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Unaffected Areas (unaffected + area)
Selected AbstractsNative harvester ants threatened with widespread displacement exert localized effects on serpentine grassland plant community compositionOIKOS, Issue 2 2005Halton A. Peters Seed-harvesting ants can influence the abundance and distribution of plant species through both the selective harvesting of seeds and the construction of nutrient-rich nest mounds, but the relative contributions of these two mechanisms have not been addressed by previous studies. Furthermore, the impact of ant seed harvesting in California serpentine grasslands remains unresolved because of divergent results from several previous experiments. This study investigates the influence of harvester ants on serpentine grassland plant species composition by examining two potential signatures of seed harvesting ants on plant community composition: species composition on versus off ant nest mounds, and species abundance as a function of distance from nest mounds. Of the 28 plant species identified in this study, 22 exhibited spatial patterns consistent with effects of seed harvesting, nest construction, or both. Although most species showed significant gradients in abundance with distance from a nest, there were no clear relationships between plant species distributions and previously reported harvester ant seed foraging patterns. Harvester ant nest mounds supported plant communities that were distinct from the surrounding serpentine grassland, with notably higher densities of legumes and invasive annual grasses. Comparison of our results with those of previous studies indicates that the patterns we observed are generally consistent over time, but affect more species and a larger fraction of the grassland than previously reported. Unaffected areas of the grassland seem likely to serve as important refuges for some plant species. [source] Surgical treatment options for hidradenitis suppurativa and critical review of own experienceEXPERIMENTAL DERMATOLOGY, Issue 6 2006Wolfgang Christian Marsch HS (acne inversa) is a chronic, progressive, initially inflammatory, ultimately a fistulating and scarring disease affecting apocrine gland-bearing skin areas. Late phases afford a broad surgical removal of affected skin areas including subcutaneous fatty tissue, with secondary mesh grafting after a period of granulation tissue formation. Fifty-three patients have been treated surgically at our Dermatology Department. Long-term results are excellent concerning satisfaction of the patients and functional objectives. Local recurrences or development of new lesions in formerly unaffected areas were noticed only in some patients who did not stop smoking. Patient details were as follows: gender distribution: male (M) 20 (38%), female (F) 33 (62%), age: M 19,62 (average 40.7), F 15,56 (average 35.4), onset: M 16,57 (32.2), F 8,50 (25.5), duration: 3 months to 37 years (8.0), F 6 months to 37 years (9.9). Sites mainly affected: axillary and perigenital. Specific regions for men: perineum and rima ani, for women: inguinal, submammary and abdominal. Multiple anatomical regions involved: men 40%, women 91%. Familiarity 0.4%. Associated acne papulo-pustulosa or nodulo-cystica (=conglobata): 19%. Cigarette smokers: men 100%, women 67%. Excised material from each operation was carefully examined histologically. The results endorse the concept of ,acne inversa' by recognizing a perifollicular accumulation of lymphocytes simultaneously at different infrainfundibula of terminal hair follicles. However, a follicular hyperkeratosis seems secondary to this, follicular perforation, and a combination of sinus, abscess and scar formation are most obviously tertiary events. Therefore, HS seems to be an inflammatory, probably an immunological disease with an initially strictly dermal target, even followed by an intradermal horizontal propagation. Laser flux imaging could visualize the subclinical peripheral extension of the basically dermal perifollicular inflammation. Biologics may have a beneficial effect on these early or perpetuating inflammatory events; however, thus far surgery remains the first-line therapy in late phases of the disease. [source] Avifauna response to hurricanes: regional changes in community similarityGLOBAL CHANGE BIOLOGY, Issue 3 2010CHADWICK D. RITTENHOUSE Abstract Global climate models predict increases in the frequency and intensity of extreme climatic events such as hurricanes, which may abruptly alter ecological processes in forests and thus affect avian diversity. Developing appropriate conservation measures necessitates identifying patterns of avifauna response to hurricanes. We sought to answer two questions: (1) does avian diversity, measured as community similarity, abundance, and species richness, change in areas affected by hurricane compared with unaffected areas, and (2) what factors are associated with the change(s) in avian diversity? We used North American Breeding Bird Survey data, hurricane track information, and a time series of Landsat images in a repeated measures framework to answer these questions. Our results show a decrease in community similarity in the first posthurricane breeding season for all species as a group, and for species that nest in the midstory and canopy. We also found significant effects of hurricanes on abundance for species that breed in urban and woodland habitats, but not on the richness of any guild. In total, hurricanes produced regional changes in community similarity largely without significant loss of richness or overall avian abundance. We identified several potential mechanisms for these changes in avian diversity, including