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Sample records for angles loa mutation

  1. Intraocular live male filarial Loa loa worm.

    PubMed

    Eballe, André Omgbwa; Epée, Emillienne; Koki, Godefroy; Owono, Didier; Mvogo, Côme Ebana; Bella, Assumpta Lucienne

    2008-12-01

    We report a case of Loa loa filariasis in an 8-month-old child who presented with a 3-month history of irritated acute red eye and insomnia. Examination revealed a living and active adult Loa loa worm in the anterior chamber of the left eye. The worm was extracted under general anesthetic.

  2. Anterior Chamber Live Loa loa: Case Report

    PubMed Central

    Kagmeni, G.; Cheuteu, R.; Bilong, Y.; Wiedemann, P.

    2016-01-01

    We reported a case of unusual intraocular Loa loa in a 27-year-old patient who presented with painful red eye. Biomicroscopy revealed a living and active adult worm in the anterior chamber of the right eye. After surgical extraction under local anesthesia, parasitological identification confirmed L. loa filariasis. PMID:27441005

  3. Anterior Chamber Live Loa loa: Case Report.

    PubMed

    Kagmeni, G; Cheuteu, R; Bilong, Y; Wiedemann, P

    2016-01-01

    We reported a case of unusual intraocular Loa loa in a 27-year-old patient who presented with painful red eye. Biomicroscopy revealed a living and active adult worm in the anterior chamber of the right eye. After surgical extraction under local anesthesia, parasitological identification confirmed L. loa filariasis.

  4. Obligatory symbiotic Wolbachia endobacteria are absent from Loa loa

    PubMed Central

    Büttner, Dietrich W; Wanji, Samuel; Bazzocchi, Chiara; Bain, Odile; Fischer, Peter

    2003-01-01

    Background Many filarial nematodes harbour Wolbachia endobacteria. These endobacteria are transmitted vertically from one generation to the next. In several filarial species that have been studied to date they are obligatory symbionts of their hosts. Elimination of the endobacteria by antibiotics interrupts the embryogenesis and hence the production of microfilariae. The medical implication of this being that the use of doxycycline for the treatment of human onchocerciasis and bancroftian filariasis leads to elimination of the Wolbachia and hence sterilisation of the female worms. Wolbachia play a role in the immunopathology of patients and may contribute to side effects seen after antifilarial chemotherapy. In several studies Wolbachia were not observed in Loa loa. Since these results have been doubted, and because of the medical significance, several independent methods were applied to search for Wolbachia in L. loa. Methods Loa loa and Onchocerca volvulus were studied by electron microscopy, histology with silver staining, and immunohistology using antibodies against WSP, Wolbachia aspartate aminotransferase, and heat shock protein 60. The results achieved with L. loa and O. volvulus were compared. Searching for Wolbachia, genes were amplified by PCR coding for the bacterial 16S rDNA, the FTSZ cell division protein, and WSP. Results No Wolbachia endobacteria were discovered by immunohistology in 13 male and 14 female L. loa worms and in numerous L. loa microfilariae. In contrast, endobacteria were found in large numbers in O. volvulus and 14 other filaria species. No intracellular bacteria were seen in electron micrographs of oocytes and young morulae of L. loa in contrast to O. volvulus. In agreement with these results, Wolbachia DNA was not detected by PCR in three male and six female L. loa worms and in two microfilariae samples of L. loa. Conclusions Loa loa do not harbour obligatory symbiotic Wolbachia endobacteria in essential numbers to enable their

  5. Genomics of Loa loa, a Wolbachia-free filarial parasite of humans

    PubMed Central

    Desjardins, Christopher A.; Cerqueira, Gustavo C.; Goldberg, Jonathan M.; Hotopp, Julie C. Dunning; Haas, Brian J.; Zucker, Jeremy; Ribeiro, Jose’ M.C.; Saif, Sakina; Levin, Joshua Z.; Fan, Lin; Zeng, Qiandong; Russ, Carsten; Wortman, Jennifer R.; Fink, Doran L.; Birren, Bruce W.

    2014-01-01

    Loa loa, the African eyeworm, is a major filarial pathogen of humans. Unlike most filariae, Loa loa does not contain the obligate intracellular Wolbachia endosymbiont. We describe the 91.4 Mb genome of Loa loa, and the genome of the related filarial parasite Wuchereria bancrofti, and predict 14,907 Loa loa genes based on microfilarial RNA sequencing. By comparing these genomes to that of another filarial parasite, Brugia malayi, and to several other nematode genomes, we demonstrate synteny among filariae but not with non-parasitic nematodes. The Loa loa genome encodes many immunologically relevant genes, as well as protein kinases targeted by drugs currently approved for humans. Despite lacking Wolbachia, Loa loa shows no new metabolic synthesis or transport capabilities compared to other filariae. These results suggest that the role played by Wolbachia in filarial biology is more subtle than previously thought and reveal marked differences between parasitic and non-parasitic nematodes. PMID:23525074

  6. Summit Crater of Mauna Loa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Astronauts obtained this detailed image of the summit caldera of Mauna Loa volcano, called Mokuaweoweo Caldera. Mauna Loa is the largest volcano on our planet-the summit elevation is 4,170 m (over 13,600 ft), but the volcano's summit rises 9 km above the sea floor. The sharp features of the summit caldera and lava flows that drain outward from the summit are tribute to the fact that Mauna Loa is one of the Earth's most active volcanoes. The most recent eruption was in 1984. The straight line the cuts through the center of the crater from top to bottom is a rift zone-an area that pulls apart as magma reaches the surface. A weather observatory run by NOAA's Climate Monitoring and Diagnostics Lab is on the volcano's north slope at 11,000 ft (3397 m). This facility, known as the Mauna Loa Observatory, is the site where scientists have documented the constantly increasing concentrations of global atmospheric carbon dioxide. Other resources about Mauna Loa: http://wwwhvo.wr.usgs.gov/maunaloa/ http://www.cmdl.noaa.gov/obop/mlo/ http://www.volcano.si.edu/gvp/usgs/vol_archive/maunaloa.htm Astronaut photograph ISS005-E-7002 was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  7. Analysis of the mdr-1 Gene in Patients Co-Infected with Onchocerca volvulus and Loa loa Who Experienced a Post-Ivermectin Serious Adverse Event

    PubMed Central

    Bourguinat, Catherine; Kamgno, Joseph; Boussinesq, Michel; Mackenzie, Charles D.; Prichard, Roger K.; Geary, Timothy G.

    2010-01-01

    Ivermectin (IVM) is exceptionally safe in humans, and is used for mass treatment of onchocerciasis and lymphatic filariasis. However, cases of encephalopathy, sometimes fatal, have been reported in a small number of individuals who harbored large numbers of Loa loa microfilariae (mf). A loss-of-function mutation in the mdr-1 gene in some dog breeds and in mice leads to accumulation of the drug in the brain, causing coma and death. This hypothesis was tested in four individuals from Cameroon who experienced a post-IVM serious adverse event (SAE) and in nine non-SAE matched controls. No loss-of-function mutation was detected in mdr-1 in any subject. However, haplotypes, associated with altered drug disposition, were present as homozygotes in two of the SAE patients (50%), but absent as homozygotes in the controls (0%). An association of high Loa mf load and a genetic predisposition to altered IVM distribution could be involved in IVM SAEs. PMID:20595473

  8. Markers of Loa loa infection in permanent residents of a loiasis endemic area of Gabon.

    PubMed

    Akue, J P; Hommel, M; Devaney, E

    1996-01-01

    Different markers of infection were analyzed in 56 permanent residents of a Loa loa endemic village in Gabon. The population was divided into those with parasitological evidence of L. loa infection and those with no history of loiasis over the period of observation (c. 5 years). 26.7% of villagers had L. loa microfilariae, 33.9% had an ocular passage of an adult worm, and 17.8% had calabar oedema. Several other clinical symptoms were present in both groups of individuals, but none was considered to be pathognomonic for L. loa infection. Most of the villagers were polyparasitized, with Plasmodium falciparum and gastrointestinal parasites being particularly prevalent. Mansonella perstans was present in 80% of the villagers and was equally distributed between L. loa microfilaraemic and amicrofilaraemic individuals. Eosinophil levels were elevated in the whole population, and were not significantly different between the groups who were infected and non-infected with L. loa. Polyclonal immunoglobulin (Ig) E levels were high in both the Ambinda villagers and in Gambian serum from patients infected with M. perstans alone and there was no significant difference between the levels of L. loa specific IgG in the Ambinda villagers and the Gambian patients. However, the level of L. loa specific IgG4 was elevated in 75.6% of amicrofilaraemic individuals and could discriminate between most individuals infected with L. loa and those infected with M. perstans, suggesting that this is the best determinant of infection status in the absence of L. loa microfilariae.

  9. New Mauna Loa coronagraph systems.

    PubMed

    Fisher, R R; Lee, R H; Macqueen, R M; Poland, A I

    1981-03-15

    A new set of instruments, consisting of two coronagraph systems, has been installed and is operating at the Mauna Loa Observing Station, Hawaii, operated by the High Altitude Observatory of Boulder, Colorado. The instruments are the 23-cm objective Mark III K-coronameter (K-III) system, a photoelectric instrument used to observe the inner solar corona from 1.2 R(0) to 2.2 R(0) and the 12.5-cm objective Prominence Monitor system used for the detection of H(alpha) limb activity. New features of the K-coronameter system include the use of achromatic wave plates for wide bandpass operation and linear diode array detectors. Raster scans of the coronal image are obtained in 1.5 min for a critical sampling scheme of 20-sec of arc resolution (10 x 10-sec of arc pixels) in the coronal p(B) image. This represents a 350 information gain factor for each detection channel when compared with the previous Mauna Loa K-coronameters.

  10. A Mouse Neurodegenerative Dynein Heavy Chain Mutation Alters Dynein Motility and Localization in Neurospora crassa

    PubMed Central

    Sivagurunathan, Senthilkumar; Schnittker, Robert R.; Nandini, Swaran; Plamann, Michael D.; King, Stephen J.

    2013-01-01

    Cytoplasmic dynein is responsible for the transport and delivery of cargoes in organisms ranging from humans to fungi. Dysfunction of dynein motor machinery due to mutations in dynein or its activating complex dynactin can result in one of several neurological diseases in mammals. The mouse Legs at odd angles (Loa) mutation in the tail domain of the dynein heavy chain has been shown to lead to progressive neurodegeneration in mice. The mechanism by which the Loa mutation affects dynein function is just beginning to be understood. In this work, we generated the dynein tail mutation observed in Loa mice into the Neurospora crassa genome and utilized cell biological and complementing biochemical approaches to characterize how that tail mutation affected dynein function. We determined that the Loa mutation exhibits several subtle defects upon dynein function in N. crassa that were not seen in mice, including alterations in dynein localization, impaired velocity of vesicle transport, and in the biochemical properties of purified motors. Our work provides new information on the role of the tail domain on dynein function and points out areas of future research that will be of interest to pursue in mammalian systems. PMID:22991199

  11. [Study of novel mutation of OPTN gene in two primary open angle glaucoma families in northeast China].

    PubMed

    Yuan, Hui-Ping; Xiao, Zheng; Xu, Na; Yang, Bin-Bin; Meng, Qing-Feng; Li, Yuan-Yuan

    2008-02-01

    To identify the mutation gene of two Chinese families with primary open angle glaucoma. It was a case control study. Clinical observation and pedigree analysis were undertaken in two families with primary open angle glaucoma. Venous blood were drawn from 6 affected and 6 unaffected subjects in family L, and from 4 affected and 4 unaffected subjects in family C. Genomic DNA was extracted. Linkage to OPTN gene locus was determined. Mutation of this gene was screened by PCR of OPTN gene exons and direct sequencing. A missense mutation A1274G in exon 10 of OPTN gene was identified in affected members of family L. The corresponding amino acid change was Lys322Glu. This mutation was not found in unaffected family members of family L, all members of family C and 87 unrelated normal controls. A novel mutation of OPTN gene with Lys322Glu change is responsible for the occurrence of primary open angle glaucoma in a Chinese family.

  12. A possible case of spontaneous Loa loa encephalopathy associated with a glomerulopathy

    PubMed Central

    Lukiana, Tuna; Mandina, Madone; Situakibanza, Nanituma H; Mbula, Marcel M; Lepira, Bompeka F; Odio, Wobin T; Kamgno, Joseph; Boussinesq, Michel

    2006-01-01

    It is well known that renal and neurological complications may occur after antifilarial treatment of patients infected with Loa loa. Conversely, spontaneous cases of visceral complications of loiasis have been rarely reported. A 31-year-old Congolese male patient who had not received any antifilarial drug developed oedema of the lower limbs, and then transient swellings of upper limbs. Two months after, he developed troubles of consciousness within several hours. At hospital, the patient was comatose with mild signs of localization. Laboratory tests and an abdominal echography revealed a chronic renal failure due to a glomerulopathy. Three weeks after admission, Loa microfilariae were found in the cerebrospinal fluid, and a calibrated blood smear revealed a Loa microfilaraemia of 74,200 microfilariae per ml. The level of consciousness of the patient improved spontaneously, without any specific treatment, but several days after becoming completely lucid, the patient died suddenly, from an undetermined cause. Unfortunately, no biopsy or autopsy could be performed. The role of Loa loa in the development of the renal and neurological troubles of this patient is questionable. But the fact that such troubles, which are known complications of Loa infection, were found concomitantly in a person harbouring a very high microfilarial load suggests that they might have been caused by the filarial parasite. In areas endemic for loiasis, examinations for a Loa infection should be systematically performed in patients presenting an encephalopathy or a glomerulopathy. PMID:16686951

  13. Rapid Molecular Assays for Specific Detection and Quantitation of Loa loa Microfilaremia

    PubMed Central

    Fink, Doran L.; Kamgno, Joseph; Nutman, Thomas B.

    2011-01-01

    Background Accurate diagnosis of Loa loa infection is essential to the success of mass drug administration efforts to eliminate onchocerciasis and lymphatic filariasis, due to the risk of fatal encephalopathic reactions to ivermectin occurring among highly microfilaremic Loa-infected individuals living in areas co-endemic for multiple filarial species. Methodology/Principal Findings From a pool of over 1,800 L. loa microfilaria (mf) expressed sequence tags, 18 candidate L. loa mf-specific PCR targets were identified. Real-time PCR (qPCR) assays were developed for two targets (LLMF72 and LLMF269). The qPCR assays were highly specific for L. loa compared with related filariae and also highly sensitive, with detection limits of 0.1 pg genomic DNA, or 1% of DNA extracted from normal blood spiked with a single L. loa microfilaria. Using various DNA extraction methods with dried blood spots obtained from Cameroonian subjects with parasitologically proven loiasis, the LLMF72 qPCR assay successfully estimated mf burden in 65 of 68 samples (50–96,000 mf/mL by microscopy), including all 12 samples subjected to a simple 10-minute boiling extraction. Additionally, the assay detected low-level microfilaremia among 5 of 16 samples from patients thought to be amicrofilaremic by microscopy. Conclusions/Significance This novel, rapid, highly sensitive and specific qPCR assay is an important step forward in the laboratory diagnosis of L. loa infection. PMID:21912716

  14. Loa loa and Mansonella perstans infections in Ijebu north, western Nigeria: a parasitological study.

    PubMed

    Agbolade, M; Akinboye, D O

    2001-06-01

    The prevalence and intensity of Loa loa and Mansonella perstans were studied in three villages of the Ijebu north area in Ogun State, western Nigeria. Blood samples were collected by finger-pricking from 373 (181 males, 192 females) subjects with an age range of 4 to 55 years. The blood samples were examined microscopically for the presence of microfilariae (mf). L. loa and M. perstans were present in the blood samples in 39 (10.5%) and 12 (3.2%) of the subjects, respectively. Neither of the infections were found to be sex-dependent. The geometric mean of the L. loa intensity was 1.8 mf per 50 microl of blood, while that of M. perstans was 1.5 mf per 50 microl. The prevalence of mixed infections of both L. loa and M. perstans was 1.0%.

