Activity In September Research Articles

High‐Frequency Communications Response to Solar Activity in September 2017 as Observed by Amateur Radio Networks

AbstractNumerous solar flares and coronal mass ejection‐induced interplanetary shocks associated with solar active region AR12673 caused disturbances to terrestrial high‐frequency (HF, 3–30 MHz) radio communications from 4–14 September 2017. Simultaneously, Hurricanes Irma and Jose caused significant damage to the Caribbean Islands and parts of Florida. The coincidental timing of both the space weather activity and hurricanes was unfortunate, as HF radio was needed for emergency communications. This paper presents the response of HF amateur radio propagation as observed by the Reverse Beacon Network and the Weak Signal Propagation Reporting Network to the space weather events of that period. Distributed data coverage from these dense sources provided a unique mix of global and regional coverage of ionospheric response and recovery that revealed several features of storm time HF propagation dynamics. X‐class flares on 6, 7, and 10 September caused acute radio blackouts during the day in the Caribbean with recovery times of tens of minutes to hours, based on the decay time of the flare. A severe geomagnetic storm with Kpmax = 8+ and SYM‐Hmin = −146 nT occurring 7–10 September wiped out ionospheric communications first on 14 MHz and then on 7 MHz starting at ∼1200 UT 8 September. This storm, combined with affects from additional flare and geomagnetic activity, contributed to a significant suppression of effective HF propagation bands both globally and in the Caribbean for a period of 12 to 15 days.

Proton beam radiotherapy: report of the first patient treated at the Centro Nazionale di Adroterapia Oncologica (CNAO) [National Center of Oncologic Hadron Therapy

Proton beam radiotherapy, an innovative treatment modality, allows delivery of high radiation doses to the target while sparing surrounding healthy structures. The Centro Nazionale di Adroterapia Oncologica (CNAO), equipped with a synchrotron and capable of using both protons and ions, initiated its clinical activity in September 2011. The first treatment of a skull base tumor with protons is reported here. The case of a 26-year-old man with an intracranial low-grade chondrosarcoma of the right petroclival junction is discussed with emphasis on technical and clinical details. Two previous surgical interventions had achieved partial removal of the tumor and the patient was treated with protons for residual disease. The prescribed dose was 70 GyE in 35 fractions of 2 GyE. Treatment was completed with minimal acute toxicity consisting of grade 1 alopecia and nausea. Nine months after treatment the disease is locally controlled. Use of high-energy protons at CNAO is a safe and effective means of treating a tumor located near critical normal structures.

Characteristics of Antioxidant Systems of Yellow Fraction of Red Deer's (Cervus elaphus L.) Semen During the Rutting Period.

The objective of this study was to make the preliminary characterization of the antioxidant defence systems of the yellow fraction (YF) of red deer's (Cervus elaphus L.) semen during the rutting period. The semen was collected using artificial vagina (AV). The studies included spectrophotometric determination of antioxidant enzymes activities such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). We also analysed the contents of low-molecular antioxidants such as L-glutathione (GSH+GSSG), L-ascorbate (ASC) and total antioxidant status (TAS). Additionally, the samples were subjected to PAGE and stained for SOD and GPx activities. It was demonstrated that the yellow fraction exhibited activities of SOD and GPx, with the highest activities in September and October. CAT activity was not detected. Staining for the SOD and GPx activities confirmed three protein bands with SOD activity and one protein band with GPx activity. The content of GSH+GSSG was similar in trials dating from October to December contrary to the content of ASC which was high in samples from September and October. The stable rate of TAS was observed during the whole rutting period. The results of this study showed that the YF of red deer semen is equipped with basic battery of antioxidant enzymes comprising SOD and GPx, with the supporting role of GSH+GSSG and ASC. Moreover, the samples obtained at the peak of the rutting period occurring from September to October had the highest enzymatic activity in comparison with remaining months of the rutting period, which contributed to the high quality of the semen by preventing it from the formation of oxidative stress during the short period of intense sexual activity of male red deer. The better understanding of the mechanisms of antioxidant defence systems in the YF of deer's semen may contribute to the potential use of this fraction in technology of wild ruminant semen preservation.

