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See detailCHARACTERISTICS OF DUCK PRODUCTION SYSTEMS IN RED RIVER AND MEKONG RIVER DELTAS
Vu Dinh, Ton; Phan Dang, Thang ULg

in Journal of Animal Husbandry Sciences and Technics (2014), 22(8), 8

In Vietnam, the economic growth in recent years has brought a strong demand for animal products consumption, particularly poultry meat. This research aims to better understand how the factors in the duck ... [more ▼]

In Vietnam, the economic growth in recent years has brought a strong demand for animal products consumption, particularly poultry meat. This research aims to better understand how the factors in the duck sector adapt to current economic conditions in Red River Delta and Mekong Delta by analyzing livestock farming systems with their various constraints. The research had been conducted by interviewing and production record keeping system at the household farms which have duck production at different scales in Hanoi Suburbs in Red River Delta from December 2008 to November 2009 and Long An Province in Mekong Delta from March to August, 2007. Three duck production systems have been identified (1) industrial duck production system with high-yield potential imported races; (2) transhumant duck production system at semi-industrial scale with local or cross-bred ducks. Broiler or layer ducks are freely grazed or transhumant on rice fields for taking the residual paddy; and (3) duck production system at small scale or backyard production. Broiler duck farms have obtained weak productivity with high mortality rate. The net income has varied from 7,358,000 to 10,151,000 Vietnam Dongs per farm per year with broiler ducks and reproductive ducks at semi-industrial and industrial systems. Backyard duck farms are widely practiced in household farms with low investment. The net income of duck production is also weak in households (728,000 Vietnam Dongs per farm per year with broiler ducks and 1,368,000 Vietnam Dongs with layer ducks. Majority surveyed farms raised various species of chickens and ducks. Duck meat production also aims to satisfy a significant share of the demand for self-consumption with ducks in small households. [less ▲]

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See detailCharacteristics of Economically Designed CUSUM and \bar{X} Control Charts
Saniga, Erwin; Davis, Darwin; Faraz, Alireza ULg et al

in Frontiers in Statistical Quality Control 11 (2013, August 22)

In this paper we investigate the characteristics of economic control chart designs for both Shewhart (¯X ) and CUSUM control charts. Authors in the past have made some suggestions regarding the design of ... [more ▼]

In this paper we investigate the characteristics of economic control chart designs for both Shewhart (¯X ) and CUSUM control charts. Authors in the past have made some suggestions regarding the design of these charts, where design is defined as finding the values of sample size, intersample interval and control limit (Shewhart chart) or control parameters (k and h) for the CUSUM chart. Here, we run a large number of experiments consisting of many configurations of the parameters and describe and model the results in terms of the actual economic designs. [less ▲]

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See detailCharacteristics of Economically Designed CUSUM and \bar{X} Control Charts
Saniga, Erwin; Davis, Darwin; Faraz, Alireza ULg et al

in Knoth, Sven; Schmid, Wolfgang (Eds.) Frontiers in Statistical Quality Control 11 (2015)

In this paper we investigate the characteristics of economic control chart designs for both Shewhart (¯X ) and CUSUM control charts. Authors in the past have made some suggestions regarding the design of ... [more ▼]

In this paper we investigate the characteristics of economic control chart designs for both Shewhart (¯X ) and CUSUM control charts. Authors in the past have made some suggestions regarding the design of these charts, where design is defined as finding the values of sample size, intersample interval and control limit (Shewhart chart) or control parameters (k and h) for the CUSUM chart. Here, we run a large number of experiments consisting of many configurations of the parameters and describe and model the results in terms of the actual economic designs. [less ▲]

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See detailCharacteristics of familial isolated pituitary adenomas (FIPA) - Review
Daly, Adrian ULg; Vanbellinghen, Jean-François ULg; Beckers, Albert ULg

in Expert Review of Endocrinology & Metabolism (2007), 2(6), 725-733

The familial occurrence of pituitary adenomas has been recognized for many years and currently accounts for approximately 5% of all cases. Molecular, genetic and clinical features of familial pituitary ... [more ▼]

