ABSTRACT
Reliable time series of vegetation optical properties are needed to improve the modeling of the terrestrial carbon budget with remote sensing data. This paper describes the development of an automatic spectral system able to collect continuous long-term in-field spectral measurements of spectral down-welling and surface reflected irradiance. The paper addresses the development of the system, named hyperspectral irradiometer (HSI), describes its optical design, the acquisition, and processing operations. Measurements gathered on a vegetated surface by the HSI are shown, discussed and compared with experimental outcomes with independent instruments.
ABSTRACT
Metadynamics is a widely used and successful method for reconstructing the free-energy surface of complex systems as a function of a small number of suitably chosen collective variables. This is achieved by biasing the dynamics of the system. The bias acting on the collective variables distorts the probability distribution of the other variables. Here we present a simple reweighting algorithm for recovering the unbiased probability distribution of any variable from a well-tempered metadynamics simulation. We show the efficiency of the reweighting procedure by reconstructing the distribution of the four backbone dihedral angles of alanine dipeptide from two and even one dimensional metadynamics simulation.
Subject(s)
Algorithms , Dipeptides/chemistry , Models, Molecular , Computer Simulation , Molecular Conformation , ThermodynamicsABSTRACT
BACKGROUND: A familial predisposition to colorectal cancer (CRC) has been clearly established, consisting of familial clustering in 15-20% and clear hereditary aetiology in 5-10% of overall CRC cases. Early identification of families and individuals at high risk is essential as intensive surveillance has been demonstrated to reduce cancer incidence and overall mortality. In the present study, the value of oral mucosal light reflectance in identifying hereditary non-polyposis colorectal cancer (HNPCC) carriers was investigated. METHODS: Twenty members of six different genetically unrelated HNPCC kindred and 30 genetically unrelated age and sex matched healthy controls were examined. Lower gingival and vestibular oral mucosal reflectance was measured using an imaging spectrophotometer. RESULTS: HNPCC carriers showed significantly lower values in the 590-700 nm wavelength range (pSubject(s)
Colorectal Neoplasms, Hereditary Nonpolyposis/diagnosis
, Mouth Mucosa
, Spectrophotometry/methods
, Adaptor Proteins, Signal Transducing/genetics
, Case-Control Studies
, Colorectal Neoplasms, Hereditary Nonpolyposis/genetics
, DNA Mismatch Repair
, Female
, Germ-Line Mutation
, Humans
, Immunohistochemistry
, Male
, Middle Aged
, MutL Protein Homolog 1
, Nuclear Proteins/genetics
, Risk Factors
ABSTRACT
We discuss the appearance of systematic spatial and spectral patterns of noise in remotely sensed images as well as the possibility of mitigating the effects of these patterns on the data. We describe the structure of two simple theoretical models that predict the appearance of patterns of noise (mainly stripe noise). Moreover, two new algorithms that have been specifically developed to mitigate the noise patterns are described. The performance of the two algorithms is assessed by use of some hyperspectral images acquired by different kinds of airborne sensor. The algorithms show an unexpected ability to reject these noise patterns.
