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Mean Density (mean + density)
Selected AbstractsThe buoyancy of the integument of Atlantic bottlenose dolphins (Tursiops truncatus): Effects of growth, reproduction, and nutritional stateMARINE MAMMAL SCIENCE, Issue 3 2010Robin C. Dunkin Abstract In Atlantic bottlenose dolphins (Tursiops truncatus) the thickness and lipid content of blubber (the integument's specialized hypodermis) varies across ontogeny and with reproductive and nutritional state. Because the integument comprises up to 25% of total body mass in this species, ontogenetic changes in its lipid content may influence whole body buoyancy. The density and volume of the integument were measured and its buoyancy calculated across an ontogenetic series of dolphins and in pregnant and emaciated adults (total n= 45). Regional differences between the metabolically labile trunk integument and the structural tailstock integument were also investigated. Mean densities of both trunk and tailstock integument were similar across life history categories (trunk = 1,040.7 ± 14.1 kg/m3; tailstock = 1,077.1 ± 21.2 kg/m3) and were statistically similar to the density of seawater (1,026 kg/m3). The mean buoyant force of integument from the trunk (,1.01 ± 1.74 N) and tailstock (,0.30 ± 0.21 N) did not vary significantly across ontogeny. In contrast, pregnancy and emaciation did influence the integument's buoyancy, which ranged between 9 N and ,45 N in these categories. Although neutral during growth, the integument's contribution to whole body buoyancy can be influenced by an individual's reproductive and nutritional status. [source] Spatial and temporal variation in the fruiting phenology of palms in isolated standsPLANT SPECIES BIOLOGY, Issue 1 2008GREGORY H. ADLER Abstract Fruiting phenologies of two species of palms, Astrocaryum standleyanum L. H. Bailey and Attalea butyracea (Mutis ex L. f) Wess. Boer, isolated on eight small (1.7,3.7 ha) forested islands in the Panama Canal were studied over a 33-month period. Individual palms were permanently marked with numbered aluminum tags and censused each month for the presence of ripe fruits. The dataset consisted of 1106 monthly observations of palms with ripe fruits among the 634 marked individuals. Mean densities of palms of reproductive size varied widely among islands, ranging from a low of 0.3 ha,1 for A. standleyanum and 3.5 ha,1 for A. butyracea to a high of 44.9 ha,1 for A. standleyanum and 33.7 ha,1 for A. butyracea. Both species showed distinctly seasonal periods of fruiting activity that varied in duration between the two species and among years. The timing of fruiting by A. standleyanum was highly synchronous among islands, whereas inter-island synchrony in A. butyracea was less pronounced. The percentages of marked individuals that fruited varied widely among islands and years. Results indicated that these palms responded to both spatially and temporally variable conditions that promoted fruit production. We suggest that pollinator abundances are a crucial factor affecting reproductive output. Conditions that favor successful reproduction and seed dispersal, such as pollinator activity and the attraction of dispersal agents, may be the ultimate factors that have influenced the reproductive phenologies of these two species of palms. [source] Parkinsonian signs and substantia nigra neuron density in decendents elders without PD,ANNALS OF NEUROLOGY, Issue 4 2004G. Webster Ross MD Substantia nigra (SN) neurons were counted on single, transverse caudal midbrain sections from 217 male participants in the Honolulu-Asia Aging Study, aged 74,97 years at death. Quadrants areas within the SN were determined with a planimeter and neuronal density was expressed as neurons/mm2 for 10 Parkinson's disease (PD) cases, 29 incidental Lewy body cases, and 178 controls with neither condition. Mean densities in all quadrants were significantly lower in the PD group compared with the other groups (p = 0.006). This relationship was strongest in the ventrolateral quadrant. In a subgroup of 50 controls who were examined with the Unified Parkinson's Disease Rating Scale an average of 2.1 years prior to death, there was an association of stooped posture (p = 0.009), postural instability (p = 0.013), body bradykinesia (p = 0.048), and gait disturbance (p = 0.05) with neuron density in the dorsolateral quadrant; and impaired speech (p = 0.014), abnormal facial expression (p = 0.022), and difficulty rising from a chair (p = 0.032) with neuron density in the dorsomedial quadrant. There was a significant association of increasing number of signs present with decreasing neuron density in both quadrants (p = 0.001 for trend). Low SN neuron density may be the basis for parkinsonian signs in the elderly without PD. Ann Neurol 2004 [source] Abundance, Population Structure and Production of Scrobicularia plana and Abra tenuis (Bivalvia: Scrobicularidae) in a Mediterranean Brackish Lagoon, Lake Ichkeul, TunisiaINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 4 2005Caterina Casagranda Abstract Abundance, growth and production of the deposit-feeding bivalves were studied in the Ichkeul wetland, northern Tunisia, from July 1993 , April 1994. Scrobicularia plana(Da Costa, 1778) occurred at annual mean densities (biomasses) of 299 ± 65 to 400 ± 100 individuals/m2 (22.54 ± 3.00 to 34.27 ± 3.96 g ash-free dry mass (AFDM)/m2) depending on the study area. The annual mean density of Abra tenuis(Montagu, 1803) amounted to 640 ± 74 individuals/m2 during the whole study period, in contrast the biomass rose from 2.87 g AFDM/m2 in July to 10.29 g AFDM/m2 in April. Both species were largely dominated by age class I. Although not very successful, recruitment presented a two-period pattern: the main period at the beginning of spring, and a secondary one in late summer/autumn. S. plana rarely exceeded 40 mm and lived for only 2 years, while most individuals of A. tenuis lived for only 15,18 months growing to a length of 12 mm. The annual bivalve deposit-feeder production for the whole lagoon system (90 km2) was 8.24 g AFDM/m2 (5.26 g C/m2, 0.65 g N/m2). The annual P/ ratio was about 0.4 and therefore in the same order of magnitude as estimates from other brackish coastal waters. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Mast cells and IgE-containing cells in gastric mucosa of Helicobacter pylori infected and non-infected patients with chronic urticariaJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 1 2004M Liutu ABSTRACT Background, Several studies have indicated that antibiotic therapy aimed at eradication of Helicobacter pylori has effects on symptoms of chronic urticaria (CU) patients. However, the possible connections and pathomechanism by which H. pylori might be linked to CU have remained largely unknown. The IgE-mediated pathway might be a possible link between H. pylori infection and CU. We therefore clarified the role of H. pylori as an inducer of IgE response. Materials and methods, Gastroscopy was performed and mucosal biopsy specimens were taken to evaluate the histology, as well as the presence of H. pylori bacteria, mast cells and IgE-containing cells in the antral mucosa, in 21 CU patients. Controls (n = 48) included 19 patients with lichen planus, nine patients with atopic dermatitis and 20 patients with no skin or allergic disease. Results, The mean densities of IgE-containing