Occurrence of perchloroethylene in surface water and fish in a river ecosystem affected by groundwater contamination.

Long-term monitoring of the content of perchloroethylene (PCE) in a river ecosystem affected by groundwater contamination was performed at a site in the Czech Republic. The quality of surface water was monitored quarterly between 1994 and 2013, and fish were collected from the affected ecosystem to analyse the content of PCE in their tissue in 1998, 2011 and 2012. Concentrations of PCE (9-140 μg/kg) in the tissue of fish collected from the contaminated part of the river were elevated compared to the part of the river unaffected by the contamination (ND to 5 μg/kg PCE). The quality of surface water has improved as a result of groundwater remediation during the evaluated period. Before the remedial action, PCE concentrations ranged from 30 to 95 μg/L (1994-1997). Following commencement of remedial activities in September 1997, a decrease in the content of PCE in the surface water to 7.3 μg/L (1998) and further to 1 μg/L (2011) and 1.1 μg/L (2012) led to a progressive decrease in the average concentration of PCE in the fish muscle tissue from 79 μg/kg (1998) to 24 (2011) and 30 μg/kg (2012), respectively. It was determined that the bioconcentration of PCE does not have a linear dependence because the decrease in contamination in the fish muscle tissue is not directly proportional to the decrease in contamination in the river water. The observed average bioconcentration factors were 24 and 28 for the lower concentrations of PCE and 11 for the higher concentrations of PCE in the river. In terms of age, length and weight of the collected fish, weight had the greatest significance for bioconcentration, followed by the length, with age being evaluated as a less significant factor.

How Prepared Are Nigerian Schools for Ebola Virus Disease Prevention and Control?

BackgroundNigeria was one of the West African countries gripped by the fear of the spread of the Ebola virus disease (EVD), leading to a long period of delay in resumption of primary and secondary schools for academic activities in September 2014. The aim of this study was to assess the preparedness of schools in the north central region of Nigeria toward EVD prevention and control within 1 month of resumption of schools. MethodsThis was a descriptive cross-sectional study among 76 schools selected using a multistage sampling method. Research instruments were self-administered, semi-structured questionnaires. Data was analyzed using the SPSS software version 17.0. FindingsHalf (38) of the schools reported that some of the children could have traveled to EVD-infected areas during the holiday period; 77.6% (59) had their teachers formally trained on EVD prevention and control before resumption; 50% (38) set up a committee on EVD prevention; and 62.9% (63) carried out awareness-raising activities on school assembly ground. Based on some preventive measures criteria, 55.2% (42) were categorized ready, whereas 44.7% (34) were not ready for EVD prevention and control within 1 month of resumption of students back to school. About 76.3% (58) said they would like to sustain these EVD prevention efforts; 14.5% (11) would like to sustain such efforts at least until the end of the present term. Determinants of readiness for EVD prevention and control include being a private school, being an urban school, belief that children could have traveled to an EVD-infected area, and school having standard operating procedure or policy guidelines on EVD prevention and control. ConclusionThe persistent call for postponement of school resumption might have been due to the unpreparedness of many of schools to meet EVD prevention and control guidelines. Schools need to take more proactive and sustainable measures toward effective control of the ongoing epidemic and prevention of future occurrences.

Comparison of asymptomatic and symptomatic rhinovirus infections in university students: incidence, species diversity, and viral load

Human rhinovirus (HRV) infections are common but poorly characterized in university students. Thus, we characterized asymptomatic and symptomatic HRV infections by incidence, species diversity, and viral load of 502 university students during September and October of 2010 and 2011 from nasal swabs and electronically submitted symptom questionnaires. We tested all symptomatic students and randomly sampled participants who remained asymptomatic (n=25/week, over 8weeks each study year) on a weekly basis by real-time PCR and sequenced HRV positives. HRV was identified in 33/400 (8.3%) and 85/92 (92.4%) of the asymptomatic and symptomatic students, respectively. We identified a higher than previously reported rate of HRV-B in both groups, although the distribution of HRV species was similar (P=0.37). Asymptomatic viral load averaged 1.2 log10 copies/mL lower than symptomatic HRV (P<0.001). In conclusion, asymptomatic HRV activity preceded peak symptomatic activity in September and October and was associated with lower viral load.

