Robust Randomness Amplifiers: Upper and Lower Bounds

A recent sequence of works, initially motivated by the study of the nonlocal properties of entanglement, demonstrate that a source of information-theoretically certified randomness can be constructed based only on two simple assumptions: the prior existence of a short random seed and the ability to ensure that two black-box devices do not communicate (i.e. are non-signaling). We call protocols achieving such certified amplification of a short random seed randomness amplifiers. We introduce a simple framework in which we initiate the systematic study of the possibilities and limitations of randomness amplifiers. Our main results include a new, improved analysis of a robust randomness amplifier with exponential expansion, as well as the first upper bounds on the maximum expansion achievable by a broad class of randomness amplifiers. In particular, we show that non-adaptive randomness amplifiers that are robust to noise cannot achieve more than doubly exponential expansion. Finally, we show that a wide class of protocols based on the use of the CHSH game can only lead to (singly) exponential expansion if adversarial devices are allowed the full power of non-signaling strategies. Our upper bound results apply to all known non-adaptive randomness amplifier constructions to date.Comment: 28 pages. Comments welcom

Microbial dynamics during various activities in residential areas of Lahore, Pakistan

Bioaerosols are ubiquitous in the atmosphere with their levels affected by a variety of environmental factors as well as type of activities being carried out at any specific time. The present study investigated how indoor activities influence bioaerosol concentrations in five residential houses of Lahore. Agar coated petri plates were exposed face upwards for twenty minutes in kitchens and living rooms during activity and non-activity periods. The temperature and relative humidity levels were noted as well. The bioaerosol concentrations in kitchens during the activity time ranged between 1022 to 4481 cfu/m3 and in living rooms from 1179 to 3183 cfu/m3 . Lower values were observed during non-activity periods. A paired-t test revealed a significant difference in bacterial loads during activity and non-activity times in both micro-environments (p = 0.038 in kitchen and p = 0.021 in living room). The predominant species identified were Micrococcus spp., Staphylococcus spp., and Bacillus spp. which are a common constituent of the indoor environment and are known to be opportunistic pathogens as well

Free randomness can be amplified

Are there fundamentally random processes in nature? Theoretical predictions, confirmed experimentally, such as the violation of Bell inequalities, point to an affirmative answer. However, these results are based on the assumption that measurement settings can be chosen freely at random, so assume the existence of perfectly free random processes from the outset. Here we consider a scenario in which this assumption is weakened and show that partially free random bits can be amplified to make arbitrarily free ones. More precisely, given a source of random bits whose correlation with other variables is below a certain threshold, we propose a procedure for generating fresh random bits that are virtually uncorrelated with all other variables. We also conjecture that such procedures exist for any non-trivial threshold. Our result is based solely on the no-signalling principle, which is necessary for the existence of free randomness.Comment: 5+7 pages, 2 figures. Updated to match published versio

Measurement of NO2 indoor and outdoor concentrations in selected public schools of Lahore using passive sampler

Higher levels of NO2 are a danger to human health especially for children. A seven day study was carried to find out the ambient concentrations of NO2in 27 schools of Lahore with the help of passive samplers. In each school three sites were selected, viz: laboratory, corridor and outdoors. After 7 days exposure the tubes were subjected to spectrophotometric analysis. Results showed that the maximum values measured in laboratory, outdoor and corridors were 376µg/m3 , 222µg/m3 and 77µg/m3 . Minimum values for laboratory, outdoor and corridors were 10µg/m3 , 20µg/m3 and 8µg/m3 . Factors affecting these values were laboratory activities and proximity to main roads. These values were significantly higher than the standard values defined by EPA. Therefore children in schools were at risk of developing health complications

Exposure to PM <inf>10</inf>, PM <inf>2.5</inf>, PM <inf>1</inf> and carbon monoxide on roads in Lahore, Pakistan

