443 research outputs found
Super Heavy Dark Matter and UHECR Anisotropy at Low Energy
Super Heavy quasi-stable particles are naturally produced in the early
universe and could represent a substantial fraction of the Dark Matter: the
so-called Super Heavy Dark Matter (SHDM). The decay of SHDM represents also a
possible source of Ultra High Energy Cosmic Rays (UHECR), with a reliably
calculated spectrum of the particles produced in the decay . The SHDM model for the production of UHECR can explain
quantitatively only the excess of UHE events observed by AGASA. In the case of
an observed spectrum not showing the AGASA excess the SHDM model can provide
only a {\it subdominant} contribution to the UHECR flux. We discuss here the
basic features of SHDM for the production of a {\it subdominant} UHECR flux, we
refer our study to the possible signatures of the model at the Auger
observatory discussing in particular the expected chemical composition and
anisotropy.Comment: 18 pages, 14 eps figures, version accepted for publication in
Astroparticle Physic
Resuming elective surgical activity after the COVID-19 wave: what the patients need to know
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing coronavirus disease 2019 (COVID-19), infected more than four million people during the first months of 2021, and Italy was reported to have the highest death toll per million population at the beginning of May2. While there is no consensus on the treatment of the disease yet, understanding how the virus and its transmission will behave in the future is a cardinal priority for planning the re-establishment of routine healthcare services, such as surgery, in view of preventing indirectly COVID-19-related deaths due to undelivered care and lack of adequate treatment. Sadly, elective surgery on patients with perioperative SARS-CoV-2 infection, has shown increased mortality risk, therefore increasing anxiety among the population waiting for surgical interventions, as most of the elective activity was suspended due to COVID-19
outbreak
Contenimento naturale di Bactrocera oleae (Rossi): clima o parassitoidi? Confronto tra Western Cape (Sud Africa) e Sicilia
Bactrocera oleae (Rossi), mosca delle olive, e\u300 presente anche in Sud Africa, ma finora non si sono avute notizie di infestazioni economicamente rilevanti negli oliveti. L\u2019accertata presenza di un maggior numero di braconidi parassitoidi della mosca delle olive rispetto alle aree mediterranee e\u300 stata ed e\u300 considerata da molti autori la principale causa di queste minori infestazioni, senza che pero\u300 siano stati eseguiti in Sud Africa adeguati studi sulle infestazioni da B. oleae e sui fattori cli- matici delle aree interessate.
Analizzando recenti dati sui livelli d\u2019infestazione di B. oleae registrati su olivo coltivato e selvatico nel Western Cape e in Sicilia, appaiono simili in una normale annata fino a meta\u300 estate, ma sono nettamente differenti a fine estate-inizio autunno, quando in Sicilia il clima diviene piu\u300 umido. Da una puntuale analisi dei corrispondenti dati climatici registrati nelle due aree e\u300 infatti emersa una sostanziale differenza nel decorso piu\u300 caldo e secco degli ultimi tre mesi precedenti la raccolta nel Western Cape; questo periodo invece in Sicilia e\u300 caratterizzato da temperature piu\u300 fresche e un aumento dell\u2019umidita\u300 relativa che favorisce l\u2019impennata delle infestazioni di B. oleae. Nei quattro mesi presi in considerazione si rileva anche una significativa differenza nell\u2019escursione termica, maggiore nel Western Cape, dovuta a minime notturne piu\u300 basse.
Da un confronto dei livelli di parassitizzazione di B. oleae del Western Cape (Sud Africa) e dell\u2019area costiera della Provincia di Trapani, recentemente registrati su olivo colti- vato e selvatico (Olea europaea subsp. cuspidata in Sud Africa, Olea europaea subsp. europaea var. sylvestris in Sicilia) non sono emerse sostanziali differenze quantitative, pur confer- mando che in Sud Africa i principali parassitoidi sono tre bra- conidi (Utetes africanus (Sze\u301pligeti), Psyttalia lounsburyi (Silvestri) e Bracon celer (Sze\u301pligeti)), con il primo preva- lente sull\u2019olivo selvatico e l\u2019ultimo sul coltivato, mentre in Sicilia il braconide parassitoide Psyttalia concolor (Sze\u301pligeti) prevale sia sull\u2019olivo selvatico che sul coltivato. Comunque in entrambe le aree la parassitizzazione su B. oleae non rag- giunge elevati ed efficaci livelli.