cells were significantly higher in H. pylori- infected patients and in patients with skin disease compared to non- H. pylori -infected patients with no skin or allergic disease. No significant difference was found in the number of IgE-containing cells between H. pylori -infected and non-infected patients with CU. There was no significant difference in the mean densities of mast cells in the different patient groups. Conclusions, Our findings suggest that H. pylori gastritis leads to increased IgE production. However, we could not show a significant difference in IgE staining between H. pylori -infected and non-infected patients with CU. [source] The origin of the initial mass function and its dependence on the mean Jeans mass in molecular cloudsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2005Matthew R. Bate ABSTRACT We investigate the dependence of stellar properties on the mean thermal Jeans mass in molecular clouds. We compare the results from the two largest hydrodynamical simulations of star formation to resolve the fragmentation process down to the opacity limit, the first of which was reported by Bate, Bonnell & Bromm. The initial conditions of the two calculations are identical except for the radii of the clouds, which are chosen so that the mean densities and mean thermal Jeans masses of the clouds differ by factors of 9 and 3, respectively. We find that the denser cloud, with the lower mean thermal Jeans mass, produces a higher proportion of brown dwarfs and has a lower characteristic (median) mass of the stars and brown dwarfs. This dependence of the initial mass function (IMF) on the density of the cloud may explain the observation that the Taurus star-forming region appears to be deficient in brown dwarfs when compared with the Orion Trapezium cluster. The new calculation also produces wide binaries (separations >20 au), one of which is a wide binary brown dwarf system. Based on the hydrodynamical calculations, we develop a simple accretion/ejection model for the origin of the IMF. In the model, all stars and brown dwarfs begin with the same mass (set by the opacity limit for fragmentation) and grow in mass until their accretion is terminated stochastically by their ejection from the cloud through dynamically interactions. The model predicts that the main variation of the IMF in different star-forming environments should be in the location of the peak (due to variations in the mean thermal Jeans mass of the cloud) and in the substellar regime. However, the slope of the IMF at high masses may depend on the dispersion in the accretion rates of protostars. [source] Histological and Clinical Findings in Different Surgical Strategies for Focal Axillary HyperhidrosisDERMATOLOGIC SURGERY, Issue 8 2008FALK G. BECHARA MD INTRODUCTION Although a variety of different surgical strategies for focal axillary hyperhidrosis (FAH) have proven effective, little is known of intraoperative and postoperative histologies of different surgical methods. OBJECTIVE The objective was to use pre-, intra-, and postoperative histologic findings to evaluate different surgical procedures for FAH in establishing a possible correlation between the interventions and clinical outcome. MATERIAL AND METHODS A total of 40 patients underwent surgery with 15 undergoing liposuction-curettage (LC), 14 radical skin excision (RSE) with Y-plasty closure, and 11 a skin-sparing technique (SST). Before surgery, density and ratio of eccrine and apocrine sweat glands were evaluated with routine histology. Further biopsies were taken directly after surgery in the RSE and SST groups and 1 year postoperatively in all patients. Additionally, gravimetry was performed, side effects were documented, and patients were asked to evaluate the aesthetic outcome of the surgical method by using an analogue scale. RESULTS Preoperatively, the mean density of eccrine glands was 11.1/cm2 compared to 16.9/cm2 apocrine glands (apocrine/eccrine ratio, 1.6). Biopsy specimen directly after surgery showed remaining sweat glands in 7/15 (46.7%) LC patients and in 4/11 (36.4%) of the SST patients. One year after surgery, sweat gland density was significantly reduced in the LC (79.1%) and the SST (74.9%) groups. In the RSE group, only scar formation was present. Gravimetry showed significantly reduced sweat rates 12 months after surgery in all groups (LC, 66.4%; SST, 62.9%; RSE, 65.3% [p<.05]). Most frequent side effects were hematoma (LC, n=3; SST, n=2; RSE, n=3), subcutaneous fibrotic bridles (LC, n=8; SST, n=3; RSE, n=0), skin erosion (LC, n=3; SST, n=4; RSE, n=0), focal hair loss (LC, n=9; SST, n=11; RSE, n=14), and paresthesia (LC, n=4; SST, n=3; RSE, n=5). CONCLUSION Histologic distribution and density of sweat glands were comparable to previous studies. All three surgical procedures evaluated are effective in the treatment of FAH. RSE and SST techniques are associated with a higher risk of side effects and cause more extensive scarring. However, one LC patient (n=1; 6.7%) did not respond to treatment. [source] Reduction of intramembranous particles in the periacrosomal plasma membrane of boar spermatozoa during in vitro capacitation: A statistical studyDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 3 2000Fumie Suzuki-Toyota Membrane remodeling in the periacrosomal plasma membrane (PAPM) of boar spermatozoa during incubation in capacitation medium was examined by the freeze-fracture technique. In the preservation medium (PM) group, the major small (about 8 nm) intramembranous particles (IMP) and the minor large (> 10 nm) IMP were distributed evenly in the PAPM. The IMP-free area increased during capacitation. To correct the IMP-free area, arithmetically redistributed (ARD)-IMP density was used for statistical analysis. In the PM group, the mean density ± SD of large IMP was 379 ± 64 and 266 ± 58/,m2, and that of small IMP was 1450 ± 155 and 672 ± 252/,m2 in protoplasmic (P) and external (E) faces, respectively. During capacitation, the significant (P < 0.01) reduction of large IMP density was encountered only in the E face of a few incubation groups, while that of the small IMP density occurred in the P face by 2 h. Consequently, reduction of the total IMP density of both faces was not significant in the large IMP, but it was significant (P < 0.01) in the small IMP. One-fifth of the total small IMP density reduced by 2 h. Filipin-sterol complexes (FSC) were numerous in the PAPM, and FSC-free areas also increased during capacitation. The mechanism of IMP-free area formation and the behavior of the small IMP in the PAPM during capacitation were discussed in relation to membrane stability. [source] Eradication of the invasive Pseudorasbora parva results in increased growth and production of native fishesECOLOGY OF FRESHWATER FISH, Issue 1 2009J. R. Britton Abstract,,, The topmouth gudgeon, Pseudorasbora parva, has been described as Europe's most invasive fish. To control their UK invasion, some lentic populations at risk of causing fluvial dispersal have been eradicated. The first of these operations was from a lake in north-west UK in March 2005 using rotenone application; prior to eradication, their mean density was estimated as 6.1 m,2 whereas since eradication, no P. parva have been recorded. Prior to rotenone application, the majority of native fishes were removed, held off-site and reintroduced following degradation of rotenone to safe levels. In the three