Low-complexity wavelet filter design for image compression

Image compression algorithms based on the wavelet transform are an increasingly attractive and flexible alternative to other algorithms based on block orthogonal transforms. While the design of orthogonal wavelet filters has been studied in significant depth, the design of nonorthogonal wavelet filters, such as linear-phase (LP) filters, has not yet reached that point. Of particular interest are wavelet transforms with low complexity at the encoder. In this article, we present known and new parameterizations of the two families of LP perfect reconstruction (PR) filters. The first family is that of all PR LP filters with finite impulse response (FIR), with equal complexity at the encoder and decoder. The second family is one of LP PR filters, which are FIR at the encoder and infinite impulse response (IIR) at the decoder, i.e., with controllable encoder complexity. These parameterizations are used to optimize the subband/wavelet transform coding gain, as defined for nonorthogonal wavelet transforms. Optimal LP wavelet filters are given for low levels of encoder complexity, as well as their corresponding integer approximations, to allow for applications limited to using integer arithmetic. These optimal LP filters yield larger coding gains than orthogonal filters with an equivalent complexity. The parameterizations described in this article can be used for the optimization of any other appropriate objective function

On the K-Winners-Take-All Network

We present and rigorously analyze a generalization of the Winner-Take-All Network: the K-Winners-Take-All Network. This network identifies the K largest of a set of N real numbers. The network model used is the continuous Hopfield model

Conceptualization of Empowerment and Pathways Through Which Cash Transfers Work to Empower Young Women to Reduce HIV Risk: A Qualitative Study in Tanzania

Although cash transfers (CT) are hypothesized to reduce AGYW’s HIV risk, little is known about the mechanisms through which CT empower AGYW. We explored the impact of a CT intervention on AGYW’s sexual decision-making in order to describe the pathways through which the cash may influence risk behavior. The study employed qualitative methods involving: 20 longitudinal in-depth interviews (IDIs), 40 cross-sectional IDIs, 20 narrative IDIs, and two focus group discussions with AGYW ages 15–23 participating in a CT intervention. AGYW’s conceptualized empowerment as: “independence”, “hope and aspiration”. Potential pathways through which CT empowered AGYW were: economic, hope and aspiration for a better future, and access to knowledge. As a result of this empowerment, AGYW reported reductions in transactional sex, experiences of intimate partner violence, and risky-sexual behaviour. A sense of responsibility developed through economic empowerment, enhanced participants’ self-esteem and confidence in decision-making leading to changes in AGYW’s sexual risk behaviors

Decision-making and cash spending patterns of adolescent girls and young women participating in a cash-transfer intervention in Tanzania: Implications for sexual health

Although cash transfers (CT) have been recommended as a strategy to address structural drivers of HIV, the evidence of the effects of CT on sexual risk and HIV outcomes is mixed. This could partly be due to CT implementation dynamics and beneficiary interpersonal factors. We conducted an assessment of CT component of the DREAMS programme in Tanzania. We explored how AGYW spent their CT over time, to whom they disclosed cash receipt, and where they sought advice on CT use. The study employed qualitative research methods including: 20 longitudinal in-depth interviews (IDIs) and 60 cross-sectional IDIs with AGYW in the CT programme. Data were analysed thematically. AGYW use of CT fell into five categories: business development, survival, self-care, helping family, and savings. The primary uses of CT funds were investment in businesses and livestock for savings. AGYW use of cash changed over instalments. AGYW consulted a variety of sources when deciding on how to use the cash, primarily mothers, programme personnel, and long-term partners/husbands. CT programmes that give cash directly to AGYW and have a strong entrepreneurial mentorship component could have implications for HIV prevention, SRH, and overall social and economic development

Pattern formation of reaction-diffusion system having self-determined flow in the amoeboid organism of Physarum plasmodium

