184 research outputs found
Climate-human-landscape interaction in the eastern foothills of Mt. Kilimanjaro (equatorial East Africa) during the last two millennia
In-situ tryptophan-like fluorescence: a real-time indicator of faecal contamination in drinking water supplies
Enteric pathogens are typically inferred from the presence of surrogate indicator organisms such as thermo-tolerant (faecal) coliforms (TTCs). The analysis of TTCs requires time-consuming incubation in suitable laboratories, which can limit sampling resolution, particularly during critical pollution events. Here, we demonstrate the use of in-situ fluorimeters targeting tryptophan-like compounds as a rapid,
reagentless indicator of TTCs in groundwater-derived potable water supplies in Africa. A range of other common indicators of TTCs were also determined including nitrate, turbidity, and sanitary risk survey scores. Sampling was conducted during both the dry and wet seasons to investigate seasonality. Tryptophan-like fluorescence was the most effective predictor of both presence/absence and number of TTCs during both seasons. Seasonal changes in tryptophan-like fluorescence in deeper supplies suggest it
is transported more efficiently through the aquifer than TTCs. Moreover, the perennial elevated concentrations in some wells suggest it is more resilient than TTCs in groundwater. Therefore tryptophan-like fluorescence could also be a better indicator of some smaller, more easily transported, and long-lived, pathogenic enteric viruses. These sensors have the potential to be included in real-time pollutionalert systems for drinking water supplies throughout the world, as well as for mapping enteric
pathogen risks in developing regions
Climate-human-landscape interaction in the eastern foothills of Mt. Kilimanjaro (equatorial East Africa) during the last two millennia
The Mt. Kilimanjaro region is known for its long history of intensive agriculture, but the temporal extent of human activity and its impact on the regional ecosystem are not well known. In this study, climate-human-landscape interactions during the past ~2200 years were examined using climate and vegetation proxies extracted from the continuous and high-resolution sediment record of Lake Chala. Ancient-to-modern regional human activity is documented against a backdrop of long-term vegetation dynamics in the low-elevation savanna woodland southeast of Mt. Kilimanjaro and riparian forest within Chala crater. During prolonged dry periods (~1170–1300 CE), succulent dry crater forest expanded relative to the moist lakeshore forest. The savanna landscape surrounding Chala crater was relatively stable through time, except that savanna grasses were stimulated by higher precipitation, consistent with the fuel-limited fire regime evidenced in the charcoal record. Expansion of subalpine ericaceous vegetation and a general decline in Afromontane forest taxa on Mt. Kilimanjaro after 550 CE may reflect a lowering of its upper forest line. The earliest robust signature of human influence on regional vegetation involves an increase in ruderal (weedy) plant taxa around 1100 CE, possibly associated with the development of Chagga homegardens and associated agroforestry in the submontane forest zone. A first hint of cereal agriculture (likely sorghum) is observed around 1550 CE, followed by a more robust signature from 1780 CE onwards which likely reflects the start of lowland irrigation agriculture. From 1780 CE we also find the first undisputed appearance of maize, introduced to East Africa about a century earlier
EUV Spectra of the Full Solar Disk: Analysis and Results of the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS)
We analyze EUV spectra of the full solar disk from the Cosmic Hot
Interstellar Plasma Spectrometer (CHIPS) spanning a period of two years. The
observations were obtained via a fortuitous off-axis light path in the 140 --
270 Angstrom passband. The general appearance of the spectra remained
relatively stable over the two-year time period, but did show significant
variations of up to 25% between two sets of Fe lines that show peak emission at
1 MK and 2 MK. The variations occur at a measured period of 27.2 days and are
caused by regions of hotter and cooler plasma rotating into, and out of, the
field of view. The CHIANTI spectral code is employed to determine plasma
temperatures, densities, and emission measures. A set of five isothermal
plasmas fit the full disk spectra well. A 1 -- 2 MK plasma of Fe contributes
85% of the total emission in the CHIPS passband. The standard Differential
Emission Measures (DEMs) supplied with the CHIANTI package do not fit the CHIPS
spectra well as they over-predict emission at temperatures below log(T) = 6.0
and above log(T) = 6.3. The results are important for cross-calibrating TIMED,
SORCE, SOHO/EIT, and CDS/GIS, as well as the recently launched Solar Dynamics
Observatory.Comment: 27 Pages, 13 Figure
Chimpanzees (Pan troglodytes) in savanna landscapes.
