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D. Brandsen D. S. Jacobs 2003 Geographic variation in the morphology, echolocation and diet of the little free-tailed bat, Chaerephon pumilus
The geographical patterns of tree species richness in forest communities have been studied widely, but little is known about the geographical variation of the estimated species richness and minimum areas using species-area curves. A differential technique based on the species-area relationships (SAR) was developed for estimating the minimum area (Amin) capturing 60- 80% of the species in each plot, which is an important characteristic of a forest community. The relationship between estimated species richness (ESR) from the SAR and the corresponding minimum area is described by the linear model ESR = 0.0051×Amin (R2 = 0.98, p < 0.0001). Both the ESR and the minimum area exhibit similar geographical variations with a significant increase along altitudinal and a decrease along latitudinal gradients. The spatial variations of the ESR were partitioned into three geographical components and their combined effects. Altitude accounted for 40% and 45% of the total variation in the ESR and the minimum area, respectively. While latitude accounted for 69% and 61% of the total variation in the ESR and the minimum area, respectively. Thus, latitude is the main determinant which influences the geographical variation of the ESR. As far as we know, this study presents the first report of the geographical patterns of the minimum area in temperate forests.
Aerva lanata collected during summer, monsoon and winter were subjected to similar extraction conditions as well as sample application conditions on precoated silica 60F254 TLC plates. The plates were developed in ethyl acetate-toluene (7:3 v/v) in order to study the seasonal variation in HPTLC fingerprints. A similar procedure was also followed for the plant samples collected from three different states of India, in order to study the geographical variation. p-Hydroxybenzoic acid, used as reference standard for comparison with each sample, was observed in samples collected in all three seasons but in different concentrations. The compound was also observed in samples collected from Gujarat and Maharashtra, but was found to be absent in the sample from Kerala. The sample from Kerala showed a different compound at R F 0.74, having a λ max of 280 nm. This compound exhibited a spectrum very different from that of p-hydroxybenzoic acid having a λ max of 252 nm, which separates out at R F 0.73 on the plate. The proposed method was validated according to ICH guidelines in terms of linearity, accuracy and specificity, intra-day and inter-day precision, repeatability of measurement of peak area, repeatability of sample application and specificity. The calibration graph was found to be linear over a range of concentration of 25.0–175.0 ng, with a regression coefficient of 0.9986. Determination of accuracy by standard addition method at three different concentration levels returned a mean recovery value of 97.24 ± 7.36. Intra-day and inter-day precision values were found to be less than 2%. The relative standard deviations (RSDs) of repeatability of sample application and measurement of area were found to be 1.24% and 0.93%, respectively.
analysing geographic variations in knowledge exchange networks, we can detect regional differences in accessibility to both local and extra-local knowledge resources and find how second tier regions may become successful in innovation. As an emerging
Abstract
This paper analyses the changing geographic balance in China’s international co-publications in general and in three molecular life science subfields in particular. No support is found for the expectation that intensive, designated institutional support for research collaboration in the form of joint laboratories has a positive impact on the number of co-publications at the systemic level. The size of partner research systems, and since the turn of the century the relative size of overseas Chinese scientific communities in various partner countries do help to explain the observed geographic variations in the share of China’s international co-publications. The paper concludes by discussing some of the potential factors underlying the perceived change in the dynamics of international co-publication behavior of mainland Chinese scientists since the turn of the century.
Abstract
The ultimate purpose of all studies on environmental contamination is to protect human life; as a consequence the knowledge of the trace element pathways from environment to man is of paramount importance because it allows the assessment of a clear relationship between any environmental contamination and its effects on man. To this extent two different kinds of environmental studies will be described in this paper: (a) Studies of the geographic variations on the whole national territory of the natural levels of trace elements in water, food and some human tissues. (b) Studies of selected areas where a critical population group is exposed to abnormal levels of some trace elements. The main trace elements considered are: Co, Cr, Cs, Fe, Hg, Ni, Rb, Sb, Sc, Se and Zn; all the measurements were performed by means of non-destructive neutron activation analysis.