growth seasons since their reintroduction and P. parva eradication, the abundance, somatic growth rate and production of roach Rutilus rutilus and common bream Abramis brama have increased significantly; production is now driven by a lower number of comparatively larger, faster growing individuals. These data suggest that the eradication of this P. parva population has been highly beneficial for the growth, recruitment and production of these native species. [source] Direct examination of soil for sporangia of Synchytrium endobioticum using chloroform, calcium chloride and zinc sulphate as extraction reagentsEPPO BULLETIN, Issue 1 2005G. C. M. Van Leeuwen Fields infested with Synchytrium endobioticum can be descheduled when the soil is found free from sporangia of S. endobioticum. For direct examination, EPPO Standard PM 3/59 describes a soil extraction technique based on the use of a sieve shaker with six sieves. We compared recovery of sporangia between this (modified) method and an extraction method employed by the Dutch Plant Protection Service (PPS method). Recovery was determined using an inoculum dilution series: 125, 25, 5, 1, 0.2 or 0.04 sporangia per g soil. Extraction reagents used were chloroform and calcium chloride in the method described by EPPO, calcium chloride and zinc sulphate in the PPS method. At 125 sporangia per g soil, the mean density determined for the modified EPPO method was 228 sporangia per g soil when chloroform was used. Using calcium chloride, recovery percentage was higher for the modified EPPO method than for the PPS method (286, 136%, n.s. P < 0.05). The advantage of the modified EPPO method was the larger soil volume to be processed; its disadvantages were use of complex equipment and noxious reagents (chloroform). Both extraction methods showed high variation in recovery between samples, making accurate estimation of sporangial densities in soil awkward. [source] Disease-specific Helicobacter pylori Virulence Factors: The Unfulfilled PromiseHELICOBACTER, Issue S1 2000David Y. Graham A number of putative virulence factors for Helicobacter pylori have been identified including cagA, vacA and iceA. The criteria for a true virulence factor includes meeting the tests of biologically plausibility with the associations being both experimentally and epidemiologically consistent. Although disease-specific associations have been hypothesized/claimed, there are now sufficient data to conclusively state that none of these putative virulence factors have disease specificity. CagA has been claimed to be associated with increased mucosal IL-8 and inflammation, increased density of H. pylori in the antrum, duodenal ulcer (DU), gastric cancer, and protection against Barrett's cancer. Only the increase in IL-8/inflammation is direct and substantiated. Different H. pylori strains with functional cag pathogenicity islands do not vary in virulance as it has been shown that mucosal IL-8 levels are proportional to the number of cagA +H. pylori independent of the disease from which the H. pylori were obtained. It is now known that the density of either cagA + and cagA,H. pylori in the antrum of patients with H. pylori gastritis is the same. In contrast, the mean density of H. pylori in the antrum in DU is greater than in the antrum of patients with H. pylori gastritis. Of interest, the density of H. pylori is higher in the corpus of patients with H. pylori gastritis than those with DU, suggesting that acid secretion plays a critical role in these phenomena. The presence of a functional cag pathogenicity island increases inflammation and it is likely that any factor that results in an increase in inflammation also increases the risk of a symptomatic outcome. Nevertheless, the presence of a functional cag pathogenicity island has no predictive value for the presence, or the future development of a clinically significant outcome. The hypothesis that iceA has disease specificity has not been confirmed and there is currently no known biological or epidemiological evidence for a role for iceA as a virulence factor in H. pylori -related disease. The claim that vacA genotyping might prove clinically useful, e.g. to predict presentation such as duodenal ulcer, has been proven wrong. Analysis of the worldwide data show that vacA genotype s1 is actually a surrogate for the cag pathogenicity island. There is now evidence to suggest that virulence is a host-dependent factor. The pattern of gastritis has withstood the test of time for its relation to different H. pylori -related diseases (e.g. antral predominant gastritis with duodenal ulcer disease). The primary factors responsible for the different patterns of gastritis in response to an H. pylori infection are environmental (e.g. diet), with the H. pylori strain playing a lesser role. Future studies should work to eliminate potential bias before claiming disease associations. Controls must exclude regional or geographic associations related to the common strain circulation and not to the outcome. The authors must also control for both the presence of the factor and for the disease association. The study should be sufficiently large and employ different diseases and ethnic groups for the results to be robust. The findings in the initial sample (data derived hypothesis) should be tested in a new group (hypothesis testing), preferably from another area, before making claims. Finally, it is important to ask whether the results are actually a surrogate for another marker (e.g. vacA s1 for cagA) masquerading for a new finding. Only the cag pathogenicity island has passed the tests of biological plausibility (increased inflammation) and experimental and epidemiological consistency. [source] Snow density variations: consequences for ground-penetrating radarHYDROLOGICAL PROCESSES, Issue 7 2006A. Lundberg Abstract Reliable hydrological forecasts of snowmelt runoff are of major importance for many areas. Ground-penetrating radar (GPR) measurements are used to assess snowpack water equivalent for planning of hydropower production in northern Sweden. The travel time of the radar pulse through the snow cover is recorded and converted to snow water equivalent (SWE) using a constant snowpack mean density from the drainage basin studied. In this paper we improve the method to estimate SWE by introducing a depth-dependent snowpack density. We used 6 years measurements of peak snow depth and snowpack mean density at 11 locations in the Swedish mountains. The original method systematically overestimates the SWE at shallow depths (+25% for 0·5 m) and underestimates the SWE at large depths (,35% for 2·0 m). A large improvement was obtained by introducing a depth,density relation based on average conditions for several years, whereas refining this by using separate relations for individual years yielded a smaller improvement. The SWE estimates were substantially improved for thick snow covers, reducing the average error from 162 ± 23 mm to 53 ± 10 mm for depth range 1·2,2·0 m. Consequently, the introduction of a depth-dependent snow density yields substantial improvements of the accuracy in SWE values calculated from GPR data. Copyright © 2005 John Wiley & Sons, Ltd. [source] No experimental evidence for local competition in the nestling phase as a driving force for density-dependent avian clutch sizeJOURNAL OF ANIMAL ECOLOGY, Issue 4 2009Marion Nicolaus Summary 1In birds, local competition for food between pairs during the nestling phase may affect nestling growth and survival. A decrease in clutch size with an increase in breeding density could be an adaptive response to this competition. To investigate whether breeding density causally affected the clutch size of great tits (Parus major), we manipulated breeding density in three out of eight study plots by increasing nest-box densities. We expected clutch size in these plots to be reduced compared to that in control plots. 