323 research outputs found
Avian Diversity and Habitat Use on Wetland Reserve Program Lands in the Lower Missouri River Valley
A primary objective of the Wetland Reserve Program (WRP) is to provide habitat for migratory birds throughout all seasons of the year. Comprehensive avian assessments are lacking and limit our ability to evaluate the benefits of the WRP to continental bird populations. I investigated avian species occurrence on WRP lands within the Lower Missouri River Valley (LMRV), Nebraska, USA, from March 2010 to February 2011. Ten WRP habitat types are described based on plant community assemblages and observed hydrological regimes. Estimates of avian species richness were greatest in lowland forest (n = 115), lowland woodland (n = 83) and upland forest (n = 77) habitats. Taxonomic measures of avian diversity differed between habitat types but was similar in respect to season. Ecological habitat types ranked according to avian preference revealed forest and wetland communities to be significantly utilized across the entire species assemblage as compared to grassland habitats. Ordination displayed similarity within grouped ecological habitat types and was supportive of a high dimensional community structure. Approximately one-half of all species documented met breeding level criteria, with 64 species confirmed as breeding. Taxonomic structure of breeding birds did not differ from the total WRP avian assemblage. I conclude that the regional and historical species pool within the LMRV remains largely intact and that WRP restorations exhibit the full complement of avian assemblage
A Late-Season Breeding Record for the Summer Tanager in Nebraska
The breeding range of the Summer Tanager (Piranga rubra) is well documented and expands across the southern U.S. extending northward to New Jersey and west along and south of the Great Lakes to the eastern edge of the Great Plains (Terres 1991; Robinson 1996). In Nebraska the species is generally confined to the Lower Missouri and Platte River Valleys where it occurs locally (Sharpe et al. 2001). Because the species exists in relatively low numbers across southeastern Nebraska, there are few breeding and nesting records for the state. Fewer than 10 breeding records, including one historical account have been described for Nebraska (Ducey 1988, Mollhoff 2001, Sharpe et al 2001, Mollhoff 2004). Due to the limited number of documented reports, our understanding of the breeding distribution and nesting ecology of the Summer Tanager in Nebraska is incomplete. Here I describe a late-season breeding effort by the Summer Tanager in southeastern Nebraska and provide comments on nesting behavior
A Late-Season Breeding Record for the Summer Tanager in Nebraska
The breeding range of the Summer Tanager (Piranga rubra) is well documented and expands across the southern U.S. extending northward to New Jersey and west along and south of the Great Lakes to the eastern edge of the Great Plains (Terres 1991; Robinson 1996). In Nebraska the species is generally confined to the Lower Missouri and Platte River Valleys where it occurs locally (Sharpe et al. 2001). Because the species exists in relatively low numbers across southeastern Nebraska, there are few breeding and nesting records for the state. Fewer than 10 breeding records, including one historical account have been described for Nebraska (Ducey 1988, Mollhoff 2001, Sharpe et al 2001, Mollhoff 2004). Due to the limited number of documented reports, our understanding of the breeding distribution and nesting ecology of the Summer Tanager in Nebraska is incomplete. Here I describe a late-season breeding effort by the Summer Tanager in southeastern Nebraska and provide comments on nesting behavior
Lying Your Way to Better Traffic Engineering
To optimize the flow of traffic in IP networks, operators do traffic
engineering (TE), i.e., tune routing-protocol parameters in response to traffic
demands. TE in IP networks typically involves configuring static link weights
and splitting traffic between the resulting shortest-paths via the
Equal-Cost-MultiPath (ECMP) mechanism. Unfortunately, ECMP is a notoriously
cumbersome and indirect means for optimizing traffic flow, often leading to
poor network performance. Also, obtaining accurate knowledge of traffic demands
as the input to TE is elusive, and traffic conditions can be highly variable,
further complicating TE. We leverage recently proposed schemes for increasing
ECMP's expressiveness via carefully disseminated bogus information ("lies") to
design COYOTE, a readily deployable TE scheme for robust and efficient network
utilization. COYOTE leverages new algorithmic ideas to configure (static)
