SOLAR INFLUENCES ON CLIMATE Gray, L. J.; Beer, J.; Geller, M. ...
Reviews of geophysics (1985),
December 2010, Letnik:
48, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Understanding the influence of solar variability on the Earth's climate requires knowledge of solar variability, solar‐terrestrial interactions, and the mechanisms determining the response of the ...Earth's climate system. We provide a summary of our current understanding in each of these three areas. Observations and mechanisms for the Sun's variability are described, including solar irradiance variations on both decadal and centennial time scales and their relation to galactic cosmic rays. Corresponding observations of variations of the Earth's climate on associated time scales are described, including variations in ozone, temperatures, winds, clouds, precipitation, and regional modes of variability such as the monsoons and the North Atlantic Oscillation. A discussion of the available solar and climate proxies is provided. Mechanisms proposed to explain these climate observations are described, including the effects of variations in solar irradiance and of charged particles. Finally, the contributions of solar variations to recent observations of global climate change are discussed.
Background
Desmoid‐type fibromatosis is a locally aggressive soft tissue tumour with a biological behaviour that varies between relatively indolent and progressive growth. Although there is a trend ...towards conservative treatment, surgery remains the standard treatment for extra‐abdominal desmoid tumours.
Methods
Databases of three hospitals were searched to identify patients who had been treated for desmoid‐type fibromatosis between November 1989 and May 2011. The risk of local recurrence was evaluated and predictive factors were assessed in patients who underwent surgical resection as initial treatment for a primary tumour.
Results
A total of 132 patients had surgical treatment for a primary tumour. A complete resection (R0) was achieved in 87 patients (65·9 per cent). In addition to surgery, 54 patients received radiotherapy. During a median follow‐up of 38 months, 18 local recurrences were detected. The estimated 5‐year cumulative risk of local recurrence was 17·6 per cent. Univariable Cox regression analysis demonstrated that the risk of local recurrence increased for extremity lesions compared with desmoids on the trunk (odds ratio 6·69, 95 per cent confidence interval 1·42 to 31·54). No significant influence of age, resection margins or adjuvant radiotherapy on the risk for local recurrence was observed.
Conclusion
Following surgical treatment of a primary extra‐abdominal desmoid tumour, the 5‐year risk of local recurrence is modest and not influenced by microscopically clear resection margins or adjuvant radiotherapy.
Conservative treatment advised
Palynological studies including records of non-pollen palynomorphs (NPP) are uncommon in the Neotropics, in spite of their demonstrated usefulness in other regions. Modern analog studies to improve ...palaeoecological interpretations of NPP are even more scarce. Here, we report the NPP assemblages recorded in modern surface samples from an altitudinal transect of the Venezuelan Andes, ranging from about 2300 and 4600
m. We compared the assemblages with the results of previous pollen analyses of the same samples. The variables considered to explain NPP patterns along the transect are altitude and the local habitat of the sampling site (“sample type”). A total of 65 NPP taxa – classified into algal and zoological remains, and fungal spores – have been found. Unidentified taxa (23) have been named with a code, depicted and described for further reference. Fungal spores are well represented along the whole transect, whereas algal and zoological remains are absent or very scarce in the lower and the uppermost ranges. The altitudinal zonation of fungal spores matches with that of pollen and the corresponding vegetation belts, suggesting a close relationship. The known environmental requirements of some of the fungi identified allowed inferences on particular ecological features, in agreement with previous palynological interpretations. Both elevation and sample type are needed to explain the observed differences in the assemblages of the three groups, the elevation being more decissive for fungal spores and the local habitat of the sampling site for algal and zoological remains. The sample type effect is minimised when the NPP studied are considered altogether, thus increasing their usefulness as palaeoecological proxies. This study reinforces the utility of modern analog surveys of NPP with palaeoecological purposes and encourages further research, particularly in poorly known areas, as for example tropical regions.
Pollen and non-pollen palynomorphs (NPP) from the Early Neolithic settlement of La Draga have provided new palaeoenvironmental data concerning the establishment of the first farming societies in NE ...Iberian Peninsula. The analysis of samples from the archaeological profiles allowed the comprehension of several processes involved in the formation of this archaeological site and the reconstruction of environmental conditions in the different phases of occupation, in addition to obtaining new data about the ecological significance of NPP in archaeological levels. New NPP have been described, illustrated, and discussed.
