295 research outputs found

    A review of Malta’s pre-temple Neolithic pottery wares

    Get PDF
    Sites from the earliest known phases of Maltese prehistory often consist of scatters of sherds for the Għar Dalam and Skorba phases (6000–4800 BCE), and tomb contexts for the Żebbuġ phase (3800–3600 BCE). Neolithic studies are, therefore, heavily reliant on the study of pottery. Although traditional typological and seriation-based analyses of the pottery record have substantially enhanced our knowledge of Early Neolithic Malta, there is a growing appreciation of the need to go beyond these approaches to gain new insights. This study reviews the accessible literature on fabric studies on assemblages found in the Maltese Islands, presenting the state of knowledge for the pottery of the Għar Dalam, Skorba (Early Neolithic), and Żebbuġ (Late Neolithic) phases. Microphotographs of pottery wares were selected from a compilation produced for an ongoing project (the MaltaPot project) to illustrate the descriptions found in the literature. The advances made by archaeologists in studying the Maltese Neolithic pottery are reviewed, and suggestions for building on them are proposed, as archaeometric and petrographic techniques have not been applied systematically to Neolithic pottery from Malta.peer-reviewe

    The error of our ways: the experience of self-reported position in a location-based game

    Get PDF
    We present a study of people’s use of positional information as part of a collaborative location-based game. The game exploits self-reported positioning in which mobile players manually reveal their positions to remote players by manipulating electronic maps. Analysis of players’ movements, position reports and communications, drawing on video data, system logs and player feedback, highlights some of the ways in which humans generate, communicate and interpret position reports. It appears that remote participants are largely untroubled by the relatively high positional error associated with self reports. Our analysis suggests that this may because mobile players declare themselves to be in plausible locations such as at common landmarks, ahead of themselves on their current trajectory (stating their intent) or behind themselves (confirming previously visited locations). These observations raise new requirements for the future development of automated positioning systems and also suggest that selfreported positioning may be a useful fallback when automated systems are unavailable or too unreliable

    Rural Malta : first results of the joint Belgo-Maltese survey project

    Get PDF
    The paper presents the first interdisciplinary results of a joint survey project in the north-west of Malta, with finds ranging from the Prehistoric till the Early Modern period. Three permanently inhabited sites were encountered dating to at least the late 6th or early 5th century BCE, with a clearer attestation in the Hellenistic/Roman and Late Antique periods. The resulting reconstructed settlement pattern of the Phoenician/Punic period suggests a managed landscape that seems to be a good reflexion of what is happening in North Africa and elsewhere in the central and western Mediterranean. At least from the Roman period on, these sites seem to have specialised on the production of olive oil.peer-reviewe

    Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

    Full text link
    The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

    Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

    Full text link
    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

    EMA-amplicon-based sequencing informs risk assessment analysis of water treatment systems

    Get PDF
    Illumina amplicon-based sequencing was coupled with ethidium monoazide bromide (EMA) pre-treatment to monitor the total viable bacterial community and subsequently identify and prioritise the target organisms for the health risk assessment of the untreated rainwater and rainwater treated using large-volume batch solar reactor prototypes installed in an informal settlement and rural farming community. Taxonomic assignments indicated that Legionella and Pseudomonas were the most frequently detected genera containing opportunistic bacterial pathogens in the untreated and treated rainwater at both sites. Additionally, Mycobacterium, Clostridium sensu stricto and Escherichia/Shigella displayed high (≥80%) detection frequencies in the untreated and/or treated rainwater samples at one or both sites. Numerous exposure scenarios (e.g. drinking, cleaning) were subsequently investigated and the health risk of using untreated and solar reactor treated rainwater in developing countries was quantified based on the presence of L. pneumophila, P. aeruginosa and E. coli. The solar reactor prototypes were able to reduce the health risk associated with E. coli and P. aeruginosa to below the 1 × 10−4 annual benchmark limit for all the non-potable uses of rainwater within the target communities (exception of showering for E. coli). However, the risk associated with intentional drinking of untreated or treated rainwater exceeded the benchmark limit (E. coli and P. aeruginosa). Additionally, while the solar reactor treatment reduced the risk associated with garden hosing and showering based on the presence of L. pneumophila, the risk estimates for both activities still exceeded the annual benchmark limit. The large-volume batch solar reactor prototypes were thus able to reduce the risk posed by the target bacteria for non-potable activities rainwater is commonly used for in water scarce regions of sub-Saharan Africa. This study highlights the need to assess water treatment systems in field trials using QMRA

    Measuring the Intrapersonal Component of Psychological Empowerment: Confirmatory Factor Analysis of the Sociopolitical Control Scale

    Full text link
    The Sociopolitical Control Scale (SPCS) is a widely used measure of the intrapersonal component of psychological empowerment. Confirmatory factor analyses (CFA) were conducted with data from two samples to test the hypothesized structure of the SPCS, the potential effects of method bias on the measure's psychometric properties, and whether a revised version of the scale (SPCS‐R) yielded improved model fit. Sample 1 included 316 randomly selected community residents of the Midwestern United States. Sample 2 included 750 community residents of the Northeastern U.S. Results indicated that method bias from the use of negatively worded items had a significant effect on the factor structure of the SPCS. CFA of the SPCS‐R, in which negatively worded items were rephrased so that all statements were positively worded, supported the measure's hypothesized two‐factor structure (i.e., leadership competence and policy control). Subscales of the SPCS‐R were found reliable and related in expected ways with measures of community involvement. Implications of the study for empowerment‐based research and practice are described, and strategies to further develop the SPCS are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/117223/1/ajcp9070.pd

    Notch and Presenilin Regulate Cellular Expansion and Cytokine Secretion but Cannot Instruct Th1/Th2 Fate Acquisition

    Get PDF
    Recent reports suggested that Delta1, 4 and Jagged1, 2 possessed the ability to instruct CD4+ T cell into selection of Th1 or Th2 fates, respectively, although the underlying mechanism endowing the cleaved Notch receptor with memory of ligand involved in its activation remains elusive. To examine this, we prepared artificial antigen-presenting cells expressing either DLL1 or Jag1. Although both ligands were efficient in inducing Notch2 cleavage and activation in CD4+ T or reporter cells, the presence of Lunatic Fringe in CD4+ T cells inhibited Jag1 activation of Notch1 receptor. Neither ligand could induce Th1 or Th2 fate choice independently of cytokines or redirect cytokine-driven Th1 or Th2 development. Instead, we find that Notch ligands only augment cytokine production during T cell differentiation in the presence of polarizing IL-12 and IL-4. Moreover, the differentiation choices of naïve CD4+ T cells lacking γ-secretase, RBP-J, or both in response to polarizing cytokines revealed that neither presenilin proteins nor RBP-J were required for cytokine-induced Th1/Th2 fate selection. However, presenilins facilitate cellular proliferation and cytokine secretion in an RBP-J (and thus, Notch) independent manner. The controversies surrounding the role of Notch and presenilins in Th1/Th2 polarization may reflect their role as genetic modifiers of T-helper cells differentiation
    corecore