Summary
Fourteen samples of fresh curry leaves (Murraya Koenigii) were collected from 13 states of India and analyzed for 6 minor (Ca, Cl, K, Mg, Na and P) and 14 trace (Br, Ce, Co, Cr, Cs, Fe, Hg, Mn, Rb, Sb, Sc, Se Th and Zn) elements by 2-minute irradiation in a reactor followed by high resolution g-ray spectrometry. Peach Leaves (SRM-1547) and Mixed Polish Herbs (MPH-2) were used as comparator standards. Phosphorus was determined by counting the b-activity from 32P using an end-window GM counter. Most elements were found to vary in a wide range depending on their origin of location, e.g., Na (104-455 mg/g), K (10.3-30.3 mg/g), Ca (9.44-28.3 mg/g), Mg (1.14-7.19 mg/g), P (0.43-1.69 mg/g), Mn (24.8-63.0 mg/g), Fe (72.5-195 mg/g), Se (40.1-131 ng/g) and Zn (7.90-70.5 mg/g). Variation in the elemental concentrations of the same species of different origin may be attributed to ecological and geographical variations. Further, column and thin layer chromatography were used for separating three organic constituents from the ethanolic extract; 3-methylthiopropanenitrile; 1,2-benzenedicarboxylic acid, mono (2-ethylhexyl ester) and 1-penten-3-ol and characterized by IR and GC-MS. Inorganic elements may be present as complexes with the organic compounds.
Összefoglaló. A Helicobacter pylori továbbra is a világ legelterjedtebb fertőzése: prevalenciája a fejlődő országokban 70–80%, a fejlett országokban csökkenő tendenciát mutat. A dél-magyarországi véradókban a prevalencia 32%-ra csökkent. A migráció a befogadó ország számára a fertőzés fokozott kockázatával jár. A szövettani diagnózisban az immunhisztokémiai vizsgálat pontosabb a hagyományos Giemsa-festésnél. A mesterséges intelligencia érzékenysége a hagyományos endoszkópiáéval összehasonlítva 87%, pontossága 86%. Az újgenerációs szekvenálással lehetséges egy biopsziás mintából több antibiotikumérzékenység meghatározása. A Helicobacter pylori kezelésének európai regisztere kimutatta, hogy 2013 és 2018 között a bizmutalapú négyes vagy a 14 napos egyidejű négyes kezelések hatásosabbak, mint a hagyományos hármas kezelés, de elterjedésük igen lassú folyamat, jelentős földrajzi különbségekkel. Az új típusú koronavírus (SARS-CoV-2) felléphet Helicobacter pylori fertőzésben is, egymás kóros hatását felerősítve. A diagnosztikai módszerek korlátozottak. Protonpumpagátlók szedése növeli a COVID–19-fertőzés kockázatát és annak súlyos kimenetelét. Előzetesen ismert peptikus fekély, vérzés, illetve antikoguláns kezelés előtt az eradikáció a vírusos fertőzés lezajlása után indokolt. A probiotikumoknak az eradikációra gyakorolt hatásáról 20, közepes minőségű metaanalízis született, így a konszenzusokban foglalt álláspontok sem egyértelműek: a jövőben ezt tisztázni kell. Orv Hetil. 2021; 162(32): 1275–1282.
Summary. Helicobacter pylori is still the most widespread infection in the world: its overall prevalence is 70–80% in developing regions, but fortunately it is decreasing in the Western world. The prevalence in blood donors from South-Eastern Hungary decreased from 63% in the 1990’s to 32% in 2019. Migration constitutes an increased risk of infection for the destination countries. Immunohistochemistry has proven to be more accurate in histological diagnosis than the conventional Giemsa stain. The sensitivity and accuracy of artificial intelligence as compared to videoendoscopy were 87% and 86%, respectively. The European Register on the management of Helicobacter pylori infection revealed that concomitant quadruple and 14-day bismuth-based therapies are more efficient than triple combinations, although their incorporation in practice is a long-lasting process, with large geographical variations. The novel type of coronavirus (SARS-CoV-2) can also occur in Helicobacter pylori-infected patients, mutually enhancing their pathogenetic effects. Diagnostic possibilities are limited in this setting. The use of proton pump inhibitors increases the risk of viral infection and the severity of the disease. Eradication treatment seems justified in patients with previously known peptic ulcers or gastrointestinal bleeding, or before starting anticoagulant treatment, but must be postponed after resolution of viral infection. The effect of probiotics on eradication was addressed by 20, medium-to-low quality meta-analyses and so, the recommendations of the guidelines are equivocal, which must be clarified in the future with higher quality studies. Orv Hetil. 2021; 162(32): 1275–1282.
geographical variation of growth habit and Vrn genotype. Plant Breed. , 120 , 107-114. Adaptation and ecological differentiation in wheat with special reference to geographical variation of growth habit and Vrn genotype
571 Iwaki, K., Haruna, S., Niwa, T., Kato, K. 2001. Adaptation and ecological differentiation in wheat with special reference to geographical variation of growth habit and Vrn . Plant