FENOLOGIA DE &lt;i&gt;Brosimum gaudichaudii&lt;/i&gt; TRÉCUL. (MORACEAE) NO CERRADO DE MATO GROSSO

http://dx.doi.org/10.5902/1980509817464Brosimum gaudichaudii Trécul., espécie típica do cerrado, é muito apreciada pelo sabor adocicado dos seus frutos e como planta medicinal no tratamento do vitiligo. Os estudos fenológicos fornecem subsídios para a compreensão da dinâmica dos ecossistemas florestais e para o manejo de espécies nativas. Desse modo, o objetivo nesta pesquisa foi avaliar a fenologia Brosimum gaudichaudii Trécul. por meio de dois métodos: a intensidade do evento fenológico caracterizada pela escala de Fournier e a presença/ausência do evento, ambos expressos pelos índices de atividade e intensidade. O acompanhamento dos estádios fenológicos foi feito a cada 20 dias, de 2006 a 2008, em 49 indivíduos selecionados aleatoriamente. O índice de sincronia (Z) foi de 0,96 para enfolhamento; 0,65 para brotação; 0,69 para floração e de 0,72 para frutificação. A abscisão foliar ocorreu em julho e a brotação foi mais intensa (80%) em outubro. A floração ocorreu entre junho e outubro de 2007, com pico de intensidade em agosto (52%) e maior atividade em setembro (92%); a frutificação ocorreu entre agosto e dezembro de 2007, com 91% dos indivíduos em atividade em outubro, porém, intensidade de 25% para o mesmo período. Brosimum gaudichaudii Trécul. é planta decídua e os eventos fenológicos estão condicionados à sazonalidade das variações climáticas, principalmente precipitação.

Behavior of antioxidant parameters in young cattle during the course of the year

To analyze the behavior of antioxidant parameters in young cattle over 1 year and to detect possible health-related deficits during certain periods. Every 2 months over the course of 1 year, six healthy 12-month-old Holstein Friesian/German black and white heifers underwent a clinical examination and blood samples were obtained. The 36 animals were kept in tie-stalls during September, November, January, March and July, and solely at pasture in May. The antioxidant parameters superoxide dismutase (SOD), glutathione peroxidase (GPX) and the Trolox equivalent antioxidant capacity (TEAC), hematocrit and the metabolic parameters β-hydroxybutyrate, bilirubin, cholesterol, protein, albumin, urea, haptoglobin, calcium, inorganic phosphate, iron, alkaline phosphatase, aspartate transaminase, glutamate dehydrogenase and creatine kinase were determined. The GPX activities in September and January were significantly lower than those from March till July. The TEAC concentrations were in particular lower in January and significantly lower in March than in September and November. Differing SOD activities were not statistically significant. The correlation between SOD and GPX during the entire period was significant as well as between SOD and TEAC throughout the year except in January, whereas GPX and the TEAC only significantly correlated in November and from March till July. Albumin significantly correlated with the TEAC. The metabolic parameters were within the physiological range at all times, except urea in November and July and phosphate in May. The young cattle showed significantly reduced GPX activities from September to January, and reduced TEAC concentrations particularly in January and March. Decreased GPX activity is indicative of a low selenium supply. Among other disadvantages, this is unfavorable for the development of heifers. A reduced provision with antioxidant agents, particularly vitamin E and β-carotene, is indicated by the TEAC and has negative effects that are comparable to those caused by a lack of selenium. In terms of health prophylaxis, particularly during winter, specific attention should be given to the supply of sufficient trace elements and good quality silage.

