An objective based classification of aggregation techniques for wireless sensor networks

Wireless Sensor Networks have gained immense popularity in recent years due to their ever increasing capabilities and wide range of critical applications. A huge body of research efforts has been dedicated to find ways to utilize limited resources of these sensor nodes in an efficient manner. One of the common ways to minimize energy consumption has been aggregation of input data. We note that every aggregation technique has an improvement objective to achieve with respect to the output it produces. Each technique is designed to achieve some target e.g. reduce data size, minimize transmission energy, enhance accuracy etc. This paper presents a comprehensive survey of aggregation techniques that can be used in distributed manner to improve lifetime and energy conservation of wireless sensor networks. Main contribution of this work is proposal of a novel classification of such techniques based on the type of improvement they offer when applied to WSNs. Due to the existence of a myriad of definitions of aggregation, we first review the meaning of term aggregation that can be applied to WSN. The concept is then associated with the proposed classes. Each class of techniques is divided into a number of subclasses and a brief literature review of related work in WSN for each of these is also presented

Identification of stingless bees (Hymenoptera: Apidae) in Kenya using Morphometrics and DNA barcoding

Stingless bees are important pollinators of wild plants and crops. The identity of stingless bee species in Africa has not been fully documented. The present study explored the utility of morphometrics and DNA barcoding for identification of African stingless bee populations, and to further employ these tools to identify potential cryptic variation within species. Stingless bee samples were collected from three ecological zones, namely Kakamega Forest, Mwingi and Arabuko-Sokoke Forest, which are geographically distant and cover high, medium and low altitudes, respectively. Forewing and hind leg morphometric characters were measured to determine the extent of morphological variation between the populations. DNA barcodes were generated from the mitochondrial cytochrome c-oxidase I (COI) gene. Principal Component Analysis (PCA) on the morphometric measurements separated the bee samples into three clusters: (1) Meliponula bocandei; (2) Meliponula lendliana + Plebeina hildebrandti; (3) Dactylurina schmidti + Meliponula ferruginea black + Meliponula ferruginea reddish brown, but Canonical Variate Analysis (CVA) separated all the species except the two morphospecies (M. ferruginea reddish brown and black). The analysis of the COI sequences showed that DNA barcoding can be used to identify all the species studied and revealed remarkable genetic distance (7.3%) between the two M. ferruginea morphs. This is the first genetic evidence that M. ferruginea black and M. ferruginea reddish brown are separate species

Supergravity Inflation Free from Harmful Relics

We present a realistic supergravity inflation model which is free from the overproduction of potentially dangerous relics in cosmology, namely moduli and gravitinos which can lead to the inconsistencies with the predictions of baryon asymmetry and nucleosynthesis. The radiative correction turns out to play a crucial role in our analysis which raises the mass of supersymmetry breaking field to intermediate scale. We pay a particular attention to the non-thermal production of gravitinos using the non-minimal Kahler potential we obtained from loop correction. This non-thermal gravitino production however is diminished because of the relatively small scale of inflaton mass and small amplitudes of hidden sector fields.Comment: 10 pages, revtex, 1 eps figure, references added, conclusion section expande

Generalizing the per-protocol treatment effect: The case of ACTG A5095

Background Intention-to-treat comparisons of randomized trials provide asymptotically consistent estimators of the effect of treatment assignment, without regard to compliance. However, decision makers often wish to know the effect of a per-protocol comparison. Moreover, decision makers may also wish to know the effect of treatment assignment or treatment protocol in a user-specified target population other than the sample in which the trial was fielded. Here, we aimed to generalize results from the ACTG A5095 trial to the US recently HIV-diagnosed target population. Methods We first replicated the published conventional intention-to-treat estimate (2-year risk difference and hazard ratio) comparing a four-drug antiretroviral regimen to a three-drug regimen in the A5095 trial. We then estimated the intention-to-treat effect that accounted for informative dropout and the per-protocol effect that additionally accounted for protocol deviations by constructing inverse probability weights. Furthermore, we employed inverse odds of sampling weights to generalize both intention-to-treat and per-protocol effects to a target population comprising US individuals with HIV diagnosed during 2008–2014. Results Of 761 subjects in the analysis, 82 dropouts (36 in the three-drug arm and 46 in the four-drug arm) and 59 protocol deviations (25 in the three-drug arm and 34 in the four-drug arm) occurred during the first 2 years of follow-up. A total of 169 subjects incurred virologic failure or death. The 2-year risks were similar both in the trial and in the US HIV-diagnosed target population for estimates from the conventional intention-to-treat, dropout-weighted intention-to-treat, and per-protocol analyses. In the US target population, the 2-year conventional intention-to-treat risk difference (unit: %) for virologic failure or death comparing the four-drug arm to the three-drug arm was −0.4 (95% confidence interval: −6.2, 5.1), while the hazard ratio was 0.97 (95% confidence interval: 0.70, 1.34); the 2-year risk difference was −0.9 (95% confidence interval: −6.9, 5.3) for the dropout-weighted intention-to-treat comparison (hazard ratio = 0.95, 95% confidence interval: 0.68, 1.32) and −0.7 (95% confidence interval: −6.7, 5.5) for the per-protocol comparison (hazard ratio = 0.96, 95% confidence interval: 0.69, 1.34). Conclusion No benefit of four-drug antiretroviral regimen over three-drug regimen was found from the conventional intention-to-treat, dropout-weighted intention-to-treat or per-protocol estimates in the trial sample or target population