2We analysed both the effects of variation in annual mean density (between-year comparisons) and experimental density (within-year comparison between plots) on clutch size variation, the occurrence of second broods and nestling growth. We examined within-female variation in clutch size to determine whether individual responses explain the variation over years. 3Over the 11 years, population breeding density increased (from 0·33 to 0·50 pairs ha,1) while clutch size and the occurrence of second broods decreased (respectively from 10·0 to 8·5 eggs and from 0·39 to 0·05), consistent with a negative density-dependent effect for the whole population. Nestling growth showed a declining but nonsignificant trend over years. 4The decline in population clutch size over years was primarily explained by changes occurring within individuals rather than selective disappearance of individuals laying large clutches. 5Within years, breeding density differed significantly between manipulated plots (0·16 pairs ha,1 vs. 0·77 pairs ha,1) but clutch size, occurrence of second broods and nestling growth were not affected by the experimental treatment, resulting in a discrepancy between the effects of experimental and annual variation in density on reproduction. 6We discuss two hypotheses that could explain this discrepancy: (i) the decline in breeding performance over time was not due to density, but resulted from other, unknown factors. (ii) Density did cause the decline in breeding performance, but this was not due to local competition in the nestling phase. Instead, we suggest that competition acting in a different phase (e.g. before egg laying or after fledgling) was responsible for the density effect on clutch size among years. [source] Impact of cocoa farming on vegetation in an agricultural landscape in GhanaAFRICAN JOURNAL OF ECOLOGY, Issue 2 2010Alex Asase Abstract Cocoa production occurs almost wholly within areas identified as biodiversity hotspots in West Africa and it has been noted as a major contributor to deforestation at the forest-agriculture interface. This study investigated the impact of cocoa farming on vegetation in relation to three land-use types of increasing cocoa production intensity from remnant native forest through shaded to unshaded cocoa farmlands in Ghana. The study used transects and forty-two 25 m × 25 m vegetation plots. The overall noncocoa plant species richness decreased significantly (95% CI) from the remnant native forest through shaded to the unshaded cocoa farmlands. Significant differences (P , 0.05) were also found in the mean density and basal area of noncocoa plants per hectare with the remnant native forest recording the highest values and the unshaded cocoa farmlands the lowest. The relative density of about 44.7% out of the 41 most abundant plant species declined in cocoa farmlands. The results of this study showed that cocoa farming could result in a drastic forest plant species loss with subsequent recruitment of nonforest species, forest plant species population decline as well as changes in the structural characteristics of the vegetation. This impact increases with increasing cocoa production intensity. Résumé En Afrique de l'Ouest, le cacao est produit presque entièrement dans des zones identifiées comme des hauts-lieux de la biodiversité et l'on a noté qu'il contribue toujours de façon importante à la déforestation à l'interface entre forêts et terres agricoles. Cette étude a analysé l'impact de la culture de cacao sur la végétation pour une utilisation des terres de trois types caractérisés par des intensités de production de cacao croissantes, allant des restes de forêt native à des exploitations ombragées et non ombragées de cacao, au Ghana. Cette étude a utilisé des transects et 42 parcelles de végétation de 25 m × 25 m. La richesse globale en espèces végétales - hors cacao - diminuait significativement (IC 95%) en passant des restes de forêt native aux exploitations de cacao ombragées et ensuite à celles qui sont exposées au soleil. On a aussi trouvé des différences significatives (P , 0,05) de la densité moyenne et de la surface basale par hectare des plants hors cacao, la forêt native restante donnant les valeurs les plus hautes et les exploitations exposées de cacao, les plus basses. La densité relative de près de 44,7% des 41 espèces végétales les plus abondantes diminuait dans les exploitations de cacao. Les résultats de cette étude ont montré que la production de cacao pouvait entraîner une perte drastique des espèces végétales forestières suivie d'un recrutement d'espèces non forestières, un déclin des populations d'espèces végétales forestières et des changements des caractéristiques structurelles de la végétation. Cette impacts augmentaient avec l'intensification de la production de cacao. [source] Spatio-temporal dynamics and local hotspots of initial recruitment in vertebrate-dispersed treesJOURNAL OF ECOLOGY, Issue 4 2008Arndt Hampe Summary 1Initial recruitment, or the arrival and establishment of propagules, is the most variable period in the life cycle of long-lived plants, and the extent to which studies of initial recruitment can be used to predict patterns of regeneration remains unresolved. 2We investigated the spatio-temporal dynamics of initial recruitment across five populations of three fleshy-fruited tree species from contrasting environments. Among-year variation in total seedfall, dispersed seedfall and seedling distributions was examined using analytical approaches that are new to the field and that explicitly incorporate space and allow comparisons among studies. 3Observed patterns ranged from remarkable across-year consistency in seedfall distributions and strong spatial coupling between seed and seedling stages to extensive variation and almost complete independence of stages. Spatial distributions of frugivore-mediated seedfall were markedly more consistent than those of the total seedfall in two of the five populations. Seedling distributions were generally more variable among years than seedfall distributions. 