The familial occurrence of pituitary adenomas has been recognized for many years and currently accounts for approximately 5% of all cases. Molecular, genetic and clinical features of familial pituitary adenomas have been well characterized in multiple endocrine neoplasia type 1 (MEN-1) and Carney's complex (CNC), which account for the majority of familial pituitary tumor cases. These conditions are caused by MEN1 and PRKAR1A gene mutations, respectively, and the clinical and pathological features of pituitary pathology in these diseases differ from those of sporadic pituitary tumors. Familial acromegaly has been recognized for many years and, more recently, the clinical features of this clinical phenotype, referred to as isolated familial somatotropinoma, have been clarified. Over the past decade, the concept of non-MEN-1/CNC familial pituitary tumors has been expanded significantly to include all phenotypes, a condition known as familial isolated pituitary adenomas (FIPA). In FIPA, tumors can present homogeneously (same phenotype) or heterogeneously (different tumor phenotypes) within the same family. Compared with sporadic pituitary adenomas, patients with FIPA have a younger age at diagnosis and have larger tumors. The clinical features of FIPA differ from those of MEN-1 in terms of a higher frequency of somatotropinomas and a lower frequency of prolactinomas. The recent discovery of the involvement of mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene in association with pituitary tumors has provided new information regarding potential mechanisms of tumorigenesis in FIPA patients. While very infrequent in sporadic pituitary tumors, approximately 15% of FIPA patients have AIP mutations, rising to half of patients with familial acromegaly. In this review, we detail the clinical features of FIPA and discuss tumor pathology and genetic findings in this increasingly recognized clinical condition. [less ▲]

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See detailCharacteristics of Jovian morning bright FUV aurora from Hubble Space Telescope/Space Telescope Imaging Spectrograph imaging and spectral observations
Gustin, Jacques ULg; Cowley, S. W. H.; Gérard, Jean-Claude ULg et al

in Journal of Geophysical Research. Space Physics (2006), 111(A9),

Observation of an exceptionally bright (peaking at similar to 1.8 MR) Jovian auroral morning arc was obtained with the Space Telescope Imaging Spectrograph (STIS) on 21 September 1999, both in the imaging ... [more ▼]

Observation of an exceptionally bright (peaking at similar to 1.8 MR) Jovian auroral morning arc was obtained with the Space Telescope Imaging Spectrograph (STIS) on 21 September 1999, both in the imaging and spectral modes. The images of the HST orbit are used to describe the variation of the position of the bright arc, while the time-tagged spectra are examined to derive the properties of the precipitating auroral electrons, such as their mean energy and the electron current density at the top of the atmosphere. The first and the last images of the HST orbit, separated by 37 min, show that the bright morning emission is situated on the reference oval, with a "leading" edge fixed in lambda(III) longitudes (i.e., rotating with the planet), and a "trailing" edge that extends into the nightside. The auroral arc is divided in two branches, as was also observed in some previous analyses. An isolated bright spot is also observed at lambda(III) similar to 184 degrees. Its brightness reaches 500 kR and it also approximately corotates with Jupiter. Four regions of the auroral morning arc captured by the STIS aperture were extracted from the spectral observation. The four associated low-resolution spectra (similar to 4.8 degrees) show very different characteristics. In particular, two spectra reveal unusually high color ratios (18.5 and 45.5), with corresponding mean electron energies of similar to 280 and similar to 460 keV, respectively. The current densities associated with three of the spectra lie in the range 0.09-0.2 mu A m(-2), consistent with previous estimates, while the fourth spectrum is characterized by a mean current density of 0.54 mu A m(-2), outside the range similar to 0.04-0.4 mu A m(-2) obtained in a previous study of G140L spectra of the Jovian main oval. Assuming that main oval aurorae are caused by field-aligned electric fields, the relationship between the energy flux and the current density derived from the spectra has been compared to the Knight's theory of field-aligned currents. Because of the very high acceleration potential derived from two of the extracted spectra, a relativistic treatment of the Knight theory was used. Assuming an electron temperature T-e = 2.5 keV, it is seen that the two regions corresponding to earlier local times (higher lambda(III) longitudes) reveal an electron source density lower than the values observed in the equatorial plane during the Voyager flybys. On the other hand, the equatorward region (lowest latitude) exhibits an electron source density in the upper range of usual values. Analysis of time-tag spectra reveals that the variations of the energy flux and the color ratios are large but continuous and generally covary. [less ▲]

