269 research outputs found
Extirpation of N otropis simus simus (Cope) and N otropis orca Woolman (Pisces: Cyprinidae) from the Rio Grande in New Mexico, with Notes on Their Life History
The Rio Grande bluntnose shiner, Notropis simus simus, and the phantom shiner, Notropis orca, once occupied warm water reaches of the Rio Grande in New Mexico, but have not been collected there since 1964 and 1949, respectively. Notropis s. simus was widespread and common until 1950; N. orca was apparently never abundant. Our collections indicated that both forms are extirpated from New Mexico, and each may be extinct. Two other cyprinids, Rio Grande shiner, Notropis jemezanus, and speckled chub, Hybopsis aestivalis, also disappeared from the Rio Grande around 1949 and 1964, respectively. A fifth cyprinid, the Rio Grande silvery minnow, Hybognathus amarus, is presently reduced in distribution and abundance. Irrigation withdrawals and mainstream dams altered natural discharge patterns of the Rio Grande prior to 1930 and probably reduced populations of this suite of mainstream fishes. Drought and increased water withdrawal after 1950 periodically dried extensive reaches of warm water Rio Grande habitat and probably eliminated remaining small populations of the aforementioned species except H. amarus. Life history attributes of N. s. simus, and the distribution and habitat of all of the other extirpated forms do not indicate special requirements other than a flowing mainstream environment. Short-lived fishes that occupy exclusively mainstream riverine environments are especially susceptible to extirpation when flow regimes are altered
Recent and subfossil diatom assemblages as indicators of environmental change (including fish introduction) in a high-mountain lake
We investigated modern-littoral and subfossil sediment-core diatoms in the shallow (max depth 6.4 m) high-mountain Lake Balma in the Orsiera Rocciavrè Nature Park (Italian Western Alps). Our study provided evidence that might be related to the response of diatom assemblages to fish introduction, in particular the decreasing of the nutrient-enrichment sensitive low-profile life-form/ecological guild and the increase in species known to react positively to the augmented nutrient availability due to fish excretions (e.g., Fragilaria nanana, Pseudostaurosira brevistriata, Staurosirella neopinnata). We are, however, aware that some of these effects could as well have been caused by pastures and cattle watering, and by increased temperatures due to global warming, and we acknowledge the typical complex-interaction pattern among different stressors. High-mountain lakes are ‘‘early warning systems’’ for the whole alpine system and can contribute valuable information also on the interactions between environmental global changes and anthropogenic impacts. Benthic diatoms, in particular, can provide useful indications on the deleterious effects of non-native fish introduction, cattle grazing, and global warming, and thus support an adaptive and sustainable management of high-mountain lakes for the sake of nature conservation
A radio continuum survey of the southern sky at 1420 MHz. Observations and data reduction
We describe the equipment, observational method and reduction procedure of an
absolutely calibrated radio continuum survey of the South Celestial Hemisphere
at a frequency of 1420 MHz. These observations cover the area 0h < R.A. < 24h
for declinations less than -10 degree. The sensitivity is about 50 mK T_B (full
beam brightness) and the angular resolution (HPBW) is 35.4', which matches the
existing northern sky survey at the same frequency.Comment: 9 pages with 9 figures, A&A, in pres
Advanced modelling of the Planck-LFI radiometers
The Low Frequency Instrument (LFI) is a radiometer array covering the 30-70
GHz spectral range on-board the ESA Planck satellite, launched on May 14th,
2009 to observe the cosmic microwave background (CMB) with unprecedented
precision. In this paper we describe the development and validation of a
software model of the LFI pseudo-correlation receivers which enables to
reproduce and predict all the main system parameters of interest as measured at
each of the 44 LFI detectors. These include system total gain, noise
temperature, band-pass response, non-linear response. The LFI Advanced RF Model
(LARFM) has been constructed by using commercial software tools and data of
each radiometer component as measured at single unit level. The LARFM has been
successfully used to reproduce the LFI behavior observed during the LFI
ground-test campaign. The model is an essential element in the database of LFI
data processing center and will be available for any detailed study of
radiometer behaviour during the survey.Comment: 21 pages, 15 figures, this paper is part of the Prelaunch status LFI
papers published on JINST:
http://www.iop.org/EJ/journal/-page=extra.proc5/jins
Noto Station Status Report
