Minimizing Bias in Biomass Allometry: Model Selection and Log‐Transformation of Data

Nonlinear regression is increasingly used to develop allometric equations for forest biomass estimation (i.e., as opposed to the traditional approach of log‐transformation followed by linear regression). Most statistical software packages, however, assume additive errors by default, violating a key assumption of allometric theory and possibly producing spurious models. Here, we show that such models may bias stand‐level biomass estimates by up to 100 percent in young forests, and we present an alternative nonlinear fitting approach that conforms with allometric theory

On the nature of rainfall intermittency as revealed by different metrics and sampling approaches

A general consensus on the concept of rainfall intermittency has not yet been reached, and intermittency is often attributed to different aspects of rainfall variability, including the fragmentation of the rainfall support (i.e., the alternation of wet and dry intervals) and the strength of intensity fluctuations and bursts. To explore these different aspects, a systematic analysis of rainfall intermittency properties in the time domain is presented using high-resolution (1-min) data recorded by a network of 201 tipping-bucket gauges covering the entire island of Sardinia (Italy). Four techniques, including spectral and scale invariance analysis, and computation of clustering and intermittency exponents, are applied to quantify the contribution of the alternation of dry and wet intervals (i.e., the rainfall support fragmentation), and the fluctuations of intensity amplitudes, to the overall intermittency of the rainfall process. The presence of three ranges of scaling regimes between 1 min to ~ 45 days is first demonstrated. In accordance with past studies, these regimes can be associated with a range dominated by single storms, a regime typical of frontal systems, and a transition zone. The positions of the breaking points separating these regimes change with the applied technique, suggesting that different tools explain different aspects of rainfall variability. Results indicate that the intermittency properties of rainfall support are fairly similar across the island, while metrics related to rainfall intensity fluctuations are characterized by significant spatial variability, implying that the local climate has a significant effect on the amplitude of rainfall fluctuations and minimal influence on the process of rainfall occurrence. In addition, for each analysis tool, evidence is shown of spatial patterns of the scaling exponents computed in the range of frontal systems. These patterns resemble the main pluviometric regimes observed on the island and, thus, can be associated with the corresponding synoptic circulation patterns. Last but not least, we demonstrate how the methodology adopted to sample the rainfall signal from the records of the tipping instants can significantly affect the intermittency analysis, especially at smaller scales. The multifractal scale invariance analysis is the only tool that is insensitive to the sampling approach. Results of this work may be useful to improve the calibration of stochastic algorithms used to downscale coarse rainfall predictions of climate and weather forecasting models, as well as the parameterization of intensity-duration-frequency curves, adopted for land planning and design of civil infrastructures

Distributed hydrologic modeling of a sparsely monitored basin in Sardinia, Italy, through hydrometeorological downscaling

The water resources and hydrologic extremes in Mediterranean basins are heavily influenced by climate variability. Modeling these watersheds is difficult due to the complex nature of the hydrologic response as well as the sparseness of hydrometeorological observations. In this work, we present a strategy to calibrate a distributed hydrologic model, known as TIN-based Real-time Integrated Basin Simulator (tRIBS), in the Rio Mannu basin (RMB), a medium-sized watershed (472.5 km2) located in an agricultural area in Sardinia, Italy. In the RMB, precipitation, streamflow and meteorological data were collected within different historical periods and at diverse temporal resolutions. We designed two statistical tools for downscaling precipitation and potential evapotranspiration data to create the hourly, high-resolution forcing for the hydrologic model from daily records. Despite the presence of several sources of uncertainty in the observations and model parameterization, the use of the disaggregated forcing led to good calibration and validation performances for the tRIBS model, when daily discharge observations were available. The methodology proposed here can be also used to disaggregate outputs of climate models and conduct high-resolution hydrologic simulations with the goal of quantifying the impacts of climate change on water resources and the frequency of hydrologic extremes within medium-sized basins

Technologically Mediated Discourse and Information Exchange through Medium Specific Syntactical Features: The 2012 Presidential Election on Twitter