traffic splitting ratios that are optimized with respect to all (even
adversarially chosen) traffic scenarios within the operator's "uncertainty
bounds". Our experimental analyses show that COYOTE significantly outperforms
today's prevalent TE schemes in a manner that is robust to traffic uncertainty
and variation. We discuss experiments with a prototype implementation of
COYOTE
Lipid peroxidation and nitric oxide metabolites in a group of subjects with obstructive sleep apnea syndrome
It is known that in OSAS the plasma lipid peroxidation has an opposite behavior in comparison with nitric oxide metabolites. In the re-examination of our survey of OSAS infjects we calculated the ratio between thiobarbituric acid reactive infstances (TBARS) and nitric oxide metabolites (NOx) in relation to OSAS severity. The study has regarded 48 OSAS infjects infdivided in two infgroups according to the apnea/hypopnea index-AHI-(Low=21 infjects with AHI 30). From the obtained data it is evident that the TBARS/NOx ratio is significantly higher in the H infgroup compared to L infgroup as well as this ratio is reduced in L infgroup in comparison with the whole group of OSAS infjects. In the entire group of OSAS infjects the TBARS/NOx ratio results positively correlated with AHI and ODI and inversely correlated with mSO2
Gelatinases and their tissue inhibitors in a group of subjects with obstructive sleep apnea syndrome
Obstructive sleep apnea syndrome (OSAS) is associated with an elevated risk of cardiovascular events and stroke. Matrix metalloproteinases (MMPs) are endopeptidases involved in extracellular matrix degradation and then in the development and progression of cardiovascular diseases. Our aim was to evaluate plasma levels of gelatinases (MMP-2 and MMP-9) and their tissue inhibitors (TIMP-1 and TIMP-2) in a group of subjects with OSAS. We enrolled 48 subjects (36 men and 12 women; mean age 49.7 \ub1 14.68 yrs) with OSAS diagnosed with a 1-night cardiorespiratory study and then we subdivided these subjects into two subgroups according to the apnea/hypopnea index (AHI): Low (L = 21 subjects with AHI <30) and High (H = 27 subjects with AHI >30). We measured plasma concentration of the gelatinases and their inhibitors using ELISA kits. We observed a significant increase in plasma concentration of MMP-9, MMP-2, TIMP-1 and TIMP-2 in the entire group of OSAS subjects and in the two subgroups, with higher levels in the H in comparison with the L subgroup. In the whole group of OSAS subjects we also noted a significant decrease in MMP-9/TIMP-1 ratio in comparison with normal controls. Only MMP-9 was significantly correlated with the severity of the disease, expressed as AHI, with the oxygen desaturation index and also with the mean oxygen saturation. MMPs pattern is altered in OSAS and significantly influenced by the severity of the disease; it probably contributes to the vascular remodeling that leads to the atherosclerotic disease and cardiovascular complications
Analysis of the Blood Viscosity Behavior in the Sicilian Study on Juvenile Myocardial Infarction
Considering the role of hemorheology in coronary circulation, we studied blood viscosity in patients with juvenile myocardial infarction. We examined whole blood viscosity at high shear rate using the cone-on-plate viscosimeter Wells-Brookfield \ubd LVT and at low shear rate employing a viscometer Contraves LS30 in 120 patients (aged <46 years) with myocardial infarction, at the initial stage and subsequently 3 and 12 months after. At the initial stage, patients had an increased whole blood viscosity in comparison to normal controls. This hemorheological profile was not influenced by the cardiovascular risk factors, nor by the extent of coronary lesions, even if some differences were evident between patients with ST-segment elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI). The blood viscosity pattern at the initial stage did not influence recurring ischemic events or the onset of heart failure during an 18 months\u2019 follow-up. The neutrophil to lymphocyte ratio did not affect the blood viscosity pattern. We reevaluated 83 patients 3 months after and 70 patients 12 months after the acute coronary syndrome, and we found that the hemorheological parameters were still altered in comparison to normal controls at both times. We observed an impairment of the hemorheological pattern in young patients with myocardial infarction, partially influenced by the infarction type (STEMI and NSTEMI) and persisting in the long term
Behaviour of the plasma concentration of gelatinases and their tissue inhibitors in subjects with venous leg ulcers.
