5,501 research outputs found
Identification of onosma visianii roots extract and purified shikonin derivatives as potential acaricidal agents against tetranychus urticae
There is an increasing need for the discovery of reliable and eco-friendly pesticides and natural plant-derived products may play a crucial role as source of new active compounds. In this research, a lipophilic extract of Onosma visianii roots extract containing 12% of shikonin derivatives demonstrated significant toxicity and inhibition of oviposition against Tetranychus urticae mites. Extensive chromatographic separation allowed the isolation of 11 naphthoquinone derivatives that were identified by spectral techniques and were tested against Tetranychus urticae. All the isolated compounds presented effects against the considered mite and isobutylshikonin (1) and isovalerylshikonin (2) were the most active, being valuable model compounds for the study of new anti-mite agents
Closing the Wedge: Search Strategies for Extended Higgs Sectors with Heavy Flavor Final States
We consider search strategies for an extended Higgs sector at the
high-luminosity LHC14 utilizing multi-top final states. In the framework of a
Two Higgs Doublet Model, the purely top final states () are
important channels for heavy Higgs bosons with masses in the wedge above
and at low values of , while a final state is most
relevant at moderate values of . We find, in the
channel, with , that both single and 3 lepton final
states can provide statistically significant constraints at low values of for as high as GeV. When systematics on the
background are taken into account, however, the 3 lepton final state is more
powerful, though the precise constraint depends fairly sensitively on lepton
fake rates. We also find that neither nor final states
provide constraints on additional heavy Higgs bosons with couplings to tops
smaller than the top Yukawa due to expected systematic uncertainties in the background.Comment: Added a Fig. and updated references. Matches journal version. 31
pages, 11 figure
Vacuum Stability and Higgs Diphoton Decays in the MSSM
Current Higgs data at the Large Hadron Collider is compatible with a SM
signal at the 2 level, but the central value of the signal strength in
the diphoton channel is enhanced with respect to the SM expectation. If the
enhancement resides in the diphoton partial decay width, the data could be
accommodated in the Minimally Supersymmetric Standard Model (MSSM) with highly
mixed light staus. We revisit the issue of vacuum instability induced by large
mixing in the stau sector, including effects of a radiatively-corrected tau
Yukawa coupling. Further, we emphasize the importance of taking into account
the dependence in the stability bound. While the metastability of
the Universe constrains the possible enhancement in the Higgs to diphoton decay
width in the light stau scenario, an increase of the order of 50% can be
achieved in the region of large . Larger enhancements may be
obtained, but would require values of associated with
non-perturbative values of the tau Yukawa coupling at scales below the GUT
scale, thereby implying the presence of new physics beyond the MSSM.Comment: 25 pages, 7 figure
The abandoned antimony-mines of SE Sardinia: impact on surface waters
This study investigates the impact of abandoned Sb-mines on the Flumendosa River, which is the most important
water resource in southern Sardinia. Hydrogeochemical surveys carried out in 2005 and 2006 indicated a
significant impact of waters flowing out from adits, slag, tailings and waste materials on surface waters. The
contaminated waters show alkaline pH, and high dissolved SO4, Sb and As (up to 1900, 9.6 and 3.5 mg/L,
respectively). Although the flow rates of drainages from the mining area are usually low (in the range of < 0.1 to
1 L/s), the contribution to dissolved concentrations of Sb in the streams downstream of mines is high. Sampling
under high flow conditions in the Flumendosa River before the confluence with the contaminated streams
showed Sb concentrations below the limits established by the guidelines of World Health Organization for
drinking water (i.e. 20 g/L), while downstream of the confluence dissolved Sb was 32 g/L. Contamination in
the Flumendosa extended 16 km, and attenuation (15 g/L Sb) was only observed close to the Flumendosa
mouth
The bronze bug Thaumastocoris peregrinus: a new insect recorded in Italy, damaging to Eucalyptus trees
The bronze bug Thaumastocoris peregrinus Carpintero et Dellape (Heteroptera Thaumastocoridae) is reported for the first time
from Italy infesting Eucalyptus spp. in several urban and rural sites of the Latium region. The host plants are very common in Italy as ornamental and forest trees. This is the first record of a member of the family Thaumastocoridae from Europe and the Mediterranean region. Preliminary bservations on general biological aspects and distribution of T.peregrinus have been conducted
Growth in transition countries: big bang versus gradualism