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See detailCharacteristics of Jupiter's auroral acceleration region
Ray, Licia; Gustin, Jacques ULg; Grodent, Denis ULg

Poster (2015, June)

Jupiter’s dynamic auroral region is the signature of magnetosphere-ionosphere coupling. The magnetospheric drivers of the emission are relatively well understood, yet the high-latitude characteristics of ... [more ▼]

Jupiter’s dynamic auroral region is the signature of magnetosphere-ionosphere coupling. The magnetospheric drivers of the emission are relatively well understood, yet the high-latitude characteristics of the interaction have not been measure in-situ. Ahead of Juno’s arrival next summer, we use HST STIS observations of Jupiter’s auroral emission to infer the location of Jupiter’s auroral acceleration region and the properties of the precipitating auroral electrons. We analyze two images of Jupiter’s northern emission, determining the precipitating electron energy and incident energy flux for the main aurora, Io spot, Ganymede footprint, and flare regions. The resulting relationships between energy flux and electron precipitation energy for the main auroral emission are compared to the theoretical relationship derived by Lundin & Sandahl [1978] for a range of auroral region locations, and temperatures and densities appropriate for the jovian system. [less ▲]

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See detailThe Characteristics of Low-Input Grasslands
Bogdan, Anca Dorina; Pacurar, Florin; Albus, Amalia et al

in ProEnvironment (2012), 5

Several studies show that the global interest in health and human nutrition is continually growing. A continuous change includes also the food production systems. There are more and more papers that ... [more ▼]

Several studies show that the global interest in health and human nutrition is continually growing. A continuous change includes also the food production systems. There are more and more papers that connect the value of agricultural production and food production system, papers that show a particular interes on the high value of products that are produced in low input agricultural systems./ On grassland canopy, these systems have a high diversity of floristic species. At European level, this concept has been extrapolated also to the farms, being a major concern regarding the quantification of inputs, aspect pursued along this paper. [less ▲]

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See detailCharacteristics of Near-Death Experiences Memories as Compared to Real and Imagined Events Memories
Thonnard, Marie ULg; Charland-Verville, Vanessa ULg; Brédart, Serge ULg et al

in PLoS ONE (2013), 8(3),

Since the dawn of time, Near-Death Experiences (NDEs) have intrigued and, nowadays, are still not fully explained. Since reports of NDEs are proposed to be imagined events, and since memories of imagined ... [more ▼]

Since the dawn of time, Near-Death Experiences (NDEs) have intrigued and, nowadays, are still not fully explained. Since reports of NDEs are proposed to be imagined events, and since memories of imagined event have, on average, fewer phenomenological characteristics than real events memories, we here compared phenomenological characteristics of NDEs reports with memories of imagined and real events. We included three groups of coma survivors (8 patients with NDE as defined by the Greyson NDE scale, 6 patients without NDE but with memory of their coma, 7 patients without memories of their coma) and a group of 18 age-matched healthy volunteers. Five types of memories were assessed using Memory Characteristics Questionnaire (MCQ – Johnson et al., 1988): target memory (NDE for NDE memory group, coma memory for coma memory group, and first childhood memory for no memory and control groups), old and recent real event memories and old and recent imagined event memories. Since NDEs are known to have high emotional content, participants were requested to choose the most emotionally salient memories for both real and imagined recent and old event memories. Results showed that, in NDE memories group, NDE memories have more characteristics than memories of imagined and real events (p<0.02). NDE memories contain more self-referential and emotional information and have better clarity than memories of coma (all p<0.02). The present study showed that NDE memories contain more characteristics than real event memories and coma memories. Thus, this suggests that they cannot be considered as imagined event memories. On the contrary, their physiological origins could lead them to be really perceived although not lived in the reality. Further work is needed to better understand this phenomenon. [less ▲]