Proton beam radiotherapy: report of the first ten patients treated at the “Centro Nazionale di Adroterapia Oncologica (CNAO)” for skull base and spine tumours

The Italian National Centre for Oncological Hadrontherapy (Centro Nazionale di Adroterapia Oncologica, CNAO), equipped with a proton and ion synchrotron, started clinical activity in September 2011. The clinical and technical characteristics of the first ten proton beam radiotherapy treatments are reported. Ten patients, six males and four females (age range 27-73 years, median 55.5), were treated with proton beam radiotherapy. After one to two surgical procedures, seven patients received a histological diagnosis of chordoma (of the skull base in three cases, the cervical spine in one case and the sacrum in three cases) and three of low-grade chondrosarcoma (skull base). Prescribed doses were 74 GyE for chordoma and 70 GyE for chondrosarcoma at 2 GyE/fraction delivered 5 days per week. Treatment was well tolerated without toxicity-related interruptions. The maximal acute toxicity was grade 2, with oropharyngeal mucositis, nausea and vomiting for the skull base tumours, and grade 2 dermatitis for the sacral tumours. After 6-12 months of follow-up, no patient developed tumour progression. The analysis of the first ten patients treated with proton therapy at CNAO showed that this treatment was feasible and safe. Currently, patient accrual into these as well as other approved protocols is continuing, and a longer follow-up period is needed to assess tumour control and late toxicity.

Immunotherapy Targeting Tau and Amyloid Aβ Pathology in AD Animal Models

Immunotherapy Targeting Tau and Amyloid Aβ Pathology in AD Animal Models

Proton Beam Radiotherapy: Report of the First Patient Treated at the Centro NAzionale di Adroterapia Oncologica (CNAO)

Proton beam radiotherapy, an innovative treatment modality, allows delivery of high radiation doses to the target while sparing surrounding healthy structures. The Centro Nazionale di Adroterapia Oncologica (CNAO), equipped with a synchrotron and capable of using both protons and ions, initiated its clinical activity in September 2011. The first treatment of a skull base tumor with protons is reported here. The case of a 26-year-old man with an intracranial low-grade chondrosarcoma of the right petroclival junction is discussed with emphasis on technical and clinical details. Two previous surgical interventions had achieved partial removal of the tumor and the patient was treated with protons for residual disease. The prescribed dose was 70 GyE in 35 fractions of 2 GyE. Treatment was completed with minimal acute toxicity consisting of grade 1 alopecia and nausea. Nine months after treatment the disease is locally controlled. Use of high-energy protons at CNAO is a safe and effective means of treating a tumor located near critical normal structures.

Seasonal variations of soil microbial biomass and activity in warm- and cool-season turfgrass systems

Plant growth can be an important factor regulating seasonal variations of soil microbial biomass and activity. We investigated soil microbial biomass, microbial respiration, net N mineralization, and soil enzyme activity in turfgrass systems of three cool-season species (tall fescue, Festuca arundinacea Schreb., Kentucky bluegrass, Poa pratensis L., and creeping bentgrass, Agrostis palustris L.) and three warm-season species (centipedegrass, Eremochloa ophiuroides (Munro.) Hack, zoysiagrass, Zoysia japonica Steud, and bermudagrass, Cynodon dactylon (L.) Pers.). Microbial biomass and respiration were higher in warm- than the cool-season turfgrass systems, but net N mineralization was generally lower in warm-season turfgrass systems. Soil microbial biomass C and N varied seasonally, being lower in September and higher in May and December, independent of turfgrass physiological types. Seasonal variations in microbial respiration, net N mineralization, and cellulase activity were also similar between warm- and cool-season turfgrass systems. The lower microbial biomass and activity in September were associated with lower soil available N, possibly caused by turfgrass competition for this resource. Microbial biomass and activity (i.e., microbial respiration and net N mineralization determined in a laboratory incubation experiment) increased in soil samples collected during late fall and winter when turfgrasses grew slowly and their competition for soil N was weak. These results suggest that N availability rather than climate is the primary determinant of seasonal dynamics of soil microbial biomass and activity in turfgrass systems, located in the humid and warm region.