Particulate matter pollution is one of the major environmental concerns in Pakistan. Over the past 20 years there has been a considerable increase in the number of motor vehicles. The present study was conducted to assess journey time and roadside exposure to particulate matter and carbon monoxide along major roads of Lahore during November, 2007. Measurements of particulate mass and carbon monoxide were carried out continuously inside an air conditioned vehicle, while commuting, and outside the vehicle at 36 different locations in the city. Additionally, monitoring was undertaken at a background site throughout the period. The overall mean journey-time concentrations of PM 10, PM 2.5, PM 1, PM 10-2.5 and CO were 103 μg/m 3, 50 μg/m 3, 38 μg/m 3, 53 μg/m 3 and 8 ppm, respectively. At the roadside average PM 10, PM 2.5, PM 1, PM 10-2.5 and CO concentrations were 489 μg/m 3, 91 μg/m 3, 52 μg/m 3, 397 μg/m 3 and 4 ppm, respectively. The highest levels were found at the sites with traffic congestion reflecting, not only, the large contribution of automobile exhaust but also the resuspension of road dust. The majority of public transport vehicles in Lahore are not air-conditioned and it is very likely that commuters are exposed to the similar high levels of pollution. © Taiwan Association for Aerosol Research

Automotive related exposure to particulate air pollution in developing countries cities

Poor urban air quality in developing countriesis a growing public health challenge due to rises in population, industries, urbanization and vehiclesalong with insufficient air quality management. Among the range of air pollutants exposure to particulate matter (PM) is of greatest concern due to its association with chronic obstructive pulmonary diseases. The present study reports traffic related exposure to PM by the roads in Lahore, Pakistan. The measurements of mass and number of PM were carried out by GRIMM analysers (Model 1.108 and Model 1.101) and condensation particle counter (TSI 3781). The heavy metals concentration in PM was determined by Graphite Furnace Atomic Absorption Spectrophotometer (Unicam atomic absorption, Cambridge, UK).The mean hourly average concentration of PM10, PM2.5, PM1 and PM10 – 2.5 at the road siteswas higher during weekdays(305 μg/m3, 84 μg/m3, 61 μg/m3 and 222 μg/m3, respectively) in comparison to the weekend (136 μg/m3, 60 μg/m3, 40 μg/m3 and 76μg/m3, respectively). At the background site the levels in the same size fractions were 206μg/m3, 63μg/m3, 31μg/m3, and 143μg/m3, respectively. Likewise, the number concentration of ultrafine particles was considerably higher at road sites (417,003 #/m3) than the background(97,300 #/m3).The concentration of heavy metals in PM decreased in the following order: Si, Al, Zn, Mn, Cu, Ni, Cd, Pb. Overall, the concentration of PM10, PM2.5 and toxic metals (Mn, Cd, Ni) was substantially higher than guidelines by the WHO. Furthermore, relatively higher levels of the fine fraction (PM2.5 and PM1) in the background reflect their higher residence time and resultant increased risk of exposure to the wider public beyond that of the vicinity to automotive sources. Everyday commuters, mostly on two and three wheelers as well asthe residential population in urban areas are at an enhanced risk of exposure to high levels of particulate pollution

Ultrafine particles in rural and urban dwellings with different household fuel use in developing countries – An example from Pakistan

Exposure to indoor particulate matter (PM) is a major public health concern, in particular, in developing countries where solid fuels are typically used as a household energy source.Despite the fact that emission from these fuels can have a dominant fraction of ultrafine particles, exposure to PM is generally characterised in terms of mass concentration of PM10 and PM2.5. The present study was carried out to examine the number concentration of ultrafine particles in rural and urban Pakistani households with different fuels. Air samples were collected from kitchens, living rooms and courtyards of two rural sites (Site I - Solid fuel; Site II - Natural gas) and an urban site (Natural gas) by using condensation particle counters.At rural site –I the 24 hour mean concentration of particles in the kitchen, living room and outdoors was 40,991#/cm3 (± 7472), 30,291#/cm3 (± 13774) and 34,534#/cm3 (± 4947), respectively. During cooking the number concentration can increase significantly with an average hourly maximum value of 169,455#/cm3. Higher outdoors levels than in living rooms highlight the effect of cooking in open kitchens on ambient levels. At the rural site II the daily average number concentration in living rooms was in the range of 10,745 – 16,126 #/cm3 with a mean of 13,542 #/cm3.These values were more than half those in living rooms at rural site I. Whereas in the kitchen the 24hour mean was 27,446#/cm3 (± 4487). At the urban site the mean 24 hour average in the living rooms and kitchens was 45,466 #/cm3 (± 5919)and 65,904 #/cm3 (± 11490), respectively. The 24 hour mean concentration was more than double in the urban kitchens than in rural kitchens at site II. The 24 hour average outdoors was 33,424 #/cm3 (± 6037)– slightly lower than outdoors at rural site I. Overall, the number concentration was higher in kitchens using natural gas fuel at the urban site than in those with solid fuels and natural gas at rural sites. While between rural sites the households with solid fuel had higher concentrations than those with natural gas. Furthermore, outdoors at rural site-I households had higher concentrations as compared to urban household outdoors