This paper analyses the impact of the speed of transition reforms on economic growth in transition countries in the context of the debate big-bang versus gradualist approach. It builds a new indicator for the speed of transition reforms based on a three-way principal component analysis. It shows that: (i) the speed of transition reforms Granger-causes economic growth and there is no reverse causation; (ii) the impact of contemporaneous speed of transition reforms on economic growth is negative but becomes positive in the longer horizon; and (iii) other factors, such as initial conditions and macroeconomic stabilization program, also drive economic growth. While the first two results are robust to different estimators, the impact of control variables depends on the econometric specification
Ultrastructure of cytoplasmic fragments in human cleavage stage embryos
Purpose: The goal of this study was to evaluate the ultrastructure of cytoplasmic fragments along with the effect of cytoplasmic fragment and perivitelline space coarse granulation removal (cosmetic microsurgery) from embryos before embryo transfer on ART outcomes. Methods: One hundred and fifty intracytoplasmic sperm injection cycles with male factor infertility were included in this prospective study. Patients were divided into three groups of case (n = 50), sham (n = 50), and control (n = 50). Embryos with 10–50 % fragmentation were included in this study. Cosmetic microsurgery and zona assisted hatching were only performed in case and sham groups respectively. Extracted fragments were evaluated ultrastructurally by transmission electron microscopy (TEM). Rates of clinical pregnancy, live birth, miscarriage, multiple pregnancies, and congenital anomaly in the three groups were also compared. Results: Micrographs from TEM showed that mitochondria were the most abundant structures found in the fragments along with mitochondria-vesicle complexes, Golgi apparatus, primary lysosomes, and vacuoles. There were no significant differences in demographic characteristics, laboratory and clinical data, or embryo morphological features between the groups. The rate of clinical pregnancy in control, sham, and case groups had no significant differences (24, 18, and 18 %, respectively). The rates of live birth, miscarriage, multiple pregnancy, and congenital anomaly were also similar between the different groups. Conclusions: Our data demonstrated that cosmetic microsurgery on preimplantation embryos had no beneficial effect on ART outcomes in unselected groups of patients. As mitochondria are the most abundant organelles found in cytoplasmic fragments, fragment removal should be performed with more caution in embryos with moderate fragmentation
Constraints on massive sterile neutrino species from current and future cosmological data
Sterile massive neutrinos are a natural extension of the Standard Model of
elementary particles. The energy density of the extra sterile massive states
affects cosmological measurements in an analogous way to that of active
neutrino species. We perform here an analysis of current cosmological data and
derive bounds on the masses of the active and the sterile neutrino states as
well as on the number of sterile states. The so-called (3+2) models with three
sub-eV active massive neutrinos plus two sub-eV massive sterile species is well
within the 95% CL allowed regions when considering cosmological data only. If
the two extra sterile states have thermal abundances at decoupling, Big Bang
Nucleosynthesis bounds compromise the viability of (3+2) models. Forecasts from
future cosmological data on the active and sterile neutrino parameters are also
presented. Independent measurements of the neutrino mass from tritium beta
decay experiments and of the Hubble constant could shed light on sub-eV massive
sterile neutrino scenarios.Comment: 9 pages, 7 figures. Journal versio
Prevalence and Tracking of Weight Disorders in Italian Primary School Students: A Three-Year Follow-Up
Obesity has been widely described as the latest epidemic, and in some areas obesity co-exists with undernutrition. The purpose of this study was to assess the variability of weight status of a cohort of 279 Italian primary school students followed longitudinally for three years. Overweight was the most common weight status disorder in both sexes and generally prevailed in females. Underweight was also more frequent in females than males, while males generally showed a higher incidence of obesity. Overweight showed the highest stability in females. In males, tracking of overweight was 62.5%, while that of normal weight was 89.36%. Overweight tracks through the three consecutive years in a high percentage of both sexes. In the whole sample (regardless of sex and weight category), overweight shows the highest increase over the three-year period. This study provides public health professionals with useful data for policy planning in regard to childhood obesity
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