  15. Epidemiology of Concomitant Infection Due to Loa loa and Mansonella perstans in Gabon

    PubMed Central

    Padilla, Cindy; Moussavou, Ghislain; Moukana, Hubert; Mbou, Roger Antoine; Ollomo, Benjamin; Leroy, Eric Maurice

    2011-01-01

    Background The filarial parasites Loa loa and Mansonnella perstans are endemic in the central and western African forest block. Loa loa is pathogenic and represents a major obstacle to the control of co-endemic filariae because its treatment can cause fatal complications such as encephalitis. Methodology/Principal Findings 4392 individuals aged over 15 years were studied both by direct examination and a concentration technique. The overall prevalence rates were 22.4% for Loa loa microfilaremia, 10.2% for M. perstans microfilaremia, and 3.2% for mixed infection. The prevalence of both filariae was higher in the forest ecosystem than in savannah and lakeland (p<0.0001). The intensity of microfilariae (mf) was also higher in the forest ecosystem for both parasites. The prevalence and intensity of microfilaria were both influenced by age and gender. Correlations were found between the prevalence and intensity of Loa loa microfilariae (r = 0.215 p = 0.036), and between the prevalence of Loa loa and the prevalence of individuals with microfilaria >8000 mf/ml (r = 0.624; p<0.0001) and microfilariae >30 000 mf/ml (r = 0.319, p = 0.002). In contrast, the prevalence of pruritis and Calabar swellings correlated negatively with the prevalence of Loa loa microfilaria (r = −0.219, p = 0.032; r = −0.220; p = 0.031, respectively). Pruritis, Calabar swellings and eye worm were not associated with L. loa mf intensity (r = −0.144, p = 0.162; r–0.061, p = 0.558; and r = 0.051, p = 0.624, respectively), or with the prevalence or intensity of M. perstans microfilariae. Conclusions/Significance This map of the distribution of filariae in Gabon should prove helpful for control programs. Our findings confirm the spatial uniformity of the relationship between parasitological indices. Clinical manifestations point to a relationship between filariae and allergy. PMID:22022623

  16. Epidemiology of concomitant infection due to Loa loa and Mansonella perstans in Gabon.

    PubMed

    Akue, Jean Paul; Nkoghe, Dieudonné; Padilla, Cindy; Moussavou, Ghislain; Moukana, Hubert; Mbou, Roger Antoine; Ollomo, Benjamin; Leroy, Eric Maurice

    2011-10-01

    The filarial parasites Loa loa and Mansonnella perstans are endemic in the central and western African forest block. Loa loa is pathogenic and represents a major obstacle to the control of co-endemic filariae because its treatment can cause fatal complications such as encephalitis. 4392 individuals aged over 15 years were studied both by direct examination and a concentration technique. The overall prevalence rates were 22.4% for Loa loa microfilaremia, 10.2% for M. perstans microfilaremia, and 3.2% for mixed infection. The prevalence of both filariae was higher in the forest ecosystem than in savannah and lakeland (p<0.0001). The intensity of microfilariae (mf) was also higher in the forest ecosystem for both parasites. The prevalence and intensity of microfilaria were both influenced by age and gender. Correlations were found between the prevalence and intensity of Loa loa microfilariae (r = 0.215 p = 0.036), and between the prevalence of Loa loa and the prevalence of individuals with microfilaria >8000 mf/ml (r = 0.624; p<0.0001) and microfilariae >30 000 mf/ml (r = 0.319, p = 0.002). In contrast, the prevalence of pruritis and Calabar swellings correlated negatively with the prevalence of Loa loa microfilaria (r = -0.219, p = 0.032; r = -0.220; p = 0.031, respectively). Pruritis, Calabar swellings and eye worm were not associated with L. loa mf intensity (r = -0.144, p = 0.162; r-0.061, p = 0.558; and r = 0.051, p = 0.624, respectively), or with the prevalence or intensity of M. perstans microfilariae. This map of the distribution of filariae in Gabon should prove helpful for control programs. Our findings confirm the spatial uniformity of the relationship between parasitological indices. Clinical manifestations point to a relationship between filariae and allergy.

  17. The Mauna Loa Observatory Photochemistry Experiment

    NASA Astrophysics Data System (ADS)

    Ridley, B. A.; Robinson, E.

    1992-06-01

    The goal of the Mauna Loa Observatory Photochemistry Experiment is to investigate the distributions, trends, and behavior of reactive photochemically related species in the remote Pacific. Concurrent measurements of selected odd nitrogen constituents, hydrocarbons, peroxides, organic acids, formaldehyde, and other species were carried out from May 1 to June 4, 1988 at the Mauna Loa Observatory. The emphasis of the experiment was on the budget and partitioning of odd species. Results provide a first glimpse of the magnitude and possible causes of the temporal variability of short-lived species at a remote maritime site.

  18. CYP1B1 Mutations are a Major Contributor to Juvenile-Onset Open Angle Glaucoma in Saudi Arabia.

    PubMed

    Abu-Amero, Khaled K; Morales, Jose; Aljasim, Leyla A; Edward, Deepak P

    2015-06-01

    To describe the genotype and phenotype in 14 unrelated Saudis with juvenile open angle glaucoma (JOAG). Detailed clinical examination was carried out and we sequenced cytochrome P450, family 1, subfamily B (CYP1B1), Myocilin (MYOC) and latent-transforming growth factor beta-binding protein 2 (LTBP2) genes. Twelve (85.7%) patients had apparent sporadic inheritance and 2 (14.3%) presented with a family history of glaucoma. Overall, 12 patients (85.7%) had CYP1B1 mutation. Nine patients had CYP1B1 mutations in a homozygous status. Eight of these had homozygous p.G61E mutation and one had a silent (no amino acid change) sequence change. Two patients had p.G61E mutation in a compound heterozygous status with another CYP1B1 mutation (p.L432V). Two patients had p.G61E in a heterozygous status with no other mutation, while one patient had no mutation(s). None of the patients had any mutation(s) in the MYOC or LTBP2 genes. JOAG associated with CYP1B1 mutations occurs at a high rate in the Saudi population. A specific genotype-phenotype relationship was not demonstrated.

  19. A novel rapid test for detecting antibody responses to Loa loa infections

    PubMed Central

    Pedram, Bijan; Pasquetto, Valérie; Drame, Papa M.; Ji, Yongchang; Gonzalez-Moa, Maria J.; Baldwin, Richard K.; Nutman, Thomas B.

    2017-01-01

    Ivermectin-based mass drug administration (MDA) programs have achieved remarkable success towards the elimination of onchocerciasis and lymphatic filariasis. However, their full implementation has been hindered in Central Africa by the occurrence of ivermectin-related severe adverse events (SAEs) in a subset of individuals with high circulating levels of Loa loa microfilariae. Extending MDA to areas with coincident L. loa infection is problematic, and inexpensive point-of-care tests for L. loa are acutely needed. Herein, we present a lateral flow assay (LFA) to identify subjects with a serological response to Ll-SXP-1, a specific and validated marker of L. loa. The test was evaluated on serum samples from patients infected with L. loa (n = 109) and other helminths (n = 204), as well as on uninfected controls (n = 77). When read with the naked eye, the test was 94% sensitive for L. loa infection and was 100% specific when sera from healthy endemic and non-endemic controls or from those with S. stercoralis infections were used as the comparators. When sera of patients with O. volvulus, W. bancrofti, or M. perstans were used as the comparators, the specificity of the LFA was 82%, 87%, and 88%, respectively. A companion smartphone reader allowed measurement of the test line intensities and establishment of cutoff values. With a cutoff of 600 Units, the assay sensitivity decreased to 71%, but the specificity increased to 96% for O. volvulus, 100% for W. bancrofti, and 100% for M. perstans-infected individuals. The LFA may find applications in refining the current maps of L. loa prevalence, which are needed to eliminate onchocerciasis and lymphatic filariasis from the African continent. PMID:28749939

  20. Loop-Mediated Isothermal Amplification for Rapid and Semiquantitative Detection of Loa loa Infection

    PubMed Central

    Drame, Papa M.; Fink, Doran L.; Kamgno, Joseph; Herrick, Jesica A.

    2014-01-01

    Rapid and accurate tests are currently needed to identify individuals with high levels of Loa loa microfilaria (mf), so that these individuals may be excluded from mass ivermectin administration campaigns against onchocerciasis and lymphatic filariasis being conducted in areas where Onchocerca volvulus, Wuchereria bancrofti, and L. loa are coendemic. To address this need, colorimetric loop-mediated isothermal amplification (LAMP) assays targeting the L. loa-specific gene sequences LLMF72 and LLMF342 were developed for the detection and quantification of L. loa microfilaremia. Both LAMP assays were highly specific (100%) for L. loa infection compared to the absence of infection or infection with related filarial pathogens. The LLMF72-based LAMP assay showed greater analytic sensitivity (limit of detection, 0.1 pg/ml of genomic DNA [gDNA] and/or 5 mf/ml) than the LLMF342-based LAMP assay (10 pg/ml of gDNA and/or 50 mf/ml), and its analytic sensitivity was similar to that of LLMF72-based quantitative PCR (qPCR). A high level of correlation was observed between microfilaria counts as determined by LLMF72-based qPCR and time to positivity by the LAMP assay, and performance measures of sensitivity, specificity, and positive and negative predictive values were similar for both assays when applied to field-collected clinical samples. By simply varying the run time, the LAMP assay was able to accurately distinguish individuals at risk for serious adverse events (SAEs) after exposure to ivermectin, using thresholds of >5,000 mf/ml and >30,000 mf/ml as indicators of increasing levels of risk. In summary, LLMF72 LAMP represents a new molecular diagnostic tool that is readily applicable as a point-of-care method for L. loa microfilarial detection and quantification in resource-limited countries where L. loa infection is endemic. PMID:24696020

  1. [Ocular involvement in systemic Loa-Loa filariasis. Case report and review of the literature].

    PubMed

    Jaksche, A; Wessels, L; Martin, S; Loeffler, K U

    2004-09-01

    Within the last few years there is more and more evidence for nonspecific ocular symptoms caused by "exotic" pathogens. We herewith report another case of such an infection to underline the increasing importance and diagnostic relevance even of rare diseases. A 35-year-old female German patient presented with recurrent left retrobulbar "feeling of pressure" after a 6-month-stay in Central Africa 5 years ago. In addition, she reported on repeated swelling of the skin and joints of her hands and arms. Multiple ophthalmologic and rheumatologic investigations had been carried out without diagnostic results. Her ophthalmologist referred her with the presumed diagnosis of a subconjunctival worm. Slit-lamp biomicroscopy confirmed the original suspicion, and after topical anesthesia a female Loa-Loa worm was easily removed with forceps through a conjunctival incision. The general examination showed symptoms of systemic infection (calabar swelling, eosinophilia). Classification and initiation of treatment with diethylcarbamazine and mebendazole were carried out by the University Institute of Parasitology. Loa-Loa is a parasitic infection endemic in the tropical rain forests of Western, Central, and Eastern Africa. It is transmitted by the Chrysops fly. An increasing number of oculosystemic infections in non-African patients with Loa-Loa are being published. Therefore, any patient with an unclassifiable eye affection should also be investigated for those rare pathogens.

  2. Mapping the distribution of Loa loa in Cameroon in support of the African Programme for Onchocerciasis Control

    PubMed Central

    Thomson, Madeleine C; Obsomer, Valérie; Kamgno, Joseph; Gardon, Jacques; Wanji, Samuel; Takougang, Innocent; Enyong, Peter; Remme, Jan H; Molyneux, David H; Boussinesq, Michel

    2004-01-01

    Background Loa loa has recently emerged as a filarial worm of significant public health importance as a consequence of its impact on the African Programme for Onchocerciasis Control (APOC). Severe, sometimes fatal, encephalopathic reactions to ivermectin (the drug of choice for onchocerciasis control) have occurred in some individuals with high Loa loa microfilarial counts. Since high density of Loa loa microfilariae is known to be associated with high prevalence rates, a distribution map of the latter may determine areas where severe reactions might occur. The aim of the study was to identify variables which were significantly associated with the presence of a Loa microfilaraemia in the subjects examined, and to develop a spatial model predicting the prevalence of the Loa microfilaraemia. Methods Epidemiological data were collected from 14,225 individuals living in 94 villages in Cameroon, and analysed in conjunction with environmental data. A series of logistic regression models (multivariate analysis) was developed to describe variation in the prevalence of Loa loa microfilaraemia using individual level co-variates (age, sex, μl of blood taken for examination) and village level environmental co-variates (including altitude and satellite-derived vegetation indices). Results A spatial model of Loa loa prevalence was created within a geographical information system. The model was then validated using an independent data set on Loa loa distribution. When considering both data sets as a whole, and a prevalence threshold of 20%, the sensitivity and the specificity of the model were 81.7 and 69.4%, respectively. Conclusions The model developed has proven very useful in defining the areas at risk of post-ivermectin Loa-related severe adverse events. It is now routinely used by APOC when projects of community-directed treatment with ivermectin are examined. PMID:15298709

  3. Mutations in MYOC gene of Indian primary open angle glaucoma patients.

    PubMed

    Mukhopadhyay, Arijit; Acharya, Moulinath; Mukherjee, Saibal; Ray, Jharna; Choudhury, Sumit; Khan, Mita; Ray, Kunal

    2002-11-15

    Glaucoma is the second leading cause of blindness worldwide after cataract. Defects in the myocilin gene (MYOC) have been shown to be associated with Primary Open Angle Glaucoma (POAG), the most common form of the disease, especially in its juvenile form. Most of the reported mutations in MYOC are in POAG patients of Caucasian origin. A few studies have been reported on Asian patients (such as Chinese, Japanese, and Koreans) but none from the Indian subcontinent. The purpose of this study was to investigate the molecular basis of POAG among Indians, using MYOC as the candidate gene, and broaden our understanding on the pathogenesis caused by MYOC. Fifty-six unrelated POAG patients, comprising 39 sporadic cases and 17 patients having familial history for POAG were enrolled in this study. The coding sequence of the gene was amplified by polymerase chain reaction (PCR) using genomic DNA from 30 POAG patients, followed by sequencing of the PCR products. Nucleotide changes were detected by identifying double peaks in the chromatogram due to heterozygosity and pairwise BLAST analysis of the sequence output data against the normal copy of the MYOC cDNA. Alteration of restriction sites due to nucleotide changes was identified. Twenty-six patients (not sequenced) and controls were screened for nucleotide changes by allele specific restriction digestion of the PCR products followed by separation of the digested DNA fragments by polyacrylamide gel electrophoresis. From a pool of 56 unrelated POAG patients two mutations were identified. A putative novel mutation (144 G->T; Gln48His) of a conserved amino acid was detected in the exon 1 of MYOC from three unrelated patients but none in the 51 control samples examined. The other mutation (1109 C->T; Pro370Leu), located in exon 3 and detected in a family affected with POAG, cosegregated with the disease and was not present in control samples. Two single nucleotide polymorphisms (SNPs) were identified; one in the promoter region

  4. Space radar image of Mauna Loa, Hawaii

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This image of the Mauna Loa volcano on the Big Island of Hawaii shows the capability of imaging radar to map lava flows and other volcanic structures. Mauna Loa has erupted more than 35 times since the island was first visited by westerners in the early 1800s. The large summit crater, called Mokuaweoweo Caldera, is clearly visible near the center of the image. Leading away from the caldera (towards top right and lower center) are the two main rift zones shown here in orange. Rift zones are areas of weakness within the upper part of the volcano that are often ripped open as new magma (molten rock) approaches the surface at the start of an eruption. The most recent eruption of Mauna Loa was in March and April 1984, when segments of the northeast rift zones were active. If the height of the volcano was measured from its base on the ocean floor instead of from sea level, Mauna Loa would be the tallest mountain on Earth. Its peak (center of the image) rises more than 8 kilometers (5 miles) above the ocean floor. The South Kona District, known for cultivation of macadamia nuts and coffee, can be seen in the lower left as white and blue areas along the coast. North is toward the upper left. The area shown is 41.5 by 75 kilometers (25.7 by 46.5 miles), centered at 19.5 degrees north latitude and 155.6 degrees west longitude. The image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/ X-SAR) aboard the space shuttle Endeavour on its 36th orbit on October 2, 1994. The radar illumination is from the left of the image. The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted, vertically received); blue represents the C-band (horizontally transmitted, vertically received). The resulting color combinations in this radar image are caused by differences in surface roughness of the lava flows. Smoother flows

  5. Space radar image of Mauna Loa, Hawaii

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This image of the Mauna Loa volcano on the Big Island of Hawaii shows the capability of imaging radar to map lava flows and other volcanic structures. Mauna Loa has erupted more than 35 times since the island was first visited by westerners in the early 1800s. The large summit crater, called Mokuaweoweo Caldera, is clearly visible near the center of the image. Leading away from the caldera (towards top right and lower center) are the two main rift zones shown here in orange. Rift zones are areas of weakness within the upper part of the volcano that are often ripped open as new magma (molten rock) approaches the surface at the start of an eruption. The most recent eruption of Mauna Loa was in March and April 1984, when segments of the northeast rift zones were active. If the height of the volcano was measured from its base on the ocean floor instead of from sea level, Mauna Loa would be the tallest mountain on Earth. Its peak (center of the image) rises more than 8 kilometers (5 miles) above the ocean floor. The South Kona District, known for cultivation of macadamia nuts and coffee, can be seen in the lower left as white and blue areas along the coast. North is toward the upper left. The area shown is 41.5 by 75 kilometers (25.7 by 46.5 miles), centered at 19.5 degrees north latitude and 155.6 degrees west longitude. The image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/ X-SAR) aboard the space shuttle Endeavour on its 36th orbit on October 2, 1994. The radar illumination is from the left of the image. The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted, vertically received); blue represents the C-band (horizontally transmitted, vertically received). The resulting color combinations in this radar image are caused by differences in surface roughness of the lava flows. Smoother flows

  6. Detection of Loa loa-specific DNA in blood from occult-infected individuals.

    PubMed

    Touré, F S; Bain, O; Nerrienet, E; Millet, P; Wahl, G; Toure, Y; Doumbo, O; Nicolas, L; Georges, A J; McReynolds, L A; Egwang, T G

    1997-07-01

    Accurate and specific diagnosis of human loiasis is of crucial importance in an endemic area where two-thirds of infected individuals are without circulating microfilariae (occult loiasis). By using the polymerase chain reaction (PCR) and specific primers to the repeat 3 region (15r3) of the gene coding for Loa loa 15-kDa polyprotein antigen, DNA was amplified from total blood lysate of occult-infected subjects. A 396-bp DNA fragment was specifically detected. We tested the specificity of this method by qualitative hybridization to PCR products using blood lysates of the following subjects: (1) from Gabon (80 individuals residing in L. loa endemic area where loiasis exists sympatrically with Mansonella perstans); (2) from Togo (12 individuals infected with Onchocerca volvulus and M. perstans); (3) from Tahiti (12 individuals infected with Wuchereria bancrofti); and (4) from Mali (12 individuals infected with O. volvulus and M. perstans). Samples from Gabon included 60 L. loa amicrofilaremics and 20 L. loa occult-infected subjects. Qualitative hybridization carried out at 50 degrees C on PCR products, using a 15r3-specific oligonucleotide probe, revealed hybridization with L. loa-infected samples from Gabon and four samples from Togo after 2 days exposure to the film. The positive samples from Togo were characterized by the use of nested PCR. Three nested PCR products have been sequenced. No differences were observed between the three sequences and they are 99.72% identical to L. loa 15r3. None of bancroftian-infected individuals from Tahiti, nor O. volvulus- and M. perstans-infected individuals from Mali reacted after 1 week's exposure (overexposure) to the film. This allows us to conclude first that our 15r3 PCR assay is specific for L. loa and secondly that L. loa infections occur in Togo. The sensitivity of this 15r3 PCR assay was further investigated with occult patients and field-collected amicrofilaremic samples. We found that 19 of the 20 occult

  7. In vitro activities of plant extracts on human Loa loa isolates and cytotoxicity for eukaryotic cells.

    PubMed

    Mengome, Line-Edwige; Akue, Jean Paul; Souza, Alain; Feuya Tchoua, Guy Raymond; Nsi Emvo, Edouard

    2010-08-01

    Loa loa, a filarial worm, can cause fatal encephalitis in humans. In an attempt to find alternatives to the standard treatments (ivermectin and diethylcarbamazine citrate), we tested 12 methanolic extracts of nine traditional plant remedies. The extracts (100-0.09 microg/ml) were incubated with 20 Loa loa microfilariae isolated from patients at 37 degrees C with 5% CO(2) in modified Eagle's medium supplemented with 10% fetal serum and antibiotics. Activity was evaluated 120 h later by counting live microfilariae under a microscope. Cytotoxicity for eukaryotic cells was estimated by measuring 3-[4,5-dimethylthiazol-2-yl]-2-5 diphenyl tetrazolium bromide transformation to formazan at 450 nM in a spectrophotometer. The plants tested were Lophira alata, Greenwayodendron suaveolens, Uapaca togoensis, Zanthoxylum heitzii, Peperomia pellucida, Piptadeniastrum africanum, Petersianthus macrocarpus, Vernonia conferta, and Vernonia hymenolepis. Chemical screening showed that most of the extracts contained reducing sugars, tannin or polyphenols, sterols or triterpenes, saponosides, and alkaloids. None contained carotinoids and few contained flavonoids. The 50% lethal concentration ranged from 0.22 to 70.28 microg/ml, while the 50% inhibitory concentration for eukaryotic cells (IC(50)) ranged from 8.52 to 119.52 microg/ml. Extracts of P. macrocarpus (selectivity index = 72.16), P. africanum (13.69), Z. heitzii (12.11), and L. alata (9.26) were highly selective for L. loa.

