Tsunami impacts on shallow groundwater and associated water supply on the East Coast of Sri Lanka: a post-tsunami well recovery support initiative and an assessment of groundwater salinity in three areas of Batticaloa and Ampara Districts

Groundwater, Aquifers, Salinity, Natural disasters, Water supply, Drinking water, Wells, Rehabilitation, Mosquitoes, Disease vectors, Environmental Economics and Policy, Health Economics and Policy, Resource /Energy Economics and Policy,

Linear functional state bounding for perturbed time-delay systems and its application

This paper considers time-delay systems with bounded disturbances. We study a new problem of finding an upper bound of an absolute value function of any given linear functional of the state vector starting from the origin of the system. Based on the Lyapunov-Krasovskii method combining with the recent Wirtinger-based integral inequality that has just been proposed by Seuret & Gouaisbaut (2013. Wirtinger-based integral inequality: application to time-delay systems. Automatica, 49, 2860-2866), sufficient conditions for the existence of an upper bound of the function are derived. The obtained results are shown to be more effective than those adapted from the existing works on reachable set bounding. Furthermore, the obtained results are applied to refine existing ellipsoidal bounds of the reachable sets. The effectiveness of the obtained results is illustrated by two numerical examples

Mechanical modelling of high power lateral IGBT for LED driver applications

An assembly exercise was proposed to replace the vertical MOSFET by lateral IGBTs (LIGBT) for LED driver systems which can provide significant advantages in terms of size reduction (LIGBTs are ten times smaller than vertical MOSFETs) and lower component count. A 6 circle, 5V gate, 800 V LIGBT device with dimension of 818μm x 672μm with deposited solder balls that has a radius of around 75μm was selected in this assembly exercise. The driver system uses chip on board (COB) technique to create a compact driver system which can fit into a GU10 bulb housing. The challenging aspect of the LIGBT package in high voltage application is underfill dielectric breakdown and solder fatigue failure. In order to predict the extreme electric field values of the underfill, an electrostatic finite element analysis was undertaken on the LIGBT package structure for various underfill permittivity values. From the electro static finite element analysis, the maximum electric field in the underfill was estimated as 38 V/μm. Five commercial underfills were selected for investigating the trade-off in materials properties that mitigate underfill electrical breakdown and solder joint fatigue failure. These selected underfills have dielectric breakdown higher than the predicted value from electrostatic analysis. The thermo-mechanical finite element analysis were undertaken for solder bump reliability for all the underfill materials. The underfill which can enhance the solder reliability was chosen as prime candidate

Chip-on-board assembly of 800V Si LIGBTs for high performance ultra-compact LED drivers

This paper presents a novel chip on board assembly design for an integrated power switch, based on high power density 800V silicon lateral insulated gate bipolar transistor (Si LIGBT) technology. LIGBTs offer much higher current densities (5-10X), significantly lower leakage currents, lower parasitic device capacitances and gate charge compared to conventional vertical MOSFETs commonly used in LED drivers. The higher voltage ratings offered (up to 1kV), the development of high voltage interconnection between parallel IGBTs, self-isolated nature and absence of termination region unlike in a vertical MOSFET makes these devices ideal for ultra-compact, low bill of materials (BOM) count LED drives. Chip on board LIGBTs also offer significant advantages over MOSFETs due to high temperatures seen on most of the LED lamp enclosures as the LIGBT's on-state losses increase only marginally with temperature. the design is based on a built-in reliability approach which focuses on a compact LED driver as a case study of a cost sensitive large volume production item

Impact of underfill and other physical dimensions on Silicon Lateral IGBT package reliability using computer model with discrete and continuous design variables

An effort to design and build a prototype LED driver system which is energy efficient, highly compact and with few component count was initiated by a consortium UK universities. The prototype system will be based on Silicon Lateral IGBT (LIGBT) device combined with chip on board technology. Part of this effort, finite element modelling and analysis were undertaken in order to mitigate the underfill dielectric breakdown failure and solder interconnect fatigue failure of the LIGBT package structure. Electro-static analysis was undertaken to predict the extreme electric field distribution in the underfill. Based on electro-static analysis, five commercial underfill were selected for thermo-mechanical finite element analysis on solder joint fatigue failure prediction under cyclic loading. A design optimisation analysis was endeavoured to maximise the solder interconnect reliability by utilising a computer model with continuous variable (physical dimensions) and discrete variables underfill type) and a stochastic optimiser such as multi-objective mixed discrete particle swarm optimisation. From the optimisation analysis best trade off solution are obtained

Sri Lankan tsunami refugees: a cross sectional study of the relationships between housing conditions and self-reported health

BACKGROUND: On the 26th December 2004 the Asian tsunami devastated the Sri Lankan coastline. More than two years later, over 14,500 families were still living in transitional shelters. This study compares the health of the internally displaced people (IDP), living in transitional camps with those in permanent housing projects provided by government and non-government organisations in Sri Lanka. METHODS: This study was conducted in seven transitional camps and five permanent housing projects in the south west of Sri Lanka. Using an interviewer-led questionnaire, data on the IDPs' self-reported health and housing conditions were collected from 154 participants from transitional camps and 147 participants from permanent housing projects. Simple tabulation with non-parametric tests and logistic regression were used to identify and analyse relationships between housing conditions and the reported prevalence of specific symptoms. RESULTS: Analysis showed that living conditions were significantly worse in transitional camps than in permanent housing projects for all factors investigated, except 'having a leaking roof'. Transitional camp participants scored significantly lower on self-perceived overall health scores than those living in housing projects. After controlling for gender, age and marital status, living in a transitional camp compared to a housing project was found to be a significant risk factor for the following symptoms; coughs OR: 3.53 (CI: 2.11-5.89), stomach ache 4.82 (2.19-10.82), headache 5.20 (3.09-8.76), general aches and pains 6.44 (3.67-11.33) and feeling generally unwell 2.28 (2.51-7.29). Within transitional camp data, the only condition shown to be a significant risk factor for any symptom was household population density, which increased the risk of stomach aches 1.40 (1.09-1.79) and headaches 1.33 (1.01-1.77). CONCLUSION: Internally displaced people living in transitional camps are a vulnerable population and specific interventions need to be targeted at this population to address the health inequalities that they report to be experiencing. Further studies need to be conducted to establish which aspects of their housing environment predispose them to poorer health