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See detailCharacteristics of Necrotoxigenic Escherichia Coli Isolated from Septicemic and Diarrheic Calves between 1958 and 1970
Van Bost, Sigrid; Babe, Marie Hélène; Jacquemin, Etienne et al

in Veterinary Microbiology (2001), 82(4), 311-20

A total of 434 Escherichia coli isolated from septicemic calves between 1958 and 1965 and 430 E. coli isolated from diarrheic calves between 1967 and 1970 were studied by colony hybridisation and PCR ... [more ▼]

A total of 434 Escherichia coli isolated from septicemic calves between 1958 and 1965 and 430 E. coli isolated from diarrheic calves between 1967 and 1970 were studied by colony hybridisation and PCR assays for the presence of the cnf1- and the cnf2-like genes. They were also studied for the presence of genes coding for putative virulence factors associated with the CNF toxins including F17-, Pap- and Sfa-fimbrial adhesins and the recently described CDT-III toxin and AfaVIII-afimbrial adhesin. Thirty (7%) of the 434 septicemic strains were positive for CNF by colony hybridisation. Twenty-six were confirmed as necrotoxigenic E. coli type 2 (NTEC2) and four as NTEC1 by PCR. Thirty-five (8%) of the 430 diarrheic strains were positive for CNF by colony hybridisation. Five of them were studied by PCR and confirmed as NTEC1. The 26 septicemic NTEC2 strains and 20 of the 35 diarrheic NTEC including three of the five NTEC1 were positive for CDT-III. All adhesins studied were present in NTEC as well as in non-NTEC. NTEC1 were mainly Pap-, Sfa- and/or Afa8-positive, whereas NTEC2 were mainly F17- and/or Afa8-positive. This study shows that necrotoxigenic E. coli with their associated adhesins and toxins were present in calves as early as 1958, but their prevalence seems to have increased since that time. [less ▲]

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See detailCharacteristics Of Participants To 'Start To Run' Programme. Comparison Between Maintenance And Drop Out Groups
Cloes, Marc ULg; Pétré, Benoît ULg

Conference (2012)

BACKGROUND. ‘Start to run’ is a 10 weeks programme designed to people who want to resume physical activity. AIM. This study aimed to identify initial characteristics differing among people who continue to ... [more ▼]

BACKGROUND. ‘Start to run’ is a 10 weeks programme designed to people who want to resume physical activity. AIM. This study aimed to identify initial characteristics differing among people who continue to run and those who stop. METHODS. 229 subjects attending to the first lesson (W0) of the autumn session organized in 20 communities of Wallonia (French speaking part of Belgium) fulfilled a questionnaire aiming to identify their characteristics. At W10, 180 of them answered to another questionnaire (68.5% of them achieved the programme). 12 weeks after the end of the latter (W22), 54 subjects who participated to the previous step and achieved the programme answered to a third questionnaire (71.1% were still running). FINDINGS. Few differences (p ≤ .05) were identified. At W10, MG subjects started with a lower BMI, had a better perception of their economical situation, a higher confidence to run during 10 weeks, a better perception of their health status, a lower consumption of alcohol. On the other hand, it was surprising to notice that they had lower perception of the neighbourhood’s safety, representation of physical activity’s effects on health and about its advantages. At W22, MG comprised more women. Subjects of this group had a higher consumption of vegetables and tried to decrease their fat consumption in the last 2 years. They considered themselves as physically active and motivated by expectations of others, perceived a higher family and children support and saw running as reassuring and rewarding. Nevertheless, they felt to meet more stray dogs in their environment. Most of the differences correspond to the literature. Moreover, among the subjects in the DG, almost 40% were injured meaning that they would have been active without this situation. DISCUSSION. Effective physical activity resumption seems to be linked to a general health climate without overestimation of one’s competences and expectations. Recommendations are proposed for sport instructors. [less ▲]

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See detailCharacteristics of patients with AIP mutation-related prolactinomas
Camby, S; Daly, Adrian ULg; VROONEN, Laurent ULg et al

in 23rd meeting of the Belgian Endocrine Society - Abstract book (2013, October 19)