  8. Rapid assessment method for prevalence and intensity of Loa loa infection.

    PubMed Central

    Takougang, Innocent; Meremikwu, Martin; Wandji, Samuel; Yenshu, Emmanuel V.; Aripko, Ben; Lamlenn, Samson B.; Eka, Braide L.; Enyong, Peter; Meli, Jean; Kale, Oladele; Remme, Jan H.

    2002-01-01

    OBJECTIVE: To assess the validity of observations on eye worm and Calabar swellings for the rapid assessment of the prevalence and intensity of loiasis at the community level. METHOD: A total of 12895 individuals over the age of 15 years living in 102 communities in Cameroon and Nigeria took part in the study. A standardized questionnaire was administered to participants from whom finger-prick blood samples were collected and examined for Loa loa microfilariae. Rapid assessments of the prevalence and intensity of loiasis were made on the basis of a history of eye worm or Calabar swellings. FINDINGS: There was a strong correlation between the indices of the rapid assessment procedures and the parasitological indices of L. loa endemicity. The rapid assessment indices were effective in diagnosing high-risk communities (sensitivity 94-100%; specificity 66-92%). The highest sensitivity (100%) and specificity (92%) were obtained with a rapid assessment procedure based on a history of eye worm lasting 1-7 days together with confirmation by the guided recognition of a photograph of adult L. loa in the eye. CONCLUSION: Rapid assessment of the prevalence and intensity of loiasis at the community level can be achieved using a procedure based on the history of eye worm lasting 1-7 days together with confirmation by the guided recognition of a photograph of an adult L. loa in the eye. PMID:12481206

  9. Formaldehyde and hydroperoxides at Mauna Loa Observatory

    SciTech Connect

    Heikes, B.G. )

    1992-11-20

    Hydrogen peroxide, formaldehyde, and a measure of organic hydroperoxides are presented from the Mauna Loa Observatory Photochemistry Experiment (MLOPEX). MLOPEX was conducted from May 1 to June 4, 1988, at the Mauna Loa Observatory on the island of Hawaii. A modified dual-enzyme serial-coil H[sub 2]O[sub 2]/ROOH method was used to quantify these species. A second enzyme method was used to measure CH[sub 2]O. The location and meteorology at the Mauna Loa Observatory site permitted 35 days of measurements to be made in free tropospheric air and in modified marine boundary layer air. Average concentrations of H[sub 2]O[sub 2], ROOH, and CH[sub 2]O were 1050, 140, and 100 pptv in free tropospheric, or down-slope air. In upslope air, or modified marine boundary layer air, average concentrations were 900, 150, and 190 pptv. Maximum concentrations for all three species were experienced during a two day photochemical haze episode and were 3230, 440, and 450 pptv for H[sub 2]O[sub 2], ROOH, and CH[sub 2]O. H[sub 2]O[sub 2] was depleted in air which had recently been processed by cloud or precipitation. The measured concentrations of these three species were comparable to prior measurements in well- aged air, but were lower than previous models have predicted. Part of this discrepancy may be due to the treatment of heterogeneous removal processes, dry and wet deposition, in these models. The measured ratio of ROOH to H[sub 2]O[sub 2] is significantly different than present theory predicts, with ROOH as measured being approximately a factor of 5 too low. 61 refs., 13 figs., 2 tabs.

  10. Loa loa and Mansonella perstans filariasis in the Chaillu mountains, Congo: parasitological prevalence.

    PubMed

    Noireau, F; Carme, B; Apembet, J D; Gouteux, J P

    1989-01-01

    1934 Bantus and 379 Pygmies were investigated for Loa loa and Mansonella perstans filariasis in 7 villages in the Chaillu forest of the Congo. Bantus were more frequently infected with L. loa than Pygmies (18.9% of microfilariae carriers compared with 10.6%). In individuals over 30 years of age, males were more frequently infected than females. Microfilarial densities increased until the age of 20 years and then remained stable. Parasite load was not significantly different in the two ethnic groups. For mansonelliasis, the microfilarial rate was higher in the Pygmies (67.5% compared with 22.0%) and males of the 2 groups were more frequently infected than females. Microfilarial load was also higher in Pygmies than in Bantus (mean microfilarial densities (MfD 50) 13 and 2 respectively). In the Pygmy group, MfD 50 for M. perstans increased with age whereas it remained stable in the Bantus. 53.8% of the 249 questioned persons had experienced worm migration under the conjunctiva. Both ethnic groups were equally exposed to the vectors of L. loa and reasons for the difference in prevalence of microfilaria carriers are discussed. For mansonelliasis increased contact with vectors may explain the higher degree of infestation observed in Pygmies. Other filariases were infrequent in (Mansonella streptocerca), or absent from (Onchocerca volvulus and Wuchereria bancrofti), the study area.

  11. Novel and known MYOC exon 3 mutations in an admixed Peruvian primary open-angle glaucoma population

    PubMed Central

    Mendoza-Reinoso, Veronica; Guevara-Fujita, Maria L.; Fernández, Silvia; Vargas, Enrique; Castillo-Herrera, Wilder; Perez-Grossmann, Rodolfo; Lizaraso-Caparó, Frank; Richards, Julia E.; Fujita, Ricardo

    2012-01-01

    Purpose The aim of this study was to characterize a representative sample of the Peruvian population suffering open-angle glaucoma (OAG) with respect to the myocilin gene (MYOC) mutations, glaucoma phenotype, and ancestry for future glaucoma risk assessment. Methods DNA samples from 414 unrelated Peruvian subjects, including 205 open-angle glaucoma cases (10 juvenile glaucoma [JOAG], 19 normal-tension glaucoma [NTG], and 176 POAG) and 209 randomly sampled controls, were screened for nucleotide changes in MYOC exon 3 by conformational sensitive gel electrophoresis (CSGE) and mutation screening. Results We identified a probable causative novel MYOC missense mutation, Gly326Ser, in one POAG case and found a consistent genotype-phenotype correlation in eight of his relatives. We also found the known causative MYOC mutation Trp286Arg in one JOAG case and one POAG case. A known causative single base MYOC deletion, T1357, was found in one POAG case. Two previously reported silent polymorphisms, Thr325Thr and Tyr347Tyr, were found in both the case and the control populations. A novel missense variant, Met476Arg, was identified in two unrelated controls. Conclusions The screening of exon 3 of MYOC in a representative sample of 205 independent POAG patients from Peru and 209 matched controls identified novel and previously reported mutations (both pathogenic and nonpathogenic) from other global regions. These results reflect the complex admixture of Amerindian and Old World ancestry in urban populations of Latin America, in general, and in Peru, in particular. It will be important to gather information about the ancestral origin of MYOC and other POAG gene mutations to develop screening panels and risk assessment for POAG in Peru. PMID:22879734

  12. Identification and Validation of Loa loa Microfilaria-Specific Biomarkers: a Rational Design Approach Using Proteomics and Novel Immunoassays

    PubMed Central

    Drame, Papa M.; Meng, Zhaojing; Bennuru, Sasisekhar; Herrick, Jesica A.; Veenstra, Timothy D.

    2016-01-01

    ABSTRACT Immunoassays are currently needed to quantify Loa loa microfilariae (mf). To address this need, we have conducted proteomic and bioinformatic analyses of proteins present in the urine of a Loa mf-infected patient and used this information to identify putative biomarkers produced by L. loa mf. In total, 70 of the 15,444 described putative L. loa proteins were identified. Of these 70, 18 were L. loa mf specific, and 2 of these 18 (LOAG_16297 and LOAG_17808) were biologically immunogenic. We developed novel reverse luciferase immunoprecipitation system (LIPS) immunoassays to quantify these 2 proteins in individual plasma samples. Levels of these 2 proteins in microfilaremic L. loa-infected patients were positively correlated to mf densities in the corresponding blood samples (r = 0.71 and P < 0.0001 for LOAG_16297 and r = 0.61 and P = 0.0002 for LOAG_17808). For LOAG_16297, the levels in plasma were significantly higher in Loa-infected (geometric mean [GM], 0.045 µg/ml) than in uninfected (P < 0.0001), Wuchereria bancrofti-infected (P = 0.0005), and Onchocerca volvulus-infected (P < 0.0001) individuals, whereas for LOAG_17808 protein, they were not significantly different between Loa-infected (GM, 0.123 µg/ml) and uninfected (P = 0.06) and W. bancrofti-infected (P = 0.32) individuals. Moreover, only LOAG_16297 showed clear discriminative ability between L. loa and the other potentially coendemic filariae. Indeed, the specificity of the LOAG_16297 reverse LIPS assay was 96% (with a sensitivity of 77%). Thus, LOAG_16297 is a very promising biomarker that will be exploited in a quantitative point-of-care immunoassay for determination of L. loa mf densities. PMID:26884435

  13. Development of a Highly Sensitive Loop-Mediated Isothermal Amplification (LAMP) Method for the Detection of Loa loa

    PubMed Central

    Fernández-Soto, Pedro; Mvoulouga, Prosper Obolo; Akue, Jean Paul; Abán, Julio López; Santiago, Belén Vicente; Sánchez, Miguel Cordero; Muro, Antonio

    2014-01-01

    The filarial parasite Loa loa, the causative agent of loiasis, is endemic in Central and Western Africa infecting 3–13 million people. L. loa has been associated with fatal encephalopathic reactions in high Loa-infected individuals receiving ivermectin during mass drug administration programs for the control of onchocerciasis and lymphatic filariasis. In endemic areas, the only diagnostic method routinely used is the microscopic examination of mid-day blood samples by thick blood film. Improved methods for detection of L. loa are needed in endemic regions with limited resources, where delayed diagnosis results in high mortality. We have investigated the use of a loop-mediated isothermal amplification (LAMP) assay to facilitate rapid, inexpensive, molecular diagnosis of loiasis. Primers for LAMP were designed from a species-specific repetitive DNA sequence from L. loa retrieved from GenBank. Genomic DNA of a L. loa adult worm was used to optimize the LAMP conditions using a thermocycler or a conventional heating block. Amplification of DNA in the LAMP mixture was visually inspected for turbidity as well as addition of fluorescent dye. LAMP specificity was evaluated using DNA from other parasites; sensitivity was evaluated using DNA from L. loa 10-fold serially diluted. Simulated human blood samples spiked with DNA from L. loa were also tested for sensitivity. Upon addition of fluorescent dye, all positive reactions turned green while the negative controls remained orange under ambient light. After electrophoresis on agarose gels, a ladder of multiple bands of different sizes could be observed in positive samples. The detection limit of the assay was found to be as little as 0.5 ag of L. loa genomic DNA when using a heating block. We have designed, for the first time, a highly sensitive LAMP assay for the detection of L. loa which is potentially adaptable for field diagnosis and disease surveillance in loiasis-endemic areas. PMID:24722638

  14. Bathymetry of southern Mauna Loa Volcano, Hawaii

    USGS Publications Warehouse

    Chadwick, William W.; Moore, James G.; Garcia, Michael O.; Fox, Christopher G.

    1993-01-01

    Manua Loa, the largest volcano on Earth, lies largely beneath the sea, and until recently only generalized bathymetry of this giant volcano was available. However, within the last two decades, the development of multibeam sonar and the improvement of satellite systems (Global Positioning System) have increased the availability of precise bathymetric mapping. This map combines topography of the subaerial southern part of the volcano with modern multibeam bathymetric data from the south submarine flank. The map includes the summit caldera of Mauna Loa Volcano and the entire length of the 100-km-long southwest rift zone that is marked by a much more pronounced ridge below sea level than above. The 60-km-long segment of the rift zone abruptly changes trend from southwest to south 30 km from the summit. It extends from this bend out to sea at the south cape of the island (Kalae) to 4 to 4.5 km depth where it impinges on the elongate west ridge of Apuupuu Seamount. The west submarine flank of the rift-zone ridge connects with the Kahuku fault on land and both are part of the ampitheater head of a major submarine landslide (Lipman and others, 1990; Moore and Clague, 1992). Two pre-Hawaiian volcanic seamounts in the map area, Apuupuu and Dana Seamounts, are apparently Cretaceous in age and are somewhat younger than the Cretaceous oceanic crust on which they are built.

  15. Mauna Loa Observatory, Hawaii Boundary Layer Observations

    NASA Astrophysics Data System (ADS)

    Barnes, J. E.; Sharma, N. C. P.

    2015-12-01

    The NOAA Mauna Loa Observatory is an atmospheric monitoring station on the North side of Mauna Loa Volcano (4169 m summit) located at an altitude of 3396 m. The bright sun, dark lava surface, and the seven percent grade of the mountain create a surface radiation wind that changes from upslope in the daytime to downslope after sunset. The radiation wind has a magnitude of 2.5-3.0 m/s. The off-island wind interacts with the mountain to create a barrier wind. The radiation wind dominates when the off-island winds are low and opposite is true when the off-island winds are strong. Temperature inversions form at sunset in the first 50 meters above the ground. Aerosol profiles, measured with a unique technique called CLidar or camera lidar, often increase and show a peak between 60 and 160 meters. The aerosol generally decreases to upper tropospheric values with a distinct change in the rate of decrease at 600 m above the ground. At night the region between the aerosol peak and 600 m is often flowing upslope, counter to the downslope surface flow. The source of the air in this counter flow region is not well understood, but appears to come from levels below the station altitude at least occasionally. This possibly would impact the interpretation of some of the air samples taken during this period.

  16. Atmospheric Carbon Dioxide Record from Mauna Loa

    DOE Data Explorer

    Keeling, R. F.; Piper, S. C.; Bollenbacher, A. F.; Walker, J. S.

    2009-01-01

    Air samples at Mauna Loa are collected continuously from air intakes at the top of four 7-m towers and one 27-m tower. Four air samples are collected each hour for the purpose of determining the CO2 concentration. Determinations of CO2 are made by using a Siemens Ultramat 3 nondispersive infrared gas analyzer with a water vapor freeze trap. This analyzer registers the concentration of CO2 in a stream of air flowing at ~0.5 L/min. Every 30 minutes, the flow is replaced by a stream of calibrating gas or "working reference gas". In December 1983, CO2-in-N2 calibration gases were replaced with the currently used CO2-in-air calibration gases. These calibration gases and other reference gases are compared periodically to determine the instrument sensitivity and to check for possible contamination in the air-handling system. These reference gases are themselves calibrated against specific standard gases whose CO2 concentrations are determined manometrically. Greater details about the sampling methods at Mauna Loa are given in Keeling et al. (1982) and Keeling et al. (2002).

  17. [Loa Loa and Mansonella perstans coinfection in a patient from Guinea].

    PubMed

    Gil-Setas, Alberto; Pérez Salazar, M; Navascués, A; Rodríguez Eleta, F; Cebamanos, J A; Rubio, M T

    2010-01-01

    We present a case of mixed infection by two filariae (Loa loa and Mansonella perstans). It seems that the infection was suspected due to a pronounced eosinophilia in a routine analysis. Sheathed and unsheathed microfilariae were observed in the spread of peripheral blood, which enabled a diagnosis to be established of mixed infection by filariae. The definitive diagnosis of the species was carried out at the National Centre of Microbiolgy of Majadahonda. A treatment was initiated with dietilcarbamazina and mebendazole which resulted in the patient's being cured and in the elimination of the microfilariae in the patient's blood. Filariasis is still endemic in many countries. Due to the increase of travellers to such zones and the migratory movements from such areas it is not unusual for us to come across such a diagnosis. The implantation of massive treatments against filariae in endemic zones by the World Health Organisation is reducing their transmission and is managing to eliminate the disease in some areas.

  18. Genome Filtering for New DNA Biomarkers of Loa loa Infection Suitable for Loop-Mediated Isothermal Amplification

    PubMed Central

    Poole, Catherine B.; Ettwiller, Laurence; Tanner, Nathan A.; Evans, Thomas C.; Wanji, Samuel; Carlow, Clotilde K. S.