The amoeboid organism, the plasmodium of Physarum polycephalum, behaves on the basis of spatio-temporal pattern formation by local contraction-oscillators. This biological system can be regarded as a reaction-diffusion system which has spatial interaction by active flow of protoplasmic sol in the cell. Paying attention to the physiological evidence that the flow is determined by contraction pattern in the plasmodium, a reaction-diffusion system having self-determined flow arises. Such a coupling of reaction-diffusion-advection is a characteristic of the biological system, and is expected to relate with control mechanism of amoeboid behaviours. Hence, we have studied effects of the self-determined flow on pattern formation of simple reaction-diffusion systems. By weakly nonlinear analysis near a trivial solution, the envelope dynamics follows the complex Ginzburg-Landau type equation just after bifurcation occurs at finite wave number. The flow term affects the nonlinear term of the equation through the critical wave number squared. Contrary to this, wave number isn't explicitly effective with lack of flow or constant flow. Thus, spatial size of pattern is especially important for regulating pattern formation in the plasmodium. On the other hand, the flow term is negligible in the vicinity of bifurcation at infinitely small wave number, and therefore the pattern formation by simple reaction-diffusion will also hold. A physiological role of pattern formation as above is discussed.Comment: REVTeX, one column, 7 pages, no figur

Cash Transfer to Adolescent Girls and Young Women to Reduce Sexual Risk Behavior (CARE): Protocol for a Cluster Randomized Controlled Trial.

BACKGROUND: The HIV epidemic in Eastern and Southern Africa is characterized by a high incidence and prevalence of HIV infection among adolescent girls and young women (AGYW) aged 15-24 years. For instance, in some countries, HIV prevalence in AGYW aged 20-24 years exceeds that in AGYW aged 15-19 years by 2:1. Sauti (meaning voices), a project supported by the United States Agency for International Development, is providing HIV combination prevention interventions to AGYW in the Shinyanga region, Tanzania. OBJECTIVE: The aim of this study is to determine the impact of cash transfer on risky sexual behavior among AGYW receiving cash transfer and HIV combination prevention interventions. This paper describes the research methods and general protocol of the study. Risky sexual behavior will be assessed by herpes simplex virus type 2 (HSV-2) incidence, compensated sex (defined as sexual encounters motivated by exchange for money, material support, or other benefits), and intergenerational sex (defined as a sexual partnership between AGYW and a man 10 or more years older). Through a qualitative study, the study seeks to understand how the intervention affects the structural and behavioral drivers of the HIV epidemic. METHODS: The trial employs audio computer-assisted self-interviewing, participatory group discussions (PGDs), and case studies to collect data. A total of 30 matched villages (15 intervention and 15 control clusters) were randomized to either receive cash transfer delivered over 18 months in addition to other HIV interventions (intervention arm) or to receive other HIV interventions without cash transfer (control arm). Study participants are interviewed at baseline and 6, 12, and 18 months to collect data on demographics, factors related to HIV vulnerabilities, family planning, sexual risk behavior, gender-based violence, and HSV-2 and HIV infections. A total of 6 PGDs (3 intervention, 3 control) were conducted at baseline to describe perceptions and preferences of different intervention packages, whereas 20 case studies are used to monitor and unearth the dynamics involved in delivery and uptake of cash transfer. RESULTS: The study was funded in June 2017; enrollment took place in December 2017. A total of two rounds of the follow-up survey are complete, and one round has yet to be conducted. The results are expected in December 2019 and will be disseminated through conferences and peer-reviewed publications. CONCLUSIONS: This study will document the synergetic impact of cash transfer in the presence of HIV combination prevention interventions on risky sexual behavior among out-of-school AGYW. The results will strengthen the evidence of cash transfer in the reduction of risky sexual behavior and provide feasible HIV prevention strategies for AGYW. TRIAL REGISTRATION: Clinicaltrials.gov NCT03597243; https://clinicaltrials.gov/ct2/show/NCT03597243. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/14696

Prevalence and correlates of partner violence among adolescent girls and young women: Evidence from baseline data of a cluster randomised trial in Tanzania.

