Improving a leaves automatic recognition process using PCA

In this work we present a simulation of a recognition process with perimeter characterization of a simple plant leaves as a unique discriminating parameter. Data coding allowing for independence of leaves size and orientation may penalize performance recognition for some varieties. Border description sequences are then used, and Principal Component Analysis (PCA) is applied in order to study which is the best number of components for the classification task, implemented by means of a Support Vector Machine (SVM) System. Obtained results are satisfactory, and compared with [4] our system improves the recognition success, diminishing the variance at the same time.

Automatic Recognition of Leaves by Shape Detection Pre-Processing with Ica

In this work we present a simulation of a recognition process with perimeter characterization of a simple plant leaves as a unique discriminating parameter. Data coding allowing for independence of leaves size and orientation may penalize performance recognition for some varieties. Border description sequences are then used to characterize the leaves. Independent Component Analysis (ICA) is then applied in order to study which is the best number of components to be considered for the classification task, implemented by means of an Artificial Neural Network (ANN). Obtained results with ICA as a pre-processing tool are satisfactory, and compared with some references our system improves the recognition success up to 80.8% depending on the number of considered independent components.

Alzheimer disease diagnosis based on automatic spontaneous speech analysis

Alzheimer’s disease (AD) is the most prevalent form of progressive degenerative dementia and it has a high socio-economic impact in Western countries, therefore is one of the most active research areas today. Its diagnosis is sometimes made by excluding other dementias, and definitive confirmation must be done trough a post-mortem study of the brain tissue of the patient. The purpose of this paper is to contribute to im-provement of early diagnosis of AD and its degree of severity, from an automatic analysis performed by non-invasive intelligent methods. The methods selected in this case are Automatic Spontaneous Speech Analysis (ASSA) and Emotional Temperature (ET), that have the great advantage of being non invasive, low cost and without any side effects.

Spreading due to heterogeneity in two-phase flow

Postprint (published version)

Basic calcium phosphate crystals induce IL-1B secretion in vitro through activation of the Nalp3 inflammasome

Objectives: We tested the effects of the three forms of basic calcium phosphate (BCP) crystals (octacalcium phosphate (OCP), carbonate-substituted apatite (CA) and hydroxyapatite (HA)) on monocytes and macrophages on IL-1β secretion. The requirement for the NALP3 inflammasome and TLR2 and TLR4 receptors in this acute response was analyzed.

Plagiarism meets paraphrasing: insights for the new generation in automatic plagiarism detection

Although paraphrasing is the linguistic mechanism underlying many plagiarism cases, little attention has been paid to its analysis in the framework of automatic plagiarism detection. Therefore, state-of-the-art plagiarism detectors find it difficult to detect cases of paraphrase plagiarism. In this article, we analyse the relationship between paraphrasing and plagiarism, paying special attention to which paraphrase phenomena underlie acts of plagiarism and which of them are detected by plagiarism detection systems. With this aim in mind, we created the P4P corpus, a new resource which uses a paraphrase typology to annotate a subset of the PAN-PC-10 corpus for automatic plagiarism detection. The results of the Second International Competition on Plagiarism Detection were analysed in the light of this annotation. The presented experiments show that (i) more complex paraphrase phenomena and a high density of paraphrase mechanisms make plagiarism detection more difficult, (ii) lexical substitutions are the paraphrase mechanisms used the most when plagiarising, and (iii) paraphrase mechanisms tend to shorten the plagiarized text. For the first time, the paraphrase mechanisms behind plagiarism have been analysed, providing critical insights for the improvement of automatic plagiarism detection systems.