    2015-01-01

    Loa loa infections have emerged as a serious public health problem in patients co-infected with Onchocerca volvulus or Wuchereria bancrofti because of severe adverse neurological reactions after treatment with ivermectin. Accurate diagnostic tests are needed for careful mapping in regions where mass drug administration is underway. Loop-mediated isothermal amplification (LAMP) has become a widely adopted screening method because of its operational simplicity, rapidity and versatility of visual detection readout options. Here, we present a multi-step bioinformatic pipeline to generate diagnostic candidates suitable for LAMP and experimentally validate this approach using one of the identified candidates to develop a species-specific LAMP assay for L. loa. The pipeline identified ~140 new L. loa specific DNA repeat families as putative biomarkers of infection. The consensus sequence of one family, repeat family 4 (RF4), was compiled from ~ 350 sequences dispersed throughout the L. loa genome and maps to a L. loa-specific region of the long terminal repeats found at the boundaries of Bel/Pao retrotransposons. PCR and LAMP primer sets targeting RF4 specifically amplified L. loa but not W. bancrofti, O. volvulus, Brugia malayi, human or mosquito DNA. RF4 LAMP detects the DNA equivalent of one microfilaria (100 pg) in 25–30 minutes and as little as 0.060 pg of L. loa DNA (~1/1600th of a microfilaria) purified from spiked blood samples in approximately 50 minutes. In summary, we have successfully employed a bioinformatic approach to mine the L. loa genome for species-specific repeat families that can serve as new DNA biomarkers for LAMP. The RF4 LAMP assay shows promise as a field tool for the implementation and management of mass drug administration programs and warrants further testing on clinical samples as the next stage in development towards this goal. PMID:26414073

  19. Population dynamics of Loa loa and Mansonella perstans infections in individuals living in an endemic area of the Congo.

    PubMed

    Noireau, F; Pichon, G

    1992-06-01

    A follow-up of Loa loa and Mansonella perstans microfilaremia was carried out in an adult population living in a highly endemic area of the Congo. Infection rates and parasite loads were found to be stable in the general population, both in the short-term (two months) and long-term (3-4 years) followup. The microfilarial status of most of the subjects examined did not change between tests. At the individual level, the microfilarial densities of L. loa and M. perstans also remained remarkably constant over time. This results in a qualitative and quantitative stability of the parasitic material available for the vectors.

  20. A novel MYOC heterozygous mutation identified in a Chinese Uygur pedigree with primary open-angle glaucoma.

    PubMed

    Cai, Su-ping; Muhemaiti, Paerheti; Yin, Yan; Cheng, Hongbo; Di Ya, A; Keyimu, Maliyamu; Cao, Xu; Fan, Ning; Jiang, Liqiong; Yan, Naihong; Zhou, Xiaomin; Wang, Yun; Liu, Xuyang

    2012-01-01

    To characterize the clinical features of a Chinese Uygur pedigree with primary open-angle glaucoma (POAG) and to identify mutations in two candidate genes, trabecular meshwork inducible glucocorticoid response (MYOC/TIGR) and human dioxin-inducible cytochrome P450 (CYP1B1). Twenty one members from a Chinese Uygur family of four generations were included in the study. All participants underwent complete ophthalmologic examinations. Five were diagnosed as POAG, four as glaucoma suspects, and the rest were asymptomatic. Molecular genetic analysis was performed on all subjects included in the study. All exons of CYP1B1 and MYOC were amplified by polymerase chain reaction (PCR), sequenced and compared with a reference database. The variations detected were evaluated in available family members as well as 102 normal controls. Possible changes in structure and function of the protein induced by amino acid variance were predicted by bioinformatics analysis. Elevated intraocular pressure and late-stage glaucomatous cupping of the optic disc were found in five patients of this family. A novel heterozygous missense mutation c.1151 A>G in exon 3 of MYOC was found in all five patients diagnosed as POAG and four glaucoma suspects, but not in the rest of the family members and 102 normal controls. This mutation caused an amino acid substitution of aspartic acid to glycine at position 384 (p. D384G) of the MYOC protein. This substitution may cause structural and functional changes of the protein based on bioinformatics analysis. No mutations were found in CYP1B1. Our study suggests that the novel mutation D384G of MYOC is likely responsible for the pathogenesis of POAG in this pedigree.

  1. [Serum filariasis due to Loa loa and Mansonella perstans in the continental area of equatorial Guinea. Preliminary results].

    PubMed

    Vila Montlleo, R

    1990-01-01

    For the first time, a parasitologic survey has been carried out in the Niefang District (continental area of equatorial Guinea) within a sample of 829 people aged of more than 10 years. Parasitologic incidence was 27.1 p.c. for Loa-Loa and 66.3 p.c. for Mansonella perstans. Significant differences were noted in the prevalence and in the mean density of microfilariae of both species according to the altitude of the villages surveyed.

  2. Influence of Mansonella perstans microfilaraemia on total IgE levels in Gabonese patients co-infected with Loa loa.

    PubMed

    Bouyou-Akotet, M K; Moussavou Boussougou, M N; Ovono-Abessolo, F; Owono-Medang, M; Kombila, M

    2014-03-01

    Mansonella (M.) perstans filariasis is widely found in Africa, including Gabon where Loa loa is also endemic. This study reports the total IgE titres according to different bioclinical forms of single or co-infection with L. loa and M. perstans in 138 patients and 20 healthy controls. The median parasite density was significantly higher in cases of loiasis. IgE titres were higher in patients with microscopic dual-infection and in the group of patients with occult loiasis plus M. perstans microfilaraemia (8425 [5292-20,679]KUI/L and 6304 [1045-10,326]KUI/L, respectively), compared to individuals with either microfilaraemic Loa loa (3368 [1414-7074]KUI/L) or Mansonella (4370 [1478-7334]KUI/L) single infections (p<0.01). IgE levels were positively correlated with M. perstans microfilaraemia (rho=0.27; p<0.01). Compared to single infections, dual M. perstans-L. loa infection induces very high total IgE titres. Studies correlating IgE titres and clinical symptoms are needed to confirm the involvement of this immunoglobulin in the pathological processes during filariasis. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Mauna Loa's submarine western flank: Landsliding, deep volcanic spreading, and hydrothermal alteration

    NASA Astrophysics Data System (ADS)

    Morgan, Julia K.; Clague, David A.; Borchers, Deanna C.; Davis, Alicé S.; Milliken, Kitty L.

    2007-05-01

    Four new remotely operated vehicle dives carried out by Monterey Bay Aquarium Research Institute (MBARI) reveal a heterogeneous distribution of lithologies and compositions along a transect across the submarine west flank of Mauna Loa, from the outer scarp of the frontal bench to the upper flank. The frontal bench is composed predominantly of volcaniclastic sediments, ranging from very fine-grained monomictic hyaloclastites to coarse-grained, compositionally mixed volcaniclastic breccias. The predominance of subaerially derived clasts suggests accumulations of landslide deposits, probably emplaced along a regional shear plane preserved in cataclastic breccias with local foliations and grain trails. Repeated packages of inversely graded strata are interpreted to reflect thrust imbrication of the resulting volcaniclastic apron during volcanic spreading of Mauna Loa's western flank, similar to that now documented along Kīlauea's south flank. Many of the rocks from the bench show evidence for alteration, ranging from low-grade burial diagenesis to higher-grade hydrothermal alteration, including phases never before observed in submarine Hawaiian rocks, including epidote, talc, sphene, and corrensite. Alteration is concentrated in deformed zones, denoting pathways for fluid flow into or out of the volcanic edifice. Formed at depth, the altered rocks were subsequently transported along low-angle thrust faults into the bench and exposed along high-angle fractures and faults. The upper submarine flanks are draped by subaerially erupted, submarine emplaced pillow lavas and interbedded hyaloclastites, generated by shoreline-crossing lava flows. Basalt glasses indicate Mauna Loa origin but imply earlier compositions than present-day lavas, consistent with Ar-Ar ages suggesting eruption 0.28 ± 0.10 Ma. Late stage detachment of a nearshore slump produced the 'Ālika 2 debris avalanche that broke through the frontal bench, perhaps portending the evolution of the active Hilina

  4. Atmospheric aerosols from Mauna Loa Observatory, Hawaii

    SciTech Connect

    Zoller, W.H.; Holmes, J.L. )

    1993-01-01

    Atmospheric aerosols have been collected for chemical analysis at the Mauna Loa Observatory in Hawaii since 1979. The samples were collected in two wind quadrants, a clean [open quotes]down-slope[close quotes] quadrant and a more contaminated [open quotes]up-slope[close quotes] quadrant. Some of the findings of this work have been the identification of Asian dust traveling to the Hawaiian Islands every spring of the year, and this dust dominates the yearly record because it is very intense and contains predominantly crustal dust along with pollutants from the Asian mainland, such as coal combustion in China. Additional interpretation of the data set of weekly samples has shown the presence of pollutants from both North and South America as well as different areas of Asia that are transported by wind systems to the central Pacific Ocean. By subtracting these episodic transport events, one can look at the oceanic background aerosols that are originating from the ocean and look at the occurrence of the natural aerosol generating systems in the oceanic region that are related to climatic change. One of the important groups of elements are the sulfur and halogen families and the naturally occurring volatile elements (selenium, arsenic, antimony, etc.) that are produced by biogenic activity in the world's oceans and affect the chemistry of the atmosphere, particularly clouds in remote marine areas. Investigations such as this work allow one to evaluate the importance of natural versus anthropogenic sources of the volatile elements to the atmosphere, allowing us to have a much better understanding of man's impact on climate. The nuclear analytical techniques are particularly well suited to this type of sample because it consists of aerosols deposited on a clean Teflon or cellulose substrate, which normally offers very little interference with the analysis.

  5. A Closer Look at Recent Deep Mauna Loa Seismicity

    NASA Astrophysics Data System (ADS)

    Okubo, P. G.; Wolfe, C. J.; Nakata, J. S.; Koyanagi, S. K.; Uribe, J. O.

    2005-12-01

    In 2002, Mauna Loa Volcano showed signs of reawakening, some 18 years since its last eruption in 1984. First, in April, a brief flurry of microearthquakes occurred at cataloged depths from 25 to 55 km beneath Mauna Loa's summit caldera. Then in May 2002, after the microearthquake swarm had ended, geodetic monitors across Mauna Loa's summit caldera registered a change, from line-length shortening to extension, interpreted as reinflation of a magma body approximately 4 km beneath the volcano's summit. Accordingly, the Hawaiian Volcano Observatory issued advisories related to Mauna Loa's stirring. In July 2004, HVO began to record deep long-period (LP) earthquakes beneath Mauna Loa. Historically, interpretations of such seismicity patterns have associated LP source volumes with magma chambers and magma pathways. Over a few weeks, this seismicity dramatically jumped to levels of several dozen per day. Between the months of July and December 2004, nearly 2000 Mauna Loa LPs were located between roughly 25 km and greater than 60 km depths by HVO seismic analysts. In late December, these earthquakes rather abruptly ceased, and their levels have remained low ever since. We seek a more detailed understanding of how these earthquakes may factor into Mauna Loa's eruptive framework. Given that their first arrivals are typically emergent, hypocentral estimates using only P-wave first-arrival times of LP earthquakes are often marginally constrained. With such hypocentral estimates, it is difficult to establish clear relationships among the earthquake locations themselves, or between the earthquakes and other processes like crustal extension or magma accumulation or withdrawl. Building on earlier applications to deep earthquakes in Hawaii and LP earthquakes beneath Kilauea, we are reexamining this unprecedented Mauna Loa deep seismicity with waveform correlation and precise earthquake relocation techniques. Work to date reveals that, although the waveform correlation coefficients

  6. Posttreatment Reactions After Single-Dose Diethylcarbamazine or Ivermectin in Subjects With Loa loa Infection.

    PubMed

    Herrick, Jesica A; Legrand, Fanny; Gounoue, Raceline; Nchinda, Godwin; Montavon, Céline; Bopda, Jean; Tchana, Steve Mbickmen; Ondigui, Bienvenu Etogo; Nguluwe, Konrad; Fay, Michael P; Makiya, Michelle; Metenou, Simon; Nutman, Thomas B; Kamgno, Joseph; Klion, Amy D

    2017-04-15

    Severe adverse reactions have been observed in individuals with Loa loa infection treated with either diethylcarbamazine (DEC), the drug of choice for loiasis, or ivermectin (IVM), which is used in mass drug administration programs for control of onchocerciasis and lymphatic filariasis in Africa. In this study, posttreatment clinical and immunologic reactions were compared following single-dose therapy with DEC or IVM to assess whether these reactions have the same underlying pathophysiology. Twelve patients with loiasis and microfilarial counts <2000 mf/mL were randomized to receive single-dose DEC (8 mg/kg) or IVM (200 µg/kg). Clinical and laboratory assessments were performed at 4, 8, 24, 48, and 72 hours and 5, 7, 9, and 14 days posttreatment. Posttreatment adverse events were similar following DEC or IVM, but peaked earlier in subjects who received DEC, consistent with a trend toward more rapid and complete microfilarial clearance in the DEC group. After a transient rise (post-IVM) or fall (post-DEC) in the first 24 hours posttreatment, the eosinophil count rose significantly in both groups, peaking at day 5 in the DEC group and day 9 in the IVM group. Serum interleukin 5 levels and eosinophil activation, as assessed by surface expression of CD69 and serum levels of eosinophil granule proteins, were increased posttreatment in both groups. Despite differences in eosinophil and lymphocyte counts during the first 24 hours posttreatment, the overall pattern of hematologic and immunologic changes suggest that posttreatment reactions following DEC and IVM share a common pathophysiology. NCT01593722.

  7. A Controlled Trial to Assess the Effect of Quinine, Chloroquine, Amodiaquine, and Artesunate on Loa loa Microfilaremia

    PubMed Central

    Kamgno, Joseph; Djomo, Patrick Nguipdop; Pion, Sébastien D.; Thylefors, Björn; Boussinesq, Michel

    2010-01-01

    Onchocerciasis control is currently based on mass ivermectin treatment. Unfortunately, this drug can induce serious adverse events (SAEs) in persons with high levels of Loa loa microfilaremia (> 30,000 microfilaria/mL). A means of preventing SAEs would be to treat at risk populations with a drug that would progressively reduce the microfilarial loads before administering ivermectin. Antimalarial drugs are a potential solution because they have shown some activity against various filarial species. A controlled trial was conducted to assess the effect of standard doses of quinine, chloroquine, amodiaquine, and artesunate on L. loa microfilaremia. Ninety-eight patients were randomly allocated into five groups (one for each drug and a control group) after stratification on microfilarial load. Loa loa microfilaremia was monitored on days 0, 3, 7, 15, 30, 60, and 90. No significant change in the loads was recorded in any of the treatment groups. A comprehensive review of the effects of antimalarial drugs against filariae is also provided. PMID:20207860

  8. Submarine radial vents on Mauna Loa Volcano, Hawai'i

    USGS Publications Warehouse

    Wanless, V. Dorsey; Garcia, M.O.; Trusdell, F.A.; Rhodes, J.M.; Norman, M.D.; Weis, Dominique; Fornari, D.J.; Kurz, M.D.; Guillou, Herve

    2006-01-01

    A 2002 multibeam sonar survey of Mauna Loa's western flank revealed ten submarine radial vents and three submarine lava flows. Only one submarine radial vent was known previously. The ages of these vents are constrained by eyewitness accounts, geologic relationships, Mn-Fe coatings, and geochemical stratigraphy; they range from 128 years B.P. to possibly 47 ka. Eight of the radial vents produced degassed lavas despite eruption in water depths sufficient to inhibit sulfur degassing. These vents formed truncated cones and short lava flows. Two vents produced undegassed lavas that created “irregular” cones and longer lava flows. Compositionally and isotopically, the submarine radial vent lavas are typical of Mauna Loa lavas, except two cones that erupted alkalic lavas. He-Sr isotopes for the radial vent lavas follow Mauna Loa's evolutionary trend. The compositional and isotopic heterogeneity of these lavas indicates most had distinct parental magmas. Bathymetry and acoustic backscatter results, along with photography and sampling during four JASON2 dives, are used to produce a detailed geologic map to evaluate Mauna Loa's submarine geologic history. The new map shows that the 1877 submarine eruption was much larger than previously thought, resulting in a 10% increase for recent volcanism. Furthermore, although alkalic lavas were found at two radial vents, there is no systematic increase in alkalinity among these or other Mauna Loa lavas as expected for a dying volcano. These results refute an interpretation that Mauna Loa's volcanism is waning. The submarine radial vents and flows cover 29 km2 of seafloor and comprise a total volume of ∼2×109 m3 of lava, reinforcing the idea that submarine lava eruptions are important in the growth of oceanic island volcanoes even after they emerged above sea level.

  9. The distribution of geochemical heterogeneities in the source of Hawaiian shield lavas as revealed by a transect across the strike of the Loa and Kea spatial trends: East Molokai to West Molokai to Penguin Bank

    NASA Astrophysics Data System (ADS)

    Xu, Guangping; Huang, Shichun; Frey, Frederick A.; Blichert-Toft, Janne; Abouchami, Wafa; Clague, David A.; Cousens, Brian; Moore, James G.; Beeson, Melvin H.