Il clima, e non la parassitizzazione dovuta ai braconidi, appare il piu\u300 importante fattore di contenimento di B. oleae anche in Sud Africa.
L\u2019introduzione di parassitoidi specifici della mosca delle olive e\u300 necessaria nelle aree colonizzate di recente dove essi mancano, ma i tentativi di fornir loro una maggiore dis- ponibilita\u300 di larve dell\u2019ospite mediante l\u2019impianto di cultivar d\u2019olivo a maturazione e permanenza dei frutti piu\u300 differen- ziata, potrebbe produrre risultati certamente piu\u300 negativi che positivi nei confronti della presenza e dei livelli d\u2019infesta- zione di B. oleae sull\u2019olivo coltivato, come avviene nelle aree pandacie dove cresce spontaneo l\u2019olivastro.Natural environmental control of Bactrocera oleae (Rossi): climate or parasitoids? A comparison between the Western Cape of South Africa and Sicily.
Bactrocera oleae (Rossi), the olive fruit fly is considered not a continuosly serious pest of olive trees in the Western Cape of South Africa, in spite of the climate similar to Mediterranean areas. South African braconid parasitoids of B. oleae are more numerous than in Mediterranean areas, and until now their action has been considered the factor lowering the level of infestation due to the olive fruit fly, but no deep studies on its infestation levels and climatic factors influencing them were carried out in the past. Analyzing recent data on infestation levels collected in the Western Cape and Sicily, they appear similar in a regular mid- summer, differing at the end of summer-beginning of autumn, when in Sicily the climate becomes more humid than in the Western Cape. A comparison of climatic data regarding four years underlines that Somerset West and Franshhoek, in comparison with Trapani, have significantly lower minimum daily temperatures, a higher daily thermal excursion and a lower relative humidity in the last three months preceding harvesting.
Parasitization rates on B. oleae of Western Cape and Sicily, recorded on both cultivated and wild olives (Olea europaea subsp. cuspidata in South Africa, Olea europaea subsp. europaea var. sylvestris in Sicily) are not substantially different, confirming that in South Africa three braconids, Utetes africanus (Sze\u301pligeti), Psyttalia lounsburyi (Silvestri) and Bracon celer (Sze\u301pligeti), are the main parasitoids, with the first one as leader in wild olives and the last one as leader in cultivated ones, while in Sicily the braconid Psyttalia concolor (Sze\u301pligeti) is the main parasitoid in both wild and cultivated olives. Nevertheless parasitism on B. oleae doesn\u2019t reach effective levels of control in bats ragions.
The climate, instead of parasitization due to braconids, is the main environmental factor limiting the olive fruit fly infestations in the Western Cape of South Africa.
The introduction of parasitoids specific to the olive fruit fly is necessary in new invaded areas where they lack, but the attempt of providing them a more available amount of host fruits along the year, planting olive trees bearing fruits up to spring, could bring serious problems as those typical of Mediterranean areas where the European wild olive naturally grows
Trissolcus kozlovi in North Italy: host specificity and augmentative releases against Halyomorpha halys in hazelnut orchards
First detection of the adventive egg parasitoid of Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) Trissolcus mitsukurii (Ashmead) (Hymenoptera: Scelionidae) in France
SIMPLE SUMMARY: The invasive brown marmorated stink bug (BMSB), Halyomorpha halys, is a polyphagous species and a serious pest worldwide. Classical biological control (CBC), i.e., the introduction of a natural enemy from the native area of the pest, is considered as the preferential solution for BMSB regulation. Adventive populations of exotic egg parasitoids of BSMB, Trissolcus japonicus and T. mitsukurii, have been reported worldwide. With the aim to characterize the French diversity of egg parasitoids associated to various stink bugs including BMSB, field surveys were conducted between 2018 and 2020. Surprisingly, morphological and molecular analyses unambiguously revealed 12 specimens of T. mitsukurii, an Asian egg parasitoid of BSMB. Although its permanent establishment has to be confirmed, this first record in France could actually facilitate CBC initiatives, T. mitsukurii being considered with T. japonicus as the two most promising biological control agents against BMSB. ABSTRACT: We report the first detection of Trissolcus mitsukurii in France. More than 1860 sentinel egg masses of Halyomorpha halys (BMSB) were exposed in the field during the 2018–2020 period, and 12 specimens of T. mitsukurii emerged from one egg mass. Their taxonomic identification was confirmed both by morphological and molecular analysis. Trissolcus mitsukurii, similar to T. japonicus, is an egg parasitoid of BMSB in its area of origin in Asia, and both species are considered to be candidates for a classical biological control strategy against BMSB. Trissolcus mitsukurii was previously recorded in Italy where it is well established and widespread, and this may be the source of the French population. Possible permanent establishment and dispersion of T. mitsukurii in France should be monitored with emphasis on its potential effect on BMSB populations