Inflationary Cosmology with Five Dimensional SO(10)

We discuss inflationary cosmology in a five dimensional SO(10) model compactified on $S^1/(Z_2\times Z_2')$, which yields $SU(3)_c\times SU(2)_L\times U(1)_Y\times U(1)_X$ below the compactification scale. The gauge symmetry $SU(5)\times U(1)_X$ is preserved on one of the fixed points, while ``flipped'' $SU(5)'\times U(1)'_X$ is on the other fixed point. Inflation is associated with $U(1)_X$ breaking, and is implemented through $F$-term scalar potentials on the two fixed points. A brane-localized Einstein-Hilbert term allows both branes to have positive tensions during inflation. The scale of $U(1)_X$ breaking is fixed from $\delta T/T$ measurements to be around $10^{16}$ GeV, and the scalar spectral index $n=0.98-0.99$. The inflaton field decays into right-handed neutrinos whose subsequent out of equilibrium decay yield the observed baryon asymmetry via leptogenesis.Comment: 1+19 pages, improved discussion of 5D cosmology, Version to appear in PR

Dynamics of a large extra dimension inspired hybrid inflation model

In low scale quantum gravity scenarios the fundamental scale of nature can be as low as TeV, in order to address the naturalness of the electroweak scale. A number of difficulties arise in constructing specific models; stabilisation of the radius of the extra dimensions, avoidance of overproduction of Kaluza Klein modes, achieving successful baryogenesis and production of a close to scale-invariant spectrum of density perturbations with the correct amplitude. We examine in detail the dynamics, including radion stabilisation, of a hybrid inflation model that has been proposed in order to address these difficulties, where the inflaton is a gauge singlet residing in the bulk. We find that for a low fundamental scale the phase transition, which in standard four dimensional hybrid models usually ends inflation, is slow and there is second phase of inflation lasting for a large number of e-foldings. The density perturbations on cosmologically interesting scales exit the Hubble radius during this second phase of inflation, and we find that their amplitude is far smaller than is required. We find that the duration of the second phase of inflation can be short, so that cosmologically interesting scales exit the Hubble radius prior to the phase transition, and the density perturbations have the correct amplitude, only if the fundamental scale takes an intermediate value. Finally we comment briefly on the implications of an intermediate fundamental scale for the production of primordial black holes and baryogenesis.Comment: 9 pages, 2 figures version to appear in Phys. Rev. D, additional references and minor changes to discussio

