535 research outputs found
Evidence from multivariate morphometric study of the quercus pubescens complex in southeast Italy
The name Quercus pubescens s.l. encompasses a complex of deciduous oak taxa with mainly southeastEuropean
distribution and a large ecological niche. As the easternmost region of Italy, Apulia is
rather isolated from a geographical and physiographical viewpoint and counts the highest number
of oak species (10). In the taxonomic and phytosociological literature, the occurrence of several
species belonging to the Quercus pubescens collective group is reported for this region. In order to
verify if different sets of morphological characters are associated with different taxa, 24 populations
of Quercus pubescens s.l. located in different ecological-geographical areas of Apulia were sampled.
A total of 367 trees, 4254 leaves and 1120 fruits were collected and morphologically analysed.
Overall, 25 morphological characters of oak leaves and fruits were statistically treated using both
univariate and multivariate analysis. Nested ANOVA showed that leaves collected from a single tree
exhibited a degree of morphological variability higher than that observed when comparing leaves
coming from different trees of the same population and from different trees of different populations
as well. Almost all the morphological characters analysed exhibited a continuous trend of variation
so that none of them can be used as a character to discriminate between populations. Only leaf
and fruit “size” and fruit petiole length emerged as slightly discriminating characters. Our results
suggest that it is unlikely that more than one species belonging to the Quercus pubescens complex
occurs in the Apulia region. Comparison between the Apulian populations and a genetically
pure Q. pubescens population coming from a different area (the Molise region) strengthened the
assumption as to the existence of a single species that can provisionally be classified under the name
of Q. pubescens s.
Morphology, geometric morphometrics, and taxonomy in relict deciduous oaks woods in northern Italy
Abstract: The Euganean Hills are a well-known refugee site for thermophilous woody flora in northern Italy. Among the species recorded here, there is Quercus dalechampii. The Euganean Hills are the only northern Italy site where the occurrence of this oak species is considered. The aim of this paper was to verify the presence of Q. dalechampii in the study area and to select possible diagnostic morphological traits that are usable to distinguish it from Q. petraea and Q. pubescens. Forest stands dominated by Q. petraea, Q. pubescens, and the presumed Q. dalechampii were sampled using the phytosociological approach to highlight their ecological features. Leaf and fruit material from 104 oak individuals was analysed from a macro-morphological and micro-morphological point of view. Leaf shape was also analysed using the geometric morphometric approach. All multivariate analysis procedures applied on the matrices of leaf and fruit traits highlighted two main clusters of morphological diversity. One was restricted to Q. pubescens individuals, and the other one was a mix of Q. petraea and presumed Q. dalechampii individuals. According to the twig and leaf trichome traits, all presumed Q. dalechampii individuals were classified as belonging to the Q. petraea collective group. Morphological differences between Q. petraea and presumed Q. dalechampii were considered not significant. In conclusion, the occurrence of a third oak species, in addition to Q. petraea and Q. pubescens, was not confirmed for the study area by the results of this paper. Graphic abstract: [Figure not available: see fulltext.]
