818 research outputs found
Global change and response of coastal dune plants to the combined effects of increased sand accretion (burial) and nutrient availability
Coastal dune plants are subjected to natural multiple stresses and vulnerable to global change. Some changes associated
with global change could interact in their effects on vegetation. As vegetation plays a fundamental role in building and
stabilizing dune systems, effective coastal habitat management requires a better understanding of the combined effects of
such changes on plant populations. A manipulative experiment was conducted along a Mediterranean dune system to
examine the individual and combined effects of increased sediment accretion (burial) and nitrogen enrichment associated
with predicted global change on the performance of young clones of Sporobolus virginicus, a widespread dune stabilizing
species. Increased burial severity resulted in the production of taller but thinner shoots, while nutrient enrichment
stimulated rhizome production. Nutrient enrichment increased total plant biomass up to moderate burial levels (50% of
plant height), but it had not effect at the highest burial level (100% of plant height). The effects of such factors on total
biomass, shoot biomass and branching were influenced by spatial variation in natural factors at the scale of hundreds of
metres. These results indicate that the effects of burial and nutrient enrichment on plant performance were not
independent. Their combined effects may not be predicted by knowing the individual effects, at least under the study
conditions. Under global change scenarios, increased nutrient input could alleviate nutrient stress in S. virginicus, enhancing
clonal expansion and productivity, but this benefit could be offset by increased sand accretion levels equal or exceeding
100% of plant height. Depletion of stored reserves for emerging from sand could increase plant vulnerability to other
stresses in the long-term. The results emphasize the need to incorporate statistical designs for detecting non-independent
effects of multiple changes and adequate spatial replication in future works to anticipate the impact of global change on
dune ecosystem functioning.
Citation
Detection of meteorological inconsistencies by GPS
GPS observations, distances from satellites to receivers and meteorological conditions in neutral atmosphere are known to obey a constraint, which provides a residual or in other words a quality index. A method is discussed which provides a residual epoch by epoch in near real time. In general, distribution of residuals during several
consecutive epochs belonging to the same satellites, allows estimates of a mean and a standard deviation of mean.
Under normal meteorological conditions distribution of residuals appears to be consistent with zero mean as expected. However, consecutive residuals sometimes appear to have a mean different from zero by more than three standard deviations of mean. Such signifi cant consecutive epochs provide a warning of existing inconsistencies among GPS observations, distances from satellites to receivers as obtained by orbital information, meteorological conditions above receivers (as obtained by ground measurements or by extrapolation of meteorological analysis).
A procedure has been set up which warns about these inconsistencies in near real time
Efficacy and safety of felbamate in children under 4 years of age: a retrospective chart review.
Background and purpose: To review our experience of the efficacy and tolerability of
felbamate in children younger than 4 years. Methods: We used a retrospective chart
review to identify 53 children with seizures who were younger than 4 years. Efficacy
was evaluated based on the occurrence of responsiveness, defined as seizure frequency
reduction of more than 50% for a minimum period of 4 months. Tolerability was
based on parent-reported side effects. Results: Twenty-two (41%) patients resulted to
be responders and 31 (59%) did not. By univariate analysis, those achieving seizure
remission were probably much older, to have a shorter history of epilepsy and a lower
frequency of seizures before felbamate therapy. The number of antiepileptic drugs
(AEDs) used before felbamate therapy was the only significant predictor of the
duration of response to felbamate, with a longer responsiveness to the drug seen in
those who were placed under fewer than three AEDs before felbamate compared with
those who had taken more than three (median, 16 months vs. 7 months; P < 0.0084).
Side effects occurred in 30% of the subjects, but these did not require discontinuation
of the drug. Discussion: Felbamate is an effective medication for a wide range of
epilepsy syndromes in children younger than 4 years. Although caution is necessary
when the drug is used in children, felbamate might represent a possible option for the
treatment of epilepsy in this age group.
Introduction
The incidence of epilepsy is high during the first year of
life and it declines steadily during childhood and
adolescence. Few of the new antiepileptic drugs (AEDs)
are indicated officially for children younger than 4 years
[1–3]. None of them is approved for children younger
than 2 years [1,3,4]. There is a striking discrepancy
between the high incidence of epilepsy in infancy and
the relatively few approved AEDs available for this age
group [5].
