Recommending with an Agenda: Active Learning of Private Attributes using Matrix Factorization

Recommender systems leverage user demographic information, such as age, gender, etc., to personalize recommendations and better place their targeted ads. Oftentimes, users do not volunteer this information due to privacy concerns, or due to a lack of initiative in filling out their online profiles. We illustrate a new threat in which a recommender learns private attributes of users who do not voluntarily disclose them. We design both passive and active attacks that solicit ratings for strategically selected items, and could thus be used by a recommender system to pursue this hidden agenda. Our methods are based on a novel usage of Bayesian matrix factorization in an active learning setting. Evaluations on multiple datasets illustrate that such attacks are indeed feasible and use significantly fewer rated items than static inference methods. Importantly, they succeed without sacrificing the quality of recommendations to users.Comment: This is the extended version of a paper that appeared in ACM RecSys 201

Clinical Profile of Retinal Vasculitis at a Tertiary Eye Care Centre and Outcomes following Management

INTRODUCTION: Retinal Vasculitis is a group of inflammatory disorders of the eye characterised by retinal vascular inflammation along with intra-ocular inflammation. It preferentially affects the veins, but rarely arteries or arterioles or both veins and arteries can be affected. It is most commonly associated with presence of retinal haemorrhages or vitreous haemorrhages. Recurrence of vitreous haemorrhages is a common feature which might later get complicated by development of retinitis proliferens followed by retinal detachment, complicated cataract and ultimately secondary glaucoma. Ophthalmoscopic examination and fundus fluorescein angiography along with other investigations play a key role in the diagnosis and management of retinal vasculitis. AIM OF THE STUDY: PRIMARY OBJECTIVES: 1. To investigate the aetiologies, association with tuberculosis and other systemic illnesses. 2. Management of retinal vasculitis with either systemic steroids, intravitreal anti VEGF, laser photocoagulation, immunosuppressants, vitrectomy or observation based on the case scenario. 3. Visual outcome following treatment of the vasculitis patient. SECONDARY OBJECTIVES: 1. To look for any complications following treatment. 2. Measures to provide rehabilitation for vasculitis patient. MATERIALS AND METHODS 50 cases of retinal vasculitis which attended the vitreo-retina clinic of Regional Institute of Ophthalmology and Government Ophthalmic Hospital, Egmore , Chennai between August 2015 and August 2016 for a period of 1 year were taken up for the study. It is a prospective study. INCLUSION CRITERIA: 1. Age > 18 years, 2. All cases of Retinal Vasculitis presenting with atleast one of the following features - a. Sheathing, b. Perivascular inflammation, c. Superficial and Deep Hemorrhages, d. Staining of vessel wall on FFA. EXCLUSION CRITERIA: 1. Age < 18 years, 2. Patient with pre existing ocular disease like diabetic retinopathy, vein occlusion, arterial occlusion, glaucoma etc. RESULTS: In this study on 77 eyes of 50 retinal vasculitis patients, 31 cases(62%) were due to Eales Disease, 15 cases (30%) were secondary to systemic disease and the remaining 4 cases (8%) were secondary to ocular disease. Amongst the 50 case of Retinal vasculitis which visited the retina clinic, maximum incidence was in the age group of 18-28 years (44%) followed by 29-38 years (42%) followed by 39-48 years (7%). The mean age was 30.02 + 12 years. In a study by Biswas [et. al], mean age of presentation was found to be 33 + 11. In a study by Donders in 1958 the average age for men was 28 years and for women it was 30 years. In our study, incidence of Retinal Vasculitis is more in males (80%) as compared to females (20%). Out of the 31 patients with Eales’s Disease, 30 were male and only 1 was female. Out of 4 cases with retinal vasculitis secondary to ocular disease, 3 were males and 1 was female. Out of 15 cases with retinal vasculitis secondary to systemic disease, 7 were males and 8 were females. CONCLUSION: Retinal vasculitis is a challenge for an ophthalmologist both to diagnose and to treat. If left untreated it may lead to total loss of vision. Ophthalmologist also play an important role in finding out systemic diseases in a patient who have no other manifestations apart from ophthalmological signs. That aids in timely treatment of the underlying cause. For each patient treatment has to be individualised based on their findings. A multidisciplinary approach is required in cases with systemic involvement. In our study, primary vasculitis is the predominant form of vasculitis accounting for 62% of the cases. Male predilection is noted with 80% cases being males and 20% being females. Most commonly involved age group is between 18-28 years of age (44%). Maximum cases had a bilateral presentation (54%) with defective vision being the chief complaint in most of the cases (88%). Oral corticosteroids were the main modality of treatment in our study. Patients treated with laser photo-coagulation did not show worsening of signs. Observation was helpful in patients with vitreous hemorrhage. Treatment of associated systemic conditions in addition to oral corticosteroids showed improvement in visual acuity. Although systemic steroids are efficacious in controlling active disease and easily administered, adverse systemic complications is a matter of concern. Since the time period of the study was short (1 year), we have kept 3 months as the criteria for assessing the outcome of management. Due to referrals to various departments, patients took time to review with us with all the work up. More long term studies are required to overcome these shortcomings

