222 research outputs found

    Using 14C and 3H to understand groundwater flow and recharge in an aquifer window

    Get PDF
    Knowledge of groundwater residence times and recharge locations is vital to the sustainable management of groundwater resources. Here we investigate groundwater residence times and patterns of recharge in the Gellibrand Valley, southeast Australia, where outcropping aquifer sediments of the Eastern View Formation form an "aquifer window" that may receive diffuse recharge from rainfall and recharge from the Gellibrand River. To determine recharge patterns and groundwater flow paths, environmental isotopes (3H, 14C, δ13C, δ18O, δ2H) are used in conjunction with groundwater geochemistry and continuous monitoring of groundwater elevation and electrical conductivity. The water table fluctuates by 0.9 to 3.7 m annually, implying recharge rates of 90 and 372 mm yr−1. However, residence times of shallow (11 to 29 m) groundwater determined by 14C are between 100 and 10 000 years, 3H activities are negligible in most of the groundwater, and groundwater electrical conductivity remains constant over the period of study. Deeper groundwater with older 14C ages has lower δ18O values than younger, shallower groundwater, which is consistent with it being derived from greater altitudes. The combined geochemistry data indicate that local recharge from precipitation within the valley occurs through the aquifer window, however much of the groundwater in the Gellibrand Valley predominantly originates from the regional recharge zone, the Barongarook High. The Gellibrand Valley is a regional discharge zone with upward head gradients that limits local recharge to the upper 10 m of the aquifer. Additionally, the groundwater head gradients adjacent to the Gellibrand River are generally upwards, implying that it does not recharge the surrounding groundwater and has limited bank storage. 14C ages and Cl concentrations are well correlated and Cl concentrations may be used to provide a first-order estimate of groundwater residence times. Progressively lower chloride concentrations from 10 000 years BP to the present day are interpreted to indicate an increase in recharge rates on the Barongarook High. © Author(s) 2014

    Differential remodelling of mitochondrial subpopulations and mitochondrial dysfunction are a feature of early stage diabetes

    Get PDF
    AbstractMitochondrial dysfunction is a feature of type I and type II diabetes, but there is a lack of consistency between reports and links to disease development. We aimed to investigate if mitochondrial structure–function remodelling occurs in the early stages of diabetes by employing a mouse model (GENA348) of Maturity Onset Diabetes in the Young, exhibiting hyperglycemia, but not hyperinsulinemia, with mild left ventricular dysfunction. Employing 3-D electron microscopy (SBF-SEM) we determined that compared to wild-type, WT, the GENA348 subsarcolemma mitochondria (SSM) are ~ 2-fold larger, consistent with up-regulation of fusion proteins Mfn1, Mfn2 and Opa1. Further, in comparison, GENA348 mitochondria are more irregular in shape, have more tubular projections with SSM projections being longer and wider. Mitochondrial density is also increased in the GENA348 myocardium consistent with up-regulation of PGC1-α and stalled mitophagy (down-regulation of PINK1, Parkin and Miro1). GENA348 mitochondria have more irregular cristae arrangements but cristae dimensions and density are similar to WT. GENA348 Complex activity (I, II, IV, V) activity is decreased but the OCR is increased, potentially linked to a shift towards fatty acid oxidation due to impaired glycolysis. These novel data reveal that dysregulated mitochondrial morphology, dynamics and function develop in the early stages of diabetes.</jats:p

    Prevalence and correlates of foot pain in a population-based study: the North West Adelaide health study