4All populations showed a positive relationship between the long-term mean density of recruitment at a given microsite and its year-to-year consistency. This relationship remained valid when considering only microsites away from fruiting tree canopies (i.e. those receiving actually dispersed seeds), and was virtually independent of their distance to the nearest fruiting tree. 5Synthesis. Our results point to the existence of some general rules behind the idiosyncratic recruitment dynamics of perennial plant populations, which should help with projecting spatial patterns of plant establishment in long-lived species. In particular, those microsites that combine a great intensity with a high year-to-year consistency of recruitment should represent potential regeneration ,hotspots' whose identification and characterization can be of great use for the management and conservation of naturally regenerating tree populations. [source] DNA ploidy in oral lichen planus, determined by image cytometryJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 3 2010Elaini Sickert Hosni J Oral Pathol Med (2010) 39: 206,211 Background:, The objective of this study was to use image cytometry to determine the degree and frequency of DNA ploidy in biopsies of reticular and atrophic-erosive oral lichen planus and to analyze 14 karyometric measurements of the nuclei of epithelial cells from each specimen. Methods:, A total of 40 slides were analyzed, each of them representing one biopsy of one oral lichen planus (OLP) lesion from each one of the 40 patients (cases) studied. Specimens were embedded in paraffin and comprised 20 slides of reticular oral lichen planus (group R) and 20 slides of atrophic-erosive oral lichen planus (group AE). Results:, Group R, the reticular lichen samples, had 18 diploid cases and two aneuploid cases. Group AE, the atrophic-erosive lichen samples, had 10 diploid cases, one tetraploid case, and nine aneuploid cases. Of the 14 karyometric measurements of the nuclei of OLP epithelial cells analyzed, the group R mean values for mean density and minimum density were significantly greater than the group AE mean values, and mean roundness in group AE was significantly greater than in group R (t- test: P < 0.05). Conclusions:, The most common degree of DNA ploidy in OLP lesions was diploidy. Comparing the two groups (chi-square test of association P = 0.021) demonstrated that diploidy was associated with the reticular clinical form of OLP, while aneuploidy was associated with the atrophic-erosive clinical form of oral lichen planus. [source] Mass Production of Juveniles of the Fat Snook Centropomus parallelus in BrazilJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2002Luis Alvarez-Lajonchegre A pilot-scale trial to rear fat snook Centropomus parallelus through larval, weaning and nursery phases was conducted in Florianópolis, Brazil. Eggs (96% fertilization) from captive broodstock, induced to spawn using 50 ,g/kg LHRHa were stocked in two 4,000-L cylindrical fiberglass tanks at a mean density of 19.2 eggs/L. Nannochloropsis oculata was stocked with the eggs and maintained at a mean density of 0.5,1.0 ± 106 cells/mL up to 31 dph (31 dph). Hatching averaged 90%. Larvae were fed rotifers Brachionus rotundiformis enriched with an oil emulsion from 3 dph to 36 dph (30,40 rotifers/mL) and Artermia meta-nauplii enriched with Selco from 22 dph to 60 dph (mean 2.9 meta-nauplii/mL). Weaning began at 45 dph with an artificial dry diet NRG (50% protein), supplied together with concentrated and enriched Artemia meta-nauplii. No critical period of mortality was observed during larval rearing. During the 43 days of weaning and nursery, less than 1% mortality was recorded. Food conversion rate during nursery was 1.17, with a change in the coefficient of variation of mean total length of 1.3%. Specific total growth rate in weight was 13.0 %/d and mean growth in total length and total weight were 0.65 mm/d and 24.0 mg/d over the whole rearing trial respectively. Mean total length and total weight of juveniles were 57.6 ± 0.1 mm and 2.11 ± 0.12 g, respectively, and the length-weight relationship was W = 8.29931 ± 10,5 TL3.049607 (r= 0.9986). on 88 dph when the trial was terminated. The condition factor on 88 dph was 1.104. On 88 dph a total of 35,000 juveniles were harvested, overall survival was 25.5% with mean final density of 4.4 fishn and biomass of 6.9 kg/m3. The present trial demonstrated the feasibility of mass production of fat snook. Possible improvements necessary for commercial cultivation of fat snook C. parallelus are discussed. [source] The development of sustainable earthworm populations at Calvert landfill site, UKLAND DEGRADATION AND DEVELOPMENT, Issue 1 2004K. R. Butt Abstract Earthworms Allolobophora chlorotica and Aporrectodea longa were inoculated into Calvert landfill site in spring 1992, in conjunction with the planting of two tree species Alnus glutinosa and Acer pseudoplatanus. Monitoring has taken place over a period of 11 years. Sampling in 2003 revealed that earthworm distribution no longer equated to the inoculation treatments; the worms had spread extensively. The presence of A. glutinosa had a significant effect (p<0,01) on earthworm number (mean density 198,m,2) and biomass (34,g,m,2) compared to plots where A. pseudoplatanus had been planted and subsequently died (mean density 118,m,2; biomass 21,g,m,2). Results suggest that tree presence may be critical to earthworm community development. In 2002, the spread of A. chlorotica from the original points of inoculation had reached 60,m with the highest recorded population density at 108,m,2 with a mass of 18,6,g,m,2. A. longa was recorded at a distance of 132,m from the nearest point of inoculation with the highest recorded population density at 70,m,2 with a mass of 49,3,g,m,2, 10,m from the original inoculation grid. Other species recorded (and % of total) were Aporrectodea rosea (0,9) Lumbricus castaneus (7,4), Eiseniella tetraedra (21,5) and Lumbricus rubellus (4,5). The two inoculated species, A. chlorotica (40,4) and A. longa (25,3), accounted for two thirds of the earthworms found on site. The highest earthworm community density was 213,m,2 with a mass of 73,9,g,m,2 at 10,m from original point of inoculation. In 1999, treatments of surface organic matter (OM), in the form of composted green waste, and rotavation were applied to non-replicated plots of 50,m2 with the effects on earthworm distribution and abundance recorded in 2002. Addition of OM alone led to an increase in number and mass (331,m,2; 95,g,m,2) compared to the control (233,m,2; 51,g,m,2), while rotavation alone (111,m,2; 36,g,m,2) had a detrimental effect over the given time period. This long-term monitoring programme has demonstrated the development of sustainable earthworm communities on a landfill site. Natural nutrient accumulation and addition of OM on or into the soil-forming material appeared to assist this process. This work may help to inform post-capping treatment at similar landfill sites Copyright © 2004 John Wiley & Sons, Ltd. [source] Fish assemblages and rapid colonization after enlargement of an artificial reef off the Algarve coast (Southern Portugal)MARINE ECOLOGY, Issue 4 2008Francisco Leitão Abstract Artificial reefs (ARs) have been deployed in Algarve (Southern Portugal) coastal waters to contribute to the sustainability of local nearshore fisheries. Herein, we describe the colonization process of the recently deployed Faro/Ancão AR, and assess the time until the fish assemblage reaches stability and their seasonal patterns. In addition, we compare the results from the present study with those previously reported for an older AR. The fish assemblages were monitored monthly over a 2-year period by means of visual census. A rapid increase in fish colonization occurred within the first 4 months. After this initial period the assemblage structure showed high similarity (> 73%). The high rate of colonization of the AR was related to the maturity already achieved by the nearby 14-year-old AR and to the fish migration from the Ria Formosa lagoon, a nearby nursery habitat. The reef fish assemblage structure showed a seasonal pattern, mainly associated with recruitment episodes of occasional demersal species (Boops boops, Trachurus trachurus and Pagellus spp.) in spring and summer. A total of 66% of the species found in AR are of commercial and recreational importance. The overall mean density and biomass were 2.8 ind·m,3 and 207 g·m,3. The occasional demersal species accounted for 42% of the fish density. The most important species in terms of biomass belong to the Sparidae family along with Dicentrarchus labrax. The fish assemblage of the new ARs showed higher mean number of species, diversity, density and biomass values than those reported for the older AR. This result was associated with enlargement of the AR area and with the fishing exploitation of the isolated, small and patchy old AR. Moreover, the high biomass values recorded in the new ARs were mainly due to the increased density of D. labrax after AR enlargement. The results of the present study are used to define guidelines for suitable management strategies for the AR areas that are exploited by the local commercial and recreational fisheries. [source] The properties of galaxies in voidsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006Santiago G. Patiri ABSTRACT We present a comparison of the properties of galaxies in the most underdense regions of the Universe, where the galaxy number density is less than 10 per cent of the mean density, with galaxies from more typical regions. We have compiled a sample of galaxies in 46 large nearby voids that were identified using the Sloan Digital Sky Survey DR4, which provides the largest coverage of the sky. We study the u,r colour distribution, morphology, specific star formation rate (SFR) and radial number density profiles for a total of 495 galaxies fainter than Mr=,20.4 + 5 log h located inside the voids and compare these properties with a control sample of field galaxies. We show that there is an excess of blue galaxies inside the voids. However, inspecting the properties of blue and red galaxies separately, we find that galaxy properties such as colour distribution, bulge-to-total ratios and concentrations are remarkably similar between the void and overall sample. The void galaxies also show the same specific SFR at fixed colour as the control galaxies. We compare our results with the predictions of cosmological simulations of galaxy formation using the Millennium Run semi-analytic galaxy catalogue. We show that the properties of the simulated galaxies in large voids are in reasonably good agreement with those found in similar environments in the real Universe. To summarize, in spite of the fact that galaxies in voids live in the least dense large-scale environment, this environment makes very little impact on the properties of galaxies. [source] A smoothed particle hydrodynamics simulation of the collapse of the interstellar mediumMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2001Y. Golanski A smoothed particle hydrodynamic (SPH) code is used to model a collapsing region of the interstellar medium (ISM). A region of the ISM is seeded with coolant material ejected from a supernova. The resulting pressure imbalance between the cooling region and the surrounding ISM induces collapse. The collapse first forms dense low-temperature regions (protoclouds) each containing several tens of solar masses of material and in quasi-equilibrium with the surrounding ISM. Turbulence is generated within the collapsing regions as they form. Collisions between protoclouds leads to regions of further increased mass and density, the final outcome being a dense cold cloud with mean density 10,18 kg m,3, mean temperature about 20 K and total mass a few hundred solar masses. The final cloud is sufficiently turbulent for star formation to occur within it. A new form of boundary condition was used in the SPH simulation to solve the problem inherent in modelling a continuum. [source] Delta Scuti Network observations of XX Pyx: detection of 22 pulsation modes and of short-term amplitude and frequency variationsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2000G. Handler We report multisite observations devoted to the main-sequence , Scuti star XX Pyx, conducted as the 17th run of the Delta Scuti Network. Over 125 nights a total of 550 h of usable time-series photometric B - and V -filter data were acquired involving both photoelectric and CCD measurements at eight observatories spread around the world, which represents the most extensive single time-series for any pulsating star other than the Sun obtained so far. We describe our observations and reduction methods, and present the frequency analysis of our new data. First, we detect six new pulsation and five new combination frequencies in the star's light curves. We also discover evidence for amplitude and/or frequency variations of some of the modes during the observations. These can occur on time-scales as short as 20 d and show quite diverse behaviour. To take them into account in the frequency analysis, a so-called non-linear frequency analysis method was developed, allowing us to quantify the temporal variability of the modes and to compensate for it. Following that we continue the frequency search and we also incorporate published multisite observations. In this way, we reveal three more pulsation and two more combination frequencies. In the end, we report a total of 30 significant frequencies , 22 of which correspond to independent pulsation modes. This is the largest number of independent modes ever detected in the light curves of a , Scuti star. The frequencies of the modes show preferred separations as already suggested by previous work on this star; they are also arranged in clear patterns. These results lead to a refinement of the stellar mean density and to a new constraint on the rotation rate of XX Pyx (,rot=1.1±0.3 d,1). However, our attempts to identify the modes by pattern recognition failed. Moreover, mode identification from multicolour photometry failed as well because the high pulsation frequencies make this method unfavourable. The diverse behaviour of the amplitude and frequency variations of some of the modes leaves resonances as the only presently known possibility for their explanation. [source] Hypoxia-inducible factor 1, may be a marker for vasculitic neuropathyNEUROPATHOLOGY, Issue 6 2007Nobuyuki Oka Neuromuscular biopsy is still an essential method for diagnosing vasculitic neuropathy, although its diagnostic sensitivity is at most 60%. Our objective was to examine the expression of hypoxia-inducible factor 1, (HIF-1,) in peripheral nerves and to evaluate its usefulness in diagnosing vasculitic neuropathy, especially for discrimination from other axonal neuropathies. Forty-one patients with vasculitic neuropathy consisting of 20 definite, 14 probable and seven possible diagnoses, 15 patients with metabolic neuropathy, five with motor neuron disease and six with chronic inflammatory demyelinating polyneuropathy were included. Nerve biopsy specimens were immunohistochemically examined for HIF-1, and various cell markers. Distinct immunoreactivity (IR) was observed in nuclei of endoneurial cells in 54% (22/41) of vasculitic patients, while specimens from metabolic neuropathies showed less nuclear IR and the difference of mean density of HIF-1,-positive nuclei was significant. Two patients with possible vasculitis who showed HIF-1,-positive nuclei in endoneurium, were later confirmed to have vasculitis by skin biopsies. Most of the cells