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See detailCharacteristics of patients with pituitary gigantism : results of an international study
Rostomyan, Liliya ULg; Daly, Adrian ULg; Tichomirowa, M et al

in Endocrine abstracts - 15th European Congress of Endocrinology (2013, May)

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See detailCharacteristics of peri-urban dairy herds of Bobo-Dioulasso (Burkina Faso)
Sidibe, M.; Boly, Hamidou ULg; Lakouetene, T. et al

in Tropical Animal Health and Production (2004), 36(1), 95-100

Peri-urban dairy cattle farms within 50 km of Bobo-Dioulasso were studied to assess herd type, disease incidence, management, feeding and breeding strategy. Out of 417 cattle farmers, 42% had dairy ... [more ▼]

Peri-urban dairy cattle farms within 50 km of Bobo-Dioulasso were studied to assess herd type, disease incidence, management, feeding and breeding strategy. Out of 417 cattle farmers, 42% had dairy objectives and were studied. Among these peri-urban dairy farmers, 60% were settled, 36% semi-settled, and 4% transhumant. In total, they held 4558 dairy cows, of which 32% lactated during the study. The prevalence of mastitis (55%) increased (p<0.05) with herd size. Advanced strategies for supplementary feeding and breeding were most frequent in small herds (< 30 cattle). None of the large herds ( > 60 cattle) had advanced breeding strategies. Bulls and cows were culled at younger ages in herds with better breeding strategy. Overall, this resulted in higher individual milk offtake in small herds (2.46 L/day) compared with large herds (1.25 L/day). Pure breeds were rarely used, and the presence of Bos taurus baoule naturally selected for trypanotolerance was low. The prevalence of trypanosomosis (40%) in herds dominated by Bos indicus zebu and Mere (Zebu x Baoule) is an argument for maintenance of biodiversity and selection of Baoule for milk production. [less ▲]

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See detailCharacteristics of poultry production systems and cost-benefit analysis of mass vaccination campaign against HPAI in poultry production systems in Long An Province, South Vietnam
Phan Dang, Thang ULg; Peyre, Marisa; Vu Dinh, Ton et al

in Journal of Science and Development (2009), 7(English.Iss.1), 8

In 2006, the poultry population of Vietnam was about 215 million heads. However, between 2004 and 2008, the Highly Pathogenic Avian Influenza (HPAI) caused by H5N1 virus was broken in affected almost all ... [more ▼]

In 2006, the poultry population of Vietnam was about 215 million heads. However, between 2004 and 2008, the Highly Pathogenic Avian Influenza (HPAI) caused by H5N1 virus was broken in affected almost all provinces in Vietnam with millions of birds culled. This had large economical and sociological impacts. A question has been raised: how could Vietnam limit this epidemic? The research aims to identify the poultry production systems with their various constraints, including diseases and to evaluate the cost-benefit impact of a mass vaccination programme implemented from March to August 2007 at local level in Long An Province within the Mekong Delta. Two principal poultry farming systems are characterised: the commercial poultry production system (system 1) with low to moderate bio-security level, and the small-scale production system (system 2) with a low bio-security level. The scenarios of cost-benefit analysis of vaccination campaigns against HAPI caused by H5N1 virus give a good strategy for the restructure of poultry production and farmers’ incentives to vaccinate. The vaccination is more cost effective for the farmer than culling operations, with the BCR scenarios are between 31 to 78 times more. [less ▲]

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See detailCharacteristics of Pregnancy-Associated glycoprotein (PAG) like proteins in red deer
Okuyama, MW; Melo de Sousa, Noelita ULg; Beckers, Jean-François ULg

Poster (2013, June 19)

The Pregnancy-Associated glycoproteins (PAGs) constitute an asparatic proteinase family and are divided into 2 groups; bovine PAG-1 (boPAG-1) group and boPAG-2 group. PAGs have been detected in many ... [more ▼]