Political discourse has been historically constrained by geographic proximity of participants. The introduction of the Internet and specifically social media has altered these geographic constraints and political discourse is now one of the most prevalent activities in social media. The increasing use of technology to acquire political information and participate in the political process in the United States creates a gap between what is understood about political activity in a democratic society and the specific technological features people use. As more individuals begin to use technology for political activity, understanding how the technology is used becomes increasingly important. Previous research exploring political discourse on social media has focused on one discrete event or a narrow time period. This narrow focus limits the understanding of the complex environment that comprises an election. This study takes a longitudinal approach and uses network analysis, co-occurrence analysis and temporal frequency analysis to examine a 53 million Twitter message (tweet) corpus collected during the 2012 Presidential Election (August 20, 2012 - November 13, 2012) to understand how individuals use Twitter to engage in political discourse. The queries used to compose the dataset were theoretically informed based on democratic theory and previous socio-technical research. This study makes three contributions to the existing literature. First, this study identifies that individuals use syntactical features differently in the context of an acute event such as a debate. Second, this study indicates that, although candidates and media are the most talked about and talked to, these interactions elicit no response. Third, this study reveals that information shared through URLs was predominantly user-generated content from Twitter and mass media information suggesting a reflexive information-sharing environment. This study illustrates that even with the availability of the numerous technological and syntactical features to facilitate interactions and share information, there is still a limited realization of the promise that technologies such as Twitter afford. Instead of fundamentally changing the political discourse process by having individuals use it for two-way communication, Twitter amplifies the existing political environment where there is limited cohesive discourse and communication is one-way.Ph.D., Information Studies -- Drexel University, 201

Investigating parameter transferability across models and events for a Semiarid Mediterranean Catchment

Physically based distributed hydrologic models (DHMs) simulate watershed processes by applying physical equations with a variety of simplifying assumptions and discretization approaches. These equations depend on parameters that, in most cases, can be measured and, theoretically, transferred across different types of DHMs. The aim of this study is to test the potential of parameter transferability in a real catchment for two contrasting periods among three DHMs of varying complexity. The case study chosen is a small Mediterranean catchment where the TIN-based Real-time Integrated Basin Simulator (tRIBS) model was previously calibrated and tested. The same datasets and parameters are used here to apply two other DHMs-the TOPographic Kinematic Approximation and Integration model (TOPKAPI) and CATchment HYdrology (CATHY) models. Model performance was measured against observed discharge at the basin outlet for a one-year period (1930) corresponding to average wetness conditions for the region, and for a much drier two-year period (1931-1932). The three DHMs performed comparably for the 1930 period but showed more significant differences (the CATHY model in particular for the dry period. In order to improve the performance of CATHY for this latter period, an hypothesis of soil crusting was introduced, assigning a lower saturated hydraulic conductivity to the top soil layer. It is concluded that, while the physical basis for the three models allowed transfer of parameters in a broad sense, transferability can break down when simulation conditions are greatly altered

Comparison between topical use of ketotifen and olopatadine in the treatment of allergic conjunctivitis

