MgO with temperature has been measured from 4.2 to 300 K. The values of the elastic constants at 4.2 K, in units of 1010 N/m2, are C11 = 30.67, C12 = 9.371 and C44 = 15.76. This gives a limiting value of θ0 = 948 K for the Debye characteristic temperature
48 citations
TL;DR: Nursing mothers who experienced relatively long or short periods of postpartum lactation amenorrhea in connection with one baby tended to repeat the same pattern with a subsequent baby; the authors designated this as “habitual postpartUM lactation Amenorrhea.”
39 citations
TL;DR: The life cycle of Argas (Persicargas) arboreus Kaiser, Hoogstraal & Kohls from oviposition through the nymphal molts to the adult stage was investigated at different constant temperature and rh levels and with 6 bird species as hosts (laboratory rabbits were not accepted as hosts).
Abstract: The life cycle of Argas (Persicargas) arboreus Kaiser, Hoogstraal & Kohls from oviposition through the nymphal molts to the adult stage was investigated at different constant temperature and rh levels and with 6 bird species as hosts (laboratory rabbits were not accepted as hosts). The data point to the need for investigating the more subtle factors operating in nature to restrict the presence of this parasite to a certain group of bird species. The length of developmental periods and of larval and nymphal survival was affected by temperature but the roles of rh and bird host species were nil or nonsignificant. The life cycle required 8 months at 21°C and 8 weeks at 37°C. The thermal constant for egg development (150 degree-days) was less than 1/2 that of A. (P.) persicus (Oken) eggs (316 degree-days). Egg hatch percentage was affected by temperature, rh, and female age, but not by the bird species on which the female had fed. Prefeeding and feeding periods were alike for larvae and nymphs that fed on each bird species except on adult herons, the natural hosts, for which the periods were longer, probably owing to the host's acquired immunity to tickbite. The relative amounts of ingested blood and emitted coxal fluid were almost constant in the different nymphal instars. The number of instars (2 or 3, rarely 4) was related to nymphal weight before and after feeding. Most adults emerged from N3 under all rearing conditions. Female-nymphs ingested more blood and were usually heavier than male-nymphs. The N2 and N3 premolting periods did not differ whether these nymphs molted to subsequent instars or to males or females.
34 citations
TL;DR: A sector in this region, namely Abu Nafla, located 25 km to the east of Sidi Barrani was chosen for the present investigation as mentioned in this paper, which is more promising regards its exploita tion.
Abstract: Ecological and phytosociological studies in the Mediterranean zone in Egypt are not immense and began since few years ago. Tadros and his co-workers (1953, 1956, 1958a & b and 1965), Long et al. (1955 & 1956), Migahid and his co-workers (1955, i960 and 1963) and El-Sharkawy (1961) conducted some ecolog ical and phytosociological studies in some parts of the coastal region. This region being less arid and supporting denser vegeta tion than the inland deserts is more promising regards its exploita tion. A sector in this region, namely Abu Nafla, located 25 km to the east of Sidi Barrani was chosen for the present investigation.
33 citations
TL;DR: Anodic charging curves have been measured on polycrystalline Bi in H 2 SO 4 solutions (0·01−6·0 N) at 30°C in this article, and the effect of various experimental procedures, eg electrode treatment and stirring, has been established.
32 citations
TL;DR: In this article, the preparation and spectral properties of twenty-five arylazocyanoacetarylamides (VI, VII, VIII, IX, X, XI) were investigated.
32 citations
TL;DR: The Egyptian Zygophyllum species, though limited in number, contribute in considerable measure to the desert vegetation and represent a group of succulent plants which are drought resistant or salt tolerant living under severe dry climatic conditions.
Abstract: The Egyptian Zygophyllum species, though limited in number, contribute in considerable measure to the desert vegetation. They represent a group of succulent plants which are drought resistant or salt tolerant living under severe dry climatic conditions. Their abundance is attributed to these characteristics in addition to their unpalatibility.The distribution of the studied species is deduced from the data collected by the present authors and others working in the Egyptian desert. The growth and distribution of some Zygophyllum species are dependant on the chemical nature of the substratum. Z. occineum is a widespread species in the limestone territories of the Eastern desert. Z. decumbens is confined to a limited area within the borders of the area inhabited by Z. coccineum. Z. album is a salt tolerant plant with wide geographical range growing in dry littoral or inland salt marshes. Z. simplex, the only ephemeral species, has wide geographical and ecological ranges. The soil carbonate content does not exercise any significant effect on its distribution though it is more ecologically related to Z. occineum than the other species. Z. decumbens is ecologically related to Z. coccineum, while Z. album has its own ecological amplitude.
TL;DR: It is suggested that gestagens may exaggerate gingival response to local irritants by disruptingGingival mast cells by disrupting gingiva mast cells.