The Pregnancy-Associated glycoproteins (PAGs) constitute an asparatic proteinase family and are divided into 2 groups; bovine PAG-1 (boPAG-1) group and boPAG-2 group. PAGs have been detected in many domestic ruminant species and their biochemical characteristics were reported. However, information in wild ruminant, especially in deer species is scarce. The aim of this study is to investigate the characteristics of placental protein extracted in red deer (cervus elaphus); placental proteins which belong to each type of PAG group were identified in purification steps. Fresh frozen placenta (fetal cotyledon (FC): 2,247 g, maternal cotyledon (MC): 2,255 g respectively) was used as following purification step; protein extraction, acid precipitation (pH 4.5), Ammonium sulfate precipitation (SA0-40%, SA40-80%) and anion exchange chromatography (DEAE-cellulose 0M, 0,02M, 0,04M, 0,08M, 0,16M and 0,32M NaCl). In every step, Immunoreactivity against anti-PAG antisera was checked by Radioimmunoassay with using anti-PAG-1 antiserum (AS706) and anti-boPAG-2 antiserum (AS438). After Ammonium sulfate precipitation, much higher concentrations were gained in SA40-80% step (AS706: 5.35 mg/FCkg and 6.73 mg/MCkg, AS438: 24.79 mg/FCkg and 84.6 mg/MCkg) than SA0-40% step (AS706: 0.64 mg/FCkg and 0.79 mg/MCkg, AS438: 1.3 mg/FCkg and 9.34 mg/MCkg) in both part of cotyledon. After DEAE chromatography, the highest concentrations of protein against AS438 were gained in 0.08M NaCl step (5.49 mg/FCkg and 17.8 mg/MCkg) and concentrations of protein against AS706 were almost same in 0.08M NaCl (1.01 mg/FCkg and 1.35 mg/MCkg) and 0.16M NaCl (0.93 mg/FCkg and 1.34 mg/MCkg). In many ruminants such as cattle, sheep and goat, PAGs are contained largely in fetal cotyledon and most amounts of PAGs are belonging to PAG-1 group. On the other hand, in red deer, much larger amount of PAGs was obtained from maternal cotyledon. And stronger immunoreactivity with anti-boPAG-2 antisera was detected than with anti-PAG-1 antisera. This characteristic is similar to the results which were reported in pig and dromedary. Therefore, these results suggest that PAGs in red deer have different characteristics from other ruminant species. [less ▲]

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See detailCharacteristics of Saturn’s FUV airglow from limb-viewing spectra obtained with Cassini-UVIS
Gustin, Jacques ULg; Stewart, Ian; Gérard, Jean-Claude ULg et al

in Icarus: International Journal of Solar System Studies (2010), 210

This study reports the analysis of far ultraviolet (FUV) limb spectra of the airglow of Saturn in the 1150–1850 Å spectral window, obtained with the Ultraviolet Imaging Spectrograph (UVIS) onboard Cassini ... [more ▼]

This study reports the analysis of far ultraviolet (FUV) limb spectra of the airglow of Saturn in the 1150–1850 Å spectral window, obtained with the Ultraviolet Imaging Spectrograph (UVIS) onboard Cassini, spanning altitudes from 1200 to 4000 km. The FUV limb emission consists of three main contributions: (1) H Ly-a peaking at 1100 km with a brightness of 0.8 kilo-Rayleighs (kR), (2) reflected sunlight longward of 1550 Å which maximizes at 950 km with 16.5 kR and (3) H2 bands in the 1150–1650 Å bandwidth, peaking at 1050 km reaching a maximum of 3.9 kR. A vertical profile of the local H2 volume emission rate has been derived using the hydrocarbon density profiles from a model of the Saturn equatorial atmosphere. It is well matched by a Chapman function, characterized by a maximum value of 3.5 photons cm-3 s-1 in the 800–1650 Å UV bandwidth, peaking at 1020 km. Comparisons between the observed spectra and a first-order synthetic airglow H2 model in the 1150–1650 Å bandwidth show that the spectral shape of the H2 bands is accounted for by solar fluorescence and photoelectron excitation. The best fits are obtained with a combination of H2 fluorescence lines and 20 eV electron impact spectra, the latter contributing 68% of the total H2 airglow emission. [less ▲]