BACKGROUND: Little has been documented about partner violence among adolescent girls and young women (AGYW) who are out of school, a factor associated with HIV acquisition. To understand areas for prioritising HIV prevention intervention efforts, we explored the prevalence and correlates of partner violence among out of school AGYW in Shinyanga, Tanzania. METHODS: A cross-sectional analysis of data from AGYW aged 15-23 years recruited in a cluster randomised trial conducted between October and December 2017 was used to examine correlates of partner violence. Data were collected through an Audio Computer-Assisted Self-interview. Multivariate logistic regression analysis was used to evaluate the association. RESULTS: 2276 (75.5%) AGYW were sexually active. Of these, 816 (35.9%) reported having experienced violence from partners in the last six months. After adjusting for other covariates, being formerly married (AOR = 1.55, 95% CI:1.02, 2.37), having children (AOR = 1.79, 95% CI:1.47, 2.16), anxiety and depression symptoms (AOR = 3.27, 95%CI: 2.15, 4.96), having engaged in sex work in the past six months (AOR = 1.92, 95% CI: 1.45, 2.53) and economic deprivation (AOR = 1.61, 95% CI: 1.34,1.92) were significantly associated with partner violence. CONCLUSIONS: Almost one in three sexually active AGYW had experienced partner violence in the 6 months preceding the survey. The findings underscore the need for future research to focus on understanding the reasons and dynamics underlying high level of partner violence among AGYW. Furthermore, there is a need for implementing intervention programs that aim to reduce economic deprivation among AGYWs and address social norms and structures perpetuating violence against AGYW. TRIAL REGISTRATION: ClinicalTrials.gov-ID NCT03597243

Anti-cancer effects and mechanism of actions of aspirin analogues in the treatment of glioma cancer

INTRODUCTION: In the past 25 years only modest advancements in glioma treatment have been made, with patient prognosis and median survival time following diagnosis only increasing from 3 to 7 months. A substantial body of clinical and preclinical evidence has suggested a role for aspirin in the treatment of cancer with multiple mechanisms of action proposed including COX 2 inhibition, down regulation of EGFR expression, and NF-κB signaling affecting Bcl-2 expression. However, with serious side effects such as stroke and gastrointestinal bleeding, aspirin analogues with improved potency and side effect profiles are being developed. METHOD: Effects on cell viability following 24 hr incubation of four aspirin derivatives (PN508, 517, 526 and 529) were compared to cisplatin, aspirin and di-aspirin in four glioma cell lines (U87 MG, SVG P12, GOS – 3, and 1321N1), using the PrestoBlue assay, establishing IC50 and examining the time course of drug effects. RESULTS: All compounds were found to decrease cell viability in a concentration and time dependant manner. Significantly, the analogue PN517 (IC50 2mM) showed approximately a twofold increase in potency when compared to aspirin (3.7mM) and cisplatin (4.3mM) in U87 cells, with similar increased potency in SVG P12 cells. Other analogues demonstrated similar potency to aspirin and cisplatin. CONCLUSION: These results support the further development and characterization of novel NSAID derivatives for the treatment of glioma

The impact of surface chemistry modification on macrophage polarisation

Macrophages are innate immune cells that have a central role in combating infection and maintaining tissue homeostasis. They exhibit remarkable plasticity in response to environmental cues. At either end of a broad activation spectrum are pro-inflammatory (M1) and anti-inflammatory (M2) macrophages with distinct functional and phenotypical characteristics. Macrophages also play a crucial role in orchestrating immune responses to biomaterials used in the fabrication of implantable devices and drug delivery systems. To assess the impact of different surface chemistries on macrophage polarisation, human monocytes were cultured for 6 days on untreated hydrophobic polystyrene (PS) and hydrophilic O2 plasma-etched polystyrene (O2-PS40) surface. Our data clearly show that monocytes cultured on the hydrophilic O2-PS40 surface are polarised towards an M1-like phenotype, as evidenced by significantly higher expression of the pro-inflammatory transcription factors STAT1 and IRF5. By comparison, monocytes cultured on the hydrophobic PS surface exhibited an M2-like phenotype with high expression of mannose receptor (MR) and production of the anti-inflammatory cytokines IL-10 and CCL18. While the molecular basis of such different patterns of cell differentiation is yet to be fully elucidated, we hypothesise that it is due to the adsorption of different biomolecules on these surface chemistries. Indeed our surface characterisation data show quantitative and qualitative differences between the protein layers on that the O2-PS40 surface compared to PS surface which could be responsible for the observed differential macrophage polarisation on each surface