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91.
Abstract: Isolated material of 13 graptolite species from the Aeronian (middle Llandovery) Lituigraptus convolutus Biozone is described. A considerable amount of late astogenetic peridermal thickening is revealed in Normalograptus scalaris and Rivagraptus bellulus . As a result, in the former, thecal morphology is modified from climacograptid to pseudoglyptograptid; in both species, the virgella becomes robust. In Metaclimacograptus minimus and Me. sp., it is shown that the dorsal metathecal wall forms the genicular hood, whereas in N. nikolayevi , the infragenicular wall of the succeeding theca forms the distal thecal apertural margin. Pribylograptus argutus exhibits typical pribylograptid thecae along the length of the available rhabdosome fragments. Characters differentiating Campograptus lobiferus from C. harpago include the greater dorso-ventral width and more rapid increase in dorso-ventral width of the former and the greater recurving of distal thecae and presence of thecal spines/processes on all thecae of the latter. Lituigraptus convolutus has rastritiform thecae proximally; thecal apertures throughout the rhabdosome are crescentic and laterally expanded. 相似文献
92.
Amount, composition, and rate of turnover of soil organic carbon (SOC) in mountainous cold regions is largely unknown, making predictions of future responses of this carbon (C) to changing environmental conditions uncertain. We hypothesized increasing amounts and declining turnover times of soil organic matter (SOM) under permanent grassland with increasing elevation and decreasing temperature. Samples from an irrigated transect in the Swiss Alps (880 to 2200 m elevation, mean annual temperatures +8.9 to +0.9 °C) were analyzed. Soil C stocks ranged from 49 to 96 t C ha−1 (0–20 cm) and were not related to elevation, though the highest site stored least C. Particulate organic carbon (POC) increased significantly with elevation and accounted for > 80% of the total soil C at 2200 m (0–5 cm). Mean residence times (MRTs) of POC computed by means of radiocarbon dating were in the order of years to decades and were positively related to elevation in the topsoil. At higher elevations, the estimated total C flux through the soil profile mainly depended on this fraction. MRT of mineral-associated matter ranged from decades to centuries and was not systematically related to elevation, but positively related to the soil mineral surface area and it increased with soil depth. Turnover rates from simulations with the soil C model RothC exceeded those from 14 C measurements by a factor of 1.7–3.3 which suggests that C dynamics at these sites is overestimated by the model. Size of model pools and amount of C in soil fractions were only weakly correlated, thereby challenging previously postulated hypotheses concerning the correspondence of pools and fractions for grasslands at higher elevations. 相似文献
93.
Abstract: The objective of this study was to analyse how stand age and precipitation influence abundance and diversity of epiphytic macrolichens in southern beech Nothofagus forests, estimated by lichen litter sampling. Five sites of Nothofagus dombeyi (Mirbel) Oersted were selected in Nahuel Huapi National Park, Argentina. At each site, lichen fragments from the forest floor were collected at 12.5 m2 plots in pairs of young and mature N. dombeyi forest. Additionally, two sites with multi‐aged subalpine Nothofagus pumilio (Poepp. et Endl.) Krasser forest were investigated in a similar manner. Average litterfall biomass per stand varied from less than 1 kg ha?1 in a young low‐precipitation stand to a maximum of 20 kg ha?1 in a mature high‐precipitation stand. In places with higher precipitation, litterfall biomass in N. dombeyi forest was considerably higher in old stands as compared with young ones. In places with less than 2000 mm of precipitation, differences in biomass were less pronounced. Old humid stands contained about twice as many taxa in the litter as old low‐precipitation stands and young stands in general. Mature stands in low‐precipitation sites only contained 17% of the litter biomass as compared with mature stands in high‐precipitation sites. Epiphytic lichen composition changed from predominating fruticose lichens (Usnea spp. and Protousnea spp.) in low‐precipitation stands to Pseudocyphellaria spp., Nephroma spp. and other foliose lichens, in the high‐precipitation stands. There were no clear differences in the proportion of fruticose and foliose lichens between young and old stands. Fruticose lichens dominated litter biomass in both N. pumilio sites. 相似文献
94.
Background: Men with breast carcinoma have a poor prognosis, especially in the younger age group (30–40 years of age), because most breast enlargements in young men are dismissed as gynecomastia, resulting in an unnecessary delay in treatment.Objective: We describe the case of a young male patient with invasive ductal breast carcinoma.Case summary: In November 2005, a 30-year-old Afro-Caribbean man presented at St. Clair Medical Centre in Port of Spain, Trinidad, with a painless lump in the right breast. Diagnostic findings revealed that the patient had stage II invasive ductal carcinoma, for which he underwent a mastectomy with total axillary clearance.Conclusion: Surgeons investigating unilateral breast swellings in young males should not dismiss them simply as gynecomastia, and should be wary of cancer. 相似文献
95.