Auditory localisation and recognition after left inferior collicular lesion: effects of work load on cortical activation patterns (fMRI study)

Evidence from neuropsychological and activation studies (Clarke et al., 2oo0, Maeder et al., 2000) suggests that sound recognitionand localisation are processed by two anatomically and functionally distinct cortical networks. We report here on a case of a patientthat had an interruption of auditory information and we show: i) the effects of this interruption on cortical auditory processing; ii)the effect of the workload on activation pattern.A 36 year old man suffered from a small left mesencephalic haemotrhage, due to cavernous angioma; the let% inferior colliculuswas resected in the surgical approach of the vascular malformation. In the acute stage, the patient complained of auditoryhallucinations and of auditory loss in right ear, while tonal audiometry was normal. At 12 months, auditory recognition, auditorylocalisation (assessed by lTD and IID cues) and auditory motion perception were normal (Clarke et al., 2000), while verbal dichoticlistening was deficient on the right side.Sound recognition and sound localisation activation patterns were investigated with fMRI, using a passive and an activeparadigm. In normal subjects, distinct cortical networks were involved in sound recognition and localisation, both in passive andactive paradigm (Maeder et al., 2OOOa, 2000b).Passive listening of environmental and spatial stimuli as compared to rest strongly activated right auditory cortex, but failed toactivate left primary auditory cortex. The specialised networks for sound recognition and localisation could not be visual&d onthe right and only minimally on the left convexity. A very different activation pattern was obtained in the active condition wherea motor response was required. Workload not only increased the activation of the right auditory cortex, but also allowed theactivation of the left primary auditory cortex. The specialised networks for sound recognition and localisation were almostcompletely present in both hemispheres.These results show that increasing the workload can i) help to recruit cortical region in the auditory deafferented hemisphere;and ii) lead to processing auditory information within specific cortical networks.References:Clarke et al. (2000). Neuropsychologia 38: 797-807.Mae.der et al. (2OOOa), Neuroimage 11: S52.Maeder et al. (2OOOb), Neuroimage 11: S33

Context specific affinity thresholds for CD8 T cell activation

After antigen driven activationnaïve CD8 T cells develop intocytolytic effector cells and subsequentlyinto memory cells. The molecularinteractions orchestrating Tcell activation are complex and we sofar have a limited understanding howindividual signals impact the Tcell response.Using OT-1 TCR transgeniccells and Listeria monocytogenesstrains expressing a set of altered peptideligands (APL) for the OT-1 TCRwe have recently studied how thelevel of TCR stimulation impacts theT cell response in vivo. We therebyobserved that even very low levels ofTCR stimulation are sufficient forfunctional effector and memoryT celldifferentiation. In order to addresshow much further the level of TCRstimulation can be reduced until the Tcells do not become activated anymore,we generated additional OT-1APL expressing Listeria strains. TheAPLused in our present study cover arange of potency down to the level ofpositive selection. Using all our APLListeria strains we can demonstratethat the threshold of peripheral T cellactivation is above the level of positiveselection but far below the levelthat is thought to be required for negativeselection. Furthermore, we characterizedthe thresholds of activatingmemory T cells and found them intrinsicallyto be very similar to thoseof naïve T cells. However, we observedthat T cell competition at thelevel of antigen presenting cells criticallyraises the activation threshold ofmemory CD8 T cells. Taken togetherour data indicate that the threshold foractivating T cells critically dependson the context and the environment inwhich T cells respond to antigen.

Adenosine A1 receptor activation is arrhythmogenic in the developing heart through NADPH oxidase/ERK- and PLC/PKC-dependent mechanisms.