Opening of an MPA to fishing: Natural variations in the structure of a coral reef fish assemblage obscure changes due to fishing

Marine Protected Areas (MPAs) are known to enhance diversity, density and biomass of coral reef fishes and to modify the size and trophic structures of these fish assemblages. Opening to fishing has the opposite effects, but on a much shorter time scale. The present study compares the evolution of the fish assemblages of two adjacent reef zones, both initially MPAs, one of them being afterwards opened to fishing. The study was conducted on Aboré Reef, a New Caledonian barrier reef (SW Pacific) which constituted a 148 km 2 marine protected area, of which 69 km 2 are within the lagoon. Two surveys of a coral reef fish assemblage, using underwater visual censuses, were performed, the first one was conducted in July 1993 following 5 years of protection from fishing, the second one was conducted in July 1995; part of the reef having been opened to fishing activity in September 1993. This study examined the effects of two factors on these fish communities: time (1993 vs. 1995) and zone (reefs protected from fishing vs. unprotected reefs); the interaction of these two factors indicating an effect of either protection or opening to fishing. Diversity (species/transect), density and biomass were tested for all species together (377 species), then according to diet, size and commercial use. There was a significant decrease over time of most values in both fished and unfished areas, the decrease being greater in the zone opened to fishing. The magnitude of decrease over time was within the range of known time variations from other studies in New Caledonia and other Pacific locations. However, this decrease was so large that it prevented the detection of effects linked to protection. Only some minor effects could be detected for 16 species with no specific pattern according to diet, size or use. The density and biomass of species of low commercial value were also affected by opening to fishing. Relative changes in diversity could be better detected than relative changes in density or biomass. This study demonstrates that on a short-term basis (2 years), natural variations can be of larger magnitude than changes that may be induced by management options, especially when fishing pressure is not very high.

Seasonal changes of sperm storage and correlative structures in male and female soft-shelled turtles, Trionyx sinensis

Reproductive ducts of male and female soft-shelled turtles, Trionyx sinensis were examined throughout the year (March, May, September, December) using brightfield and electron microscopes (TEM and SEM), to determine the location and histomorphological characteristics of sperm storage structures as well as their changes at different phases of the seasonal reproductive cycle. Sperm stored in the epididymis were also examined. In the male, spermatogenesis is initiated in spring (May), and then the mature sperm are released in autumn as an episodic event. Spermatogenesis is inactive in winter. However, in this species, the epididymis contains sperm throughout the entire year. Sperm observed in the epididymis are intact and some structures are uniquely different from other reptiles, and is characterized by 35–40 concentric mitochondria with a dense core in the centre. Many glycogen granules are observed in the cytoplasm of the midpiece. However, the epithelial cell type of epididymal duct change in different seasons. The cells are fully developed with a highly secretory activity in September. The materials secreted from the epithelium might have the function as nourishment for the stored sperm. Sperm storage structures in the form of tubules are observed in the wall of the isthmus of the oviduct in hibernating females but are absent in the groups of May and September. These tubules develop either by folding or fusion of the oviductal mucosal folds and are lined by both ciliated and secretory cells. These tubules might provide a microenvironment for the sperm to enable its long-term storage. After being separated 4 months (December–March) from the male, sperm are observed in the tubules of the isthmus of the oviduct. The unique character of the sperm combined with the special sperm storage structures enable the sperm to maintain fertility and activity during their storage.

