Space-dependent color gamut mapping: a variational approach.

Gamut mapping deals with the need to adjust a color image to fit into the constrained color gamut of a given rendering medium. A typical use for this tool is the reproduction of a color image prior to its printing, such that it exploits best the given printer/medium color gamut, namely the colors the printer can produce on the given medium. Most of the classical gamut mapping methods involve a pixel-by-pixel mapping and ignore the spatial color configuration. Recently proposed spatial-dependent approaches for gamut mapping are either based on heuristic assumptions or involve a high computational cost. In this paper, we present a new variational approach for space-dependent gamut mapping. Our treatment starts with the presentation of a new measure for the problem, closely related to a recent measure proposed for Retinex. We also link our method to recent measures that attempt to couple spectral and spatial perceptual measures. It is shown that the gamut mapping problem leads to a quadratic programming formulation, guaranteed to have a unique solution if the gamut of the target device is convex. An efficient numerical solution is proposed with promising results.     

Introduction of a nonlinearity measure for principal component models

Although principal component analysis (PCA) is an important tool in standard multivariate data analysis, little interest has been devoted to assessing whether the underlying relationship within a given variable set can be described by a linear PCA model or whether nonlinear PCA must be utilized. This paper addresses this deficiency by introducing a nonlinearity measure for principal component models. The measure is based on the following two principles: (i) the range of recorded process operation is divided into smaller regions; and (ii) accuracy bounds are determined for the sum of the discarded eigenvalues. If this sum is within the accuracy bounds for each region, the process is assumed to be linear and vice versa. This procedure is automated through the use of cross-validation. Finally, the paper shows the utility of the new nonlinearity measure using two simulation studies and with data from an industrial melter process.     

Fuzzy coding of genetic algorithms

A new chromosome encoding method, named fuzzy coding, is proposed for representing real number parameters in a genetic algorithm. Fuzzy coding provides the value of a parameter on the basis of the optimum number of selected fuzzy sets and their effectiveness in terms of degree of membership. Thus, it represents the knowledge associated with each parameter and is an indirect method of encoding compared with alternatives, where the parameters are directly represented in the encoding. Fuzzy coding is described and compared with conventional binary coding, gray coding, and floating-point coding. Two test examples, along with neural identification of a nonlinear pH process from experimental data, are studied. It is shown that fuzzy coding is better than the conventional methods and is effective for parameter optimization in problems where the search space is complicated.     

Effect of duodenum-preserving resection of the head of the pancreas on endocrine and exocrine pancreatic function in patients with chronic pancreatitis

Two mobilizable cloning vectors, designated pABW1 and pAWB2, were constructed basing on the E. coli vector pBGS18 and oriT originating from RK2. In pABW2 the kanamycin resistance gene was replaced by a novel tetracycline resistance cassette derived from Tn1721. Both vectors, specific for E. coli, allow to perform the cloning steps in E. coli and then to efficiently transfer the constructs by conjugation to the host of choice. A vector which cannot propagate in the given host can be applied for identification of the host specific plasmid replicator regions. With the use of pABW2 we defined the minimal replicator region of pTAV202-a mini-derivative of the large pTAV1 plasmid of P. versutus. We also proved that RepC' encoded on this fragment is the principal initiator replication protein and that oriV is located along its coding sequence.     

MRI of primary malignant cardiovascular tumors

In 1895 Trendelenburg described his sign to determine the integrity of hip function. We found the sign to be positive in a patient whose hip was clinically and radiologically normal, and therefore investigated this in other patients. We confirmed that a medial shift of the mechanical axis of the leg below the hip may cause a positive Trendelenburg sign. This has not been previously described.     

Behavioral and pharmacologic approaches to smoking cessation

Cigarette smoking continues to be the single, most preventable cause of death and disability in the United States. For individuals who have cancer, continuing to smoke negatively impacts their treatment, survival, and risk for second primary tumors. This review of behavioral and pharmacological approaches to smoking cessation focuses on the recent comprehensive review of cessation interventions by the Agency for Health Care Policy and Research (AHCPR), as well as on new developments in the field. An intervention model is outlined that provides oncologists with a brief and easily implemented method of systematically treating patients who smoke. By assessing patient smoking status, advising smoking patients to quit, and proactively assisting their patients in quitting, oncologists can significantly influence patient health and fulfill their professional and ethical responsibility to address this life-threatening behavior.     

Immunity and depression: insomnia, retardation, and reduction of natural killer cell activity

The contribution of chloride to the haemodynamic changes of salt-dependent deoxycorticosterone (DOC) hypertension was studied in young Wistar rats subjected to dietary loading with sodium chloride (NaCl) or sodium bicarbonate (NaHCO3). Mean arterial pressure (MAP), cardiac output, systemic resistance (TPR) and arterial rigidity (estimated from pulse pressure/stroke volume ratio, PP/SV) were determined in conscious chronically cannulated rats. DOC-induced increase of MAP and TPR appeared earlier in NaCl-loaded than in NaHCO3-loaded rats. After 4-6 weeks of hypertensive treatment MAP, TPR and PP/SV ratio were higher in DOC-treated rats fed NaCl diet than in those fed NaHCO3 diet. In contrast, after a long-term hypertensive regimen (lasting for 7-9 weeks) there was no significant difference in either MAP or TPR between rats loaded with NaCl or NaHCO3. On the other hand, DOC hypertension induced by a long-term feeding of NaHCO3 diet was not associated with an increase of arterial rigidity which was characteristic for DOC-NaCl hypertensive rats. Thus, a sufficiently long selective dietary sodium loading is capable to increase the systemic resistance but not to alter the arterial rigidity. This was also confirmed by a comparison of blood pressure-matched DOC hypertensive rats fed NaCl or NaHCO3 diets. These animals did not differ in the degree of systemic resistance elevation but the arterial rigidity was increased only in NaCl-loaded rats.     

Transgenic overproduction of islet amyloid polypeptide (amylin) is not sufficient for islet amyloid formation

Islet amyloid polypeptide forms islet amyloid deposits in non-insulin-dependent diabetes mellitus. We have generated transgenic mice which express human islet amyloid polypeptide in their pancreatic beta cells yet do not develop islet amyloid deposits despite producing levels of the amyloidogenic human peptide 2 - 3 fold higher than the native (mouse) peptide. To determine whether marked overproduction of islet amyloid polypeptide is a potential cause of islet amyloid formation, we increased expression of this transgene by producing homozygous transgenic animals and by making heterozygous mice experimentally insulin resistant with nicotinic acid. Pancreatic content of islet amyloid polypeptide-like immunoreactivity in homozygous and nicotinic acid-treated mice was 2-fold (25 +/- 7 fmol/microg; n = 6) and 3.5-fold (47 +/- 20 fmol/microg; n = 3) higher, respectively, than that of untreated heterozygous animals (13+/-2 fmol/microg; n = 11; both p < 0.05). Despite this marked increase in production of islet amyloid polypeptide, neither group of mice developed gross islet amyloid deposits even after 16 months of age. We conclude that overproduction of islet amyloid polypeptide, even as produced by extreme insulin resistance, is not in itself sufficient for islet amyloid formation.