expressing HIF were demonstrated to be Schwann cells. There was a trend in the vasculitic patients with early phase nerve damage to display higher endoneurial HIF-1,-IR. HIF-1, may be an immunohistochemical marker for vasculitic neuropathy, especially when the observed section contains no vasculitic lesions. [source] Strength of asymmetric competition between predators in food webs ruled by fluctuating prey: the case of foxes in tundraOIKOS, Issue 1 2010John-André Henden In food webs heavily influenced by multi-annual population fluctuations of key herbivores, predator species may differ in their functional and numerical responses as well as their competitive ability. Focusing on red and arctic fox in tundra with cyclic populations of rodents as key prey, we develop a model to predict how population dynamics of a dominant and versatile predator (red fox) impacted long-term growth rate of a subdominant and less versatile predator (arctic fox). We compare three realistic scenarios of red fox performance: (1) a numerical response scenario where red fox acted as a resident rodent specialist exhibiting population cycles lagging one year after the rodent cycle, (2) an aggregative response scenario where red fox shifted between tundra and a nearby ecosystem (i.e. boreal forest) so as to track rodent peaks in tundra without delay, and (3) a constant subsidy scenario in which the red fox population was stabilized at the same mean density as in the other two scenarios. For all three scenarios it is assumed that the arctic fox responded numerically as a rodent specialist and that the mechanisms of competition is of a interference type for space, in which the arctic fox is excluded from the most resource rich patches in tundra. Arctic fox is impacted most by the constant subsidy scenario and least by the numerical response scenario. The differential effects of the scenarios stemmed from cyclic phase-dependent sensitivity to competition mediated by changes in temporal mean and variance of available prey to the subdominant predator. A general implication from our result is that external resource subsidies (prey or habitats), monopolized by the dominant competitor, can significantly reduce the likelihood for co-existence within the predator guild. In terms of conservation of vulnerable arctic fox populations this means that the likelihood of extinction increases with increasing amount of subsidies (e.g. carcasses of large herbivores or marine resources) in tundra and nearby forest areas, since it will act to both increase and stabilize populations of red fox. [source] Seedling Establishment and Survival on Restored Campsites in Subalpine ForestRESTORATION ECOLOGY, Issue 3 2007David N. Cole Abstract This study experimented with common restoration techniques (scarification, soil amendments, mulch, and seeding) on six closed wilderness campsites in subalpine forests in Oregon. Effectiveness in encouraging seedling establishment, growth, and survival was assessed every year for the first 7 years following treatment. Closure and restoration of the campsites increased the density of plants established from seed. Despite an original density of virtually zero, mean density of perennial plants was 55 plants/m2 7 years after closure. All the treatments, with the exception of the biodegradable mulch mat, increased plant density. Seven years after treatment, seeding had increased plant density 5-fold, whereas scarification and soil amendments (organic matter, compost, and soil inoculum) had each increased density 3-fold. The organic and compost amendments also had the positive benefit of increasing growth rates and shortening the time-to-reproductive maturity. Results suggest that restoration of the herbaceous cover on these campsites can occur rapidly using the techniques employed. All but one of the species we seeded established in substantial quantities and survived at densities exceeding their density in the naturally sparse herbaceous cover on these sites. Thirty-six perennial species volunteered on these sites. The remaining challenge is reestablishment of the shrub species that comprise much of the ground cover in these forests. These species seldom establish from seed. [source] The Mechanism of Hearing Loss in Paget's Disease of Bone,THE LARYNGOSCOPE, Issue 4 2004Edwin M. Monsell MD Abstract Objectives/Hypothesis The mechanism of hearing loss (HL) in Paget's disease of bone was investigated. The present study was a systematic, prospective, controlled set of clinical investigations to test the hypothesis that there is a general underlying mechanism of HL in Paget's disease of bone and to gain additional insights into the auditory and otologic dynamics of this disease. Specific questions were 1) whether the mechanism is cochlear or retrocochlear and 2) whether the bone mineral density of the cochlear capsule is related to hearing levels. Study Design Several double-blinded, cross-sectional, prospective, correlational studies were conducted in a population of elderly human subjects with skull involvement with Paget's disease versus a control population of elderly subjects free of Paget's disease. Demographic and clinical data were recorded. Longitudinal observations were made in subjects under treatment. Methods Subjects were recruited from a Paget's disease clinic. Pure-tone auditory thresholds, word recognition, and auditory brainstem responses (ABRs) were recorded. The dimensions of the internal auditory canals were measured using computed tomographic (CT) images and digital image analysis. The precision, accuracy, and temporal stability of methods to measure the bone mineral density of the cochlear capsule and an adjacent area of nonotic capsule bone were validated and applied. Correlations were sought between hearing levels and cochlear capsule bone mineral density. Results ABRs were recorded in 64 ears with radiographically confirmed Paget's disease involving the skull. Responses were absent in eight ears, all of which had elevated high pure-tone thresholds. ABRs were interpreted as normal in 56 ears; none were abnormal. The mid-length diameter and minimum diameter of the internal auditory canal of 68 temporal bones from subjects with Paget's disease were found to have no statistically significant relationship to hearing thresholds. The Pearson product-moment correlation coefficients (age- and sex-adjusted) in the group with Paget's disease involving the temporal bone were ,0.63 for left ears and ,0.73 for right ears for high-frequency air conduction pure-tone thresholds (mean of 1, 2, and 4 kHz) versus cochlear capsule density. Correlation coefficients (age- and sex-adjusted) between cochlear capsule density and air-bone gap (mean at 0.5 and 1 kHz) for the affected group were ,0.67 for left ears and ,0.63 for right ears. All correlations between hearing thresholds and cochlear capsule density in pagetic subjects were significant at P < .001. The regressions were consistent throughout the ranges of hearing level. There were no significant correlations between cochlear capsule mean density and hearing level in the volunteer subjects. Conclusions The evidence supports the existence of a general, underlying, cochlear mechanism of pagetic HL that is closely related to loss of bone mineral density in the cochlear capsule. This mechanism accounts well for both the high-frequency sensorineural HL and the air-bone gap. Early