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1.
S. Distaso A. De Lucia M. P. Circella F. Cassano F. Palasciano M. Scattarella 《International Journal of Anthropology》2004,19(1-2):19-32
For more than a century Italian emigration contributed to rebalancing the labour market in Italy, through the absorption of significant numbers of the Italian workforce abroad and by alleviating unemployment levels, and also represented a source of national economic wealth. In the last two decades the Italian migratory trend has been reversed: there has, in fact, been an intensification of migratory flows towards Italy owing to the return of our compatriots, whose economic goals have been realised, and to the arrival of citizens either from poorer countries whose growth rate is zero or negative, or from developing countries. It is certainly necessary to bear in mind that the foreigners are not all workers: there are spouses, children, family members and other persons present for reasons other than work or family, and there are the children of immigrants born in Italy. The data regarding the wealth produced by the work of the immigrants could be significant, also and above all, in view of demographic shrinkage and the ageing of the Italian population forecast for the next fifty years. In view of this, immigration could become a real source of wealth both in economic terms and in terms of human capital. If we evaluate separately and comparatively the immigrations that take place for the demand for manpower and those due to flight from situations of economic and political hardship, we can see that Apulia, starting from 1990s, has become not only a land of passage towards the rest of Europe, but also an objective for settlement. 相似文献
2.
We analysed the mitochondrial control region sequences of 150 Ryukyu robins (Erithacus komadori) from five migratory and three sedentary populations. E. komadori is endemic to the subtropical Asian islands, is well differentiated among populations in morphology and migratory behaviour within its narrow habitat range, and is ideal for examining the effects of altered migratory habits on population differentiation. Maximum-likelihood analysis among the haplotypes resulted in the generation of a single tree in which two phylogenetic clades corresponding to the two subspecies were evident. Within the northern lineage, three distinctive subgroups of populations (one migratory and two sedentary groups) were observed by population genetic analysis. The migration-related wing morphology and molecular data were then compared among groups. The wing shape of the northern lineage was significantly more pointed than that of the southern sedentary lineage, and they were exclusively discriminated from each other. The difference was not so apparent between the sedentary and migratory groups within the northern lineage, suggesting that the present northern subspecies is primarily a migratory lineage. The different migratory behaviours of the robin played an apparent role in maintaining the genetic structure at two different levels--one between the southern and northern lineages and the other between the sedentary and migratory groups within the northern lineage. While gene flow had long been maintained among the islands occupied by migratory individuals, migrants have been unable to contribute to the gene pool of the sedentary populations despite passing through the breeding range of such populations twice each year. 相似文献
3.
HUnter D. M. and Webster J. M. 1973. Determination of the migratory route of botfly larvae, Cuterebra grisea (Diptera: Cuterebridae) in deermice. International Journal for Parasitology3:311–316. Cuterebra grisea larvae introduced into deermice (Peromyscus manicutatus) occurred in the nasal passages (nose or eye entry) or were associated with the esophagus and trachea (mouth entry) in the first three days after entry. During this period, some deermice exhibited a violent wheezing reaction. From day 4 to 6 after entry, larvae migrated to the final development site in the inguinal region of the deermouse. Migrating larvae were found on the front and top of the head, on the back and at the base of the tail. The similarity of this migratory path for C. grisea with the final development sites of other Cuterebra species is discussed. 相似文献
4.
I. Barrai 《Human Evolution》1993,8(1):33-42
The population structure of two alleles similarly affected by selection, HbS and Beta-thalassemia, was studied in the same area, in Sicily. It was observed that Beta-thalassemia has uniform frequencies over the island, and that HbS shows a South-North cline. A singularity exists for HbS, in the twon of Butera, where the frequency of the S gene is six times higher than the island average. It was advanced that probably HbS entered Sicily from North Africa, when the Beta-thalassemia allele was already established in the Island. From the correlation analysis concluded that HbS came to Sicily with the frequency of HbS, it was concluded that HbS came to Sicily before the Arab invasions of the 700 's AD. 相似文献
5.