Response of a Lake Michigan coastal lake to anthropogenic catchment disturbance

A paleolimnological investigation of post-European sediments in a Lake Michigan coastal lake was used to examine the response of Lower Herring Lake to anthropogenic impacts and its role as a processor of watershed inputs. We also compare the timing of this response with that of Lake Michigan to examine the role of marginal lakes as ‘early warning’ indicators of potential changes in the larger connected system and their role in buffering Lake Michigan against anthropogenic changes through biotic interactions and material trapping. Sediment geochemistry, siliceous microfossils and nutrient-related morphological changes in diatoms, identified three major trophic periods in the recent history of the lake. During deforestation and early settlement (pre-1845–1920), lake response to catchment disturbances results in localized increases in diatom abundances with minor changes in existing communities. In this early phase of disturbance, Lower Herring Lake acts as a sediment sink and a biological processor of nutrient inputs. During low-lake levels of the 1930s, the lake goes through a transitional period characterized by increased primary productivity and a major shift in diatom communities. Post-World War II (late 1940s–1989) anthropogenic disturbances push Lower Herring Lake to a new state and a permanent change in diatom community structure dominated by Cyclotella comensis . The dominance of planktonic summer diatom species associated with the deep chlorophyll maximum (DCM) is attributed to epilimnetic nutrient depletion. Declining Si:P ratios are inferred from increased sediment storage of biogenic silica and morphological changes in the silica content of Aulacoseira ambigua and Stephanodiscus niagarae . Beginning in the late 1940s, Lower Herring Lake functions as a biogeochemical processor of catchment inputs and a carbon, nutrient and silica sink. Microfossil response to increased nutrients and increased storage of biogenic silica in Lower Herring Lake and other regional embayments occur approximately 20–25 years earlier than in a nearby Lake Michigan site. Results from this study provide evidence for the role of marginal lakes and bays as nutrient buffering systems, delaying the impact of anthropogenic activities on the larger Lake Michigan system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43091/1/10933_2004_Article_1688.pd

Integral Role of Water in the Solid-State Behavior of the Antileishmanial Drug Miltefosine

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. Open access articleMiltefosine is a repurposed anticancer drug and currently the only orally administered drug approved to treat the neglected tropical disease leishmaniasis. Miltefosine is hygroscopic and must be stored at sub-zero temperatures. In this work we report the X-ray structures of miltefosine monohydrate and methanol solvate, along with 12- and 14-carbon chain analogue hydrates and a solvate. The three hydrates are all isostructural and are conformational isomorphs with Z' = 2. The water bridges the gap between phosphocholine head groups caused by the interdigitated bilayer structure. The two methanol solvates are also mutually isostructural with the head groups adopting a more extended conformation. Again, the solvent bridges the gap between head groups in the bilayer. No anhydrous form of miltefosine or its analogues were isolated, with dehydration resulting in significantly reduced crystallinity. This arises as a result of the integral role that hydrogen bond donors (in the form of water or solvent molecules) play in the stability of the zwitterionic structures

Quasi-free photoproduction of η-mesons off 3He nuclei

Quasi-free photoproduction of η-mesons has been measured off nucleons bound in 3He nuclei for incident photon energies from the threshold region up to 1.4 GeV. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with an almost 4π covering electromagnetic calorimeter, combining the TAPS and Crystal Ball detectors. The η-mesons were detected in coincidence with the recoil nucleons. This allowed a comparison of the production cross section off quasi-free protons and quasi-free neutrons and a full kinematic reconstruction of the final state, eliminating effects from nuclear Fermi motion. In the S11(1535) resonance peak, the data agree with the neutron/proton cross section ratio extracted from measurements with deuteron targets. More importantly, the prominent structure observed in photoproduction off quasi-free neutrons bound in the deuteron is also clearly observed. Its parameters (width, strength) are consistent with the expectations from the deuteron results. On an absolute scale the cross sections for both quasi-free protons and neutrons are suppressed with respect to the deuteron target pointing to significant nuclear final-state interaction effects

Remittance micro-worlds and migrant infrastructure: circulations, disruptions, and the movement of money

Remittances are increasingly central to development discourses in Africa. The development sector seeks to leverage transnational migration and rapid innovations in financial technologies (fintech), to make remittance systems cheaper for end-users and less risky for states and companies. Critical scholarship, however, questions the techno-fix tendency, calling for grounded research on the intersections between remittances, technologies, and everyday life in African cities and beyond. Building on this work, we deploy the concepts of “micro-worlds” and “migrant infrastructure” to make sense of the complex networks of actors, practices, regulations, and materialities that shape remittance worlds. To ground the work, we narrate two vignettes of remittance service providers who operate in Cape Town, South Africa, serving the Congolese diaspora community. We showcase the important role of logistics companies in the “informal” provision of remittance services and the rise of fintech companies operating in the remittance space. These vignettes give substance to the messy and relational dynamics of remittance micro-worlds. This relationality allows us to see how remittances are circulations, not unidirectional flows; how they are not split between formal and informal, but in fact intersect in blurry ways; how digital technologies are central to the story of migrant infrastructures; and how migrants themselves are compositional of these networks. In doing so, we tell a more relational story about how remittance systems are constituted and configured