Influence of distance from the host on parasitisation by Psyttalia concolor (Szépligeti) (Hymenoptera: Braconidae)
The olive fruit fly, Bactrocera oleae, is considered the main olive pest worldwide, and has been the target of biological control programmes through the release of the braconid parasitoid Psyttalia concolor. Laboratory tests were performed to evaluate the influence of distance from the host on parasitisation, placing larvae of the substitute host Ceratitis capitata at seven distances (0, 0.5, 1, 1.5, 2, 2.5, 3 mm) and four different time periods (7, 15, 30, 60 min). Moreover, field collected olives of Ogliarola Barese cultivar infested by B. oleae were exposed to P. concolor females to confirm its ability to parasitise B. oleae in small olives. Psyttalia concolor oviposition was inhibited at 2.5 and 3 mm due to the ovipositor length of the parasitoid females (2.7 mm). Hosts were easily parasitised at distances between 0 and 1.5 mm. The thin fruit pulp (up to 3.5 mm) of field collected olives allowed the parasitisation to occur also in mature fruits. At the best combination distance/time (0 mm, 30 min), tests performed with different larvae/parasitoid female ratio showed an increasing emergence of P. concolor (from 20% to 57%) with larvae/parasitoid ratio increasing from 0.11 to 0.74. The results of the present study might optimise the mass rearing of P. concolor, through a proper setting of its parameters, such as the host/parasitoid ratio, exposure distances, and interaction time
Expression of cyclooxygenase-1 and cyclooxygenase-2 in normal and pathological human oral mucosa.
Cyclooxigenase (COX) is the rate-limiting enzyme for the conversion of arachidonic acid (AA) to prostaglandins (PGs). Two isoforms of COX have been identified: COX-1 is constitutively expressed in many cells and is involved in cell homeostasis, angiogenesis and cell-cell signalling; COX-2 is not expressed in normal condition however it is strongly expressed in inflammation. The oral cavity is constantly exposed to physical and chemical trauma that could lead to mucosal reactions such as hyperplasia, dysplasia and cancer. Early diagnosis is the most important issue to address for a positive outcome of oral cancer; therefore it would be useful to identify molecular markers whose expression is associated with the various stages of oral cancer progression. Since COX enzyme has been involved, with different mechanisms, in the development and progression of malignancies we decided to investigate the expression and localization of COX-1 and COX-2 in normal human oral mucosa and three different pathologies (hyperplasia, dysplasia and carcinoma) by immunohistochemistry and RT-PCR. COX-1 mRNA and protein have been detected already in normal oral mucosa and their expression progressively increases from normal samples towards hyperplasia, dysplasia and finally carcinoma. On the contrary, COX-2 is not expressed in the normal tissue, starts to be expressed in hyperplasia, reaches the maximum activation in dysplasia and then starts to be downregulated in carcinoma
A morphological, biological and molecular approach reveals four cryptic species of Trissolcus Ashmead (Hymenoptera, Scelionidae), egg parasitoids of Pentatomidae (Hemiptera)
Accurate identification of parasitoids is crucial for biological control of the invasive brown marmorated stink bug, Halyomrpha halys (Stål). A recent work by Talamas et al. (2017) revised the Palearctic fauna of Trissolcus Ashmead, egg-parasitoids of stink bugs, and treated numerous species as junior synonyms of T. semistriatus (Nees von Esenbeck). In the present paper, we provide a detailed taxonomic history and treatment of T. semistriatus and the species treated as its synonyms by Talamas et al. (2017) based on examination of primary types, molecular analyses and mating experiments. Trissolcus semistriatus, T. belenus (Walker), T. colemani (Crawford), and T. manteroi (Kieffer) are here recognized as valid and a key to species is provided. The identification tools provided here will facilitate the use of Trissolcus wasps as biological control agents and as the subject of ecological studies
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