    Get PDF
    Background: Few population-based studies have examined the prevalence of foot pain in thegeneral community. The aims of this study were therefore to determine the prevalence, correlatesand impact of foot pain in a population-based sample of people aged 18 years and over living in the northwest region of Adelaide, South Australia.Methods: The North West Adelaide Health Study is a representative longitudinal cohort study ofn = 4,060 people randomly selected and recruited by telephone interview. The second stage of datacollection on this cohort was undertaken between mid 2004 and early 2006. In this phase,information regarding the prevalence of musculoskeletal conditions was included. Overall, n = 3,206 participants returned to the clinic during the second visit, and as part of the assessment were asked to report whether they had pain, aching or stiffness on most days in either of their feet. Data were also collected on body mass index (BMI); major medical conditions; other joint symptoms and health-related quality of life (the Medical Outcomes Study Short Form 36 [SF-36]).Results: Overall, 17.4% (95% confidence interval 16.2 – 18.8) of participants indicated that theyhad foot pain, aching or stiffness in either of their feet. Females, those aged 50 years and over,classified as obese and who reported knee, hip and back pain were all significantly more likely to report foot pain. Respondents with foot pain scored lower on all domains of the SF-36 afteradjustment for age, sex and BMI.Conclusion: Foot pain affects nearly one in five of people in the community, is associated withincreased age, female sex, obesity and pain in other body regions, and has a significant detrimental impact on health-related quality of life.Catherine L Hill, Tiffany K Gill, Hylton B Menz and Anne W Taylo

    The Evolution of Compact Binary Star Systems

    Get PDF
    We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Binary NSs and BHs are thought to be the primary astrophysical sources of gravitational waves (GWs) within the frequency band of ground-based detectors, while compact binaries of WDs are important sources of GWs at lower frequencies to be covered by space interferometers (LISA). Major uncertainties in the current understanding of properties of NSs and BHs most relevant to the GW studies are discussed, including the treatment of the natal kicks which compact stellar remnants acquire during the core collapse of massive stars and the common envelope phase of binary evolution. We discuss the coalescence rates of binary NSs and BHs and prospects for their detections, the formation and evolution of binary WDs and their observational manifestations. Special attention is given to AM CVn-stars -- compact binaries in which the Roche lobe is filled by another WD or a low-mass partially degenerate helium-star, as these stars are thought to be the best LISA verification binary GW sources.Comment: 105 pages, 18 figure

    Search for the standard model Higgs boson at LEP

    Get PDF

    Prevalence of hallux valgus in the general population: a systematic review and meta-analysis

    Get PDF
    BACKGROUND: Hallux valgus (HV) is a foot deformity commonly seen in medical practice, often accompanied by significant functional disability and foot pain. Despite frequent mention in a diverse body of literature, a precise estimate of the prevalence of HV is difficult to ascertain. The purpose of this systematic review was to investigate prevalence of HV in the overall population and evaluate the influence of age and gender. METHODS: Electronic databases (Medline, Embase, and CINAHL) and reference lists of included papers were searched to June 2009 for papers on HV prevalence without language restriction. MeSH terms and keywords were used relating to HV or bunions, prevalence and various synonyms. Included studies were surveys reporting original data for prevalence of HV or bunions in healthy populations of any age group. Surveys reporting prevalence data grouped with other foot deformities and in specific disease groups (e.g. rheumatoid arthritis, diabetes) were excluded. Two independent investigators quality rated all included papers on the Epidemiological Appraisal Instrument. Data on raw prevalence, population studied and methodology were extracted. Prevalence proportions and the standard error were calculated, and meta-analysis was performed using a random effects model. RESULTS: A total of 78 papers reporting results of 76 surveys (total 496,957 participants) were included and grouped by study population for meta-analysis. Pooled prevalence estimates for HV were 23% in adults aged 18-65 years (CI: 16.3 to 29.6) and 35.7% in elderly people aged over 65 years (CI: 29.5 to 42.0). Prevalence increased with age and was higher in females [30% (CI: 22 to 38)] compared to males [13% (CI: 9 to 17)]. Potential sources of bias were sampling method, study quality and method of HV diagnosis. CONCLUSIONS: Notwithstanding the wide variation in estimates, it is evident that HV is prevalent; more so in females and with increasing age. Methodological quality issues need to be addressed in interpreting reports in the literature and in future research

    Recull de propostes per minimitzar l'impacte negatiu de gènere del sistema de teletreball a l'Ajuntament de Barcelona

