412 research outputs found
Is the blue tit falling into an ecological trap in Argentine ant invaded forests?
Because insectivorous birds must evaluate
resources for reproduction before settling into a breed-
ing habitat, they can fall into an ecological trap if
informative cues about habitat suitability become
dissociated from their actual yield. Given their potential
to affect ecological networks, invasive ant species are
potential candidates for triggering such ecological traps.
We combined observational and experimental
approaches to examine whether the variation in food
supply for nestlings resulting from the invasion of the
Argentine ant, Linepithema humile, had any influence
on the breeding ecology of the blue tit, Cyanistes
caeruleus, an insectivorous foliage-gleaner. We inves-
tigated the effects of the ant invasion on breeding
performance (nesting success, clutch size, brood size
and breeding success) and offspring quality (body size
and condition, developmental stability and plumage
colour) in replicated Mediterranean forest areas over a
period of 3 years. There was no evidence that the
reduction in caterpillar availability resulting from the
invasion had a concurrent negative effect on the blue titâs ability to successfully rear nestlings in optimal conditions, at least as measured here. Although the raw figures suggest an increased level of nutritional stress in
blue tits breeding in invaded forests, the data analyses
showed no significant alterations in terms of productiv-
ity or offspring fitness. The reproductive performance of
the blue tit has been shown to be remarkably resilient to
the Argentine ant-mediated food shortage, either
because the prey reduction following the invasion did
not reach a critical threshold or because of compensa-
tory activity by the progenitors. We cannot conclusively
reject an ecological trap triggered by the ant invasion on
blue tits, since neither fledgling recruitment nor the
prospective survival of parents were assessed. Even
though we could not confirm short-term consequences
of the Argentine ant invasion on blue tit reproductive fitness, the long-term bottom-up effects of the invasion remain unknown and should not be ruled outPeer reviewe
A Large-Scale FPGA-Based Trigger and Dead-Time Free DAQ System for the Kaos Spectrometer at MAMI
The Kaos spectrometer is maintained by the A1 collaboration at the Mainz
Microtron MAMI with a focus on the study of (e,e'K^+) coincidence reactions.
For its electron-arm two vertical planes of fiber arrays, each comprising
approximately 10 000 fibers, are operated close to zero degree scattering angle
and in close proximity to the electron beam. A nearly dead-time free DAQ system
to acquire timing and tracking information has been installed for this
spectrometer arm. The signals of 144 multi-anode photomultipliers are collected
by 96-channel front-end boards, digitized by double-threshold discriminators
and the signal time is picked up by state-of-the-art F1 time-to-digital
converter chips. In order to minimize background rates a sophisticated trigger
logic was implemented in newly developed Vuprom modules. The trigger performs
noise suppression, signal cluster finding, particle tracking, and coincidence
timing, and can be expanded for kinematical matching (e'K^+) coincidences. The
full system was designed to process more than 4 000 read-out channels and to
cope with the high electron flux in the spectrometer and the high count rate
requirement of the detectors. It was successfully in-beam tested at MAMI in
2009.Comment: Contributed to 17th IEEE Real Time Conference (RT10), Lisbon, 24-28
May 201
Fertility after expanded polytetrafluoroethylene use after endometrioma cystectomy: a pilot study
IntroductionPregnancy rates after the placement of expanded polytetrafluoroethylene (ePTFE, trade name Gore-TexÂź) for adhesion prevention following cystectomy of endometriomas â„3 cm and excision of endometriosis were analyzed in this pilot study.MethodsA prospective cohort study was performed at a single tertiary care center. 56 women qualified for the study and underwent surgery. Expanded polytetrafluoroethylene placement around affected ovaries was self-selected. Inclusion criteria for analysis were pathology-confirmed endometrioma â„3 cm, no hysterectomy at time of surgery, â„1 year of postoperative survey completion, and absence of strategies to avoid pregnancy. 18 women in the ePTFE group and 11 women in the control group met inclusion criteria for analysis. 16 of the 18 women in the ePTFE group and 7 of the 11 women in the control group were affected by infertility. Absolute pregnancy rates and cumulative 4-year pregnancy rates, which are based on survival analysis using lifetables and adjust for varying follow-up times, were calculated for all women as well as for women with infertility only.ResultsHigh cumulative 4-year pregnancy rates were observed for women with expanded polytetrafluoroethylene compared to women without (85% vs. 65%, pâ=â0.69). High cumulative 4-year pregnancy rates for women with infertility prior to surgery were observed for women with expanded polytetrafluoroethylene compared to women without (83% vs. 33%, pâ=â0.89).DiscussionThere are consistent trends, although not statistically significant, seen in pregnancy rates for women with ePTFE compared to women without, particularly in those with a history of infertility prior to ePTFE use. This is the first study examining how adhesion prevention strategy targeting the adnexa during surgery for endometriosis affects pregnancy rates. The trend towards increased pregnancy rates with expanded polytetrafluoroethylene use, particularly in patients with a history of infertility, is promising and warrants further study with larger groups