identification, radiographic diagnosis of temporal bone involvement, and vigorous treatment with third-generation bisphosponates are important to limit the development and progression of pagetic HL. [source] Seasonal dynamics, dispersion, sequential sampling plans and treatment thresholds for the citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), in a mature lemon block in coastal New South Wales, AustraliaAUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 3 2008Zhong Min Liu Abstract, Studies of citrus leafminer in a coastal orchard in NSW, Australia indicated that an increase in abundance to about one mine per flush was followed during the midseason flush by a rapid increase in population that was related to an increase in the percentage of leaves infested within flushes and the number of mines per leaf. The fits of frequency distributions and Iwao's patchiness regression indicated that populations were highly contagious initially, and as the exponent k of the negative binomial distribution increased with increasing population density, the distribution approached random. Concurrently, the coefficient of variation of mines per flush (which was strongly related to the proportion of un-infested flushes) decreased to about unity as the proportion of un-infested flushes reached zero and fell further as the number of mines per flush increased. Both numerative and binomial sequential sampling plans were developed using a decision threshold based on 1.2 mines per flush. The binomial sampling plan was based on a closely fitting model of the functional relationship between mean density and proportion of infested flushes. Functional relationships using the parameters determined from Iwao's patchiness regression and Taylor's power law were equally satisfactory, and one based on the negative binomial model also fitted well, but the Poisson model did not. The three best fitting models indicated that a decision threshold of 1.2 mines per flush was equivalent to 50% of flushes infested. From a practical point of view, the transition from 25% infestation of flushes through 50% is so rapid that it may be prudent to take action when the 25% level is reached; otherwise, the 50% may be passed before the crop is checked again. For valuable nursery stock should infestation be detected in spring, it may be advisable to apply prophylactic treatment as the midseason flush starts. [source] Accurate calculation of the density of proteinsACTA CRYSTALLOGRAPHICA SECTION D, Issue 7 2000Michael L. Quillin On the basis of theoretical calculations, Andersson & Hovmöller have recently suggested that the long-established value of 1.35,g,cm,3 for the mean density of proteins should be revised to 1.22,g,cm,3[Andersson & Hovmller (2000), Acta Cryst. D56, 789790]. To substantiate their assertion, these authors used the Voronoi algorithm to calculate the mean atomic volume for 30 representative protein structures. The Voronoi procedure requires that atoms of interest be bounded on all sides by other atoms. Volume calculations for surface atoms that are not surrounded or are only sparsely surrounded by other atoms either are not possible or may be unreliable. In an attempt to circumvent this problem, Andersson & Hovmöller rejected atoms with calculated volumes that were indeterminate or were greater than 50,Å3. In the present study, it is shown that this criterion is not sufficiently restrictive to ensure accurate volume determinations. When only strictly buried atoms are included in the volume calculations using the Voronoi algorithm, the mean density is found to be 1.47 ± 0.05,g,cm,3. In addition, an alternate procedure based on the Connolly algorithm that permits all protein atoms to be included in volume calculations gives 1.43 ± 0.03,g,cm,3 for the mean density of the same set of proteins. The latter two calculated values are mutually consistent and are in better agreement with the experimental value. [source] Decreased GABAA receptors and benzodiazepine binding sites in the anterior cingulate cortex in autismAUTISM RESEARCH, Issue 4 2009A. Oblak Abstract The anterior cingulate cortex (ACC; BA 24) via its extensive limbic and high order association cortical connectivity to prefrontal cortex is a key part of an important circuitry participating in executive function, affect, and socio-emotional behavior. Multiple lines of evidence, including genetic and imaging studies, suggest that the ACC and gamma-amino-butyric acid (GABA) system may be affected in autism. The benzodiazepine binding site on the GABAA receptor complex is an important target for pharmacotherapy and has important clinical implications. The present multiple-concentration ligand-binding study utilized 3H-muscimol and 3H-flunitrazepam to determine the number (Bmax), binding affinity (Kd), and distribution of GABAA receptors and benzodiazepine binding sites, respectively, in the ACC in adult autistic and control cases. Compared to controls, the autistic group had significant decreases in the mean density of GABAA receptors in the supragranular (46.8%) and infragranular (20.2%) layers of the ACC and in the density of benzodiazepine binding sites in the supragranular (28.9%) and infragranular (16.4%) lamina. In addition, a trend for a decrease in for the density of benzodiazepine sites was found in the infragranular layers (17.1%) in the autism group. These findings suggest that in the autistic group this downregulation of both benzodiazepine sites and GABAA receptors in the ACC may be the result of increased GABA innervation and/or release disturbing the delicate excitation/inhibition balance of principal neurons as well as their output to key limbic cortical targets. Such disturbances likely underlie the core alterations in socio-emotional behaviors in autism. [source] 2143: Corneal keratocyte population after laser subepithelial keratectomy (LASEK) with mitomycin C (MMC): 3 months vs 15 months comparisonACTA OPHTHALMOLOGICA, Issue 2010P CANADAS SUAREZ Purpose To study corneal keratocyte population after LASEK with mitomycin C (MMC) 15 months vs 3 months after surgery Methods Sixty eyes were included in this study, all of them treated with LASEK with intraoperative 0.02% MMC, divided into 2 groups. 32 eyes had LASEK performed 3 months before, versus 28 in the 15 months post-op group. Keratocyte density was examined by using confocal microscopy in the anterior, mid and posterior stroma in both groups, and the mean density was compared with a control group of healthy eyes Results Keratocyte density in the anterior stroma was 16993,75+ 8001,7 cells/mm3 and 18529,1 + 2917,7 cells/mm3(p=0,3) in the 3 months and in the 15 months groups respectively, in the mid stroma it was 30783,3+ 9300 cells/mm3 in the 3 months and 20754,7 + 3615,3 cells/mm3 in the 15 months groups (p= 0,0001) and 30286,75+ 8321 cells/mm3and 19994+ 3085,9 cells/mm3 (p= 0,0001) in the posterior stroma in the 3 months and in the 15 months groups respectively. The comparison between the average densities through the whole cornea showed statistically significant difference between the 3 months vs 15 months group and 3 months vs normals, but it was not statistically significant different between 15 months vs normals Conclusion The changes in the corneal keratocyte population after LASEK + MMC seen in the early post-op, seem to change towards the normal values 15 months after the procedure. [source] | |||||||||||||||||||||||||||||||