Antenatal care service delivery and factors affecting effective tetanus vaccine coverage in low- and middle-income countries: results of the Maternal Immunisation and Antenatal Care Situational Analysis (MIACSA) project

Objectives:To map the integration of existing maternal tetanus immunization programmes within ante-natal care (ANC) services for pregnant women in low- and middle-income countries (LMICs) and to identify and understand the challenges, barriers and facilitators associated with high performance maternal vaccine service delivery.Design:A mixed methods, cross sectional study with four data collection phases including a desk review,online survey, telephone and face-to-face interviews and in country visits was undertaken between 2016 and 2018. Associations of different service delivery process components with protection at birth (PAB) andwithcountrygroupswereestablished.PABwasdefinedastheproportionofneonatesprotectedatbirthagainstneonataltetanus. Regression analysis and structural equation modelling was used to assess associations of different variables with maternal tetanus immunization coverage. Latent class analysis (LCA), was used to group country performance for maternal immunization, and to address the problem of multicollinearity.Setting:LMICs.Results: The majority of LMICs had a policy on recommended number of ANC visits, however most were yet toimplementtheWHOguidelinesrecommendingeightANCcontacts.Countriesthatrecommended>4ANC contacts were more likely to have high PAB > 90%. Passive disease surveillance was the most common form of dis-ease surveillance performed but the maternal and neonatal morbidity and mortality indicators recorded differed between countries. The presence of user fees for antenatal care and maternal immunization was significantly associated with lower PAB (<90%).Conclusions:Recommendations include implementing the current WHO ANC guideline to facilitate increased opportunities for vaccination during each pregnancy. Improved utilisation of ANC services by increasing the demand side by increasing the quality of services, reducing any associated costs and supporting user fee exemptions, or the supply side can also enhance utilisation of ANC services which are positioned as an ideal platform for delivery of maternal vaccine

Environmental chemicals impact dog semen quality in vitro and may be associated with a temporal decline in sperm motility and increased cryptorchidism

Adverse temporal trends in human semen quality and cryptorchidism in infants have been associated with exposure to environmental chemicals (ECs) during development. Here we report that a population of breeding dogs exhibit a 26 year (1988–2014) decline in sperm quality and a concurrent increased incidence of cryptorchidism in male offspring (1995–2014). A decline in the number of males born relative to the number of females was also observed. ECs, including diethylhexyl phthalate (DEHP) and polychlorinated biphenyl 153 (PCB153), were detected in adult dog testes and commercial dog foods at concentrations reported to perturb reproductive function in other species. Testicular concentrations of DEHP and PCB153 perturbed sperm viability, motility and DNA integrity in vitro but did not affect LH stimulated testosterone secretion from adult testis explants. The direct effects of chemicals on sperm may therefore contribute to the decline in canine semen quality that parallels that reported in the human

Definition of treatment goals for moderate to severe psoriasis: a European consensus

Patients with moderate to severe psoriasis are undertreated. To solve this persistent problem, the consensus programme was performed to define goals for treatment of plaque psoriasis with systemic therapy and to improve patient care. An expert consensus meeting and a collaborative Delphi procedure were carried out. Nineteen dermatologists from different European countries met for a face-to-face discussion and defined items through a four-round Delphi process. Severity of plaque psoriasis was graded into mild and moderate to severe disease. Mild disease was defined as body surface area (BSA) ≤10 and psoriasis area and severity index (PASI) ≤10 and dermatology life quality index (DLQI) ≤10 and moderate to severe psoriasis as (BSA > 10 or PASI > 10) and DLQI > 10. Special clinical situations may change mild psoriasis to moderate to severe including involvement of visible areas or severe nail involvement. For systemic therapy of plaque psoriasis two treatment phases were defined: (1) induction phase as the treatment period until week 16; however, depending on the type of drug and dose regimen used, this phase may be extended until week 24 and (2) maintenance phase for all drugs was defined as the treatment period after the induction phase. For the definition of treatment goals in plaque psoriasis, the change of PASI from baseline until the time of evaluation (ΔPASI) and the absolute DLQI were used. After induction and during maintenance therapy, treatment can be continued if reduction in PASI is ≥75%. The treatment regimen should be modified if improvement of PASI is <50%. In a situation where the therapeutic response improved ≥50% but <75%, as assessed by PASI, therapy should be modified if the DLQI is >5 but can be continued if the DLQI is ≤5. This programme defines the severity of plaque psoriasis for the first time using a formal consensus of 19 European experts. In addition, treatment goals for moderate to severe disease were established. Implementation of treatment goals in the daily management of psoriasis will improve patient care and mitigate the problem of undertreatment. It is planned to evaluate the implementation of these treatment goals in a subsequent programme involving patients and physicians