The first farming societies settled at La Draga in a humid and densely forested area, with the predominance of deciduous trees (deciduous Quercus and Corylus) and Pinus and Abies in the surrounding mountains. Following their establishment at the site, abrupt changes in vegetation are recorded, in terms of deforestation of oak and riparian forests. Sedimentation dynamics involved in the formation of the archaeological site influenced the composition of the NPP spectra, reflected in the contraposition between waterlogged and subaerial layers, but especially, between organic peaty layers formed at local level and sediments transported by erosive processes in the layers belonging to the second phase of occupation.
•Pollen and NPP analysis evidence human impact in the Neolithic site of La Draga.•Carbonicolous/lignicolous fungi spores were documented in collapsed wooden structures.•Integration of pollen, NPP and LOI shows evidence of soil erosion episodes.•Coprophilous fungi spores indicate local evidence of animals within the settlement.
This paper focuses on high-resolution analysis of pollen and sedimentology and botanical macro-remains analysis in a core from Lake Banyoles (Girona, Spain). The core sequence comprises a high ...resolution mid-Holocene (ca. 8.9–3.35calkaBP) vegetation succession, and sedimentological, geochemical and geomorphological proxies are related to both climatic and anthropogenic causes. Deforestation processes affected natural vegetation development in the Early Neolithic (7.25–5.55calkaBP) and Late Neolithic (5.17–3.71calkaBP), in the context of broadleaf deciduous forest resilience against cooling and drying oscillations. Changes in sedimentation dynamics and in lake water level caused the emergence of dry land on the lake margin where riparian forest was established from 5.55calkaBP onwards. The data show that in the context of an increasing aridification process, Neolithic land-use played an important role in vegetation history and environmental evolution.
•Human-environment relationships are studied around Lake Banyoles (NE Spain).•Broadleaf deciduous forests were resilient against cooling and drying oscillations.•Riparian forest was established in emerged dry land due to changes in sedimentation.•Anthropic deforestation affected vegetation and lake sedimentation during Neolithic.
Background
Symptoms of anxiety and depression affect the daily life of people with multiple sclerosis (MS). This study examined work difficulties and their relationship with anxiety, depression and ...coping style in people with MS.
Methods
219 employed people with MS (median age = 43 years, 79% female) completed questionnaires on anxiety, depression, coping style, demographics and work difficulties, and underwent a neurological examination. Two regression analyses were performed with work difficulties as the dependent variable and either anxiety or depression as continuous independent variables. Coping style, age, gender, educational level, MS-related disability and disease duration were added as additional predictors, as well as interaction terms between coping style and either symptoms of depression or anxiety.
Results
A significant model was found (F(10,205) = 13.14, p < 0.001, R2 = 0.39) in which anxiety, emotion- and avoidance-oriented coping and MS-related disability were positively related to work difficulties. The analysis of depression resulted in a significant model (F(10,205) = 14.98, p < 0.001, R2 = 0.42) in which depression, emotion- and avoidance-oriented coping and MS-related disability were positively related to work difficulties. None of the interaction effects were significant.
Conclusions
Work difficulties were positively related to anxiety, depression, emotion- and avoidance-oriented coping and MS-related disability in workers with MS.
ABSTRACT
Three hundred forty‐one radiocarbon dates from the Groningen radiocarbon database are compiled in this study. They show for the first time that organic sediment samples from the eastern ...Netherlands and mammal bones from Doggerland reflect shifts in the presence and the density of vegetation (food for herbivores) and mammal biomass during the last ice age (Weichselian Stage, ~119–14.7 ka cal bp). Comparison with oxygen isotope curves of Greenland ice cores and geomorphological data shows that cold climate, in particular during the younger part of the Weichselian Middle Pleniglacial and during the Late Pleniglacial, and related scarcity or even absence of vegetation, were limiting factors for the carrying capacity of the landscape and thus for the population density of large herbivores during the period covered by 14C dating (last ca. 55 000 years). A ‘fossil gap’ during the Late Pleniglacial lasted ca. 13 000 years from ca. 28 to 15 ka cal
bp. Previous research from the nearby Eifel region in Germany shows that environmental conditions were less extreme (‘refugium conditions’) than in the Netherlands, taking into account the continuous presence of spores of coprophilous fungi in the Eifel, indicating uninterrupted food supply for herbivores.