Reproductive biology and per-recruit analyses of striped trumpeter ( Latris lineata) from Tasmania, Australia: Implications for management

This paper profiles the reproductive biology of and investigates the resilience of Tasmanian striped trumpeter under different levels of fishing pressure and size at entry to the fishery using per-recruit analysis. The spawning season around Tasmania occurs in the austral spring, with peak spawning activity in September and October. Size at 50% maturity was estimated at 543 mm fork length (FL) for females (estimated age = 6.8 years) and 529 mm FL for males (estimated age = 6.2 years). Striped trumpeter is a multiple spawner with batch fecundity estimates ranging from 205,054 for a 2 kg fish (540 mm FL) to 2,351,029 for a 9.5 kg fish (800 mm FL). At the current minimum legal size limit of 450 mm total length (equivalent to approximately 425 mm FL), yield-per-recruit was estimated to be close to maximum, and spawning biomass-per-recruit (SPR) ranged from 35 to 52% of virgin stock, depending on the mortality estimates used. Although these SPR are at a level considered sustainable, this methodology does not incorporate temporal variability, specifically recruitment variability. Therefore, conservative management measures are recommended until a dynamic model is applied to the striped trumpeter population.

Satellite‐observed pollution from Southern Hemisphere biomass burning

Biomass burning is a major source of pollution in the tropical Southern Hemisphere, and fine mode carbonaceous particles are produced by the same combustion processes that emit carbon monoxide (CO). In this paper we examine these emissions with data from the Terra satellite, CO profiles from the Measurement of Pollution in the Troposphere (MOPITT) instrument, and fine‐mode aerosol optical depth (AOD) from the Moderate‐Resolution Imaging Spectroradiometer (MODIS). The satellite measurements are used in conjunction with calculations from the MOZART chemical transport model to examine the 2003 Southern Hemisphere burning season with particular emphasis on the months of peak fire activity in September and October. Pollutant emissions follow the occurrence of dry season fires, and the temporal variation and spatial distributions of MOPITT CO and MODIS AOD are similar. We examine the outflow from Africa and South America with emphasis on the impact of these emissions on clean remote regions. We present comparisons of MOPITT observations and ground‐based interferometer data from Lauder, New Zealand, which indicate that intercontinental transport of biomass burning pollution from Africa often determines the local air quality. The correlation between enhancements of AOD and CO column for distinct biomass burning plumes is very good with correlation coefficients greater than 0.8. We present a method using MOPITT and MODIS data for estimating the emission ratio of aerosol number density to CO concentration which could prove useful as input to modeling studies. We also investigate decay of plumes from African fires following export into the Indian Ocean and compare the MOPITT and MODIS measurements as a way of estimating the regional aerosol lifetime. Vertical transport of biomass burning emissions is also examined using CO profile information. Low‐altitude concentrations are very high close to source regions, but further downwind of the continents, vertical mixing takes place and results in more even CO vertical distributions. In regions of significant convection, particularly in the equatorial Indian Ocean, the CO mixing ratio is greater at higher altitudes, indicating vertical transport of biomass burning emissions to the upper troposphere.

The new strategy of the CEN Environmental Helpdesk

In 1999, the CEN Environmental Helpdesk (hereinafter referred to as ‘EHD’) was set up by the CEN Technical Board. This Helpdesk started its activities in September 1999, with the aim of supporting the various CEN TCs in their task of incorporating environmental aspects when drafting product standards, and raising awareness amongst the TCs. It was intended that the EHD would screen draft standards with respect to their environmental implications and then provide comments to the TC or Working Group preparing the draft standard. On the other hand, the TCs would be able to contact the EHD for environmental advice and expertise, as needed.

Stages of gonad development during the reproductive cycle of the blackfin snook, Centropomus medius Gunther