Whether adenosine, a crucial regulator of the developing cardiovascular system, can provoke arrhythmias in the embryonic/fetal heart remains controversial. Here, we aimed to establish a mechanistic basis of how an adenosinergic stimulation alters function of the developing heart. Spontaneously beating hearts or dissected atria and ventricle obtained from 4-day-old chick embryos were exposed to adenosine or specific agonists of the receptors A(1)AR (CCPA), A(2A)AR (CGS-21680) and A(3)AR (IB-MECA). Expression of the receptors was determined by quantitative PCR. The functional consequences of blockade of NADPH oxidase, extracellular signal-regulated kinase (ERK), phospholipase C (PLC), protein kinase C (PKC) and L-type calcium channel (LCC) in combination with adenosine or CCPA, were investigated in vitro by electrocardiography. Furthermore, the time-course of ERK phosphorylation was determined by western blotting. Expression of A(1)AR, A(2A)AR and A(2B)AR was higher in atria than in ventricle while A(3)AR was equally expressed. Adenosine (100μM) triggered transient atrial ectopy and second degree atrio-ventricular blocks (AVB) whereas CCPA induced mainly Mobitz type I AVB. Atrial rhythm and atrio-ventricular propagation fully recovered after 60min. These arrhythmias were prevented by the specific A(1)AR antagonist DPCPX. Adenosine and CCPA transiently increased ERK phosphorylation and induced arrhythmias in isolated atria but not in ventricle. By contrast, A(2A)AR and A(3)AR agonists had no effect. Interestingly, the proarrhythmic effect of A(1)AR stimulation was markedly reduced by inhibition of NADPH oxidase, ERK, PLC, PKC or LCC. Moreover, NADPH oxidase inhibition or antioxidant MPG prevented both A(1)AR-mediated arrhythmias and ERK phosphorylation. These results suggest that pacemaking and conduction disturbances are induced via A(1)AR through concomitant stimulation of NADPH oxidase and PLC, followed by downstream activation of ERK and PKC with LCC as possible target.

Cell death-induced activation of epidermal growth factor receptor in keratinocytes: implications for restricting epidermal damage in dermatitis.

Recent findings have implicated Fas/Fas ligand (FasL) in mediating the death of keratinocytes in spongiotic lesions. We asked whether dying keratinocytes could potentially initiate a protective response of the skin to limit the destruction of the epidermis in the spongiotic areas. In addition to apoptosis, treatment of keratinocyte cultures in vitro with FasL triggers a profound phoshorylation of the epidermal growth factor receptor (EGFR) and of its downstream effectors ERK and protein kinase B (PKB/Akt). Using a variety of inhibitors and blocking antibodies, we demonstrated that: (i) apoptosis is required for the generation of the signal(s) leading to the activation of EGFR, ERK, and Akt; (ii) the activation of EGFR, ERK, and Akt by FasL is indeed mediated by its bona fide receptor Fas; (iii) the activation of EGFR is essential for the subsequent activation of ERK and Akt; and (iv) apoptotic keratinocytes secrete soluble EGFR ligands (including amphiregulin) that are processed from membrane-bound proligand forms by metalloproteinase(s). Our findings demonstrate a potential mechanism for the restriction and repair of spongiotic damage in eczemas.

Computed tomography commissioning programmes: how to obtain a reliable MTF with an automatic approach?

The purpose of this study was to assess the spatial resolution of a computed tomography (CT) scanner with an automatic approach developed for routine quality controls when varying CT parameters. The methods available to assess the modulation transfer functions (MTF) with the automatic approach were Droege's and the bead point source (BPS) methods. These MTFs were compared with presampled ones obtained using Boone's method. The results show that Droege's method is not accurate in the low-frequency range, whereas the BPS method is highly sensitive to image noise. While both methods are well adapted to routine stability controls, it was shown that they are not able to provide absolute measurements. On the other hand, Boone's method, which is robust with respect to aliasing, more resilient to noise and provides absolute measurements, satisfies the commissioning requirements perfectly. Thus, Boone's method combined with a modified Catphan 600 phantom could be a good solution to assess CT spatial resolution in the different CT planes.

Multicentric carpotarsal osteolysis is caused by mutations clustering in the amino-terminal transcriptional activation domain of MAFB.

Multicentric carpotarsal osteolysis (MCTO) is a rare skeletal dysplasia characterized by aggressive osteolysis, particularly affecting the carpal and tarsal bones, and is frequently associated with progressive renal failure. Using exome capture and next-generation sequencing in five unrelated simplex cases of MCTO, we identified previously unreported missense mutations clustering within a 51 base pair region of the single exon of MAFB, validated by Sanger sequencing. A further six unrelated simplex cases with MCTO were also heterozygous for previously unreported mutations within this same region, as were affected members of two families with autosomal-dominant MCTO. MAFB encodes a transcription factor that negatively regulates RANKL-induced osteoclastogenesis and is essential for normal renal development. Identification of this gene paves the way for development of novel therapeutic approaches for this crippling disease and provides insight into normal bone and kidney development.