Abstract: This investigation was undertaken to determine the gingival condition of women taking oral contraceptives for varying periods. The gingival condition and amount of calculus around the 12 anterior teeth were recorded for 125 healthy Egyptian women 18 to 39 years old who were taking 4 mg megestrol acetate and .05 mg ethenyl estradiol (Volidan) daily for periods varying from 1 month to 2 years. A control group of 50 women was also studied. There was no significant difference in the calculus formation. A statistical difference was shown in the scoring of gingival inflammation between all those taking the contraceptive and the controls (p less than .01). The greatest effect on the gingiva was seen during the first 3 months of therapy. Continued therapy for 3 more months only slightly increased the inflammatory findings. After 1 or 2 years there was some improvement so that conditions returned to almost the same as noted during the first 3 months. It is suggested that gestagens may exaggerate gingival response to local irritants by disrupting gingival mast cells.
TL;DR: The term bone atrophy or osteolysis should be reserved for a particular clinical entity and should not be used to designate histologic changes, as this finding is not universal.
TL;DR: Hysterograms were performed on 172 women fitted with 30 mm Lippes Loops to determine uterine dimensions and Congenital anomalies and devices incorrectly positioned caused intermenstrual bleeding.
TL;DR: In this paper, anodic charging curves have been measured by the galvanostatic technique on Bi in 0·05 M solutions of Na 2 SO 4, Na 2 CO 3 and NaOH at 30°C.
TL;DR: Bari ewes of 2, 3, 4 and 6 years of age and weighing 25–45 kg were put under close observation so as to study the subjective and objective aspects of their behaviour during parturition.
Abstract: A number of 237 Barki ewes of 2, 3, 4 and 6 years of age and weighing 25–45 kg were put under close observation so as to study the subjective and objective aspects of their behaviour during parturition.During the choice and preparation of the parturition site ingestive behaviour ceased and an investigatory behaviour took place using the visual and olfactory senses. Ewes showed preference for the less illuminated and less disturbed places. They pawed the chosen spots with their hooves so as to prepare them for parturition. The parturient behaviour was characterized by signs of uneasiness and of pain, which increased gradually until the lamb's expulsion.The overall average pre-partum time of labour was 46·1 plusmn; 1·6 min. The 2-year-old ewes took longer to give birth than older ones. The pre-partum labour was not significantly affected by body weights of ewes. The overall average duration of the post-partum labour was 143·27 min. Age and weight of ewes had no significant effect on the duration of the post-partum labour. Births were not evenly distributed over the period of observation.
TL;DR: In this article, the metabolic products and accumulated ions were estimated at different stages of development of a number of native and introduced plant species grown under different conditions of moisture stress corresponding to different levels of water supply equivalent to 125, 200, 275 and 350 mm.
Abstract: Estimations of the metabolic products and accumulated ions were made at the different stages of development of a number of native and introduced plant species grown under different conditions of moisture stress corresponding to different levels of water supply equivalent to 125, 200, 275 and 350 mm.
TL;DR: Galvanostatic anodization of W has been studied in 10N solutions of HCl, H 2 SO 4, HNO 3, H 3 PO 4, and HClO 4 at 30°C as mentioned in this paper.
TL;DR: In this article, the effects of different periods of variation, different depths of the conducting core and different locations of the edge of the continental shelf on the Earth's conductivity were considered.
Abstract: Summary
Electromagnetic induction in a perfectly conducting spherical shell covered by a concentric non-uniformly conducting hemispherical shell by an external magnetic field is considered. The two conductors represent the Earth's conductivity and a large ocean respectively. The integrated conductivity of the outer shell is axisymmetric and reaches a maximum before tending to zero at the edge, hence it is continuous there. The parameters of the problem allow for the consideration of the effects of different periods of variation, different depths of the conducting core and different locations of the edge of the continental shelf.
Spherical harmonics are used and the properties of certain vector functions involving Legendre functions are given. The problem is then reduced to the solution of an infinite system of linear equations.
The effects of a uniform inducing field are considered in the two cases when its direction is either parallel or normal to the axis of symmetry. The results indicate that the components of the observed field are enhanced in sea and land in the vicinity of the coastline. This enhancement is more pronounced if the continental shelf is near the coastline and for the shorter periods of variations. The effect of taking the Earth's conductivity into account is to reduce the enhancement of the field near the coast.
The analysis and the computer program can both be adapted to allow for the estimation of the modification to the external field at any particular station with no conductivity anomaly in the vicinity.
TL;DR: In this article, a method for calculating the shapes of positive and negative corona pulses, their amplitudes and repetition rates is presented, and the calculated positive corona pulse has an almost double exponential shape, while the negative pulse is considerably steeper and shorter in duration.
Abstract: A method for calculating the shapes of positive and negative corona pulses, their amplitudes and repetition rates is presented. The calculated positive corona pulse has an almost double exponential shape, while the negative pulse is considerably steeper and shorter in duration.