Chimpanzees (Pan troglodytes) are the only great apes that inhabit hot, dry, and open savannas. We review the environmental pressures of savannas on chimpanzees, such as food and water scarcity, and the evidence for chimpanzees' behavioral responses to these landscapes. In our analysis, savannas were generally associated with low chimpanzee population densities and large home ranges. In addition, thermoregulatory behaviors that likely reduce hyperthermia risk, such as cave use, were frequently observed in the hottest and driest savanna landscapes. We hypothesize that such responses are evidence of a "savanna landscape effect" in chimpanzees and offer pathways for future research to understand its evolutionary processes and mechanisms. We conclude by discussing the significance of research on savanna chimpanzees to modeling the evolution of early hominin traits and informing conservation programs for these endangered apes
Environmental monitoring : phase 5 final report (April 2019 - March 2020)
This report presents the results and interpretation for Phase 5 of an integrated environmental
monitoring programme that is being undertaken around two proposed shale gas sites in England –
Preston New Road, Lancashire and Kirby Misperton, North Yorkshire. The report should be read
in conjunction with previous reports freely available through the project website1
. These provide
additional background to the project, presentation of earlier results and the rationale for
establishment of the different elements of the monitoring programme
Environmental monitoring : phase 4 final report (April 2018 - March 2019)
This report describes the results of activities carried out as part of the Environmental
Monitoring Project (EMP) led by the British Geological Survey (BGS) in areas around two
shale gas sites in England – Kirby Misperton (Vale of Pickering, North Yorkshire) and Preston
New Road (Fylde, Lancashire). It focuses on the monitoring undertaken during the period April
2018–March 2019 but also considers this in the context of earlier monitoring results that have
been covered in reports for earlier phases of the project (Phases I–IV)
2
.
The EMP project is a multi-partner project involving BGS together with Public Health England
(PHE), University of Birmingham, University of Bristol, University of Manchester, Royal
Holloway University of London (RHUL) and University of York. The work has been enabled
by funding from a combination of the BGS National Capability programme, a grant awarded
by the UK Government’s Department for Business Energy & Industrial Strategy (BEIS) and
additional benefit-in-kind contributions from all partners.
The project comprises the comprehensive monitoring of different environment compartments
and properties at and around the two shale-gas sites. The component parts of the EMP are all
of significance when considering environmental and human health risks associated with shale
gas development. Included are seismicity, ground motion, water (groundwater and surface
water), soil gas, greenhouse gases, air quality, and radon.
The monitoring started before hydraulic fracturing had taken place at the two locations, and so
the results obtained before the initiation of operations at the shale-gas sites represent baseline
conditions. It is important to characterise adequately the baseline conditions so that any future
changes caused by shale gas operations, including hydraulic fracturing, can be identified. This
is also the case for any other new activities that may impact those compartments of the
environment being monitored as part of the project.
In the period October 2018–December 2018, an initial phase of hydraulic fracturing took place
at the Preston New Road (PNR) shale-gas site (shale gas well PNR1-z) in Lancashire. This was
followed by a period of flow testing of the well to assess its performance (to end of January
2019). The project team continued monitoring during these various activities and several
environmental effects were observed. These are summarised below and described in more
detail within the report. The initiation of operations at the shale-gas site signified the end of
baseline monitoring. At the Kirby Misperton site (KMA), approval has not yet been granted
for hydraulic fracturing of the shale gas well (KM8), and so no associated operations have
taken place during the period covered by this report. The effects on air quality arising from the
mobilisation of equipment in anticipation of hydraulic fracturing operations starting was
reported in the Phase III report, and in a recently published paper3
. Following demobilisation of the equipment and its removal from the site, conditions returned to baseline and the on-going
monitoring (reported in this report) is effectively a continuation of baseline monitoring
Measurement of the Hadronic Photon Structure Function F_2^gamma at LEP2
The hadronic structure function of the photon F_2^gamma is measured as a
function of Bjorken x and of the factorisation scale Q^2 using data taken by
the OPAL detector at LEP. Previous OPAL measurements of the x dependence of
F_2^gamma are extended to an average Q^2 of 767 GeV^2. The Q^2 evolution of
F_2^gamma is studied for average Q^2 between 11.9 and 1051 GeV^2. As predicted
by QCD, the data show positive scaling violations in F_2^gamma. Several
parameterisations of F_2^gamma are in agreement with the measurements whereas
the quark-parton model prediction fails to describe the data.Comment: 4 pages, 2 figures, to appear in the proceedings of Photon 2001,
Ascona, Switzerlan
A measurement of the tau mass and the first CPT test with tau leptons
We measure the mass of the tau lepton to be 1775.1+-1.6(stat)+-1.0(syst.) MeV
using tau pairs from Z0 decays. To test CPT invariance we compare the masses of
the positively and negatively charged tau leptons. The relative mass difference
is found to be smaller than 3.0 10^-3 at the 90% confidence level.Comment: 10 pages, 4 figures, Submitted to Phys. Letts.
Measurement of the B0 Lifetime and Oscillation Frequency using B0->D*+l-v decays
The lifetime and oscillation frequency of the B0 meson has been measured
using B0->D*+l-v decays recorded on the Z0 peak with the OPAL detector at LEP.
The D*+ -> D0pi+ decays were reconstructed using an inclusive technique and the
production flavour of the B0 mesons was determined using a combination of tags
from the rest of the event. The results t_B0 = 1.541 +- 0.028 +- 0.023 ps, Dm_d
= 0.497 +- 0.024 +- 0.025 ps-1 were obtained, where in each case the first
error is statistical and the second systematic.Comment: 17 pages, 4 figures, submitted to Phys. Lett.
- …