Venous leg ulcers are common in subjects with chronic venous insufficiency. The increased intraluminal pressure causes alteration of the skin microcirculation, leukocyte activation and release of proteolytic enzymes leading to ulceration. An impaired expression and activity of matrix metalloproteases (MMPs) and their tissue inhibitors (TIMPs) might influence extracellular matrix degradation and deposition in chronic venous ulcers with the failure of the healing process. Our aim was to evaluate plasma concentration of gelatinases (MMP-2 and MMP-9) and their inhibitors (TIMP-1 and TIMP-2) in subjects with venous leg ulcers before and after the compression therapy. We enrolled 36 subjects (12 men and 24 women, mean age 67.38 ± 12.7 yrs) with non-infected venous leg ulcers (CEAP C6), which underwent a color Duplex scan examination of the veins and arteries of the inferior limbs and were treated with a multi-layer bandaging system. The ulcer healing was obtained in 23 subjects only (9 men and 14 women). We evaluated, on fasting venous blood, the plasma levels of MMP-2, MMP-9, TIMP-1 and TIMP-2 using ELISA kit, before and after the treatment. We observed a significant increase in plasma concentration of gelatinases and their inhibitors and in MMP-2/TIMP-2 ratio in subjects with leg ulcers in comparison with normal controls. In subjects with healed ulcers we found a decrease in MMP-9 and TIMP-1 levels and in MMP-2/TIMP-2 ratio compared to the baseline values, although higher levels of all the examined parameters in comparison with normal controls. In conclusion, plasma MMPs profile is impaired in subjects with venous leg ulcers and it improves after the healing, persisting anyway altered in respect to healthy controls
Counter-propagating radiative shock experiments on the Orion laser and the formation of radiative precursors
We present results from new experiments to study the dynamics of radiative
shocks, reverse shocks and radiative precursors. Laser ablation of a solid
piston by the Orion high-power laser at AWE Aldermaston UK was used to drive
radiative shocks into a gas cell initially pressurised between and $1.0 \
bar with different noble gases. Shocks propagated at {80 \pm 10 \ km/s} and
experienced strong radiative cooling resulting in post-shock compressions of {
\times 25 \pm 2}. A combination of X-ray backlighting, optical self-emission
streak imaging and interferometry (multi-frame and streak imaging) were used to
simultaneously study both the shock front and the radiative precursor. These
experiments present a new configuration to produce counter-propagating
radiative shocks, allowing for the study of reverse shocks and providing a
unique platform for numerical validation. In addition, the radiative shocks
were able to expand freely into a large gas volume without being confined by
the walls of the gas cell. This allows for 3-D effects of the shocks to be
studied which, in principle, could lead to a more direct comparison to
astrophysical phenomena. By maintaining a constant mass density between
different gas fills the shocks evolved with similar hydrodynamics but the
radiative precursor was found to extend significantly further in higher atomic
number gases (\sim4$ times further in xenon than neon). Finally, 1-D and 2-D
radiative-hydrodynamic simulations are presented showing good agreement with
the experimental data.Comment: HEDLA 2016 conference proceeding
Y chromosome microdeletions in infertile men with idiopathic oligo- or azoospermia
About 30–40% of male infertility is due to unknown reasons. Genetic contributions to the disruption of spermatogenesis are suggested and amongst the genetic factors studied, Y chromosome microdeletions represent the most common one. Screening for microdeletions in AZFa, b and c region of Y chromosome showed a big variation among different studies. The purpose of this study was to investigate the prevalence of such deletions in Saudi men. A total of 257 patients with idiopathic oligo- or azoospermia were screened for Y chromosome microdeletions by 19 markers in AZF region. Ten (3.9%) patients had chromosomal rearrangements, six of them showed sex chromosome abnormalities and four patients had apparently balanced autosomal rearrengements. Eight of the remaining 247 patients (3.2%) with a normal karyotype and no known causes of impaired spermatogenesis had Y chromosome microdeletions. Among these, six patients had deletions in AZFc region, one case had a deletion in AZFb and another had both AZFa and AZFc deletions. In conclusion, our study shows that Y chromosome microdeletions are low in our population. We also report for the first time a case with unique point deletions of AZFa and AZFc regions. The lower frequency of deletions in our study suggest that other genetic, epigenetic, nutritional and local factors may be responsible for idiopathic oligo- or azoospermia in the Saudi population
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