TL;DR: In this paper, anodization of Bi has been studied in 0.05 M solutions of H3PO4, NaH2PO4 and NaHPO4 at 30°C using the galvanostatic technique.
TL;DR: In this article, the authors measured anodic charging curves on Ti in Na2SO4, NaCl, NaNO3, NaH2PO4 and Na3PO4 solutions in the cd range 5-35 μA/cm2.
TL;DR: The effect of CCC was sprayed at two different times (49 and 64 days after planting) with different doses (500, 1000, 2000 g active ingredient/ ha) to study the growth and yield of potatoes under field conditions, showing some differences between the two seasons.
Abstract: Two experiments, one in the summer and one in the winter season, were conducted under field conditions to study the effect of CCC3 on the growth and yield of potatoes. CCC was sprayed at two different times (49 and 64 days after planting) with different doses (500, 1000, 2000 g active ingredient/ ha). Stem height was depressed proportionately to the dose applied. Dry matter content of leaves, of total foliage, as well as of tubers per plant showed increases during growth due to some treatments. Total tuber yield was also increased.
TL;DR: In this article, the authors present a study towards an international program to deal with the ecological aspects and problems of the River Nile and its catchment basin, and an outline is given of an international programme for its management.
TL;DR: This paper recommends a simple method which regards the force of mortality as constant within each age interval, and produces numerical results that are close to those obtained by other methods.
Abstract: The construction of life tables is often marred by one or more of the following restrictions: (1) assumptions that are either unjustifiable or of questionable generality; (2) rough approximations; (3) exacting data requirements This paper recommends instead a simple method which regards the force of mortality as constant within each age interval The reasoning is readily comprehensible and all life table functions are easily calculated from the age-specific death rates without any need for further assumptions, approximations, or data Furthermore, this method produces numerical results that are close to those obtained by other methods
TL;DR: In this article, the bound state of three $\ensuremath{\alpha}$ particles is considered for the cluster model and the Coulomb Green's function in the nucleus is calculated.
Abstract: The bound state of three $\ensuremath{\alpha}$ particles is considered. For the $\ensuremath{\alpha}$-cluster model, we consider the Coulomb Green's function in the nucleus $^{12}\mathrm{C}$. The calculated binding energy of the $^{12}\mathrm{C}$ nucleus is consistent with previous calculations.
TL;DR: The dust from Egyptian homes is a potent inhalant allergen when tested on British and Egyptian allergic patients and the allergenic component is the mite Dermatophagoides culinae.
Abstract: Summary
The dust from Egyptian homes is a potent inhalant allergen when tested on British and Egyptian allergic patients. The allergenic component is the mite Dermatophagoides culinae.
TL;DR: The authors compare les preferences esthetiques of huit echantillons d'etudiants, differant par le sexe, la nationalite (anglaise ou egyptienne) and la discipline etudiee (artistique ou non), a qui on demande de juger une serie de 90 polygones a l'aide d'une echelle en 7 points.
Abstract: On compare les preferences esthetiques de huit echantillons d'etudiants, differant par le sexe, la nationalite (anglaise ou egyptienne) et la discipline etudiee (artistique ou non), a qui on demande de juger une serie de 90 polygones a l'aide d'une echelle en 7 points. Les resultats ne confirment pas l'hypothese d'une relativite des preferences esthetiques: le degre moyen de preference ne differe pas selon les groupes, ni selon le sexe; la nationalite rend compte de 50 % de la variance; la discipline etudiee joue plus chez les Britanniques que chez les Egyptiens et de plus, les differences sont inversees; les etudiants en art britanniques preferent les polygones simples, les Egyptiens, les complexes. Quand les jugements des deux echantillons egyptiens sont soumis a une analyse factorielle, on voit appara[icaron]tre des facteurs semblables a ceux qu'on trouve chez les Anglais, a l'exception des facteurs les moins saillants.
TL;DR: Physiological studies with Fusarium oxysporum Schl.sp.
Abstract: Physiological studies with Fusarium oxysporum Schl. f.sp. vasinfectum (Atk.) Snyder & Hansen were undertaken aiming at finding the environmental conditions that might affect its activity in the Egyptian soil. A temperature of 25–30°C was found to be favourable for germination, germ-tube elongation, sporulation and growth, although the fungus could tolerate higher temperatures. The activity of the fungus was favoured at high relative humidities. The optimum moisture-holding capacity for growth was 40%. Germination, sporulation and growth rate were best around neutrality. The presence of a suitable concentration of nitrogen source (c. 0·5%) was found to stimulate the fungus activity. Although the fungus responded favourably to all of the utilized nitrogen sources, yet the presence of organic nitrogen source appeared to be much preferred. Mediumtextured soil was found to be the most favourable for its growth. Macroconidia retained their viability on glass surfaces for as long as 3 months.