7,883 research outputs found
A Bayesian Model for Presence-Only Semicontinuous Data, With Application to Prediction of Abundance of Taxus Baccata in Two Italian Regions
Evaluation of the similarity between drought indices by correlation analysis and Cohen's Kappa test in a Mediterranean area
AbstractIn the literature, numerous papers report comparative analyses of drought indices. In these types of studies, the similarity between drought indices is usually evaluated using the Pearson correlation coefficient, r, calculated between corresponding severity time series. However, it is well known that the correlation does not describe the strength of agreement between two variables. Two drought indices can exhibit a high degree of correlation but can, at the same time, disagree substantially, for example, if one index is consistently higher than the other. From an operational point of view, two indices can be considered in agreement when they indicate the same severity category for a given period (e.g. moderate drought). In this work, we compared six meteorological drought indices based on both correlation analysis and Cohen's Kappa test. This test is typically used in medical or social sciences to obtain a quantitative assessment of the degree of agreement between different methods or analysts. The indices considered are five timescale-dependent indices, i.e. the Percent of Normal Index, the Deciles Index, the Percentile Index, the Rainfall Anomaly Index, and the Standardised Precipitation Index, computed at the 1-, 3-, and 6-month timescales, and the Effective Drought Index, a relatively new index, which has a self-defined timescale. The indices were calculated for 15 stations in the Abruzzo region (central Italy) during 1951–2018. We found that the strength of agreement depends on both the criteria of drought severity classification and the different indices' calculation method. The Cohen's Kappa test indicates a prevailing moderate or fair agreement among the indices considered, despite the generally very high correlation between the corresponding severity times series. The results demonstrate that the Cohen's Kappa test is more effective than the correlation analysis in discriminating the actual strength of agreement/disagreement between drought indices
Voltage evolution and electrochemical behaviour of Soil microbial fuel cells operated in different quality soils
The desire for a net-zero carbon future is a key driver for innovation in renewable energy. Amongst several emerging solutions, soil microbial fuel cells (SMFCs) pose an interesting addition as a low-cost, carbon–neutral technology. A full understanding on the electro-generative processes in SMFCs has, however, yet to be achieved, hindering the technology's translation into practical applications. In this study, an in-depth investigation into the evolution of the output voltage generated by membrane-less, flat-plate SMFCs that accounts for the contribution of both the anode and cathode potential is provided for the first time, along with a study of the influence that organic matter content and porosity in soil has on voltage dynamics. Four stages in voltage evolution over time were observed, which depended on soil properties. The content of organic matter had the greatest effect, leading to an output voltage nearly-three times higher, when it increased from 10 % to 50 %. In this case, the anode potential reached a value of −450 mV, which prompted an exponential increase in the cathode potential and led to a power density of 68 mWm−2. The experimental findings were used to develop a novel computational model that, by predicting the electrochemical behaviour of the SMFC in different soils, becomes a powerful guide for operating strategies that can markedly enhance electricity generation. Consequently, this study sets the foundation for effective system optimisation and real applications
Malignant Scalp Tumors: Retrospective Analysis of 1000 Patients.
Abstract
Background: Limited data on large cohort of patients with malignant tumors of the scalp are available in the literature. e aim of this study was to review a large cohort of patients with malignant scalp tumors to determine epidemilogy, tumor characteristics of this region and treatment.
Materials and Method: A retrospective review of patients with malignant scalp tumors diagnosed histopathologically between 2005 and 2021 was performed. Demographic features and tumor characteristics were analyzed.
Results: A total of 1080 patients (M: F 3,5:1) were treated and followed up for a mean period of 42 months (12-120 months). Age at diagnosis ranged from 12 to 98 years. Most malignant scalp tumors (95,1%) occurred in those 50 years or older and in bald patients (87%). Basal cell carcinomas (59,2%), squamous cell carcinomas (32,2%) and melanomas were the most common histologic types. Incidence was highest on the frontal of temporal region (66,1%). Recurrence was frequently in squamous and basal cell carcinomas but uncommon in melanoma.
Conclusions: Tumors of the scalp accounted about 8,01 % of all skin cancers. Tend to be basal and squamous cell carci- nomas, many of which occur in the temporal and frontal region of bald men. e outlook for patients with scalp tumor is positive, although we suggest excision margins of at least 3-4 mm and continued clinical vigilance is warranted given their higher recurrence rates.