Assessment of potential cardiotoxic side effects of mitoxantrone in patients with multiple sclerosis
Previous studies showed that mitoxantrone can reduce disability progression in patients with multiple sclerosis (MS). There is, however, concern that it may cause irreversible cardiomyopathy with reduced left ventricular (LV) ejection fraction (EF) and congestive heart failure. The aim of this prospective study was to investigate cardiac side effects of mitoxantrone by repetitive cardiac monitoring in MS patients. The treatment protocol called for ten courses of a combined mitoxantrone (10 mg/m(2) body surface) and methylprednisolone therapy. Before each course, a transthoracic echocardiogram was performed to determine the LV end-diastolic diameter, the end-systolic diameter and the fractional shortening; the LV-EF was calculated. Seventy-three patients participated (32 males; age 48 +/- 12 years, range 20-75 years; 25 with primary progressive, 47 with secondary progressive and 1 with relapsing-remitting MS) who received at least four courses of mitoxantrone. Three of the 73 patients were excluded during the study (2 patients discontinued therapy; 1 patient with a previous history of ischemic heart disease developed atrial fibrillation after the second course of mitoxantrone). The mean cumulative dose of mitoxantrone was 114.0 +/- 33.8 mg. The mean follow-up time was 23.4 months (range 10-57 months). So far, there has been no significant change in any of the determined parameters (end-diastolic diameter, end-systolic diameter, fractional shortening, EF) over time during all follow-up investigations. Mitoxantrone did not cause signs of congestive heart failure in any of the patients. Further cardiac monitoring is, however, needed to determine the safety of mitoxantrone after longer follow-up times and at higher cumulative doses. Copyright (C) 2005 S. Karger AG, Basel
Modelling the hydrological behaviour of a coffee agroforestry basin in Costa Rica
UMR LISAH, Equipe Eau et Polluants en Bassins VersantsThe profitability of hydropower in Costa Rica is affected by soil erosion and sedimentation in dam reservoirs, which are in turn influenced by land use, infiltration and aquifer interactions with surface water. In order to foster the provision and payment for Hydrological Environmental Services (HES), a quantitative assessment of the impact of specific land uses on the functioning of drainage-basins is required. The present paper aims to study the water balance partitioning in a volcanic coffee agroforestry microbasin (1 km(2), steep slopes) in Costa Rica, as a first step towards evaluating sediment or contaminant loads. The main hydrological processes were monitored during one year, using flume, eddy-covariance flux tower, soil water profiles and piezometers. A new Hydro-SVAT lumped model is proposed, that balances SVAT (Soil Vegetation Atmosphere Transfer) and basin-reservoir routines. The purpose of such a coupling was to achieve a trade-off between the expected performance of ecophysiological and hydrological models, which are often employed separately and at different spatial scales, either the plot or the basin. The calibration of the model to perform streamflow yielded a Nash-Sutcliffe (NS) coefficient equal to 0.89 for the year 2009, while the validation of the water balance partitioning was consistent with the independent measurements of actual evapotranspiration (R-2 = 0.79, energy balance closed independently), soil water content (R-2 = 0.35) and water table level (R-2 = 0.84). Eight months of data from 2010 were used to validate modelled streamflow, resulting in a NS = 0.75. An uncertainty analysis showed that the streamflow modelling was precise for nearly every time step, while a sensitivity analysis revealed which parameters mostly affected model precision, depending on the season. It was observed that 64% of the incident rainfall R flowed out of the basin as streamflow and 25% as evapotranspiration, while the remaining 11% is probably explained by deep percolation, measurement errors and/or inter-annual changes in soil and aquifer water stocks. The model indicated an interception loss equal to 4% of R, a surface runoff of 4% and an infiltration component of 92%. The modelled streamflow was constituted by 87% of baseflow originating from the aquifer, 7% of subsurface non-saturated runoff and 6% of surface runoff. Given the low surface runoff observed under the current physical conditions (andisol) and management practices (no tillage, planted trees, bare soil kept by weeding), this agroforestry system on a volcanic soil demonstrated potential to provide valuable HES, such as a reduced superficial displacement- capacity for fertilizers, pesticides and sediments, as well as a streamflow regulation function provided by the highly efficient mechanisms of aquifer recharge and discharge. The proposed combination of experimentation and modelling across ecophysiological and hydrological approaches proved to be useful to account for the behaviour of a given basin, so that it can be applied to compare HES provision for different regions or management alternatives
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