Kernel density classification and boosting: an L2 sub analysis
Kernel density estimation is a commonly used approach to classification. However, most of the theoretical results for kernel methods apply to estimation per se and not necessarily to classification. In this paper we show that when estimating the difference between two densities, the optimal smoothing parameters are increasing functions of the sample size of the complementary group, and we provide a small simluation study which examines the relative performance of kernel density methods when the final goal is classification. A relative newcomer to the classification portfolio is “boosting”, and this paper proposes an algorithm for boosting kernel density classifiers. We note that boosting is closely linked to a previously proposed method of bias reduction in kernel density estimation and indicate how it will enjoy similar properties for classification. We show that boosting kernel classifiers reduces the bias whilst only slightly increasing the variance, with an overall reduction in error. Numerical examples and simulations are used to illustrate the findings, and we also suggest further areas of research
Sarcopenia and vitamin d deficiency in patients with crohn’s disease: Pathological conditions that should be linked together
Sarcopenia is a prevalent condition in patients with Crohn’s disease (CD), representing an independent predictor factor for the development of major postoperative complications. Thus, a proper assessment of the muscle strength, by using different validated tools, should be deemed an important step of the clinical management of these patients. Patients with CD are frequently malnourished, presenting a high prevalence of different macro-and micro-nutrient deficiencies, including that of vitamin D. The available published studies indicate that vitamin D is involved in the regulation of proliferation, differentiation, and regeneration of muscle cells. The relationship between vitamin D deficiency and sarcopenia has been extensively studied in other populations, with interesting evidence in regards to a potential role of vitamin D supplementation as a means to prevent and treat sarcopenia. The aim of this review was to find studies that linked together these pathological conditions
Temperature effect on the sensitivity of the copepod Eucyclops serrulatus (Crustacea, Copepoda, Cyclopoida) to agricultural pollutants in the hyporheic zone
Abstract
The sensitivity of freshwater invertebrates to agricultural pollutants is supposed to increase with rising temperature due to global warming. The aim of this study was to measure the effect of temperature on the lethal toxicity of ammonia-N, the herbicide Imazamox and the mixture of the two chemicals, in the adults and the juveniles of a population of the copepod Eucyclops serrulatus. This is a widely distributed species found in surface waters, in transitional habitats between surface water and groundwater, and in genuine groundwater environments. We tested the sensitivity by short-term bioassays (96 h) at 15°C and 18°C, respectively. Our results highlighted the following: (1) increasing temperature affected the sensitivity of the adults to ammonia-N and of the juveniles to the mixture, all of which were more sensitive to its detrimental effects at 18°C; (2) the juvenile stages were more sensitive than the adults to all toxicants, and (3) for all combinations of chemicals and temperatures, the effects were synergistic and approximately one order of magnitude greater than those expected according to a concentration addition model when comparing the LC50 for each chemical in the mixture with the LC50s of chemicals individually assayed. Overall, in a context of global change, ammonia-N and mixtures of agricultural pollutants may affect the survival rate of species that spend a part or the whole life-cycle in the hyporheic habitat, with detrimental effects to biodiversity and ecosystem services provided by the hyporheic biota
Solitary fibrous tumour of the pleura: surgical treatment
OBJECTIVE: Solitary fibrous tumours (SFT) of the pleura are rare tumours originated from the mesenchimal tissue underlying the mesothelial layer of the pleura. This tumours present unpredictable clinical course probably related to their histological and morphological characteristics. METHODS: Twenty-one patients affected by SFT of the pleura were referred to us for surgical resection from September 1984 to April 2000. They were 15 males and six females with median age of 51 (range 15--73) years. Nine patients (43%) were symptomatic and predominant clinical symptoms or signs were dyspnoea (19%), coughing (14.3%), chest pain (28.5%), finger clubbing (14.3%) and hypoglycaemia (14.3%). Hypoglycaemia was related to a pathological incretion of insulin-like growth factor 2 by the tumour. Chest radiograph and computed tomography of the chest revealed intra-thoracic homogeneous sharply delineated round or lobulated mass sometimes associated with ipsilateral pleural effusion (19%) or causing pulmonary atelectasis with opacification of the complete hemithorax (19%). Surgical excision required 14 posterolateral thoracotomies, six anterior thoracotomies and one video-assisted thoracoscopy. Thirteen tumours arose from visceral pleura and wedge resection was performed, seven tumours arose from parietal pleura and extrapleural resection was carried out without any chest-wall resection, one tumour growth within the upper left lobe and required lobectomy. Tumours weighted from 22 to 1942 g and measured from 22x12x8 to 330x280x190 mm. At cut section seven cases (34%) revealed focal necrosis and hemorrhagic zones and on light microscopy six cases (28.5%) were characterized by high mitotic count: characteristics related with uncertain clinical behaviour. Immuno-histochemical reactions were in all cases positive for CD34. RESULTS: In all our patients resections were complete. Paraneoplastic syndromes like hypoglycaemia and clubbing receded after surgery. No intraoperative or perioperative medical or surgical complications occurred. Median chest-drain duration timed 3 (range 2--5) days and median hospital stay was 5 (range 4--7) days. Perioperative mortality rate was 0%. Median follow-up was 68 (range 2--189) months: during this period patients were submitted to chest X-ray with 6-months interval to evaluate possible local recurrence. Only one patient experienced tumour recurrence after 124 months follow-up: the tumour was suspected after observation of finger clubbing. The tumour was detected and excised by redo-thoracotomy. CONCLUSIONS: Surgical resection of benign solitary fibrous tumours is usually curative, but local recurrences can occur years after seemingly adequate surgical treatment. Malignant solitary fibrous tumours generally have a poor prognosis. Clinical follow-up and radiological follow-up are indicated for both benign and malignant solitary fibrous tumours
Co-delivering of Docetaxel and Curcumin using polymeric nanoconstructs for the treatment of Neuroblastoma
Thrombosis of the left anterior descending artery due to compression from giant pseudoaneurysm late after a bentall operation.