Review of Flying Ad-hoc Networks (FANETs)

As a result of recent advances in processors, sensors, communications, and networking technologies, the roles and capabilities of Unmanned Aerial Vehicles (UAVs) have evolved rapidly, and their usage in military and civilian areas has become commonplace. The focus is now changing from the use of one large UAV to that of multiple UAVs that can coordinate to achieve high-level goals. Using the concept of Mobile Ad-hoc Networks (MANETs), new networking paradigms like Flying Ad-hoc Networks (FANETs) have evolved to tackle high mobility and fast topology change. This paper focuses on Static Routing protocols, namely, LCAD, multi-level hierarchical routing and data centric routing. The mobility models employed for FANETs are also addressed. Finally, the future scope of this technology is highlighted

The interactions between xenobiotics and soil microbial communities

Excessive use and lack of appropriate disposal technology for industrial xenobiotics have resulted in the contamination of ecosystems globally impacting the self-regulating capacity of the biosphere. This often results in irreversible alterations of ecosystem’s structure and function, but the outcomes of these events on soil microbial communities (and their functional capabilities) are poorly understood. Assessing the impact of xenobiotics on soil microbial communities is of paramount importance as they play a vital role in ecosystem services and maintain soil health, which are key requirements for sustainable land use in terms of food security and environmental sustainability. Bacteria are the most abundant and diverse soil micro-flora and play a key role in the biogeochemical cycles of important elements including carbon (C), nitrogen (N), and phosphorus (P) and sulphur (S). The current work aimed to unravel the two-way interactions between xenobiotics and soil microbial communities; i.e., how soil microbial communities modulate xenobiotic persistence through biodegradation and what impacts xenobiotic have on soil microbial community’s structure and functions, with particular focus on widely used pesticides (chlorpyrifos and imidacloprid) and industrial solvents (trichloroethene). In Chapter 2, characterisation of active methanotrophs involved in trichloroethene (TCE) degradation under different methane (CH4) concentrations was evaluated. Methane (CH4) enriched methanotrophic consortia from three Australian soils (Sydney University, Victoria Park and Botany Industrial Park) were examined for their effectiveness in TCE (50μM) degradation at 1%, 10% and 33% CH4 concentration at 20oC. Only the methanotrophic consortium from Sydney University (SU) soil was able to co-metabolically degrade TCE. The (SU) methanotrophic growth and TCE degradation was accelerated under high CH4 concentration degrading up to 30% (within 2 days) and 20% (within 5 days) TCE under 33% and 10% CH4, respectively. No degradation of TCE was observed at 1% CH4 concentration or in the absence of CH4 suggesting the dependence on relatively high CH4 availability for TCE degradation. pmoA-based stable isotope probing (SIP), terminal restriction fragment length polymorphism (T-RFLP), clone library construction and sequencing of TCE degrading SU methanotroph consortium revealed the dominance of novel uncultivable Type I methanotrophs (distantly related to Methylovulum-88%) belonging to TRF-53 in TCE degradation. In Chapter 3, the effects of the pesticides chlorpyrifos (CP) and imidacloprid (IC) on soil microbial processes (e.g. biodegradation and respiration) and community structure were evaluated. Two soil treatments (from five sugarcane farms), one with no history of pesticide application (non-treated; 1H, 2H, 3H, 4H and 5H) and the other with ~20 