    2014-05-01

    An important feature of <2 Ma Hawaiian volcanoes is that they define two sub-parallel spatial trends known as the Loa- and Kea-trends. On the Island of Hawaii, the <1.5 Ma shield lavas on the Loa and Kea spatial trends have distinctive geochemical characteristics that are designated as Loa-type and Kea-type. These geochemical differences are clearly expressed in Sr, Nd, Hf and Pb isotopic ratios, major element contents, and ratios of incompatible elements. They are interpreted to reflect varying proportions of sediment, basalt, gabbro and peridotite in subducted oceanic lithosphere. Pb isotopic ratios indicate that the Loa-type component reflects ancient subduction, >2.5 Ga, whereas the Kea-type component reflects younger subduction, <1.5 Ga. To evaluate the temporal persistence of these geochemical differences in the source of Hawaiian shield lavas, we analyzed lavas from the ˜1.5 to 2 Ma Molokai Island volcanoes, East and West Molokai, and the adjacent submarine Penguin Bank. The three volcanoes form a nearly east-west trend that crosscuts the Loa and Kea spatial trends at a high angle; consequently we can determine if these older lavas are Kea-type in the east and Loa-type in the west. All lavas collected from the subaerial flanks of East Molokai, a Kea-trend volcano, have Kea-type geochemical characteristics; however, dive samples collected from Wailau landslide blocks, probably samples of the East Molokai shield that are older than those exposed on the subaerial flanks, include basalt with Loa-type geochemical features. Shield lavas from West Molokai and Penguin Bank, both on the Loa-trend, are dominantly Loa-type, but samples with Kea-type compositions also erupted at these Loa-trend volcanoes. The Loa-trend volcanoes, Mahukona, West Molokai, Penguin Bank, and Koolau, have also erupted lavas with Kea-type geochemical characteristics, and the Kea-trend volcanoes, Mauna Kea, Kohala, Haleakala, and East Molokai, have erupted lavas with Loa-type geochemical

  10. Filaricidal activities on Onchocerca ochengi and Loa loa, toxicity and phytochemical screening of extracts of Tragia benthami and Piper umbellatum.

    PubMed

    Cho-Ngwa, Fidelis; Monya, Elvis; Azantsa, Boris K; Manfo, Faustin Pascal T; Babiaka, Smith B; Mbah, James A; Samje, Moses

    2016-08-30

    Onchocerciasis is the world's second leading infectious cause of blindness. Its control is currently hampered by the lack of a macrofilaricidal drug and by severe adverse events observed when the lone recommended microfilaricide, ivermectin is administered to individuals co-infected with Loa loa. Therefore, there is the need for a safe and effective macrofilaricidal drug that will be able to cure the infection and break transmission cycles, or at least, an alternative microfilaricide that does not kill L. loa microfilariae (mf). Fourteen extracts from two medicinal plants, Tragia benthami and Piper umbellatum were screened in vitro against Onchocerca ochengi parasite and L. loa mf. Activities of extracts on male worms and microfilariae were assessed by motility reduction, while MTT/Formazan assay was used to assess biochemically the death of female worms. Cytotoxicity and acute toxicity of active extracts were tested on monkey kidney cells and Balb/c mice, respectively. At 500 μg/mL, all extracts showed 100 % activity on Onchocerca ochengi males and microfilariae, while 9 showed 100 % activity on female worms. The methylene chloride extract of Piper umbellatum leaves was the most active on adult male and female worms (IC50s: 16.63 μg/mL and 35.65 μg/mL, respectively). The three most active extracts on Onchocerca ochengi females were also highly active on Loa loa microfilariae, with IC50s of 35.12 - 13.9 μg/mL. Active extracts were generally more toxic to the worms than to cells and showed no acute toxicity to Balb/c mice. Phytochemical screening revealed the presence of saponins, steroids, tannins and flavanoids in the promising extracts. These results unfold potential sources of novel anti-Onchocerca lead compounds and validate the traditional use of the plants in onchocerciasis treatment.

  11. Serious reactions after mass treatment of onchocerciasis with ivermectin in an area endemic for Loa loa infection.

    PubMed

    Gardon, J; Gardon-Wendel, N; Demanga-Ngangue; Kamgno, J; Chippaux, J P; Boussinesq, M

    1997-07-05

    In 1995, the World Bank launched an African Programme for Onchocerciasis Control to eliminate Onchocerca volvulus disease from 19 African countries by means of community-based ivermectin treatment (CBIT). Several cases of encephalopathy have been reported after ivermectin in people heavily infected with microfilariae of Loa loa (loiasis). We assessed the incidence of serious events in an area where onchocerciasis and loiasis are both endemic. Ivermectin (at 150 micrograms/kg) was given to 17877 people living in the Lékié area of Cameroon. 50 microL samples of capillary blood were taken during the daytime before treatment from all adults (aged > or = 15 years), and the numbers of L loa and Mansonella perstans microfilariae in them were counted. Patients were monitored for 7 days after treatment. Adverse reactions were classified as mild, marked, or serious. Serious reactions were defined as those associated with a functional impairment that required at least a week of full-time assistance to undertake normal activities. We calculated the relative risk of developing marked or serious reactions for increasing L loa microfilarial loads. Risk factors for serious reactions were identified and assessed with a logistic regression model. 20 patients (0-11%) developed serious reactions without neurological signs but associated with a functional impairment lasting more than a week. Two other patients were in coma for 2-3 days, associated with L loa microfilariae in cerebrospinal fluid. Occurrence of serious reactions was related to the intensity of pretreatment L loa microfilaraemia. The relative risk of developing marked or serious reactions was significantly higher when the L loa load exceeded 8000 microfilariae/mL; for serious reactions, the risk is very high (odds ratio > 1000) for loads above 50000 microfilariae/mL. Epidemiological surveys aimed at assessing the intensity of infection with L loa microfilariae should be done before ivermectin is distributed for

  12. 47 CFR 54.632 - Letters of agency (LOA).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Universal Service Support for Health Care Providers Healthcare Connect Fund § 54.632 Letters of agency (LOA). (a) Authorizations. Under the Healthcare Connect Fund, the Consortium Leader must obtain...

  13. 47 CFR 54.632 - Letters of agency (LOA).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... and post the request for proposal on behalf of the member. (2) Prior to the submission of the funding... manage invoicing and payments on behalf of the member. (b) Optional two-step process. The Consortium Leader may secure both required authorizations from each consortium member in either a single LOA or in...

  14. Solar spectral irradiance and atmospheric transmission at Mauna Loa Observatory

    SciTech Connect

    Shaw, G.E.

    1982-06-01

    A radiometer was operated at the Mauna Loa Observatory during calendar year 1980 to estimate the spectral irradiance of the sun and its possible fluctuation in time near the peak of solar activity. Data were also acquired on seasonal trends of atmospheric transmissivity above the marine mixing layer in the central Pacific. Spectral irradiance remained c constant to at least 1/2% at all wavelengths monitored. Furthermore its absolute magnitude was in agreement with the Labs and Neckel values to +- 2% except at blue wavelengths where the Mauna Loa values are from 4 to 12% higher and at lambda = 850 nm where the Mauna Loa value is 9% lower. The residual aerosol optical depth above Mauna Loa Observatory during 1980 averaged tau/sub 0/ = 0.020. An intrusion of dust into the central Pacific from the Gobi Desert (as deduced by the composition of collected particles) invaded the Central Pacific from Mar. to May 19890 and caused a perturbation in optical depth (at lambda = 500 nm) of ..delta..tau/sub 0/approx.0.01--0.02. The optical depth increment caused by the Mt. St. Helens volcano was <0.005 in the 2-month period following the eruption.

  15. Solar spectral irradiance and atmospheric transmission at Mauna Loa Observatory.

    PubMed

    Shaw, G E

    1982-06-01

    A radiometer was operated at the Mauna Loa Observatory during calendar year 1980 to estimate the spectral irradiance of the sun and its possible fluctuation in time near the peak of solar activity. Data were also acquired on seasonal trends of atmospheric transmissivity above the marine mixing layer in the central Pacific. Spectral irradiance remained constant to at least (1/2)% at all wavelengths monitored. Furthermore its absolute magnitude was in agreement with the Labs and Neckel values to +/-2% except at blue wavelengths where the Mauna Loa values are from 4 to 12% higher and at lambda = 850 nm where the Mauna Loa value is 9% lower. The residual aerosol optical depth above Mauna Loa Observatory during 1980 averaged tau(0) = 0.020. An intrusion of dust into the central Pacific from the Gobi Desert (as deduced by the composition of collected particles) invaded the Central Pacific from Mar. to May 1980 and caused a perturbation in optical depth (at lambda = 500 nm) of Deltatau(0) ~ 0.01-0.02. The optical depth increment caused by the Mt. St. Helens volcano was <0.005 in the 2-month period following the eruption.

  16. Is the Hawaiian Archipelago dominantly Loa-trend?

    NASA Astrophysics Data System (ADS)

    Weis, D.; Harrison, L.; Garcia, M. O.; Rhodes, M. M.

    2015-12-01

    Hawaiian volcanoes are distributed en echelon on the islands along two chains, the Loa and Kea trends, that are geographically and geochemically distinct1,2. These geochemical differences may be attributed to source zoning (concentric or bilateral) of the Hawaiian mantle plume (HMP) or to variations in pressure and temperature of melting. Most of these models assume a degree of independence of the two trends that is perhaps not realistic. To explore the isotopic characteristics of two "Kea"-trend volcanoes with transitional signatures, we analyzed 11 samples of Kohala shield-stage tholeiitic lavas and three from Haleakala for high-precision Pb-Nd-Sr-Hf isotopes. These samples are transitional in all isotopic systems between Loa and Kea compositions and cross-over the Pb-Pb boundary3. Minor cross-overs had been documented in Mauna Kea4, Kilauea5, and W Molokai6 basalts. A bilateral or concentric view of the HMP is thus too simplistic. Statistical analysis of the MC-ICP-MS or triple-spike shield tholeiite data (n>600) and the existence of three Pb-Pb trends originating from average Loa indicate that Loa is the dominant mantle source composition on the archipelago. Isotopically, four geochemical groups are identified: Kea (Mauna Kea, Kilauea), average Loa (Mauna Loa, Hualalai, Kauai, Waianae, W. Molokai, Loihi), enriched Loa (Koolau Makapuu, Lanai, Kahoolawe) and transitional Kea (E. Molokai, W. Maui, Haleakala, Kohala). The implications are: 1) HMP source components refresh and grade into and out of existence on a smaller timescale than previously thought; 2) the Kea trend is also heterogeneous; and 3) vertical heterogeneity of the plume is important on a regional scale as well as at the scale of individual volcanoes6. 1Jackson et al., 1972, GSA Bull. 83, 1-17. 2Weis et al., 2011, Nat. Geosci., 4, 831-838. 3Abouchami et al., 2005, Nature, 434, 851-856. 4Eisele et al., 2003, G-cubed, 4, 5, 32 pages. 5Marske et al., 2007, EPSL, 259, 34-50. 6Xu et al., 2014, GCA, 132

  17. Epidemiology of concomitant infections due to Loa loa, Mansonella perstans, and Onchocerca volvulus in rain forest villages of Cameroon.

    PubMed

    Wanji, S; Tendongfor, N; Esum, M; Ndindeng, S; Enyong, P

    2003-02-01

    An epidemiological survey was conducted in 16 remote villages of the rain forest of southern Cameroon to ascertain the prevalence and intensity of three species of filariae: Loa loa, Onchocerca volvulus, and Mansonella perstans. We examined 1458 individuals for blood-dwelling microfilariae and 1255 of these were also for the presence of palpable nodules. All the villages surveyed were found highly endemic for onchocerciasis and mansonellosis with prevalence ranging from 28.44% to 87.17% for O. volvulus and 52.48% to 100% for M. perstans. The intensities of infection were also found high for M. perstans with arithmetic means of microfilaremia ranging from 280.94 to 4947.57 mf/ml. The loiasis prevalence was relatively low with value from 2.22% to 19.23%. Males were found more infected than females for the three species of filariae, and the prevalence and intensities of microfilaremia vary differently in males and females at different ages. The three species of filariae displayed different degrees of association in the inhabitants with a low prevalence of co-occurrence between L. loa/O. volvulus and between L. loa/M. perstans. In contrast, there was a high prevalence of co-occurrence between M. perstans and O. volvulus. The implications of the co-occurrence of the three species of filariae in the populations of these remote villages on the intervention programs based on mass treatment with mectizan are discussed.

  18. Altitude effects on UV spectral irradiance deduced from measurements at Lauder, New Zealand, and at Mauna Loa Observatory, Hawaii

    NASA Astrophysics Data System (ADS)

    McKenzie, Richard L.; Johnston, Paul V.; Smale, Dan; Bodhaine, Barry A.; Madronich, Sasha

    2001-10-01

    Measurements from Lauder, New Zealand, and from the high-altitude Mauna Loa Observatory, Hawaii, are used to determine the altitude effects on spectral UV irradiance and to relate these altitude differences to other factors that influence UV radiation. The measured ratios UVMauna Loa/UVLauder are complex functions of both wavelength and solar zenith angle (SZA). Spectrally, the ratios tend to increase toward shorter wavelengths through most of the UV-A region. For small SZA (SZA < ˜40°) the ratios continue to increase as wavelength decreases throughout the UV-B region. For SZA = 60° a local maximum occurs in the UV-B region. As the SZA increases, this turning point moves to longer wavelengths and its peak value decreases. For SZA >˜80°, local minima in the ratios are seen at shorter wavelengths in the UV-B region. For biologically weighted irradiances, the peak ratios occur near SZA = 70°, where UV-A, erythemally weighted UV, UV-B, and DNA-weighted UV irradiances at Mauna Loa Observatory exceeded those at Lauder by ˜17%, 26%, 27%, and 29% respectively. The ratios of irradiances at the two altitudes, as functions of SZA and wavelength, were related to differences expected from radiative transfer calculations. For small SZA, modeled and measured ratios agreed within the limits of experimental uncertainty without taking differences in altitude distributions of ozone and temperature into account. However, for larger SZA and shorter wavelengths these profile shapes had a significant effect. In the model calculations, satisfactory agreement with the measurements was achieved only when the contribution from radiation scattered from air or cloud tops below the observation height at Mauna Loa Observatory was included. To model this accurately, a three-dimensional radiative transfer code should be used in conjunction with a topographical model of the surrounding terrain.

  19. Flat Anterior Chamber after Trabeculectomy in Secondary Angle-Closure Glaucoma with BEST1 Gene Mutation: Case Series

    PubMed Central

    Xiao, Hui; Luo, Jingyi; Zuo, Chengguo; Huang, Xiaobo; Huang, Jingjing; Mi, Lan; Zhang, Qingjiong; Liu, Xing

    2017-01-01

    Purpose Trabeculectomy has been regarded as a mainstay of initial treatment in eyes of angle closure glaucoma (ACG) with peripheral anterior synechia > 180° in the Chinese population while its efficacy in secondary ACG with BEST1 gene mutation remains unclear. We set out to investigate the treatment outcome of trabeculectomy for secondary ACG in a group of patients with autosomal recessive bestrophinopathy (ARB). Methods In this retrospective case series study, 8 secondary ACG patients with ARB and their 4 recruited family members underwent a thorough ophthalmic examination including best-corrected visual acuity, Goldmann applanation tonometry, gonioscopy, and fundus examinations. Ultrasound biomicroscopy, optical coherence tomography (OCT), ultrasound A-scan, B-scan, electro-oculography (EOG), Humphrey perimetry, fundus photography, fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA) were also performed. Blood samples were obtained in the patients and their available family members to analyze the variants of the BEST1 gene. Trabeculectomy was performed in the 8 patients (15 eyes). Results The age of onset varied from 13 to 38 years. The average axial length (AL) of the affected eyes was 21.82 ± 0.92 mm and the average anterior chamber depth (ACD) was 2.19 ± 0.29 mm. There was marked axial shallowing of the anterior chamber in all 15 eyes after trabeculectomy, and was not improved with potent mydriatics. The IOP was elevated in 3 eyes. Variable degree of yellowish subretinal deposits was observed in the posterior retina. The FFA showed punctuate or patched hyperfluorescence suggesting retinal pigment epithelium impairment. The ICGA demonstrated dilatation of choroidal vessels. The OCT revealed diffused neuroretinal detachment in the posterior and midperipheral retina, with intraretinal fluid collections, and hyperreflective subretinal accumulations. The average subfoveal choroidal thickness of the patients was 382.36 ± 80.09 μm. All

  20. Parasitological, Hematological and Biochemical Characteristics of a Model of Hyper-microfilariaemic Loiasis (Loa loa) in the Baboon (Papio anubis)

    PubMed Central

    Wanji, Samuel; Eyong, Ebanga-Echi; Tendongfor, Nicholas; Ngwa, Che; Esuka, Elive; Kengne-Ouafo, Arnaud; Datchoua-Poutcheu, Fabrice; Enyong, Peter; Hopkins, Adrian; Mackenzie, Charles D.

    2015-01-01

    Background Loiasis, a filarial infection caused by Loa loa usually thought to cause relatively minor morbidity, can cause serious and often fatal reactions in patients carrying very high levels of circulating Loa loa microfilariae (mf) following administration of microfilaricidal drugs. An experimental model of this condition would greatly aid the definition of the optimal management of this important clinical presentation. Methodology/Principle Findings Fifteen baboons (Papio anubis) were infected with 600 infective larvae (L3) isolated from Chrysops vector flies. Animals were observed for any clinical changes; blood samples were collected every 1–2 months for 22 months, and analysed for parasitological, hematological and biochemical profiles using standard techniques. All animals became patent but remained clinically normal throughout the study. The parasitological pre-patent period was between 4–8 months, with a majority (60%) of animals becoming patent by 5 months post infection (MPI); all animals were patent by 8 MPI. Microfilarial loads increased steadily in all animals and reached a peak at 18 MPI. By 10 MPI >70% of animals had mf >8,000 mf/mL, and at 18 MPI >70% of animals had mf >30,000mf/mL with 50% of these animals with mf >50,000mf/mL. Absolute eosinophil, creatinine, Ca2+ and K+ levels were generally above normal values (NV). Positive associations were seen between microfilariaemia and eosinophilia, Hb, Ca2+, and gamma-GT values, whilst significant negative associations were seen between microfilariaemia and potassium, glucose and mononuclear leukocyte levels. Conclusions Infection of splenectomised baboons with L. loa can induce levels of circulating microfilariae, and corresponding haematological profiles, which parallel those seen in those humans in danger of the severe post-microfilariacide clinical responses. Utilization of this experimental model could contribute to the improved management of the loiasis related adverse responses in humans

  1. Identification of Mutations in Myocilin and Beta-1,4-galactosyltransferase 3 Genes in a Chinese Family with Primary Open-angle Glaucoma.