BACKGROUND: A postoperative pseudoaneurysm may develop and gradually expand in the mediastinal space even late following Bentall operation for aortic root replacement, particularly in patients with dissection of the aorta.
METHODS: A very large (148 mm) pseudoaneurysm originating of the right coronary ostium suture line was observed in a patient admitted with unstable angina 6 years after Bentall procedure for type A aortic dissection. Angiograms showed reduced flow in the right coronary and thrombotic subocclusion of the left anterior descending (LAD) coronary artery due to extrinsic compression from the expanding mediastinal mass.
RESULTS: Reoperation was performed during femoro-femoral cardiopulmonary bypass and brief period of circulatory arrest to clamp the tubular graft. After closure of the detected right coronary ostium in the tubular graft double bypass, grafting to the right coronary and LAD arteries was required. Postoperative course was uneventful.
CONCLUSIONS: Close long-term follow-up after a Bentall procedure is required to minimize the risk of developing a large pseudoaneurysmal mass, in particular, after dissection of the aorta
Novel aromatic ring-hydroxylating dioxygenase genes from coastal marine sediments of Patagonia
<p>Abstract</p> <p>Background</p> <p>Polycyclic aromatic hydrocarbons (PAHs), widespread pollutants in the marine environment, can produce adverse effects in marine organisms and can be transferred to humans through seafood. Our knowledge of PAH-degrading bacterial populations in the marine environment is still very limited, and mainly originates from studies of cultured bacteria. In this work, genes coding catabolic enzymes from PAH-biodegradation pathways were characterized in coastal sediments of Patagonia with different levels of PAH contamination.</p> <p>Results</p> <p>Genes encoding for the catalytic alpha subunit of aromatic ring-hydroxylating dioxygenases (ARHDs) were amplified from intertidal sediment samples using two different primer sets. Products were cloned and screened by restriction fragment length polymorphism analysis. Clones representing each restriction pattern were selected in each library for sequencing. A total of 500 clones were screened in 9 gene libraries, and 193 clones were sequenced. Libraries contained one to five different ARHD gene types, and this number was correlated with the number of PAHs found in the samples above the quantification limit (<it>r </it>= 0.834, <it>p </it>< 0.05). Overall, eight different ARHD gene types were detected in the sediments. In five of them, their deduced amino acid sequences formed deeply rooted branches with previously described ARHD peptide sequences, exhibiting less than 70% identity to them. They contain consensus sequences of the Rieske type [2Fe-2S] cluster binding site, suggesting that these gene fragments encode for ARHDs. On the other hand, three gene types were closely related to previously described ARHDs: archetypical <it>nahAc</it>-like genes, <it>phnAc</it>-like genes as identified in <it>Alcaligenes faecalis </it>AFK2, and <it>phnA1</it>-like genes from marine PAH-degraders from the genus <it>Cycloclasticus</it>.</p> <p>Conclusion</p> <p>These results show the presence of hitherto unidentified ARHD genes in this sub-Antarctic marine environment exposed to anthropogenic contamination. This information can be used to study the geographical distribution and ecological significance of bacterial populations carrying these genes, and to design molecular assays to monitor the progress and effectiveness of remediation technologies.</p
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