An experimental test of all theories with predictive power beyond quantum theory

According to quantum theory, the outcomes of future measurements cannot (in general) be predicted with certainty. In some cases, even with a complete physical description of the system to be measured and the measurement apparatus, the outcomes of certain measurements are completely random. This raises the question, originating in the paper by Einstein, Podolsky and Rosen, of whether quantum mechanics is the optimal way to predict measurement outcomes. Established arguments and experimental tests exclude a few specific alternative models. Here, we provide a complete answer to the above question, refuting any alternative theory with significantly more predictive power than quantum theory. More precisely, we perform various measurements on distant entangled photons, and, under the assumption that these measurements are chosen freely, we give an upper bound on how well any alternative theory could predict their outcomes. In particular, in the case where quantum mechanics predicts two equally likely outcomes, our results are incompatible with any theory in which the probability of a prediction is increased by more than ~0.19. Hence, we can immediately refute any already considered or yet-to-be-proposed alternative model with more predictive power than this.Comment: 13 pages, 4 figure

Heavy metal composition of particulate matter in rural and urban residential built environments in Pakistan

Heavy metals in outdoor and indoor airborne particulate matter (PM) and dust in different residential built environmentsat two rural and one urban site in Pakistan were analysed. An eight stage non-viable impactor (Thermo Fisher Scientific Inc., USA) loaded with EMP 2000 glass microfiber filter papers (Whatman, England) was used to collect airborne PM.The indoordust samples (settled dust) were collected from different indoor surfaces (floor, cupboards) in living rooms and kitchens from houses at rural sites. The outdoor samples were collected from courtyards of the houses.At the urban site dust samples were also collected by the roads at 27 different locations around Lahoreand at a background site (University of Veterinary and Animal Sciences).Additionally, samples of dung cake, used as solid fuel, at one of the rural sites were taken.Heavy metals (Si, Al, Zn, Mn, Cu, Ni, Cd, Pb, Co and As) were determined by Graphite Furnace Atomic Absorption Spectrophotometer. At rural site I, in general, the concentrations of metals were higher outdoors than indoors, except for slightly higher indoor levels of Cu (0.85μg/m3 indoor: 0.56 outdoorμg/m3), Si (3.31μg/m3 indoor: 3.17 outdoorμg/m3) and Pb(11.99 ng/m3 indoor: 9.32 outdoor ng/m3). At the rural site II the mean concentration were higher outdoors than indoors, excluding Ni which was considerably higher indoors (55.68 ng/m3) than outdoors (31.91 ng/m3).At the urban site,outdoors, Si had the highest concentration (3.46 μg/m3) followed by Al, Zn, Mn, Cu, Ni, Cd, Pb and Co. Similarly, the indoor levels had a maximum contribution from Si (12.30 μg/m3) followed by Al, Mn, Zn, Cu, Cd, As, Pb, Ni and Co.With reference to dust at rural site I the top five metals outdoors were Si (708 mg/kg), Al, Cu, Zn and Pb (52 mg/kg) while, indoors Al was highest (281 mg/kg), followed by Si, Cu, Zn and Pb (57 mg/kg). At rural site II, both outdoors and indoors, Al (274 mg/kg – outdoor: 266 mg/kg - indoor), Si, Zn, Cu and Pb (61 mg/kg – outdoor: 80 mg/kg - indoor) were the five most abundant metals.The main five metals in decreasing order of their concentration in the road dust around Lahore were Si (686 mg/kg), Al, Cu, Zn and Pb (81 mg/kg). On the other hand, the dust samples from the background site showed Si (345 mg/kg) > Al >Pb> Cu > Zn (73 mg/kg). The airborne metal concentration of Pb was within the guideline value of WHO (0.5 μg/m3) but the levels of Mn, Cd and Ni were higher at all sites than the guidelines proposed by European Commission and WHO highlighting the risk of exposure to toxic metals in non-occupational environments