Neha Agarwal Swati Srivastava Shalie Malik Vinod Kumar 《Biological Rhythm Research》2015,46(5):647-657
Photoperiod is the most consistent environmental cue, and therefore, any change in anticipated light environment may affect subsequent response under long days. To test this hypothesis, photosensitive migratory redheaded buntings (Emberiza bruniceps) were exposed to altered photoperiods for 4 weeks [short days (SP, 8L:16D, group 1; control), short days alternated with constant dim light (SP/LLdim; group 2), constant dim light (LLdim; group 3) and constant bright light (LLbright; group 4)] before being transferred to long days (LP; 16L:8D) for 15 weeks. Group differences in long-day-induced responses were observed. The onset of migratory restlessness (Zugunruhe) was earliest in LLbright but persisted for maximum period in LLdim group. The LLdim group attained peak testis size significantly delayed and had more food consumption under long days. The results suggest that the altered photoperiodic exposure during photosensitive stage affects the seasonal phenotypes such as migration and reproduction in migratory buntings. 相似文献
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Patrick W. Zwartjes 《Conservation Genetics》2003,4(6):749-758
Low genetic variation is thought to increase the risk of extinction in island species; however, these species can differ both
in terms of endemism and gene flow. In a previous study, the endemic species of Puerto Rico (V. latimeri) and Jamaica (V. modestus and V. osburni) were shown to have less genetic variability than a continental relative, V. griseus. In this study, a migratory island species, V. altiloquus, is analyzed together with the endemics in order to (1) compare levels of genetic variation in migratory and endemic island
species, and (2) assess this variation using both molecular markers and morphological traits. Each island species is also
compared to a continental relative (V. griseus for the endemic species, and V. olivaceus for the migratory species). Variability in random amplified polymorphic DNA markers was significantly lower in the endemic
species than in either migratory population. All island populations had significantly lower levels of variation than their
respective continental relatives, but with significantly greater reduction in the endemic species. In contrast, the morphological
measures revealed only two cases with a significantly lower CV in an endemic species compared to V. altiloquus or V. griseus. All others exhibited either no differences in CV or greater levels in the island populations. While the molecular results generally correspond to predictions of lower variability
in endemic vs. migratory island species and island vs. continental species, the morphological comparisons do not, and therefore
may not be useful for quick, field-based assessments of underlying genetic variability.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
Hieracium busambarense (Asteraceae), a new species from calcareous-dolomite cliffs of Rocca Busambra (western Sicily, Italy) is described and illustrated here. 相似文献
9.
A new species of Anthemis sect. Hiorthia (Asteraceae) is described from Sicily. This taxon, named A. piagnattiorum, is confined to a restricted area of the Hyblaean territory (SE Sicily), in the Natural Reserve of Cava Grande (Cassibile, Siracuse), where it takes shelter on carbonate rocky habitat and participates, with other Sicilian endemic taxa, to the composition of a termophilous chasmophytic community (Putorio calabricae–Micromerietum microphyllae). 相似文献
10.
S. Sciandrello C. Brullo S. Brullo G. Giusso Del Galdo P. Minissale 《Plant biosystems》2013,147(3):812-820
Among the suffruticose cabbages of Brassica sect. Brassica, a new species from Sicily, named B. raimondoi, is described and illustrated. It is a chasmophyte restricted to some steep limestone cliffs near Taormina (NE Sicily) and is morphologically related to B. incana, with which it shares densely hairy, broad, amplexicaul leaves and winged petioles, but differs principally in its white corolla, larger floral pieces, more developed stigmatic papillae, shorter siliquae with keeled valves and a smaller, seedless beak, smaller seeds differing in testa microsculpture. A key for the identification of the currently known Sicilian taxa of the section is provided. 相似文献
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The direct comparison between microcharcoal and pollen data from the Holocene sediment core of Lago di Pergusa (central Sicily, Italy) led us to investigate the linkages between fire, vegetation, and climate in the Mediterranean Basin. The role of human populations in shaping the environment of the last millennia was closely examined as well. Pollen and charcoal were extracted using a standard pollen methodology and both identified from the same pollen slides. At Lago di Pergusa the importance of fire in maintaining and favouring a Mediterranean vegetation, a basic concept in ecology, seems to be inconsistent, as important fires took place in the open environments with xeric vegetation at the beginning of the Holocene well before the expansion of evergreen vegetation. On the contrary some big fires seem to have happened in the period (around 8000 years BP) in which the greatest wetness, the thickest forest canopy, and the most important expansion of submontane vegetation of the record are found. A probable explanation of this phenomenon can be found in the precipitation regime, in the increased available biomass and in the resulting increase in combustible material, indicating also that the highest humidity achieved in central Sicily during the Holocene was not strong enough to prevent fires. During this period drops in arboreal pollen concentration match in minima in the charcoal curves. Fires were practically absent during the Neolithic and Eneolithic periods and not responsible for the general trend towards aridification identified in the pollen record, at times in which prehistoric populations are generally believed to have caused forest clearance by burning. Important and frequent burnings are documented for the Bronze and Iron Ages and probably not all of them were fires of living trees, but burning of wood for producing metals, cooking or heating. The occurrence of a fire around 3700 years BP temporarily caused a minor decrease of arboreal pollen concentration. In the open landscapes of the two last millennia an almost continuous sign of regional burnings is recognized, confirming the historical evidence of an intense land use in central Sicily at least since Roman times. 相似文献
13.
In locusts, olfaction plays a crucial role for initiating and controlling behaviours, including food seeking and aggregation with conspecifics, which underlie the agricultural pest capacity of the animals. In this context, the molecular basis of olfaction in these insects is of particular interest. Here, we have identified genes of two orthopteran species, Locusta migratoria and Schistocera gregaria, which encode the olfactory receptor co-receptor (Orco). It was found that the sequences of LmigOrco and SgreOrco share a high degree of identity to each other and also to Orco proteins from different insect orders. The Orco-expressing cells in the antenna of S. gregaria and L. migratoria were visualized by in situ hybridization. Orco expression could be assigned to clusters of cells in sensilla basiconica and few cells in sensilla trichodea, most likely representing olfactory sensory neurons. No Orco-positive cells were detected in sensilla coeloconica and sensilla chaetica. Orco expression was found already in all nymphal stages and was verified in some other tissues which are equipped with chemosensory hairs (mouthparts, tarsi, wings). Together, the results support the notion for a decisive role of Orco in locust olfaction. 相似文献
14.
