Automatic detection of benthos & birds: Microphytobenthos cover and bird number detection on the Galgeplaat mudflat using terrestrial imagery

Ecological monitoring, i.e. the process of assessing the quality and health of natural habitats, is required to assess the impact of anthropogenic influence. This process is often inhibited by the expenses involved and a limited accessibility to the study site. The use of remotely sensed data then logically comes to mind as a potential solution. This thesis focuses on the ecological monitoring of an intertidal mudflat located in the Oosterschelde known as the Galgeplaat. It possesses a monitoring platform standing 15 meters tall producing imagery that was previously used for monitoring the morphology of the mudflat. The goal is to examine the potential of using this available terrestrial imagery for ecological monitoring of the mudflat and whether it is possible to do this automatically. Two separate case studies were formulated to investigate this potential; 1. automatic detectionof microphytobenthos and 2. automatic detection of bird numbers. The primary focus in this thesis was put on the microphytobenthos case study which elicited the most interest from involved parties. The main inhibiting factor for microphytobenthos detection was the presence of macroalgae (in particular brown macroalgae) in the images, which possess similar spectral properties to that of microphytobenthos. Two methods were used to detect microphytobenthos: I. maximum likelihood classification combined with the masking of the macroalgae (the undesired target) and II. Kohonen’s self organising maps (SOM). The results of this case study indicated that distinguishment between microphytobenthos and macroalgae was best achieved with the Self organizing map (SOM) approach. For the detection of bird numbers consecutive snapshot images of the camera were used such that the motion of birds could be taken advantage of. Background subtraction using a weighted mean background image and a standard deviation image was the most promising of the methods used to count the birds in the 20 frame video sequences. The video sequences with the least zoom (far scale) produced the most erroneous detections. This probably as a result of the lack of movement visible in the video and the small size of the birds (more interference from noise). The results suggest ecological monitoring, in this case of microphytobenthos cover and bird numbers on the Galgeplaat, is indeed possible by using the available terrestrial imagery from the platform. In the current state of development however, the process cannot be claimed fully automatic yet as some a priori knowledge from the user’s part is still required. Regardless, the use of remotely sensed imagery for ecological monitoring proves promising in comparison with current ecological monitoring for several reasons. Provided that unsuitable images are filtered out (images where raindrops are on the camera lens, or other irreparable images) the problem of limited accessibility to the mudflat is ruled out. This makes it possible to produce high time resolution data. Additionally, no costs are required for lab work or transport to the mudflat for bird counting and the collection of specimen.Msc. GeomaticsGeoscience and Remote SensingCivil Engineering and Geoscience

Kelvin-Helmholtz instability at the interface of a disc-corona system

We study Kelvin-Helmholtz (KH) instability at the interface of a disc and corona system by doing a linear perturbation analysis. The disc is assumed to be thin; however, the corona is considered to be nearly quasi-spherical because of its high temperature. Under these circumstances, the interface is subject to the KH instability for a given set of the input parameters. Growth rates of the KH unstable modes are calculated for a wide range of the input parameters. We show that for a certain range of the perturbations, the unstable KH perturbations are growing with time-scales comparable to the inverse of the angular velocity of the accretion disc (dynamical time-scale). Thus, KH instability at the interface of a disc-corona may have enough time to affect the dynamical structure of its underlying accretion disc by possible exchange of the mass, angular momentum or even energy. Our linear analysis shows that KH instability may provide a mechanism for such exchanges between a disc and its corona. © 2010 The Authors. Journal compilation © 2010 RAS

Depressive Symptoms in Patients with Congenital Heart Disease: Incidence and Prognostic Value of Self-Rating Depression Scales

Objective: To determine the presence of depressive symptoms in adolescent and adult patients with CHD and their impact on prognosis, using self-rating depression scales. Design: Prospective study. Setting: Outpatient clinic of a tertiary center. Patients: Sixty ambulatory adolescent and adult patients admitted at the outpatient clinic for regular evaluation. Methods: Self-rating depression questionnaires (Beck Depression Inventory [BDI] and Zung Self-Rating Depression Scale [Zung SDS]) were administered on admission. Patients were characterized as having depressive symptoms when scores on both questionnaires were above cutoff levels and were subsequently followed for 5.1 ± 1.1 years for major adverse cardiovascular events (MACEs; death or hospitalization for cardiac reasons). Results: Seventeen patients (mean age 28.9 ± 11.4 years) were characterized as having depressive symptoms. According to univariate Cox regression analysis, the presence of depressive symptoms was independently associated with adverse clinical outcome. During the follow-up period, patients with depressive symptoms had a shorter event-free survival (1559 ± 92days vs. 1077 ± 188days, P = .00215) and a twofold higher risk of getting a MACE, compared with patients without (95% CI 1.630 to 3.616, P < .05). Based on receiver operator characteristics, the BDI had a better prognostic value for future MACEs (area under curve = 0.662, 95% CI 0.5442 to 0.7792; P < .05) compared with the Zung SDS. Mean event-free survival for patients with BDI ≥ 10 was 986 ± 179 days vs. 1624 ± 83 days for patients with BDI < 10. Conclusions: The incidence of depressive symptomatology in patients with CHD is rather high and is associated with poorer prognosis. The BDI seems to independently predict adverse clinical outcome. Standardized screening tools and psychosocial interventions to improve the well being of these patients should be a priority in the overall care of this population. © 2014 Wiley Periodicals, Inc