The reproductive biology of the Blackfin snook Centropomus medius was studied to expand our current knowledge on its aquaculture potential. From April 2001 to November 2002, 301 females and 193 males were captured. A 1:1.6 (male:female) ratio was found. Gonadosomatic (GSI) and hepatosomatic (HSI) indices suggested that the spawning period (SP) extended from September to November, with peak spawning activity in September (GSI=0.98% and HSI=0.7%). The period of pre-gametogenesis extended from January to June. During the post-SP in December, 90% of oocytes were pre-vitellogenic and 10% were atretic. Histological analysis of gonads (haematoxylin–eosin, Sudan black B, Alcian blue PAS, Cleveland Wolfe) showed five stages of oocyte development, each occurring at a characteristic range of oocyte diameters (μm): (I) pre-vitellogenic (25–55); (II) cortical alveoli (56–250); (III) vitellogenic (251–340); (IV) maturation (341–645) and (V) atretic (21–100). Five reproductive stages were identified for testis morphology: (I) regressed; (II) early maturation; (III) mid-maturation; (IV) full maturation and (V) regression. The type of ovarian development in C. medius was identified as a group synchronous.

Climatologies of subtropical mixing derived from 3D models

Abstract. Fingerlike structures reaching from lower into extra-tropical latitudes significantly contribute to the tropical-extratropical exchange of air masses. This is also an exchange of upper tropospheric and stratospheric air. Those so called streamers can, on a horizontal plane, be detected in N2O or O3 since they are characterised by high N2O or low O3 values compared to undisturbed mid-latitude values. A climatology of streamer events has been established, employing the chemical-transport model KASIMA, which is driven by ECMWF re-analyses (ERA) and operational analyses. For the first time, the seasonal and geographical distribution of streamer frequencies has been determined on the basis of 9 years of meteorological analyses. For the current investigation, a meridional gradient criterion has been newly formulated and applied to the N2O distributions calculated with KASIMA. A climatology has been derived by counting all streamer events between 21 and 25 km for the years 1990 to 1998. The results have been compared with a streamer climatology which has been established in the same way employing data of a multi-year simulation with the coupled chemistry-climate model ECHAM4.L39(DLR)/CHEM (E39/C). Both climatologies are qualitatively in agreement, in particular in the northern hemisphere, where much higher streamer frequencies are found in winter than in summer. In the southern hemisphere, the KASIMA analyses indicate strongest streamer activity in September. E39/C streamer frequencies clearly displays an offset from June to October, pointing to model deficiencies with respect to tropospheric dynamics. KASIMA and E39/C results agree well from November to May. Some of the findings give strong indications that the streamer events found in the altitude region between 21 and 25 km are mainly forced from the troposphere and are not directly related to the dynamics of the stratosphere, in particular not to the dynamics of the polar vortex. Sensitivity simulations with E39/C, which represent recent and possible future atmospheric conditions, have been employed to answer the question how climate change would alter streamer frequencies. This shows that the seasonal cycle does not change but that significant changes occur in months of minimum and maximum streamer frequencies. This could have an impact on the mid-latitude distribution of chemical tracers and compounds.

Multiparameter monitoring of Fogo Island, Cape Verde, for volcanic risk mitigation

Fogo Island in the Cape Verde Archipelago (North Atlantic) is a stratovolcano of nearly conical shape that rises 2829 m above sea level and ∼6000 m above the surrounding seafloor. With a population of 40 000, the island has known intense historical volcanic activity since AD 1500, with an average interval between eruptions of the order of 20 years. Twentieth-century rates were more subdued, with only two flank eruptions in 1951 and 1995. Following the 1995 eruption, increased awareness of the volcanic hazard affecting the population of the island led to the deployment of the permanent VIGIL Network. Seismographic stations (both broadband and short-period), tiltmeters and a CO 2 sensor where installed in Fogo, together with a telemetry infrastructure to allow remote real-time monitoring. A broadband seismographic station was installed in neighbour Brava Island. The operation of the network was complemented by the introduction of routine geodetic and microgravity surveying and the operation of an automatic meteorological station. In this paper, we describe the methodology adopted to monitor the volcanic activity, combining real-time data analysis (volcanotectonic and volcanic earthquakes, volcanic tremor and tilt) with repeated surveying at intervals of several months (GPS, microgravity). Examples of data from the first years of operation are presented. In particular, the data pertaining to a period of anomalous activity in September–October 2000 are discussed, in the context of the risk mitigation strategy currently being developed.