The Noto VLBI station was fully operational in 2012, and the upgrade projects could be restarted, involving mainly the receiver area. Another important improvement was the activation of the 1 Gbps network
The Low Frequency Instrument in the ESA Planck mission
Measurements of the cosmic microwave background (CMB) allow high precision
observation of the cosmic plasma at redshift z~1100. After the success of the
NASA satellite COBE, that in 1992 provided the first detection of the CMB
anisotropy, results from many ground-based and balloon-borne experiments have
showed a remarkable consistency between different results and provided
quantitative estimates of fundamental cosmological properties. During the
current year the team of the NASA WMAP satellite has released the first
improved full-sky maps of the CMB since COBE, leading to a deeper insight in
the origin and evolution of the Universe. The ESA satellite Planck, scheduled
for launch in 2007, is designed to provide the ultimate measurement of the CMB
temperature anisotropy over the full sky, with an accuracy that will be limited
only by astrophysical foregrounds, and robust detection of polarisation
anisotropy. Planck will observe the sky with two instruments over a wide
spectral band (the Low Frequency Instrument, based on coherent radiometers,
from 30 to 70 GHz and the High Frequency Instrument, based on bolometric
detectors, from 100 to 857 GHz). The mission performances will improve
dramatically the scientific return compared to WMAP. Furthermore the LFI
radiometers (as well as some of the HFI bolometers) are intrinsically sensitive
to polarisation so that by combining the data from different receivers it will
be possible to measure accurately the E mode and to detect the B mode of the
polarisation power spectrum. Planck sensitivity will offer also the possibility
to detect the non-Gaussianities imprinted in the CMB.Comment: 4 pages, 2 figures, to appear in "Proc of International Symposium on
Plasmas in the Laboratory and in the Universe: new insights and new
challenges", September 16-19, 2003, Como, Ital
Planck pre-launch status: Low Frequency Instrument calibration and expected scientific performance
We give the calibration and scientific performance parameters of the Planck
Low Frequency Instrument (LFI) measured during the ground cryogenic test
campaign. These parameters characterise the instrument response and constitute
our best pre-launch knowledge of the LFI scientific performance. The LFI shows
excellent stability and rejection of instrumental systematic effects;
measured noise performance shows that LFI is the most sensitive instrument of
its kind. The set of measured calibration parameters will be updated during
flight operations through the end of the mission.Comment: Accepted for publications in Astronomy and Astrophysics. Astronomy &
Astrophysics, 2010 (acceptance date: 12 Jan 2010
Pharmacokinetic of myriocin in rabbit’s eyes
Myriocin (Myr) is a suicide inactivator of ceramide synthesis with a complex lipid multifunctional structure. Its biological activity is exerted at very low doses, and thus highly performing quantitative method are
needed [1]. The pharmacological development of Myr to modulate ceramide levels also requires currently unavailable ADME information in healthy and pathological animal models
Adjuvant treatment for elderly patients with colon cancer. An observational study
Background: Adjuvant. 5-fluoruracil-based chemotherapysignificantly reduces mortality in. patients with: stage II-III colon cancer, but is less prescribed with rising age. In this study we were interested in the pattern of adjuvant treatment and possible effects on survival among elderly patients. Patients and methods: From January to December 2004, 63 questionnaires on the management of stage II-III resected colon cancer patients aged over 70 years, collected from 10 Italian Centres, were retrospectively examined. Determinants of receipt of adjuvant chemotherapy and their relation to survival were considered. Results: The proportion of elderly patients receiving adjuvant chemotherapy was 79.4%, distinct of age, gender, educational level and comorbidities. Grade 3-4 toxicities were the following: haematological in 4 (8.5.%) patients, mucositis in 4 (8.5%), diarrhoea in 2 (4.2%) and nausea in 1 (2.1%). The disease-free survival (DFS) and overall survival (OS) at two years were 79.9% and 95.6%, respectively. Due to the paucity of events, the impact of prognostic factors (patient's age and comorbidity, tumour stage and grade) on DFS and OS could not be assessed. Conclusion: An increasing proportion of elderly patients with colon cancer may be treated with a tolerability and OS similar to those observed in the younger population. Development of age-based guidelines and increased awareness of both physicians and patients through education is important to prevent undertreatment of those elderly patients who are eligible for chemotherapy
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