Background
The health benefits of breastfeeding are well documented in public health and medical literature worldwide. Despite this, global rates of breastfeeding steadily decline during the first couple of months postpartum. Although immigrant women have higher initiation rates and a longer duration of breastfeeding overall, breastfeeding practices are compromised because of a myriad of socioeconomic and cultural factors, including the acculturation process. The objective of this study was to show how acculturation and cultural identity influenced breastfeeding practices among Indian immigrants in Melbourne, Australia.Methods
Twelve case studies were employed to gather narratives of women’s lived experiences. Ethnographic field research methods were used to collect data, including participant observation, semi-structured interviews, case studies, and life histories. This provided in-depth information from women on various aspects of the immigrant experience of motherhood, including infant care and feeding. Participants were opportunistically recruited from Indian obstetricians and gynaecologists. Women identifying as ethnic Indian and in their third trimester of pregnancy were recruited. Interviews were conducted in women’s homes in metropolitan Melbourne over a 12 month period between 2004 and 2005. Data were coded and analysed thematically.Results
All women identified as ethnic Indian and initiated breastfeeding in accordance with their cultural identity. Social support and cultural connectivity impacted positively on duration of breastfeeding. However, acculturation (adopting Australian cultural values and gender norms, including returning to paid employment) negatively influenced breastfeeding duration. In addition, the high reliance of recent immigrants on the advice of healthcare professionals who gave inconsistent advice negatively affected exclusive breastfeeding.Conclusions
For ethnic Indian immigrant women breastfeeding practice is closely linked to acculturation and identity construction, both personal and communal. The lack of social and cultural networks for recent immigrants prevents their involvement in the cultural systems that traditionally support breastfeeding. With this in mind, healthcare professionals should deliver services in a culturally appropriate and sensitive manner where women feel supported as well as empowered.96.
ALEXANDER GALLÉ SILKE LAUTNER JAUME FLEXAS MIQUEL RIBAS‐CARBO DAVID HANSON JOHN ROESGEN JÖRG FROMM 《Plant, cell & environment》2013,36(3):542-552
In recent years, the effect of heat‐induced electrical signalling on plant photosynthetic activity has been demonstrated for many plant species. However, the underlying triggers of the resulting transient inhibition of photosynthesis still remain unknown. To further investigate on this phenomenon, we focused in our present study on soybean (Glycine max L.) on the direct effect of signal transmission in the leaf mesophyll on conductance for CO2 diffusion in the mesophyll (gm) and detected a drastic decline in gm following the electrical signal, whereas the photosynthetic electron transport rate (ETR) was only marginally affected. In accordance with the drop in net photosynthesis (AN), energy dispersive X‐ray analysis (EDXA) revealed a shift of K, Mg, O and P on leaf chloroplasts. Control experiments under elevated CO2 conditions proved the transient reduction of AN, ETR, the chloroplast CO2 concentration (Cc) and gm to be independent of the external CO2 regime, whereas the effect of the electrical signal on stomatal conductance for CO2 (gs) turned out much less distinctive. We therefore conclude that the effect of electrical signalling on photosynthesis in soybean is triggered by its immediate effects on gm. 相似文献
97.
Arun Kumar Bilal A. Mir Deepmala Sehgal Tanvir H. Dar Sushma Koul Maharaj K. Kaul Soom N. Raina Ghulam N. Qazi 《Plant Systematics and Evolution》2011,291(3-4):141-151
Realizing the inconsistencies that exist in the extent and nature of differentiation in the Withania somnifera genetic resources in India, the 21 cultivated and wild accessions, and the two hybrids (cultivated?×?wild accessions and vice versa) were investigated for morphological, cytogenetical, chemical profiling, and crossability features. Their nuclear and chloroplast genomes were also assayed at the nucleotide sequence level, and by use of DNA markers. Chloroplast DNA diversity and somatic chromosome number (2n?=?48) were not helpful in identifying the differences. Other approaches, on the other hand, especially restriction endonuclease digests, types and sequence length composition of ITS 1 and ITS 2 of nuclear ribosomal DNA, AFLP fingerprinting, and crossability barriers unambiguously provided startling discrete differences between the cultivated and wild accessions, indicating a clear division of W. somnifera into two distinct lineages. These data, therefore, are indicative of the fact that because of the unique characteristics of its nuclear genome, and strong crossability barriers vis-à-vis wild accessions of W. somnifera, the cultivated accessions should be relegated to the rank of the separate species, W. ashwagandha. 相似文献
98.
KLARA BJÖRG JAKOBSDÓTTIR þÓRA DÖGG JÖRUNDSDÓTTIR SIGURLAUG SKÍRNISDÓTTIR SIGRÍÐUR HJÖRLEIFSDÓTTIR GUÐMUNDUR Ó. HREGGVIÐSSON ANNA KRISTÍN DANÍELSDÓTTIR CHRISTOPHE PAMPOULIE 《Molecular ecology resources》2006,6(2):337-339
Nine out of 22 microsatellite primers tested were successfully amplified on three samples of cod Gadus morhua L. (two contemporary and one archived otolith samples). All loci were polymorphic (5–23 alleles/locus). The average observed heterozygosity across loci and samples was 0.625, ranging from 0.294 to 0.895 at each locus. All loci were under Hardy–Weinberg equilibrium, except PGmo56 that showed significant excess of heterozygotes in all studied samples. The isolated loci were suitable for degraded DNA and therefore useful for conducting a long‐term temporal study with DNA obtained from archived otoliths of cod. 相似文献
99.
100.
Vikesh Nandlal Dhayendre Moodley Anneke Grobler Jayanthilall Bagratee Niren R. Maharaj Paul Richardson 《PloS one》2014,9(9)