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See detailCharacteristics of Saturn's FUV aurora observed with the Space Telescope Imaging Spectrograph
Gérard, Jean-Claude ULg; Grodent, Denis ULg; Gustin, Jacques ULg et al

in Journal of Geophysical Research. Space Physics (2004), 109

We analyze a set of 15 FUV images obtained between October 1997 and January 2001 with the Hubble Space Telescope Imaging Spectrograph (STIS), providing a good view of Saturn's south auroral oval. It is ... [more ▼]

We analyze a set of 15 FUV images obtained between October 1997 and January 2001 with the Hubble Space Telescope Imaging Spectrograph (STIS), providing a good view of Saturn's south auroral oval. It is found that the morphology and brightness distribution of the aurora are dynamical with variations occurring on time scales of hours or less. The dayside main oval lies between 70° and 80° and is generally brighter and thinner in the morning than in the afternoon sector. The afternoon sector is characterized by more diffuse emission at higher latitudes. Weak emission is also observed poleward of the main oval up to the pole. A spot of enhanced auroral precipitation, tentatively identified as the optical signature of the dayside cusp, is sometimes observed poleward of the main oval in the noon sector, especially during periods when the morning arc is not fully developed. A spiral structure of the main oval with arcs at two latitudes in the same sector is occasionally observed. The brightness of the main oval ranges from below the STIS threshold of 1 kR of H[SUB]2[/SUB] emission up to ~75 kR. The total electron precipitated power varies between 20 and 140 GW, that is, comparable to the Earth's active aurora but about two orders of magnitude less than on Jupiter. An increasing trend of the precipitated power between the 1997 and the 2000-2001 observations may be related to the rising solar activity. Six spectra of the aurora in the noon sector covering the 1200-1700 Å range are dominated by emissions of the Lyman-alpha line and H[SUB]2[/SUB] Werner and Lyman bands. Their comparison with a synthetic model of electron excited H[SUB]2[/SUB] emissions indicates the presence of a weak absorption below 1400 Å by a column of methane ranging between 7 × 10[SUP]15[/SUP] and 2 × 10[SUP]16[/SUP] cm[SUP]-2[/SUP]. The corresponding energy of the primary auroral electrons is estimated 12 +/- 3 keV, using a low-latitude model atmosphere based on Voyager occultation measurements. The main oval brightness and the characteristic electron energy are generally consistent with recent models of Saturn's aurora, which colocate the main oval with the narrow upward field-aligned current system associated with departure from plasma corotation near the open-closed field line boundary. The latitude of the bright morning arc is somewhat lower than model predictions based on the plasma flow velocity measured by Voyager in the middle magnetosphere. [less ▲]

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See detailCharacteristics of Saturn's polar atmosphere and auroral electrons derived from HST/STIS, FUSE and Cassini/UVIS spectra
Gustin, Jacques ULg; Pryor, W.; Feldman, P. et al

Poster (2008, December 01)

Ultraviolet spectra of Saturn's aurora obtained with the Hubble Space Telescope Imaging Spectrograph (STIS), the Cassini Ultraviolet Imaging Spectrograph (UVIS) and the Far Ultraviolet Spectroscopic ... [more ▼]

Ultraviolet spectra of Saturn's aurora obtained with the Hubble Space Telescope Imaging Spectrograph (STIS), the Cassini Ultraviolet Imaging Spectrograph (UVIS) and the Far Ultraviolet Spectroscopic Explorer (FUSE) have been compared to synthetic spectra of electron-excited H2 in order to derive various auroral characteristics, such as the energy of the primary precipitating electrons and the H2 temperature at the altitude of the aurora. Two physical processes have been exploited: the absorption by hydrocarbons in the FUV and H2 self-absorption in the EUV. We find energies in the range 10-18 keV, which locates Saturns's aurora between 0.1 and 0.3 μ bar. We also determined that the auroral H2 emission is characterized by a temperature of ~400K, consistent with temperatures measured in the infrared, but much higher than what is expected from equatorial atmospheric models. These new results bring valuable constraints on both polar atmospheric models and theoretical studies of the ionosphere-magnetosphere coupling. [less ▲]

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