    PubMed

    Liao, Rong-Feng; Zhong, Zi-Lin; Ye, Min-Jie; Han, Li-Yun; Ye, Dong-Qing; Chen, Jian-Jun

    2016-12-05

    Glaucoma is a major cause of irreversible blindness worldwide. There is evidence showing that a subset of the disease is genetically determined. In this study, we screened for mutations in chromosome 1q-linked open-angle glaucoma (GLC1A) in a Chinese family with primary open-angle glaucoma (POAG). A total of 23 members from five generations of a family were enrolled and underwent thorough ophthalmologic examinations. In addition, 200 unrelated healthy Chinese controls were also recruited as normal control. GLC1A gene was amplified by polymerase chain reaction, and DNA sequencing was performed to screen for mutations. Six members were diagnosed as POAG, with severe clinical manifestations, and history of high intraocular pressures. The mean age of disease onset was 26.3 years. However, the others were asymptomatic. In six affected and three asymptomatic members, gene sequencing revealed a mutation c.C1456T in exon 3 of myocilin gene (MYOC). Furthermore, we also identified a novel mutation c.G322A in beta-1,4-galactosyltransferase 3 (B4GALT3) gene in all six affected and three asymptomatic members, which was not reported previously in POAG patients. The two newly identified variants were absent in other family members as well as controls. The mutations c.1456C < T (p.L486F) in MYOC and c.322G < A (p.V108I) in B4GALT3 are likely responsible for the pathogenesis of POAG in this family.

  2. [Clinical phenotype of a Japanese family with primary open-angle glaucoma caused by a Ala 363 Thr mutation in the MYOC gene].

    PubMed

    Ohyama, Akihiro; Fujimaki, Takuro; Kimura, Tairoh; Kawabata, Kiho; Fujiki, Keiko; Ishikawa, Karin; Mashima, Yukihiko; Murakami, Akira

    2006-01-01

    Myocilin is a gene that causes primary open-angle glaucoma (POAG). We report a family whose members had an Ala 363 Thr mutation in the myocilin gene. We present the clinical phenotype of this family. The proband was a 57-year-old man diagnosed with POAG. His younger sister (50 years old) was also diagnosed with POAG. Visual field impairment did not worsen and ocular pressure decreased with eyedrop treatment. Although two of their children in their 30s had ocular hypertension, they did not have any sign of glaucomatous optic neuropathy. Genetic analysis revealed that all four family members had an Ala 363 Thr mutation in myocilin gene. Ala 363 Thr mutation was considered to be the cause of open-angle glaucoma. In this family, age at onset was comparatively high The two patients in their 30s had high intraocular pressure but no loss in visual acuity. The family members who had POAG and those who did not have POAG were not different from each other in the results of standard ocular examinations, only in age. Patients with this mutation will develop high intraocular pressure after 30 years of age and glaucomatous neuropathy after 50 years of age. When this gene mutation is detected in juvenile patients, careful follow-up and early therapy are necessary.

  3. Map Showing Lava Inundation Zones for Mauna Loa, Hawaii

    USGS Publications Warehouse

    Trusdell, F.A.; Graves, P.; Tincher, C.R.

    2002-01-01

    Introduction The Island of Hawaii is composed of five coalesced basaltic volcanoes. Lava flows constitute the greatest volcanic hazard from these volcanoes. This report is concerned with lava flow hazards on Mauna Loa, the largest of the island shield volcanoes. Hilo lies 58 km from the summit of Mauna Loa, the Kona coast 33 km, and the southernmost point of the island 61 km. Hawaiian volcanoes erupt two morphologically distinct types of lava, aa and pahoehoe. The surfaces of pahoehoe flows are rather smooth and undulating. Pahoehoe flows are commonly fed by lava tubes, which are well insulated, lava-filled conduits contained within the flows. The surfaces of aa flows are extremely rough and composed of lava fragments. Aa flows usually form lava channels rather than lava tubes. In Hawaii, lava flows are known to reach distances of 50 km or more. The flows usually advance slowly enough that people can escape from their paths. Anything overwhelmed by a flow will be damaged or destroyed by burial, crushing, or ignition. Mauna Loa makes up 51 percent of the surface area of the Island of Hawaii. Geologic mapping shows that lava flows have covered more than 40 percent of the surface every 1,000 years. Since written descriptions of its activity began in A.D. 1832, Mauna Loa has erupted 33 times. Some eruptions begin with only brief seismic unrest, whereas others start several months to a year following increased seismic activity. Once underway, the eruptions can produce lava flows that reach the sea in less than 24 hours, severing roads and utilities. For example, the 1950 flows from the southwest rift zone reached the ocean in approximately three hours. The two longest flows of Mauna Loa are pahoehoe flows from the 50-kilometer-long 1859 and the 48-kilometer-long 1880-81 eruptions. Mauna Loa will undoubtedly erupt again. When it does, the first critical question that must be answered is: Which areas are threatened with inundation? Once the threatened areas are

  4. Loa loa vectors Chrysops spp.: perspectives on research, distribution, bionomics, and implications for elimination of lymphatic filariasis and onchocerciasis.

    PubMed

    Kelly-Hope, Louise; Paulo, Rossely; Thomas, Brent; Brito, Miguel; Unnasch, Thomas R; Molyneux, David

    2017-04-05

    Loiasis is a filarial disease caused Loa loa. The main vectors are Chrysops silacea and C. dimidiata which are confined to the tropical rainforests of Central and West Africa. Loiasis is a mild disease, but individuals with high microfilaria loads may suffer from severe adverse events if treated with ivermectin during mass drug administration campaigns for the elimination of lymphatic filariasis and onchocerciasis. This poses significant challenges for elimination programmes and alternative interventions are required in L. loa co-endemic areas. The control of Chrysops has not been considered as a viable cost-effective intervention; we reviewed the current knowledge of Chrysops vectors to assess the potential for control as well as identified areas for future research. We identified 89 primary published documents on the two main L. loa vectors C. silacea and C dimidiata. These were collated into a database summarising the publication, field and laboratory procedures, species distributions, ecology, habitats and methods of vector control. The majority of articles were from the 1950-1960s. Field studies conducted in Cameroon, Democratic Republic of Congo, Equatorial Guinea, Nigeria and Sudan highlighted that C. silacea is the most important and widespread vector. This species breeds in muddy streams or swampy areas of forests or plantations, descends from forest canopies to feed on humans during the day, is more readily adapted to human dwellings and attracted to wood fires. Main vector targeted measures proposed to impact on L. loa transmission included personal repellents, household screening, indoor residual spraying, community-based environmental management, adulticiding and larviciding. This is the first comprehensive review of the major L. loa vectors for several decades. It highlights key vector transmission characteristics that may be targeted for vector control providing insights into the potential for integrated vector management, with multiple diseases

  5. Phenology of Acacia koa on Mauna Loa, Hawaii

    Treesearch

    Ronald M. Lanner

    1965-01-01

    Flowering of koa was strongly seasonal on the Mauna Loa Strip. At 4,000 feet heavy flowering began in early December and lasted until early March. At 6,700 feet it extended from early March until mid-May. Heaviest flower losses occurred during anthesis, and were due to wind, rain, and possibly the dropping of unpollinated heads. Large insects were important as...

  6. Solar radiation: absence of air pollution trends at Mauna Loa.

    PubMed

    Ellis, H T; Pueschel, R F

    1971-05-21

    Measurements of solar radiation made at Mauna Loa, Hawaii, over a period of 13 years give no evidence that human activities affect atmospheric turbidity on a global scale. Short-term fluctuations in insolation appear to be associated with naturally produced tropospheric aerosols. The intrusion of volcanic dust into the stratosphere results in prolonged increases in atmospheric opacity due to the extended residence times of aerosols in the stratosphere.

  7. The novel Y371D myocilin mutation causes an aggressive form of juvenile open-angle glaucoma in a Caucasian family from the Middle-East.

    PubMed

    Avisar, Inbal; Lusky, Moshe; Robinson, Anat; Shohat, Mordechai; Dubois, Stéphane; Raymond, Vincent; Gaton, Dan D

    2009-09-24

    To search for the genetic cause of juvenile open-angle glaucoma (JOAG) in a Caucasian family and to perform genotype/phenotype correlation studies in the kindred. Six members of a three-generation family originating from Uzbekistan and now living in the Middle East were recruited from one large clinic in Israel. Ophthalmologic investigations comprised of visual field assessments, intraocular pressure measurements, optic disc evaluation, and gonioscopy. Medical charts were obtained to date the onset of glaucoma and to evaluate aggressivity of the trait. We screened the myocilin gene (MYOC, OMIM 601652) by direct genomic sequencing of its three exons in all family members. JOAG segregated as an autosomal dominant trait in four members of the family. The proband, a 14-year-old girl, had been diagnosed with juvenile open-angle glaucoma at 12 years old. Her mother, maternal aunt, and maternal grandfather all had JOAG that started at an early age. The disorder progressed rapidly even under optimal medical treatment, and all four patients had to undergo trabeculectomy. One missense mutation, Y371D (1111t-->g, Tyr [Y] 371 Asp [D]), was identified. This mutation cosegregated with the disorder in all affected members and was absent in 200 Caucasian controls. The Y371D MYOC mutation has not been reported before. One cousin of the proband was a silent heterozygotic carrier of the mutation and was still asymptomatic at nine years of age. We identified a novel mutation (Y371D) in MYOC from a Caucasian family who presented with an aggressive form of JOAG that required early trabeculectomy. Genetic screening of the MYOC mutation was beneficial in predicting one asymptomatic heterozygotic carrier.

  8. Molecular Epidemiology of Blood-Borne Human Parasites in a Loa loa-, Mansonella perstans-, and Plasmodium falciparum-Endemic Region of Cameroon.

    PubMed

    Drame, Papa M; Montavon, Céline; Pion, Sébastien D; Kubofcik, Joseph; Fay, Michael P; Nutman, Thomas B

    2016-06-01

    The study of the interactions among parasites within their hosts is crucial to the understanding of epidemiology of disease and for the design of effective control strategies. We have conducted an assessment of infections with Loa loa, Mansonella perstans, Wuchereria bancrofti, and Plasmodium falciparum in eastern Cameroon using a highly sensitive and specific quantitative polymerase chain reaction assay using archived dried whole blood spots. The resident population (N = 1,085) was parasitized with M. perstans (76%), L. loa (39%), and P. falciparum (33%), but not with W. bancrofti Compared with single infections (40.1%), coinfection was more common (48.8%): 21.0% had L. loa-M. perstans (Ll(+)/Mp(+)/Pf(-)), 2.7% had L. loa-P. falciparum (Ll(+)/Pf(+)/Mp(-)), 15.1% had M. perstans-P. falciparum (Mp(+)/Pf(+)/Ll(-)), and 10.0% had L. loa-M. perstans-P. falciparum (Ll(+)/Mp(+)/Pf(+)). Interestingly, those with all three infections (Ll(+)/Mp(+)/Pf(+)) had significantly higher L. loa microfilaria (mf) counts than either single Ll(+) (P = 0.004) or double Ll(+)/Mp(+) (P = 0.024) infected individuals. Of those infected with L. loa, the mean estimated counts of L. loa mf varied based on location and were positively correlated with estimated intensities of M. perstans mf. Finally, at a community level, heavy L. loa infections were concentrated in a few individuals whereby they were likely the major reservoir for infection. © The American Society of Tropical Medicine and Hygiene.

  9. Positivity of Antigen Tests Used for Diagnosis of Lymphatic Filariasis in Individuals Without Wuchereria bancrofti Infection But with High Loa loa Microfilaremia.

    PubMed

    Pion, Sébastien D; Montavon, Céline; Chesnais, Cédric B; Kamgno, Joseph; Wanji, Samuel; Klion, Amy D; Nutman, Thomas B; Boussinesq, Michel

    2016-12-07

    Since the mid-2000s, the immunochromatographic card test (ICT), a point-of-care test for detecting Wuchereria bancrofti circulating filarial antigens (CFAs), has been the backbone for mapping and monitoring lymphatic filariasis (LF) worldwide. Recently, there have been instances in which CFA positivity has been associated with Loa loa microfilaremia. Here, we examined the association, at both the community and individual levels, between L. loa and CFA using additional diagnostic tools (quantitative polymerase chain reaction [qPCR], Og4C3 enzyme-linked immunosorbent assay, and IgG4 antibodies to Wb123 assays) to demonstrate the relationship between L. loa microfilaremia and ICT positivity. In May 2013, peripheral blood was collected during the day from 1,812 individuals living in southern Cameroon. ICT tests were done on the spot, and positive individuals were resampled at night. Results of qPCR and Wb123 assays concurred proving the absence of W. bancrofti infection. Og4C3 assays indicate a quantitative relationship between the level of L. loa microfilaremia and that of CFA. This was confirmed by epidemiological analyses, which reveal a strong association between L. loa microfilaremia and ICT positivity, with 50% of ICT reacting to L. loa when its microfilarial density exceeds 30,000 microfilariae/mL. At the community level, the proportion of positive ICT would exceed 2% when the prevalence of L. loa microfilaremia in the total population is above 20%. This has significant implications in terms of mapping and control of LF caused by W. bancrofti in Loa-endemic areas. Cross-reactivity of ICT with L. loa has to be considered in the context of both individual and community diagnostics. © The American Society of Tropical Medicine and Hygiene.

  10. Positivity of Antigen Tests Used for Diagnosis of Lymphatic Filariasis in Individuals Without Wuchereria bancrofti Infection But with High Loa loa Microfilaremia

    PubMed Central

    Pion, Sébastien D.; Montavon, Céline; Chesnais, Cédric B.; Kamgno, Joseph; Wanji, Samuel; Klion, Amy D.; Nutman, Thomas B.; Boussinesq, Michel

    2016-01-01

    Since the mid-2000s, the immunochromatographic card test (ICT), a point-of-care test for detecting Wuchereria bancrofti circulating filarial antigens (CFAs), has been the backbone for mapping and monitoring lymphatic filariasis (LF) worldwide. Recently, there have been instances in which CFA positivity has been associated with Loa loa microfilaremia. Here, we examined the association, at both the community and individual levels, between L. loa and CFA using additional diagnostic tools (quantitative polymerase chain reaction [qPCR], Og4C3 enzyme-linked immunosorbent assay, and IgG4 antibodies to Wb123 assays) to demonstrate the relationship between L. loa microfilaremia and ICT positivity. In May 2013, peripheral blood was collected during the day from 1,812 individuals living in southern Cameroon. ICT tests were done on the spot, and positive individuals were resampled at night. Results of qPCR and Wb123 assays concurred proving the absence of W. bancrofti infection. Og4C3 assays indicate a quantitative relationship between the level of L. loa microfilaremia and that of CFA. This was confirmed by epidemiological analyses, which reveal a strong association between L. loa microfilaremia and ICT positivity, with 50% of ICT reacting to L. loa when its microfilarial density exceeds 30,000 microfilariae/mL. At the community level, the proportion of positive ICT would exceed 2% when the prevalence of L. loa microfilaremia in the total population is above 20%. This has significant implications in terms of mapping and control of LF caused by W. bancrofti in Loa-endemic areas. Cross-reactivity of ICT with L. loa has to be considered in the context of both individual and community diagnostics. PMID:27729568

  11. SBAS-InSAR analysis of a decade of surface deformation at Mauna Loa (Hawai'i): Preliminary results

    NASA Astrophysics Data System (ADS)

    La Marra, Daniele; Poland, Michael; Miklius, Asta; Acocella, Valerio

    2015-04-01

    The Big Island of Hawai`i consists five coalesced volcanoes: Hualālai, Mauna Loa, Kilauea, Mauna Kea, Kohala. Mauna Loa, the largest, has erupted 39 times since 1832, with the last eruption in 1984. The volcano summit hosts the Moku'aweoweo caldera from which two volcanic rift zones radiate: the Northeast Rift Zone (NERZ) and Southwest Rift Zone (SWRZ). These rifts are the reflection of past dike intrusions combined with instability of the SE flank of the volcano, possibly related to slip along a low angle decollement thrust fault 12-14 km beneath the volcano. Geodetic (InSAR, GPS) and seismic data have been used to characterize recent periods of unrest at Mauna Loa. InSAR studies spanning the period between 2002 and 2005 suggest a magma chamber 4.7-km depth below the summit, with a radius of 1.1 km, and a dike intrusion at 4 to 8-km depth and 8 km-long. These studies, however, are focused on relatively short-term processes (up to a few years), and a longer-term reconstruction of the volcano's evolution is lacking. In this work, we use SAR data, exploiting the SBAS technique, to study deformation of Mauna Loa from 2003 to 2014, and we try to relate this overall evolution to that the neighboring Kilauea. We use acquisitions from two satellites: ENVISAT (descending track 200 and ascending track 365), spanning from 2003 to the end of 2010, and COSMO-SkyMed (descending and ascending orbits), spanning from 2012 to the middle of 2014. These data are merged time series data from 24 continuously operating GPS stations, which allows us to calibrate the InSAR SBAS time series. Results show an overall good agreement between the InSAR and GPS time series. The displacement of each portion of the volcano between 2003-2014 has been thus constrained in detail. The summit area of Mauna Loa has under gone a long-term inflation from 2003 to 2014, with a peak of about 8 cm of vertical deformation between mid-2004 to mid-2005, especially on the summit. Part of this deformation may be

  12. Filarial Antigenemia and Loa loa Night Blood Microfilaremia in an Area Without Bancroftian Filariasis in the Democratic Republic of Congo

    PubMed Central

    Bakajika, Didier K.; Nigo, Maurice M.; Lotsima, Jean Pierre; Masikini, Germain A.; Fischer, Kerstin; Lloyd, Melanie M.; Weil, Gary J.; Fischer, Peter U.