MLN: Melanom
A difficult case of necrotizing fasciitis caused by Acinetobacter baumannii
This study reports the case of a 55-year-old woman with diabetes with a necrotizing fasciitis of the right lower limb and the perineum, first admitted at the emergency department for septic shock with cardiac arrest, and later transferred to the department of surgery. Microbiological and histopathological examination confirmed the diagnosis of necrotizing fasciitis caused by Acinetobacter baumannii. A broad-spectrum antibiotic therapy was administered and later readjusted according to the results of microbiological culture. Intensive hemodynamic support was required. Wounds were dressed daily with a 3 percent boric acid solution and a silver sulfadiazine-impregnated dressing. An extensive surgical debridement was promptly performed and repeated until complete control of the infection. Wounds were finally covered with split-thickness skin grafts. The infection was overcome 35 days after admission. The graft take was 100%. Postoperative rehabilitation was required because of the functional limitation of lower limb movements. Follow-up at 6 months showed no functional deficit and an acceptable aesthetic result. Necrotizing fasciitis is a life-threatening disorder, especially in patients with diabetes, whose clinical diagnosis may sometimes be challenging. Early recognition and treatment represent the most important factors influencing surviva
Genetic and biochemical analyses of chromosome and plasmid gene homologues encoding ICL and ArCP domains in Vibrioanguillarum strain 775
Anguibactin, the siderophore produced by Vibrio anguillarum 775 is synthesized from 2,3-dihydroxybenzoic acid (DHBA), cysteine and hydroxyhistamine via a nonribosomal peptide synthetase (NRPS) mechanism. Most of the genes encoding anguibactin biosynthetic proteins are harbored by the pJM1 plasmid. In this work we report the identification of a homologue of the plasmid-encoded angB on the chromosome of strain 775. The product of both genes harbor an isochorismate lyase (ICL) domain that converts isochorismic acid to 2,3-dihydro-2,3-dihydroxybenzoic acid, one of the steps of DHBA synthesis. We show in this work that both ICL domains are functional in the production of DHBA in V. anguillarum as well as in E. coli. Substitution by alanine of the aspartic acid residue in the active site of both ICL domains completely abolishes their isochorismate lyase activity in vivo. The two proteins also carry an aryl carrier protein (ArCP) domain. In contrast with the ICL domains only the plasmid encoded ArCP can participate in anguibactin production as determined by complementation analyses and site-directed mutagenesis in the active site of the plasmid encoded protein, S248A. The site-directed mutants, D37A in the ICL domain and S248A in the ArCP domain of the plasmid encoded AngB were also tested in vitro and clearly show the importance of each residue for the domain function and that each domain operates independently.
changes in aqueductal csf stroke volume and progression of symptoms in patients with unshunted idiopathic normal pressure hydrocephalus
BACKGROUND AND PURPOSE: Idiopathic normal pressure hydrocephalus (iNPH) represents a diagnostic challenge, given its variable presentation and progression. Stroke volume (SV), defined as the mean volume of CSF passing through the aqueduct during both systole and diastole, greater than or equal to 42 μL, serves as a selection criterion for patients with good probabilities of improvement after ventriculoperitoneal shunt surgery (VPS). In this study, we evaluated the changes in SV during the progression of clinical symptoms in patients with suspected NPH. MATERIALS AND METHODS: Nine patients who presented with clinical and radiologic evidence of NPH, but refused treatment with VPS, were evaluated every 6 months for up to 2 years for progression in their clinical symptoms and changes in their SV, as measured by phase-contrast cine MR imaging (PCCMR). RESULTS: SV seems to increase between the onset of the symptoms and the following 18 to 20 months, then seems to plateau, followed in the next 18 to 20 months by a slight decline, and finally to a more precipitous drop in the next 12 months. During this time, however, the patient9s clinical symptoms progressively worsen. CONCLUSION: Patients with a low SV have not necessarily had brain atrophy and can show, in the following months, a progressive increase in SV, which qualifies them as good candidates for VPS. The progressive reduction of the SV in untreated patients with worsening clinical symptoms may be a sign of a progressive cerebral ischemic injury, which renders the NPH irreversible
Apolarity, Hessian and Macaulay polynomials
A result by Macaulay states that an Artinian graded Gorenstein ring R of
socle dimension one and socle degree b can be realized as the apolar ring of a
homogeneous polynomial f of degree b. If R is the Jacobian ring of a smooth
hypersurface g=0, then b is just equal to the degree of the Hessian polynomial
of g. In this paper we investigate the relationship between f and the Hessian
polynomial of g.Comment: 12 pages. Improved exposition, minor correction
The polyphasic Protocol for the Keloid
The occurrence of keloids is a common clinical problem that can cause functional impairment and
cosmetic deformities. They are pathological cutaneous scars that occur due to surgery, burns or
other traumatic wounds. Keloids are manifestations of a loss of the control mechanism that regulates
wound repair (inflammation, neoangiogenesis and synthesis of extracellular matrix).
The authors present their polyphasic protocol for the treatment of keloids: it consists of a combination
of intralesional excision, steroid injections and dye-laser treatment over a period of four months.
In our research, we have selected patients who have been clinically diagnosed to have keloid scars,
which have been diagnosed for at least one year (50 patients, from January 2005 to December 2014).
Our polyphasic protocol works on the different phases of the scarring process, altered in keloids;
the uncontrolled process in keloid scars is kept in check by the combination of surgical and nonsurgical approaches, and is based on the knowledge on wound healing.
In all cases the results obtained are satisfactory, with a keloid scar size decrease of at least 75% from
the original dimensions and an improvement of the adaptation of the keloid to surrounding skin.
The occurrence of keloids is a common clinical problem that can cause functional impairment and cosmetic deformities. They are pathological cutaneous scars that occur due to surgery, burns or other traumatic wounds. Keloids are manifestations of a loss of the control mechanism that regulates wound repair (inflammation, neoangiogenesis and synthesis of extracellular matrix). The authors present their polyphasic protocol for the treatment of keloids: it consists of a combination of intralesional excision, steroid injections and dye-laser treatment over a period of four months. In our research, we have selected patients who have been clinically diagnosed to have keloid scars, which have been diagnosed for at least one year (50 patients, from January 2005 to December 2014). Our polyphasic protocol works on the different phases of the scarring process, altered in keloids; the uncontrolled process in keloid scars is kept in check by the combination of surgical and nonsurgical approaches, and is based on the knowledge on wound healing. In all cases the results obtained are satisfactory, with a keloid scar size decrease of at least 75% from the original dimensions and an improvement of the adaptation of the keloid to surrounding skin
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
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