Introduction
Familial Mediterranean fever (FMF) is an autosomal recessive disease, caused by mutations in the FMF gene MEFV (MEditerranean FeVer). It has a large phenotypic diversity even in patients with similar genotypes. Despite evidence that environmental factors (EFs) and genetic factors, including MEFV mutations (such as M694V, E148Q) and background modifier genes (MGs), affect the clinical manifestations of FMF, the relative contribution of each remains unknown.Methods
To investigate the relative contribution of environmental and genetic factors to the phenotype of FMF, we compared the intra-pair clinical concordance of 10 mono and 7 dizygotic twins with FMF. The part played by EFs was determined by the phenotypic discordance of the monozygous twins, and the MGs effect was determined by deducing the environmental effect, computed for MZ twins, from the phenotypic discordance of the dizygous twins.Results
The mean ± SD of intra-pair concordance was higher in the MZ than in DZ twin group (88.1 ± 13.2 vs. 70.7 ± 14.1 respectively, P value < 0.05). Based on the concordance in clinical manifestations in MZ and DZ twins, the environmental effect on the phenotype of FMF is estimated as 11.9% ± 6.6% and the MGs effect as 17.4% ± 15.5% in average.Conclusions
In FMF the phenotype is affected by MEFV mutations, MGs and EFs in an estimated ratio of about 6:1.5:1 respectively. 相似文献15.
16.
P. J. Byard K. Sharma J. M. Russell D. C. Rao 《American journal of physical anthropology》1984,64(2):97-104
Path analysis is used to characterize family resemblance for anthropometrics in twins and nuclear families from the Punjabi population of India. Significant positive assortative mating exists with respect to many body measurements, but not for cranial or facial variables. Evidence of a maternal effect for five measurements of bone diameter is reported. Twin resemblance is increased by a component not found in other pairs of relatives for all variables except nasal height, facial length, ear length, and head breadth. Although all variables have significant transmissible components, many have parameter estimates which are not consistent with strictly polygenic inheritance. Some form of cultural transmission is implicated for such variables, especially for those related to fatness levels. 相似文献
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18.
The visual behavior of adult Melanoplus sanguinipesF. (Orthoptera: Acrididae) was investigated by placing individuals in the center of an arena and recording their orientation responses to visual targets at the perimeter of the arena. Targets that reflected more 540- to 570-nm light were approached more frequently; however, when reflectance in the 540 -to 570-nm region was combined with reflectance in the 400- to 520-nm region, orientation responses were reduced significantly. This suggests that spectral discrimination in M. sanguinipesinvolves at least two classes of photoreceptors, which respond to different regions of the wavelength spectrum. In addition, grasshoppers oriented to vertical, but not horizontal, contrasting stripes. However, when vertical stripes were added to targets reflecting 520- to 650-nm light, responses to verticals on these targets were not enhanced relative to verticals presented against a target background of 400- to 520-nm + 520- to 650-nm light. Thus, spectral discrimination and vertical stripe fixation appear to be two distinct visual behaviors, controlled by outputs from two classes of photoreceptors and a single class of photoreceptors, respectively, and may be used in different physiological or ecological contexts. 相似文献
19.
柳杉毛虫防治试验研究 总被引:3,自引:0,他引:3
用白僵菌、苏云金杆菌、2 4 .5 %全力、2 0 %氰戊菊酯等 4种杀虫剂的不同浓度对柳杉毛虫 (Dendrolimushoui L ajonquiere)进行室内毒力测定和林间防治试验 ,结果表明 ,野外防治柳杉毛虫以氰戊菊酯 6 0 0 0倍液 +苏云金杆菌 1.4× 10 9n/ ml+全力 80 0 0倍液 +白僵菌 1.2× 10 8n/ ml林间喷雾效果最佳 ,杀虫效果达 90 %以上。应用该复合剂大面积防治 2 0 hm2 ,效果达 80 %以上。 相似文献
20.
E. R. Trueman 《Journal of Zoology》1971,165(4):453-469
Donax denticulatus burrows in a similar manner to other infaunal bivalves, but also reacts to stimulation by activity and so proved to be suitable material for experiments on the control of locomotion. Tactile responses of the foot initiate burrowing and pedal stretch receptors control the duration of each digging cycle. Prevention of adduction of the valves, removal of ligament or cardinal hinge teeth, had little effect on burrowing and it is suggested that part of the digging cycle is programmed within the nervous system without peripheral feedback. Experiments on migratory behaviour are discussed and indicate that no intrinsic mechanism is required for its control beyond the adaptation of behavioural responses, common to most bivalves, to different physical conditions. 相似文献