    Get PDF
    Finançat amb el projecte "Impacto de GÉnero del TEletrabajo y rutinas de COnfinamiento: más allá de lo obvio" (Ref. SUPERACOVID19_2.2.IGETECO) i a través de l'Ajuntament de Barcelona pel Servei d'Estudi sobre propostes per minimitzar l'impacte negatiu de gènere del sistema de teletreball a l'Ajuntament de Barcelona (exp.20002682)El present document recull les propostes d'actuació contingues a l'estudi Propostes per minimitzar l'impacte negatiu de gènere del sistema de teletreball a l'Ajuntament de Barcelona realitzat pel Centre d'Estudis Sociològics sobre la Vida Quotidiana i el Treball (QUIT) de la Universitat Autònoma de Barcelona. L'emergència sanitària provocada per la Covid19 i el necessari confinament de la població per combatre la pandèmia ha significat, des del punt de vista de l'organització del treball, un canvi molt important cap a l'impuls de formes de treball a distància. Però aquest impuls del teletreball ha estat una resposta fruit de l'emergència, lògica davant la situació viscuda i, com a tal, no ha pogut ser planificada amb el temps i els mitjans necessaris

    Searches for neutral Higgs bosons in e+ee^{+}e^{-} collisions at centre-of-mass energies from 192 to 202 GeV

    Get PDF
    Searches for neutral Higgs bosons are performed with the 237 pb^-1 of data collected in 1999 by the ALEPH detector at LEP, for centre-of-mass energies between 191.6 and 201.6 GeV. These searches apply to Higgs bosons within the context of the Standard Model and its minimal supersymmetric extension (MSSM) as well as to invisibly decaying Higgs bosons. No evidence of a signal is seen. A lower limit on the mass of the Standard Model Higgs boson of 107.7 GeV/c^2 at 95% confidence level is set. In the MSSM, lower limits of 91.2 and 91.6 GeV/c^2 are derived for the masses of the neutral Higgs bosons h and A, respectively. For a Higgs boson decaying invisibly and produced with the Standard Model cross section, masses below 106.4 GeV/c^2 are excluded

    Measurement of W-pair production in e+ee^+ e^- collisions at 189 GeV

    Get PDF
    The production of W-pairs is analysed in a data samplecollected by ALEPH at a mean centre-of-mass energy of 188.6 GeV,corresponding to an integrated luminosity of 174.2 pb^-1. Crosssections are given for different topologies of W decays intoleptons or hadrons. Combining all final states and assumingStandard Model branching fractions, the total W-pair cross sectionis measured to be 15.71 +- 0.34 (stat) +- 0.18 (syst) pb.Using also the W-pair data samples collected by ALEPH at lowercentre-of-mass energies, the decay branching fraction of the W bosoninto hadrons is measured to be BR (W hadrons) = 66.97+- 0.65 (stat) +- 0.32 (syst) %, allowing a determination of theCKM matrix element |V(cs)|= 0.951 +- 0.030 (stat) +- 0.015 (syst)

    Determination of sin2 θeff w using jet charge measurements in hadronic Z decays

    Get PDF
    The electroweak mixing angle is determined with high precision from measurements of the mean difference between forward and backward hemisphere charges in hadronic decays of the Z. A data sample of 2.5 million hadronic Z decays recorded over the period 1990 to 1994 in the ALEPH detector at LEP is used. The mean charge separation between event hemispheres containing the original quark and antiquark is measured for bb̄ and cc̄ events in subsamples selected by their long lifetimes or using fast D*'s. The corresponding average charge separation for light quarks is measured in an inclusive sample from the anticorrelation between charges of opposite hemispheres and agrees with predictions of hadronisation models with a precision of 2%. It is shown that differences between light quark charge separations and the measured average can be determined using hadronisation models, with systematic uncertainties constrained by measurements of inclusive production of kaons, protons and A's. The separations are used to measure the electroweak mixing angle precisely as sin2 θeff w = 0.2322 ± 0.0008(exp. stat.) ±0.0007(exp. syst.) ± 0.0008(sep.). The first two errors are due to purely experimental sources whereas the third stems from uncertainties in the quark charge separations
    corecore