years pesticide application (pesticide-treated; 1R, 2R, 3R, 4R and 5R), were used in this study. MicroRespTM, q-PCR and T-RFLP analyses were combined to explore the relationship between pesticide degradation and soil microbial communities in soils spiked (3 times) with 10 mg/kg of CP or IC, under lab conditions. The results showed that the half-lives of CP decreased with application frequency and were 23-47, 8-20 and 3-17 days following the first, second and third application, respectively (for soils from five sugarcane farms). In particular, the soils from 4R, 4H and 5R showed enhanced CP degradation even when not exposed to CP for last 13 years due to legacy effect of the pesticide. Parallel analyses of IC degradation (10 mg/kg) showed high persistence of this pesticide in soil where repeated application increased half-lives from 30-60 days for the first treatment to 45-65 days for second treatment. The application of both pesticides (CP and IC) reduced soil respiration (basal and substrate-induced) between 7-76% with the lowest respiration found in 5R and highest in 1R after the pesticides treatment, indicating that application of pesticides had an adverse impact on soil functional activity. The molecular analyses showed that both CP and IC significantly altered the soil bacterial community structure and reduced diversity, evenness and richness. In Chapter 4, sequential soil and liquid culture enrichments enabled the isolation of six bacterial CP degraders with sequence homologies to Xanthomonas sp. (3), Pseudomonas sp. (1), Rhizobium sp. (1) and Lysobacter sp. (1). The efficacy of the isolated strains: Xanthomonas sp. 4R3-M1, Pseudomonas sp. 4H1-M3 and Rhizobium sp. 4H1-M1 were further investigated for biodegradation of CP and its primary metabolic product, TCP (3,5,6-trichloro-2-pyridinol). The results indicated that all three bacterial strains utilised CP (10 mg/l) and TCP (as CP degradation product) in mineral salt media (MSM) as a sole source of C and N. Bacterial strains Xanthomonas sp. 4R3-M1 and Pseudomonas sp. 4H1-M3 could also degrade 10 mg/l TCP as a sole C- and N-source, when provided externally. Thus, these bacterial strains promise to be effective in practical application of bioremediation of both CP and TCP. In Chapter 5, using next-generation sequencing, the structure and potential functions of bacterial communities in pesticide-treated and non-treated reference sites was compared at finer levels. Across all soils, the functional beta diversity was correlated with taxonomic diversity indicating possible linkages between the structure and functioning of soil microbial communities. The pesticide-treated sites had higher relative abundance of Proteobacteria and Bacteroidetes, with Archaea exhibiting the opposite pattern. Metagenomic analysis revealed increases in the relative abundance of genes associated with key specialised functions (iron acquisition and metabolism, motility, cell signalling, stress response) at pesticide-treated sites. The results suggested impacts of long-term pesticide application on soil microbial community composition and potential functions. Despite, a CP legacy effect, no marked difference was observed in abundance of genes related to P-metabolism between pesticide-treated and non-treated sites. Overall, the results supported taxonomic and functional adaptations in the soil microbial communities following pesticide treatment. Overall, this study provides the novel insights into the interaction between xenobiotics and soil microbial communities both at structural (diversity, community structure) and functional (degradation) levels and should be considered in developing new bioremediation technologies and agronomic practices such as number and frequency of pesticide applications