    2014-01-01

    Implementation of mass drug administration for lymphatic filariasis (LF) has been delayed in central Africa because of incomplete mapping and coendemic loiasis. We mapped two regions in eastern Democratic Republic of Congo that were suspected to have LF. Night blood samples were collected from 2,724 subjects in 30 villages. Filarial antigenemia rates by card test exceeded 1% in 28 villages (range = 0–14%). Prevalence rates for large sheathed microfilariae (Mf) ranged from 4% to 40%; Mansonella perstans rates ranged from 22% to 98%. Large Mf were exclusively Loa loa by microscopy, and only 1 of 337 samples tested by quantitative polymerase chain reaction (qPCR) was positive for Wuchereria bancrofti DNA. Filarial antigen positivity was strongly associated with high L. loa Mf counts. Periodicity studies revealed atypical patterns, with no significant diurnal periodicity in some individuals. Thus, methods routinely used for LF mapping may not be reliable in areas in central Africa that are highly endemic for loiasis. PMID:25223938

  13. Filarial antigenemia and Loa loa night blood microfilaremia in an area without bancroftian filariasis in the Democratic Republic of Congo.

    PubMed

    Bakajika, Didier K; Nigo, Maurice M; Lotsima, Jean Pierre; Masikini, Germain A; Fischer, Kerstin; Lloyd, Melanie M; Weil, Gary J; Fischer, Peter U

    2014-12-01

    Implementation of mass drug administration for lymphatic filariasis (LF) has been delayed in central Africa because of incomplete mapping and coendemic loiasis. We mapped two regions in eastern Democratic Republic of Congo that were suspected to have LF. Night blood samples were collected from 2,724 subjects in 30 villages. Filarial antigenemia rates by card test exceeded 1% in 28 villages (range = 0-14%). Prevalence rates for large sheathed microfilariae (Mf) ranged from 4% to 40%; Mansonella perstans rates ranged from 22% to 98%. Large Mf were exclusively Loa loa by microscopy, and only 1 of 337 samples tested by quantitative polymerase chain reaction (qPCR) was positive for Wuchereria bancrofti DNA. Filarial antigen positivity was strongly associated with high L. loa Mf counts. Periodicity studies revealed atypical patterns, with no significant diurnal periodicity in some individuals. Thus, methods routinely used for LF mapping may not be reliable in areas in central Africa that are highly endemic for loiasis. © The American Society of Tropical Medicine and Hygiene.

  14. Serum immunoglobulin G4 antibodies to the recombinant antigen, Ll-SXP-1, are highly specific for Loa loa infection.

    PubMed

    Klion, Amy D; Vijaykumar, Aarthi; Oei, Tamara; Martin, Brian; Nutman, Thomas B

    2003-01-01

    The clinical manifestations and geographic distribution of loiasis overlap with those of other human filarial parasites, presenting challenges in the specific diagnosis of loiasis that may lead to delays in appropriate therapy. A recombinant antigen (Ll-SXP-1), preferentially recognized by serum samples from experimentally infected rhesus monkeys, was identified from a Loa loa L3 cDNA library. IgG4 antibody reactivity to purified Ll-SXP-1 was assessed by means of ELISA, using serum samples from patients with loiasis, lymphatic filariasis, onchocerciasis, mansonellosis, or other helminthiases and healthy control subjects. The assay was 56% sensitive and 98% specific for loiasis. Antibody reactivity was detectable before microfilaremia in experimentally infected rhesus monkeys and declined (but did not disappear) after diethylcarbamazine therapy in infected patients. IgG4 antibodies to recombinant Ll-SXP-1 are a highly specific marker of L. loa infection and may be useful for the diagnostic evaluation of persons with filariasis of unclear etiology.

  15. Identification of Mutations in Myocilin and Beta-1,4-galactosyltransferase 3 Genes in a Chinese Family with Primary Open-angle Glaucoma

    PubMed Central

    Liao, Rong-Feng; Zhong, Zi-Lin; Ye, Min-Jie; Han, Li-Yun; Ye, Dong-Qing; Chen, Jian-Jun

    2016-01-01

    Background: Glaucoma is a major cause of irreversible blindness worldwide. There is evidence showing that a subset of the disease is genetically determined. In this study, we screened for mutations in chromosome 1q-linked open-angle glaucoma (GLC1A) in a Chinese family with primary open-angle glaucoma (POAG). Methods: A total of 23 members from five generations of a family were enrolled and underwent thorough ophthalmologic examinations. In addition, 200 unrelated healthy Chinese controls were also recruited as normal control. GLC1A gene was amplified by polymerase chain reaction, and DNA sequencing was performed to screen for mutations. Results: Six members were diagnosed as POAG, with severe clinical manifestations, and history of high intraocular pressures. The mean age of disease onset was 26.3 years. However, the others were asymptomatic. In six affected and three asymptomatic members, gene sequencing revealed a mutation c.C1456T in exon 3 of myocilin gene (MYOC). Furthermore, we also identified a novel mutation c.G322A in beta-1,4-galactosyltransferase 3 (B4GALT3) gene in all six affected and three asymptomatic members, which was not reported previously in POAG patients. The two newly identified variants were absent in other family members as well as controls. Conclusion: The mutations c.1456C

  16. Molecular Epidemiology of Blood-Borne Human Parasites in a Loa loa-, Mansonella perstans-, and Plasmodium falciparum-Endemic Region of Cameroon

    PubMed Central

    Drame, Papa M.; Montavon, Céline; Pion, Sébastien D.; Kubofcik, Joseph; Fay, Michael P.; Nutman, Thomas B.

    2016-01-01

    The study of the interactions among parasites within their hosts is crucial to the understanding of epidemiology of disease and for the design of effective control strategies. We have conducted an assessment of infections with Loa loa, Mansonella perstans, Wuchereria bancrofti, and Plasmodium falciparum in eastern Cameroon using a highly sensitive and specific quantitative polymerase chain reaction assay using archived dried whole blood spots. The resident population (N = 1,085) was parasitized with M. perstans (76%), L. loa (39%), and P. falciparum (33%), but not with W. bancrofti. Compared with single infections (40.1%), coinfection was more common (48.8%): 21.0% had L. loa–M. perstans (Ll+/Mp+/Pf−), 2.7% had L. loa–P. falciparum (Ll+/Pf+/Mp−), 15.1% had M. perstans–P. falciparum (Mp+/Pf+/Ll−), and 10.0% had L. loa–M. perstans–P. falciparum (Ll+/Mp+/Pf+). Interestingly, those with all three infections (Ll+/Mp+/Pf+) had significantly higher L. loa microfilaria (mf) counts than either single Ll+ (P = 0.004) or double Ll+/Mp+ (P = 0.024) infected individuals. Of those infected with L. loa, the mean estimated counts of L. loa mf varied based on location and were positively correlated with estimated intensities of M. perstans mf. Finally, at a community level, heavy L. loa infections were concentrated in a few individuals whereby they were likely the major reservoir for infection. PMID:27044568

  17. Boundary Layer Observations at Mauna Loa Observatory, Hawaii

    NASA Astrophysics Data System (ADS)

    Barnes, John; Sharma, Nimmi

    2016-04-01

    The NOAA Mauna Loa Observatory is an atmospheric monitoring station on the North side of Mauna Loa Volcano (4169 m summit) located at an altitude of 3396 m. The bright sun, dark lava surface, and the seven percent grade of the mountain create a surface radiation wind that changes from upslope in the daytime to downslope after sunset. The radiation wind has a magnitude of 2.5-3.0 m/s. The off-island wind interacts with the mountain to create a barrier wind. The radiation wind dominates when the off-island winds are low and opposite is true when the off-island winds are strong. Temperature inversions form at sunset in the first 50 meters above the ground. Aerosol profiles, measured with a unique technique called CLidar or camera lidar, often increase and show a peak between 60 and 160 meters. The aerosol generally decreases to upper tropospheric values with a distinct change in the rate of decrease at 600 m above the ground. At night the region between the aerosol peak and 600 m is often flowing upslope, counter to the downslope surface flow. The source of the air in this counter flow region is not well understood, but appears to come from levels below the station altitude at least occasionally. This possibly would impact the interpretation of some of the air samples taken during this period.

  18. The 1950 sulfur flow of Mauna Loa: Considerations for Io

    NASA Technical Reports Server (NTRS)

    Greeley, R.; Theilig, E.; Christensen, P.

    1984-01-01

    Some of the geological relationships observed in the Mauna Loa sulfur flow may apply in considering volcanic processes on Io. Given the presence of sulfur/sulfur compounds in the eruption plumes and on the surface of Io, it is likely that extensive secondary deposits of sulfur exist, some of which may be of fumarolic origin and analogous to the Mauna Loa deposit. Given the likelihood of silicate volcanism of Io based on the inferred material properties of some flows, and the attendant high temperatures for silicate volcanism, it is likely that the secondary surface deposits of sulfur would have been mobilized without being heated to the high viscosity stage. Mobilized sulfur flows on Io may flow long distances as a result of: (1) low viscosities in the melting range; (2) sustained effusion resulting from continued heating source area; (3) continued remobilization within the flow as a consequence of surges from the source; and (4) extension via lava tubes, or similar conduits through which there is little heat loss. Sulfur flows may form a relatively thin veneer over silicate flows and other surface units, given their fluidity and low mobilization temperature. Active splashing and splattering may spread sulfur over a wider area contributing the bright blooms observed in association with some Ionian flows.

  19. Species-specific sequence in the repeat 3 region of the gene encoding a putative Loa loa allergen: a diagnostic tool for occult loiasis.

    PubMed

    Toure, F S; Egwang, T G; Wahl, G; Millet, P; Bain, O; Georges, A J

    1997-01-01

    A polymerase chain reaction (PCR)-based method to detect Loa loa DNA in the blood lysate of infected individuals is described. A set of primers was designed to amplify the repeat 3 sequence (15r3) of the gene encoding a putative L. loa allergen. The qualitative PCR was carried out using blood lysates from subjects from an L. loaendemic area of Gabon where loiasis exists sympatrically with Mansonella perstans, and from individuals from a loiasis-free area in Togo infected concomitantly with M. perstans and Onchocerca volvulus. No specific amplification was observed after ethidium bromide staining of a gel containing M. perstans and O. volvulus control samples. In contrast, a 396-basepair (bp) DNA was detected in all L. loa microfilaremic individuals and in seven of the 20 L. loa amicrofilaremic subjects diagnosed by leukoconcentration. Qualitative Southern blots carried out at high stringency (65 degrees C) using 15r3 oligonucleotide probe revealed hybridization only with L. loa samples (5 of 5 microfilaremic individuals and 15 of 20 amicrofilaremic individuals), confirming the results obtained with ethidium bromide staining of PCR products. We conclude that this 396-bp sequence could be used as a species-specific diagnostic tool for occult loiasis in an endemic area with concurrent filarial infections.

  20. Snow on Mauna Kea and Mauna Loa, Hawaii

    NASA Technical Reports Server (NTRS)

    2002-01-01

    With summits of 13,792 ft (4,205 m) and 13,674 ft (4,169 m), it's not unusual for the Mauna Kea (north) and Mauna Loa (south) volcanoes on Hawaii's Big Island to get wintertime snowfall. In this true-color MODIS image from February 28, 2002, a late winter snow has settled on the volcanoes' flanks, creating large white circles in the north and central portions of the island. The white patchy areas along the west coast are clouds, and not snow, which is more evident in the false color image, in which ice crystals on the ground appear solid red and clouds appear peach. Don't be fooled by the red outlines on the eastern coast. They aren't snow, but rather are used to mark locations where MODIS detected the thermal signature of the volcanoes in Hawaii Volcanoes National Park. The dark streaks and patches reveal the location of lava flows.

  1. Bathymetry of the southwest flank of Mauna Loa Volcano, Hawaii

    USGS Publications Warehouse

    Chadwick, William W.; Moore, James G.; Fox, Christopher G.

    1994-01-01

    Much of the seafloor topography in the map area is on the southwest submarine flank of the currently active Mauna Loa Volcano. The benches and blocky hills shown on the map were shaped by giant landslides that resulted from instability of the rapidly growing volcano. These landslides were imagined during a 1986 to 1991 swath sonar program of the United States Hawaiian Exclusive Economic Zone, a cooperative venture by the U.S. Geological Survey and the British Institute of Oceanographic Sciences (Lipman and others, 1988; Moore and others, 1989). Dana Seamount (and probably also the neighboring Day Seamount) are apparently Cretaceous in age, based on paleomagnetic studies, and predate the growth of the Hawaiian Ridge volcanoes (Sager and Pringle, 1990).

  2. Identification of a novel MYOC mutation, p.(Trp373), in a family with open angle glaucoma.

    PubMed

    Crawford, April; Souzeau, Emmanuelle; Agar, Ashish; Ridge, Bronwyn; Dubowsky, Andrew; Burdon, Kathryn P; Craig, Jamie E

    2014-07-25

    MYOC gene variants are associated with autosomal dominant primary open angle glaucoma (POAG). In this study, we describe a previously unreported MYOC variant segregating with a POAG phenotype in an Australian family. Two individuals affected with POAG and three unaffected individuals from the same family were recruited through the Australian and New Zealand Registry of Advanced Glaucoma (ANZRAG). Direct sequencing of all MYOC coding exons identified the novel heterozygous single nucleotide transition MYOC:c.1119G>A, p.(Trp373), predicted to encode an aberrant truncated MYOC protein in two affected siblings. Two unaffected siblings and an unaffected niece were negative for the MYOC sequence variant.

  3. Analysis of the atmospheric aerosol size distribution information retrievable from near-limb angular radiance measurements taken on Mauna Loa, Hawaii

    SciTech Connect

    Grant, K.E.

    1981-12-01

    Angular radiance measurements of the near-limb solar aureole were analyzed for information regarding the light-scattering aerosol particles in the atmospheric column above Mauna Loa, Hawaii. The Mauna Loa Observatory, located at 19/sup 0/ 33' N latitude, 155/sup 0/ 35' W longitude, and 3460 metres elevation, is in unpolluted air above the easterly trade wind inversion and has been designated as a site for the Geophysical Monitoring for Climatic Change (GMCC) program. Circumsolar radiance and polarization measurements have been collected on Mauna Loa since 1963 by the High Altitude Observatory (HAO), National Center for Atmospheric Research (NCAR) as part of a program for the daily observation of the solar corona. Strip charts containing radiance measurements made from January 1976 through June 1978 were made available for this study. By the use of Mie scattering theory, generalized to treat the sun as a finite diameter light source with limb-darkening, a theoretical scattering matrix was calculated for observation angles between 17' and 300' measured from the center of the solar disk, and aerosol size parameters (2..pi..r/lambda) between 10 and 300. An information content criterion is presented, based on the expected relative norm of the measurement errors and on the eigenvalues of the radiance covariance matrix of the scattering matrix. The observed aureole radiance gradients and two test gradients were inverted to obtain aerosol size distributions using a constrained linear inversion algorithm.

  4. Coastal lava flows from Mauna Loa and Hualalai volcanoes, Kona, Hawaii

    USGS Publications Warehouse

    Moore, J.G.; Clague, D.

    1987-01-01

    A major carbonate reef which drowned 13 ka is now submerged 150 m below sea level on the west coast of the island of Hawaii. A 25-km span of this reef was investigated using the submersible Makali'i. The reef occurs on the flanks of two active volcanoes, Mauna Loa and Hualalai, and the lavas from both volcanoes both underlie and overlie the submerged reef. Most of the basaltic lava flows that crossed the reef did so when the water was much shallower, and when they had to flow a shorter distance from shoreline to reef face. Lava flows on top of the reef have protected it from erosion and solution and now occur at seaward-projecting salients on the reef face. These relations suggest that the reef has retreated shoreward as much as 50 m since it formed. A 7-km-wide "shadow zone" occurs where no Hualalai lava flows cross the reef south of Kailua. These lava flows were probably diverted around a large summit cone complex. A similar "shadow zone" on the flank of Mauna Loa volcano in the Kealakekua Bay region is downslope from the present Mauna Loa caldera, which ponds Mauna Loa lava and prevents it from reaching the coastline. South of the Mauna Loa "shadow zone" the - 150 m reef has been totally covered and obscured by Mauna Loa lava. The boundary between Hualalai and Mauna Loa lava on land occurs over a 6-km-wide zone, whereas flows crossing the - 150 m reef show a sharper boundary offshore from the north side of the subaerial transition zone. This indicates that since the formation of the reef, Hualalai lava has migrated south, mantling Mauna Loa lava. More recently, Mauna Loa lava is again encroaching north on Hualalai lava. ?? 1987 Springer-Verlag.

  5. Dueling Volcanoes: How Activity Levels At Kilauea Influence Eruptions At Mauna Loa

    NASA Astrophysics Data System (ADS)

    Trusdell, F.