Felbamate (2-phenyl-1,3-propanediol dicarbamate) is
a derivative of the anti-anxiety drug meprobamate,
exerting additional anticonvulsant and neuroprotective
properties [6–8]. The drug has been approved since 1993
for the treatment of several types of epilepsy. Experimental
studies suggested that felbamate might inhibit
voltage-dependen
Phosphine Oxide Porous Organic Polymers Incorporating Cobalt(II) Ions: Synthesis, Characterization, and Investigation of H2Production
Suitably functionalized porous matrices represent versatile platforms to support well-dispersed catalytic centers. In the present study, porous organic polymers (POPs) containing phosphine oxide groups were fabricated to bind transition metals and to be investigated for potential electrocatalytic applications. Cross-linking of mono- and di-phosphine monomers with multiple phenyl substituents was subject to the Friedel-Crafts (F-C) reaction and the oxidation process, which generated phosphine oxide porous polymers with pore capacity up to 0.92 cm3/g and a surface area of about 990 m2/g. The formation of the R3P·BH3 borohydride adduct during synthesis allows to extend the library of phosphine-based monomeric entities when using FeCl3. The porous polymers were loaded with 0.8-4.2 w/w % of cobalt(II) and behaved as hydrogen evolution reaction (HER) catalysts with a Faradaic efficiency of up to 95% (5.81 × 10-5 mol H2 per 11.76 C) and a stable current density during repeated controlled potential experiments (CPE), even though with high overpotentials (0.53-0.68 V to reach a current density of 1 mA·cm-2). These studies open the way to the effectiveness of tailored phosphine oxide POPs produced through an inexpensive and ecofriendly iron-based catalyst and for the insertion of transition metals in a porous architecture, enabling electrochemically driven activation of small molecules
Efficacy and safety of levetiracetam in infants and young children with refractory epilepsy
SummaryThe aim of this multicentric, retrospective, and uncontrolled study was to evaluate the efficacy and safety of levetiracetam (LEV) in 81 children younger than 4 years with refractory epilepsy. At an average follow-up period of 9 months, LEV administration was found to be effective in 30% of patients (responders showing more than a 50% decrease in seizure frequency) of whom 10 (12%) became seizure free. This efficacy was observed for focal (46%) as well as for generalized seizures (42%). In addition, in a group of 48 patients, we compared the initial efficacy (evaluated at an average of 3 months of follow-up) and the retention at a mean of 12 months of LEV, with regard to loss of efficacy (defined as the return to the baseline seizure frequency). Twenty-two patients (46%) were initial responders. After a minimum of 12 months of follow-up, 9 of 48 patients (19%) maintained the improvement, 4 (8%) of whom remained seizure free. A loss of efficacy was observed in 13 of the initial responders (59%). Maintained LEV efficacy was noted in patients with focal epilepsy and West syndrome. LEV was well tolerated. Adverse events were seen in 18 (34%) patients. The main side effects were drowsiness and nervousness. Adverse events were either tolerable or resolved in time with dosage reduction or discontinuation of the drug.We conclude that LEV is safe and effective for a wide range of epileptic seizures and epilepsy syndromes and, therefore, represents a valid therapeutic option in infants and young children affected by epilepsy
Elastic Pion Scattering on the Deuteron in a Multiple Scattering Model
Pion elastic scattering on deuterium is studied in the KMT multiple
scattering approach developed in momentum space. Using a Paris wave function
and the same methods and approximations as commonly used in pion scattering on
heavier nuclei excellent agreement with differential cross section data is
obtained for a wide range of pion energies. Only for MeV and very
backward angles, discrepancies appear that are reminiscent of disagreements in
pion scattering on He, H, and He. At low energies the second order
corrections have been included. Polarization observables are studied in detail.
While tensor analyzing powers are well reproduced, vector analyzing powers
exhibit dramatic discrepancies.Comment: 25 pages LATEX and 9 postscript figures in a self-extracting uufile
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Clinical‐epidemiological aspects of the Monkeypox 2022 epidemic: a multicenter study by the Italian SIDeMaST Group of Sexually Transmitted, Infectious and Tropical Diseases
Dear Editor,In spring 2022, an increase of monkeypox (mpox) cases was reported in Europe. Mpox is a zoonotic virus of the Poxviridae family, is endemic in the Congo Basin and just few cases outside Africa were reported before 2022. Its cutaneous presentation is similar to smallpox, usually preceded by a prodromal phase of fever, lymphadenopathy, headache and asthenia. Infection can occur through various means, including skin-to-skin contact, respiratory droplets or contact with fomites. The new outbreak is unique due to the increased human-to-human transmission, without an animal reservoir, particularly among men who have sex with men (MSM). As of February 13, 2023, 85.860 confirmed cases have been reported in 110 countries
Diprosopus: A Rare Case of Craniofacial Duplication and a Systematic Review of the Literature
In 1990, Gorlin et al. described four types of craniofacial duplications: (1) single mouth with duplication of the maxillary arch; (2) supernumerary mouth laterally placed with rudimentary segments; (3) single mouth with replication of the mandibular segments; and (4) true facial duplication, namely diprosopus. We describe a newborn born with wide-spaced eyes, a very broad nose, and two separate mouths. Workup revealed the absence of the corpus callosum and the presence of a brain midline lipoma, wide sutures, and a Chiari I malformation with cerebellar herniation. We conducted a systematic review of the literature and compared all the cases described as diprosopus. In 96% of these, the central nervous system is affected, with anencephaly being the most commonly associated abnormality. Other associated anomalies include cardiac malformations (86%), cleft palate (63%), diaphragmatic hernia (13%), and disorder of sex development (DSD) (13%). Although the facial features are those that first strike the eye, the almost obligate presence of cerebral malformations suggests a disruptive event in the cephalic pole of the forming embryo. No major monogenic contribution has been recognized today for this type of malformation
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