Purpose: To evaluate and compare the efficacy and tolerance to the topical use of 0.05% ketotifen fumarate and 0.1% olopatadine hydrochloride in the treatment of patients with allergic conjunctivitis. Methods: A masked, randomized clinical study was performed in order to compare the efficacy, safety and side effects of the use of 0.05% ketotifen fumarate and 0.1% olopatadine hydrochloride ophthalmic solutions for the alleviation of symptoms and signs in patients with allergic conjunctivitis. Thirty-four patients, fulfilling the inclusion criteria of the protocol were divided into two groups and received a flask with the masked drug, instilling one drop twice daily in each eye for 30 days. Signs and symptoms of these patients were evaluated on a visit before treatment and on five visits during the treatment (days 1, 2, 7, 14 and 30). Results: Severity of allergic conjunctivitis was the same in both studied groups. Both ketotifen and olopatadine were equivalent and efficient regarding decrease in itching, burning and lacrimation symptoms. Bulbar conjunctival hyperemia was attenuated in both groups. Evaluation of adverse reactions showed the occurrence of burning on administration of both drugs and ketotifen led to occurrence of itching. No hypersensitivity reaction to the studied drugs was observed. Conclusions: This study evidences that 0.05% ketotifen fumarate and 0.1% olopatadine hydrochloride ophthalmic solutions, when instilled twice daily for 30 days, were efficient and safe regarding alleviation of the main symptoms and signs of allergic conjunctivitis.Objetivo: Avaliar e comparar a eficácia e tolerância do uso tópico do fumarato de cetotifeno a 0,05% e cloridrato de olopatadina a 0,1% no tratamento de pacientes com conjuntivite alérgica. Método: Foi realizado estudo clínico mascarado, randomizado comparando a eficácia, segurança e os efeitos colaterais com o uso da solução oftálmica de fumarato de cetotifeno a 0,05% e cloridrato de olopatadina a 0,1% no alívio dos sintomas e sinais em pacientes com conjuntivite alérgica. Trinta e quatro pacientes obedecendo aos critérios de inclusão do protocolo receberam um frasco com a droga mascarada e instilaram uma gota duas vezes por dia em cada olho durante 30 dias. Os sintomas e sinais dos pacientes foram avaliados em uma visita pré-tratamento e cinco com tratamento (1º dia, 2º dia, 7º dia, 14º dia e 30º dia). Resultados: A gravidade da conjuntivite alérgica foi semelhante nos dois grupos do estudo. Tanto cetotifeno como a olopatadina foram equivalentes e eficazes na diminuição dos sintomas de prurido, ardor e lacrimejamento. Quanto aos sinais, a hiperemia em conjuntiva bulbar foi atenuada nos dois grupos. Na avaliação das reações adversas observou-se ardor após a administração de ambos colírios e a ocorrência de prurido no grupo do cetotifeno. Não foi observada nenhuma reação de hipersensibilidade das drogas estudadas. Conclusões: Este estudo evidencia que a solução oftálmica de fumarato de cetotifeno a 0,05% e o cloridrato de olopatadina a 0,1% quando instilados duas vezes ao dia durante 30 dias, são eficazes e seguros no alívio dos principais sintomas das conjuntivites alérgicas.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de OftalmologiaUNIFESP, EPM, Depto. de OftalmologiaSciEL

BIOGENIC AMINE CONTENT AND CHEMICAL AND PHYSICAL FEATURES OF ITALIAN FORMAGGIO DI FOSSA

Formaggio di Fossa is an Italian traditional cheese of the Montefeltro area (Emilia Romagna and Marche regions) characterized by a particular step of ripening that is carried out into pits (infossamento) borne in the sandstone. Since the XIV century, the inhabitants were used to set food, especially cereals and cheese, into pits to preserve them during winter and to protect them from invaders. The aim of the present work is to study physical and chemical features of this product with particular reference to the presence of the most important biogenic amines ( -Phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermine and spermidine), compared with a control cheese fully ripened in factory. Formaggio di Fossa showed higher values of Aw, pH, humidity, proteins, pH 4,6-soluble nitrogen (NCN) and water soluble nitrogen (NPN) and much lower amounts of fat. Much higher amounts of total biogenic amines were detected in Formaggio di Fossa than in control cheese, where their concentration was very low. Cadaverine, putrescine and tyramine were the most concentrated biogenic amines. Nevertheless, thyramine was present at levels suggested as compatible with GMPs. Histamine was detected at low amounts, far from potentially toxic levels

A Mutation (G281E) of the Human Uroporphyrinogen Decarboxylase Gene Causes Both Hepatoerythropoietic Porphyria and Overt Familial Porphyria Cutanea Tarda: Biochemical and Genetic Studies on Spanish Patients

Hepatoerythropoietic porphyria is a severe cutaneous porphyria caused by deficiency of uroporphyrinogen decarboxylase and is considered to be the homozygous form of familial (type II) porphyria cutanea tarda. To elucidate further the relation between these conditions, we studied five Spanish families with hepatoerythropoietic porphyria and nine unrelated Spanish patients with familial porphyria cutanea tarda. Immunoreactive and catalytic uroporphyrinogen decarboxylase was decreased by greater than 95% in the five patients with hepatoerythropoietic porphyria. Hepatic uroporphyrinogen decarboxylase activity was decreased to 22% of normal. Four patients were homozygous for a mutation (G281E) originally identified in a Tunisian family; the fifth patient was a compound heterozygote for this mutation. The calculated carrier frequency for G281E in Spain is one in 1800. None of the nine familial porphyria cutanea tarda patients carried the G281E mutation. However, one G281E heterozygote in a family with hepatoerythropoietic porphyria had overt porphyria cutanea tarda. These findings suggest that the G281E mutation is functionally less severe than erythrocyte measurements indicate, that its clinical penetrance is very low in heterozygotes, and that, for this particular mutation, hepatoerythropoietic porphyria is the homozygous form of familial porphyria cutanea tarda