hurricane-induced changes in forest habitat and the use of refugia by birds displaced from hurricane-damaged forests. The prospect of increasing frequency and intensity of hurricanes is not likely to invoke a conservation crisis for birds provided we maintain sufficient forest habitat so that avifauna can respond to hurricanes by shifting to areas of suitable habitat. [source] Erythema dyschromicum perstans and hepatitis C virus infectionINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 5 2001George J. Kontochristopoulos MD A 48-year-old woman with a 10-month history of widespread, hyperpigmented, slightly pruritic macules, with a red border, involving the trunk and the proximal limbs (Fig. 1) was referred to our outpatient department. The oral mucosa, palms, soles, scalp, and nails were normal. Figure 1. Multiple hyperpigmented macules with an active border on the trunk Laboratory tests showed elevated liver enzymes [alanine aminotransferase (ALT), 68 IU/L (normal value, <,40 IU/L); aspartate aminotransferase (AST), 41 IU/L (normal value, <,40 IU/L)], the presence of antibodies to hepatitis C virus (anti-HCV) and HCV RNA (Amplicor Roche). In addition, cryoglobulinemia type III (IgM,,,, IgG,,,) was detected with a high cryocrit value, and there was detectable C-reactive protein, rheumatoid factor, and a low titer of antinuclear antibodies (1 : 80). A percutaneous liver biopsy showed changes compatible with mild chronic hepatitis (grade, 6; stage, 0). The possible source of infection was unknown, as the patient had no history of parenteral transmission (e.g. blood transfusions, intravenous illicit drug use). A skin biopsy specimen from the active border of a lesion showed hyperkeratosis, parakeratosis, and hydropic degeneration of the basal cell layer, with the formation of colloid bodies in the epidermis. A moderate perivascular lymphohistiocytic infiltrate with melanophages and free melanin granules was observed in the upper dermis (Fig. 2). Immunostaining of paraffin-embedded tissue sections with the TORDJT-22 IgG1 mouse monoclonal antibody to HCV (Biogenex, Son Ramon, USA), which is specific for the nonstructural region of HCV (NS3-NSH, C100 antigen) using the avidin,biotin,peroxidase complex (ABC) as well as the alkaline phosphatase antialkaline phosphatase (APAAP) methods, failed to detect HCV in the lesion of erythema dyschromicum perstans (EDP) (Nakopoulou L, Manolaki N, Lazaris A et al. Tissue immunodetection of C100 hepatitis C virus antigen in major thalassemic patients. Hepato-Gastroenterol 1999; 46: 2515,2520). Direct immunofluorescence showed IgG, IgM, IgA, and fibrinogen deposits on colloid bodies. EDP was diagnosed on the basis of these clinical and laboratory findings. Figure 2. Hydropic degeneration of the basal cell layer with colloid bodies in the epidermis. Moderate perivascular lymphohistiocytic infiltrate with melanophages and free melanin granules in the upper dermis (hematoxylin and eosin, ×,200) The patient was treated with interferon-,2b (Intron-A, Schering Plough Athens, Greece), 3 MU thrice weekly subcutaneously for 12 months, with additional topical steroid application. There was no response to this treatment with new lesions appearing in previously unaffected areas of the trunk and extremities. HCV RNA remained persistently positive. Thus, a modified regimen with interferon-,2b, 6 MU thrice weekly for 6 months, was tried. At the end of the treatment course, the eruption of EDP had greatly improved. Liver enzymes were normal (ALT, 22 IU/L; AST, 24 IU/L) and HCV RNA had become negative. Four months later, however, cutaneous lesions reappeared and hepatitis C relapsed. At this time point, combination therapy of interferon-,2b, 3 MU thrice weekly, with ribavirin, 1000 mg daily, was given. Six months later, liver enzymes were normal (ALT, 42 IU/L; AST, 39 IU/L), HCV RNA was negative, and the lesions of EDP had resolved. [source] LANDSCAPE-SCALE ANALYSIS AND MANAGEMENT OF CUMULATIVE IMPACTS TO RIPARIAN ECOSYSTEMS: PAST, PRESENT, AND FUTURE,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 6 2001Eric D. Stein ABSTRACT: Analyses of cumulative impacts to riparian systems is an important yet elusive goal. Previous analyses have focused on comparing the number of hectares impacted to the number of hectares restored, without addressing the loss of riparian function or the effect of the spatial distribution of impacts. This paper presents an analysis of the spatial distribution of development-related impacts to riparian ecosystems, that were authorized under Section 404 of the Clean Water Act. Impacts on habitat structure, contiguity, and landscape context were evaluated using functional indices scaled to regional reference sites. Impact sites were mapped using GIS and analyzed for spatial associations. Positive spatial autocorrelation (i.e. clustering of impact sites) resulted from the piecemeal approach to impact assessment, which failed to prevent cumulative impacts. Numerous small projects in close proximity have resulted in adverse impacts to entire stream reaches or have fragmented the aquatic resources to a point where overall functional capacity is impaired. Additionally, the ecological functions of unaffected areas have been diminished due to their proximity to degraded areas. A proactive approach to managing cumulative impacts is currently being used in Orange County, California as part of a Corps of Engineers sponsored Special Area Management Plan (SAMP). The SAMP process is evaluating the ecological conditions and physical processes of the study watersheds and attempting to plan future development in a manner that will guard against cumulative impacts. [source] | |||||||||||||