Abstract
Background
Seizures can be part of the clinical presentation of central nervous system (CNS) infections. We describe patients suspected of a neurological infection who present with a seizure ...and study diagnostic accuracy of clinical and laboratory features predictive of CNS infection in this population.
Methods
We analyzed all consecutive patients presenting with a seizure from two prospective Dutch cohort studies, in which patients were included who underwent cerebrospinal fluid (CSF) examination because of the suspicion of a CNS infection.
Results
Of 900 episodes of suspected CNS infection, 124 (14%) presented with a seizure. The median age in these 124 episodes was 60 years (IQR 45–71) and 53% of patients was female. CSF examination showed a leukocyte count ≥ 5/mm
3
in 41% of episodes. A CNS infection was diagnosed in 27 of 124 episodes (22%), a CNS inflammatory disorder in 8 (6%) episodes, a systemic infection in 10 (8%), other neurological disease in 77 (62%) and in 2 (2%) episodes another systemic disease was diagnosed. Diagnostic accuracy of clinical and laboratory characteristics for the diagnosis of CNS infection in this population was low. CSF leukocyte count was the best predictor for CNS infection in patients with suspected CNS infection presenting with a seizure (area under the curve 0.94, 95% CI 0.88 – 1.00).
Conclusions
Clinical and laboratory features fail to distinguish CNS infections from other causes of seizures in patients with a suspected CNS infection. CSF leukocyte count is the best predictor for the diagnosis of CNS infection in this population.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Here we developed a composite pollen-based record of altitudinal vegetation changes from Lake Fúquene (5° N) in Colombia at 2540 m elevation. We quantitatively calibrated Arboreal Pollen percentages ...(AP%) into mean annual temperature (MAT) changes with an unprecedented ~60-year resolution over the past 284 000 years. An age model for the AP% record was constructed using frequency analysis in the depth domain and tuning of the distinct obliquity-related variations to the latest marine oxygen isotope stacked record. The reconstructed MAT record largely concurs with the ~100 and 41-kyr (obliquity) paced glacial cycles and is superimposed by extreme changes of up to 7 to 10° Celsius within a few hundred years at the major glacial terminations and during marine isotope stage 3, suggesting an unprecedented North Atlantic – equatorial link. Using intermediate complexity transient climate modelling experiments, we demonstrate that ice volume and greenhouse gasses are the major forcing agents causing the orbital-related MAT changes, while direct precession-induced insolation changes had no significant impact on the high mountain vegetation during the last two glacial cycles.
Questions: What are the long-term effects of climate change on the plant species composition and carbon sequestration in peat bogs? Methods: We developed a bog ecosystem model that includes ...vegetation, carbon, nitrogen and water dynamics. Two groups of vascular plant species and three groups of Sphagnum species compete with each other for light and nitrogen. The model was tested by comparing the outcome with long-term historic vegetation changes in peat cores from Denmark and England. A climate scenario was used to analyse the future effects of atmospheric CO2, temperature and precipitation. Results: The main changes in the species composition since 1766 were simulated by the model. Simulations for a future warmer, and slightly wetter, climate with doubling CO2 concentration suggest that little will change in species composition, due to the contrasting effects of increasing temperatures (favouring vascular plants) and CO2 (favouring Sphagnum). Further analysis of the effects of temperature showed that simulated carbon sequestration is negatively related to vascular plant expansion. Model results show that increasing temperatures may still increase carbon accumulation at cool, low N deposition sites, but decrease carbon accumulation at high N deposition sites. Conclusions: Our results show that the effects of temperature, precipitation, N-deposition and atmospheric CO2 are not straightforward, but interactions between these components of global change exist. These interactions are the result of changes in vegetation composition. When analysing long-term effects of global change, vegetation changes should be taken into account and predictions should not be based on temperature increase alone.
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