Correlations of sialic acid with markers of inflammation, atherosclerosis and cardiovascular events in hemodialysis patients

Background: Serum total sialic acid (S-TSA) is associated with atherosclerotic process in general population. The aim of our study was to evaluate possible correlations of S-TSA with markers of inflammation and atherosclerosis in hemodialysis (HD) patients. Methods: We involved 53 asymptomatic, nondiabetic HD patients and 28 healthy controls. Atherosclerosis was evaluated by carotid ultrasonography, estimating intima media wall thickness and wall to lumen ratio bilaterally. To confirm our findings, we performed a 32-month cohort study, during which cardiovascular (CV) events were analyzed in relation to S-TSA concentration. Results: HD patients had higher S-TSA compared to controls (adjusted OR: 1.04, p = 0.026). In HD patients, S-TSA independently correlated with hs-CRP (p < 0.0001), lipoprotein(a) (p = 0.02), intima media wall thickness (p = 0.023) and wall to lumen ratio (p = 0.028). Increased S-TSA concentration was associated with more CV events (p = 0.03). Conclusions: Serum TSA seems to correlate with inflammation, accelerated atherosclerosis and CV events in nondiabetic HD patients, but more studies need to confirm our findings. Copyright © 2008 S. Karger AG

Assessment of bone mineral density and markers of bone turnover in children under long-term oral anticoagulant therapy

Oral anticoagulants antagonize vitamin K action and potentially impair the carboxylation of osteocalcin, a protein essential for normal bone matrix formation. In the present study, bone mineral density (BMD) and bone turnover markers were evaluated in 23 children under long-term oral anticoagulant therapy. BMD of the lumbar spine was assessed (Dual Energy x-ray Absorptiometry) and reported as z score. Osteoblast [bone alkaline phosphatase, osteocalcin (Gla-Oc), amino-terminal procollagen 1 extension peptide] and osteoclast (urinary calcium and deoxypyridinoline, serum cross-linked C telopeptide) activity markers were measured. Vitamin D ([25(OH) D], parathormone, calcium, phosphorus, magnesium) and vitamin K status [factors II, VII, IX, X, protein C, protein S, undercarboxylated osteocalcin (Glu-Oc)] were determined. The above parameters were also evaluated in 25 healthy controls. Patients presented with higher levels in Glu-Oc, parathormone, and bone resorption markers, lower levels in bone formation markers and 25(OH) D, whereas 52% of them showed signs of osteopenia (-1> BMD z score > -2.5). Statistical analysis demonstrated that anticoagulant therapy was an independent predictor of alterations in Glu-Oc, Gla-Oc, bone alkaline phosphatase, amino-terminal procollagen 1 extension peptide, and serum cross-linked C telopeptide levels. It seems that long-term use of coumarin derivatives may cause osteopenia in children with the risk of developing osteoporosis later in life. © 2008 by Lippincott Williams & Wilkins

KardiaSoft Architecture -A Software Supporting Diagnosis and Therapy Monitoring of Heart Failure Patients Exploiting Saliva Biomarkers

The aim of this work is to present the architecture of the KardiaSoft software, a clinical decision support tool allowing the healthcare professionals to monitor patients with heart failure by providing useful information and suggestions in terms of the estimation of the presence of heart failure (heart failure diagnosis), stratification-patient profiling, long term patient condition evaluation and therapy response monitoring. KardiaSoft is based on predictive modeling techniques that analyze data that correspond to four saliva biomarkers, measured by a point-of-care device, along with other patient's data. The KardiaSoft is designed based on the results of a user requirements elicitation process. A small clinical scale study with 135 subjects and an early clinical study with 90 subjects will take place in order to build and validate the predictive models, respectively

Dietary Nitrate Supplementation Improves Revascularization in Chronic Ischemia

BACKGROUND: Revascularization is an adaptive repair mechanism that restores blood flow to undersupplied ischemic tissue. Nitric oxide plays an important role in this process. Whether dietary nitrate, serially reduced to nitrite by commensal bacteria in the oral cavity and subsequently to nitric oxide and other nitrogen oxides, enhances ischemia-induced remodeling of the vascular network is not known. METHODS AND RESULTS: Mice were treated with either nitrate (1 g/L sodium nitrate in drinking water) or sodium chloride (control) for 14 days. At day 7, unilateral hind-limb surgery with excision of the left femoral artery was conducted. Blood flow was determined by laser Doppler. Capillary density, myoblast apoptosis, mobilization of CD34(+)/Flk-1(+), migration of bone marrow-derived CD31(+)/CD45(-), plasma S-nitrosothiols, nitrite, and skeletal tissue cGMP levels were assessed. Enhanced green fluorescence protein transgenic mice were used for bone marrow transplantation. Dietary nitrate increased plasma S-nitrosothiols and nitrite, enhanced revascularization, increased mobilization of CD34(+)/Flk-1(+) and migration of bone marrow-derived CD31(+)/CD45(-) cells to the site of ischemia, and attenuated apoptosis of potentially regenerative myoblasts in chronically ischemic tissue. The regenerative effects of nitrate treatment were abolished by eradication of the nitrate-reducing bacteria in the oral cavity through the use of an antiseptic mouthwash. CONCLUSIONS: Long-term dietary nitrate supplementation may represent a novel nutrition-based strategy to enhance ischemia-induced revascularization