    2011-12-01

    The eruption of Kilauea at Pu`u `O`o is approaching its 29th anniversary. During this time, Mauna Loa has slowly inflated following its most recent eruption in 1984. This is Mauna Loa's longest inter-eruptive interval observed in HVO's 100 years of operation. When will the next eruption of Mauna Loa take place? Is the next eruption of Mauna Loa tied to the current activity at Kilauea? Historically, eruptive periods at Kilauea and Mauna Loa volcanoes appear to be inversely correlated. In the past, when Mauna Loa was exceptionally active, Kilauea Volcano was in repose, recovery, or in sustained lava lake activity. Swanson and co-workers (this meeting) have noted that explosive activity on Kilauea, albeit sporadic, was interspersed between episodes of effusive activity. Specifically, Swanson and co-workers note as explosive the time periods between 300 B.C.E.-1000 C.E and 1500-1800 C.E. They also point to evidence for low magma supply to Kilauea during these periods and few flank eruptions. During the former explosive period, Mauna Loa was exceedingly active, covering approximately 37% of its surface or 1882 km2, an area larger than Kilauea. This period is also marked by summit activity at Mauna Loa sustained for 300 years. In the 1500-1800 C.E. period, Mauna Loa was conspicuously active with 29 eruptions covering an area of 446 km2. In the late 19th and early 20th century, Kilauea was dominated by nearly continuous lava-lake activity. Meanwhile Mauna Loa was frequently active from 1843 C.E. to 1919 C.E., with 24 eruptions for an average repose time of 3.5 years. I propose that eruptive activity at one volcano may affect eruptions at the other, due to factors that impact magma supply, volcanic plumbing, and flank motion. This hypothesis is predicated on the notion that when the rift zones of Kilauea, and in turn its mobile south flank, are active, Mauna Loa's tendency to erupt is diminished. Kilauea's rift zones help drive the south flank seaward, in turn, as Mauna

  6. Seismic detection of a low-velocity layer beneath the southeast flank of Mauna Loa, Hawaii

    SciTech Connect

    Thurber, C.H.; Li, Yingping ); Johnson, C.

    1989-07-01

    The authors have identified seismic phases reflected off the top and bottom of a low velocity layer (LVL) by analysis of seismograms from six small earthquakes in Hawaii. These events occurred almost directly beneath station AIN of the Hawaiian Volcano Observatory (HVO) seismic network, located within the Kaoiki seismic zone on the southeast flank of Mauna Loa. The polarity reversals of the first reflected phases provide clear evidence for the existence of a LVL beneath this station. The LVL is estimated to be at a depth of about 11.5 km, with a thickness of about 800 m. The estimated depth to the top of the LVL is consistent with the depth distribution of low-angle thrust faulting events from the aftershock sequence of the 1983 Kaoiki earthquake. Presumably, this zone is the marine sediment layer buried beneath the volcanic pile, along which the volcanic edifice may slip easily to cause large earthquakes. Mapping the interface between the volcanic pile and oceanic crust and thus determining the depth and thickness of the buried sediment layer is essential for understanding the tectonics of large earthquakes in Hawaii.

  7. Lava inundation zone maps for Mauna Loa, Island of Hawaiʻi, Hawaii

    USGS Publications Warehouse

    Trusdell, Frank A.; Zoeller, Michael H.

    2017-10-12

    Lava flows from Mauna Loa volcano, on the Island of Hawaiʻi, constitute a significant hazard to people and property. This report addresses those lava flow hazards, mapping 18 potential lava inundation zones on the island.

  8. A Step Toward Eradication of Human Filariases in Areas Where Loa Is Endemic

    PubMed Central

    2016-01-01

    ABSTRACT Mass drug administration (MDA) programs have achieved remarkable success in limiting the pathology and transmission of the human parasitic infections onchocerciasis and lymphatic filariasis. The full implementation of MDA campaigns for filariasis elimination has been stymied by the unacceptable incidence of severe adverse events observed following drug treatment of a subset of individuals who harbor high loads of Loa loa microfilaria. Extending MDA strategies to regions where loiasis is coendemic could be done confidently if a simple, inexpensive, and rapid diagnostic method was available that could accurately identify individuals who have L. loa microfilarial loads above the risk threshold and could thus be excluded from treatment. A recent paper in mBio reports the discovery of an antigen unique to L. loa microfilaria that can be detected in blood and urine and may form the basis for such an assay. Further work will reveal whether this discovery will smooth the path to achieve filariasis eradication. PMID:27073095

  9. Using Community-Level Prevalence of Loa loa Infection to Predict the Proportion of Highly-Infected Individuals: Statistical Modelling to Support Lymphatic Filariasis and Onchocerciasis Elimination Programs.

    PubMed

    Schlüter, Daniela K; Ndeffo-Mbah, Martial L; Takougang, Innocent; Ukety, Tony; Wanji, Samuel; Galvani, Alison P; Diggle, Peter J

    2016-12-01

    Lymphatic Filariasis and Onchocerciasis (river blindness) constitute pressing public health issues in tropical regions. Global elimination programs, involving mass drug administration (MDA), have been launched by the World Health Organisation. Although the drugs used are generally well tolerated, individuals who are highly co-infected with Loa loa are at risk of experiencing serious adverse events. Highly infected individuals are more likely to be found in communities with high prevalence. An understanding of the relationship between individual infection and population-level prevalence can therefore inform decisions on whether MDA can be safely administered in an endemic community. Based on Loa loa infection intensity data from individuals in Cameroon, the Republic of the Congo and the Democratic Republic of the Congo we develop a statistical model for the distribution of infection levels in communities. We then use this model to make predictive inferences regarding the proportion of individuals whose parasite count exceeds policy-relevant levels. In particular we show how to exploit the positive correlation between community-level prevalence and intensity of infection in order to predict the proportion of highly infected individuals in a community given only prevalence data from the community in question. The resulting prediction intervals are not substantially wider, and in some cases narrower, than the corresponding binomial confidence intervals obtained from data that include measurements of individual infection levels. Therefore the model developed here facilitates the estimation of the proportion of individuals highly infected with Loa loa using only estimated community level prevalence. It can be used to assess the risk of rolling out MDA in a specific community, or to guide policy decisions.

  10. Using Community-Level Prevalence of Loa loa Infection to Predict the Proportion of Highly-Infected Individuals: Statistical Modelling to Support Lymphatic Filariasis and Onchocerciasis Elimination Programs

    PubMed Central

    Ndeffo-Mbah, Martial L; Takougang, Innocent; Ukety, Tony; Wanji, Samuel; Galvani, Alison P; Diggle, Peter J

    2016-01-01

    Lymphatic Filariasis and Onchocerciasis (river blindness) constitute pressing public health issues in tropical regions. Global elimination programs, involving mass drug administration (MDA), have been launched by the World Health Organisation. Although the drugs used are generally well tolerated, individuals who are highly co-infected with Loa loa are at risk of experiencing serious adverse events. Highly infected individuals are more likely to be found in communities with high prevalence. An understanding of the relationship between individual infection and population-level prevalence can therefore inform decisions on whether MDA can be safely administered in an endemic community. Based on Loa loa infection intensity data from individuals in Cameroon, the Republic of the Congo and the Democratic Republic of the Congo we develop a statistical model for the distribution of infection levels in communities. We then use this model to make predictive inferences regarding the proportion of individuals whose parasite count exceeds policy-relevant levels. In particular we show how to exploit the positive correlation between community-level prevalence and intensity of infection in order to predict the proportion of highly infected individuals in a community given only prevalence data from the community in question. The resulting prediction intervals are not substantially wider, and in some cases narrower, than the corresponding binomial confidence intervals obtained from data that include measurements of individual infection levels. Therefore the model developed here facilitates the estimation of the proportion of individuals highly infected with Loa loa using only estimated community level prevalence. It can be used to assess the risk of rolling out MDA in a specific community, or to guide policy decisions. PMID:27906982

  11. Report of a Scientific Working Group on Serious Adverse Events following Mectizan® treatment of onchocerciasis in Loa loa endemic areas

    PubMed Central

    2003-01-01

    The occurrence of Serious Adverse Experiences (SAEs) following Mectizan® treatment of onchocerciasis in Loa loa endemic areas has been increasingly reported over the past decade. These SAEs include a severely disabling, and potentially fatal, encephalopathy, which appears to correlate with a high load of L. loa microfilariae (> 30,000 mf/ml). Previous consultations organized by the Mectizan® Donation Program (MDP) in 1995 and 1999 have developed useful "case" definitions of encephalopathic SAEs following Mectizan® treatment and have summarized available evidence on its pathogenesis and optimal clinical management. At both meetings, the need for better understanding of the pathogenesis of the encephalopathy was emphasized, including the need for biological and autopsy specimens from the affected cases. Following a recommendation at the Joint Action Forum of the African Programme for Onchocerciasis Control in December 2001, the MDP, on behalf of the Mectizan® Expert Committee, organized a Scientific Working Group on L. loa associated SAEs following Mectizan® treatment in May 2002. The present report includes the background, new evidence, conclusions and recommendations from that Scientific Working Group. The following points represent a summary of the present status: 1. Although there are more and better quality clinical and epidemiological data on L. loa, the pathogenesis of the Mectizan®-related L. loa encephalopathy remains obscure. 2. Very limited progress has been made in research on the pathogenesis of encephalopathy, because of the lack of specimens from cases, and the lack of animal models. 3. There has been no particular breakthrough in terms of the medical management of patients with L. loa encephalopathy; however, a favorable outcome usually results from prompt general nursing and nutritional care which remain the major interventions. The main recommendations for future actions are as follows: 1. Validate and update the mapping of L. loa with a

  12. Report of a Scientific Working Group on Serious Adverse Events following Mectizan(R) treatment of onchocerciasis in Loa loa endemic areas.

    PubMed

    2003-10-24

    The occurrence of Serious Adverse Experiences (SAEs) following Mectizan(R) treatment of onchocerciasis in Loa loa endemic areas has been increasingly reported over the past decade. These SAEs include a severely disabling, and potentially fatal, encephalopathy, which appears to correlate with a high load of L. loa microfilariae (> 30,000 mf/ml).Previous consultations organized by the Mectizan(R) Donation Program (MDP) in 1995 and 1999 have developed useful "case" definitions of encephalopathic SAEs following Mectizan(R) treatment and have summarized available evidence on its pathogenesis and optimal clinical management. At both meetings, the need for better understanding of the pathogenesis of the encephalopathy was emphasized, including the need for biological and autopsy specimens from the affected cases.Following a recommendation at the Joint Action Forum of the African Programme for Onchocerciasis Control in December 2001, the MDP, on behalf of the Mectizan(R) Expert Committee, organized a Scientific Working Group on L. loa associated SAEs following Mectizan(R) treatment in May 2002. The present report includes the background, new evidence, conclusions and recommendations from that Scientific Working Group. The following points represent a summary of the present status:1. Although there are more and better quality clinical and epidemiological data on L. loa, the pathogenesis of the Mectizan(R)-related L. loa encephalopathy remains obscure.2. Very limited progress has been made in research on the pathogenesis of encephalopathy, because of the lack of specimens from cases, and the lack of animal models.3. There has been no particular breakthrough in terms of the medical management of patients with L. loa encephalopathy; however, a favorable outcome usually results from prompt general nursing and nutritional care which remain the major interventions.The main recommendations for future actions are as follows:1. Validate and update the mapping of L. loa with a

  13. What’s New at the Mauna Loa Solar Observatory

    NASA Astrophysics Data System (ADS)

    Burkepile, Joan; de Toma, Giuliana; Galloy, Michael; Kolinski, Don; Berkey, Ben; Stueben, Allen; Tomczyk, Steven; De Wijn, Alfred; Casini, Roberto; Card, Greg; Larson, Brandon; Stanger, Andrew; Oakley, Phil; Gallagher, Dennis; Waters, Lisa; Rose, Greg; Sewell, Scott

    2016-05-01

    The Mauna Loa Solar Observatory (MLSO) is located at 3440 meters on the island of Hawaii. The site provides the dark, clear skies required for observing the solar corona. The National Center for Atmosphere Research (NCAR) High Altitude Observatory (HAO) operates two coronagraphs at the site: the Coronal Multi-Channel Polarimeter (CoMP) and the COSMO K-Coronagraph (K-Cor). CoMP is designed to study coronal magnetic fields by observing full Stokes polarimetry of two forbidden emission lines of FeXIII at 1074.7 and 1079.8 nm. CoMP also observes active and erupting prominences over the solar limb in neutral Helium emission at 1083.nm. The K-Cor is designed to study the onset and early evolution of coronal mass ejections (CMEs). It is the only white light coronagraph to routinely view the low corona down to 1.05 solar radii in order to capture the formation of CMEs. Information is provided on new Helium data products of active and erupting prominences observed by the CoMP instrument as well as results from the K-Cor observations of CMEs. Information on current and upcoming upgrades to the MLSO facility, instrument hardware, and calibrations are reported along with an accounting of new data products, tools and services from the MLSO website.

  14. Neuromuscular junction defects in mice with mutation of dynein heavy chain 1.

    PubMed

    Courchesne, Stephanie L; Pazyra-Murphy, Maria F; Lee, Daniel J; Segal, Rosalind A

    2011-02-04

    Disruptions in axonal transport have been implicated in a wide range of neurodegenerative diseases. Cramping 1 (Cra1/+) and Legs at odd angles (Loa/+) mice, with hypomorphic mutations in the dynein heavy chain 1 gene, which encodes the ATPase of the retrograde motor protein dynein, were originally reported to exhibit late onset motor neuron disease. Subsequent, conflicting reports suggested that sensory neuron disease without motor neuron loss underlies the phenotypes of Cra1/+ and Loa/+ mice. Here, we present behavioral and anatomical analyses of Cra1/+ mice. We demonstrate that Cra1/+ mice exhibit early onset, stable behavioral deficits, including abnormal hindlimb posturing and decreased grip strength. These deficits do not progress through 24 months of age. No significant loss of primary motor neurons or dorsal root ganglia sensory neurons was observed at ages where the mice exhibited clear symptomatology. Instead, there is a decrease in complexity of neuromuscular junctions. These results indicate that disruption of dynein function in Cra1/+ mice results in abnormal morphology of neuromuscular junctions. The time course of behavioral deficits, as well as the nature of the morphological defects in neuromuscular junctions, suggests that disruption of dynein function in Cra1/+ mice causes a developmental defect in synapse assembly or stabilization.

  15. Neuromuscular Junction Defects in Mice with Mutation of dynein heavy chain 1

    PubMed Central

    Lee, Daniel J.; Segal, Rosalind A.

    2011-01-01

    Disruptions in axonal transport have been implicated in a wide range of neurodegenerative diseases. Cramping 1 (Cra1/+) and Legs at odd angles (Loa/+) mice, with hypomorphic mutations in the dynein heavy chain 1 gene, which encodes the ATPase of the retrograde motor protein dynein, were originally reported to exhibit late onset motor neuron disease. Subsequent, conflicting reports suggested that sensory neuron disease without motor neuron loss underlies the phenotypes of Cra1/+ and Loa/+ mice. Here, we present behavioral and anatomical analyses of Cra1/+ mice. We demonstrate that Cra1/+ mice exhibit early onset, stable behavioral deficits, including abnormal hindlimb posturing and decreased grip strength. These deficits do not progress through 24 months of age. No significant loss of primary motor neurons or dorsal root ganglia sensory neurons was observed at ages where the mice exhibited clear symptomatology. Instead, there is a decrease in complexity of neuromuscular junctions. These results indicate that disruption of dynein function in Cra1/+ mice results in abnormal morphology of neuromuscular junctions. The time course of behavioral deficits, as well as the nature of the morphological defects in neuromuscular junctions, suggests that disruption of dynein function in Cra1/+ mice causes a developmental defect in synapse assembly or stabilization. PMID:21346813

  16. Reproducibility study of fetal 3-D volumetry in the first trimester: effect of fetal size and rotational angle of VOCAL software.

    PubMed

    Papastefanou, Ioannis; Kappou, Dimitra; Souka, Athena P; Pilalis, Athanasios; Chrelias, Charalambos; Siristatidis, Charalambos; Kassanos, Dimitrios

    2014-05-01

    Intra- and inter-observer reproducibility of fetal volume measurement by 3-D ultrasound scan (using VOCAL [Virtual Organ Computer-Aided Analysis] software) in 27 fetuses at 7 to 13 wk was studied. For intra-observer variability, the mean difference (MD) and 95% limits of agreement (95% LOA) at 12°, 18° and 30° were MD(12) = 0.097, 95% LOA(12) = -0.87 to +1.06; MD(18) = 0.07, 95% LOA(18) = -1.31 to +1.45; and MD(30) = -0.07, 95% LOA(30) = -1.55 to +1.41. The standard deviation of the differences (SD(DIF)) increased with crown-rump length at 12° (p = 0.0016), 18° (p = 0.0011) and 30° (p = 0.02). For inter-observer variability, MD(12) = 0.15, 95% LOA(12) = -1.65 to +1.95; MD(18) = 0.042, 95% LOA(18) = -1.79 to +1.87; and MD(30) = 0.19, 95% LOA(30) = -1.24 to +1.62. SDDIF increased with crown-rump length at 18° (p = 0.0084) and 30° (p = 0.0073). The accuracy of fetal volume measurement was not influenced by rotational angle or fetal size. Precision deteriorated for wider rotational angles and larger fetuses.

  17. Failed attempts at experimental transplantation and transmission of nocturnally-periodic simian Loa from monkey to man

    PubMed Central

    Duke, BOL

    2004-01-01

    This paper describes unsuccessful attempts to induce a nocturnally-periodic infection with simian Loa in a human volunteer (the author of this paper) by means of 1. Transplanting adult simian Loa worms from a wild drill (Mandrillus leucophaeus) to man; and 2. Infecting the same volunteer by sub-cutaneous inoculation with infective larvae of simian Loa from a laboratory-bred, experimentally infected Chrysops silacea. PMID:15283865

  18. The changing carbon cycle at Mauna Loa Observatory.

    PubMed

    Buermann, Wolfgang; Lintner, Benjamin R; Koven, Charles D; Angert, Alon; Pinzon, Jorge E; Tucker, Compton J; Fung, Inez Y

    2007-03-13

    The amplitude of the CO(2) seasonal cycle at the Mauna Loa Observatory (MLO) increased from the early 1970s to the early 1990s but decreased thereafter despite continued warming over northern continents. Because of its location relative to the large-scale atmospheric circulation, the MLO receives mainly Eurasian air masses in the northern hemisphere (NH) winter but relatively more North American air masses in NH summer. Consistent with this seasonal footprint, our findings indicate that the MLO amplitude registers North American net carbon uptake during the warm season and Eurasian net carbon release as well as anomalies in atmospheric circulation during the cold season. From the early 1970s to the early 1990s, our analysis was consistent with that of Keeling et al. [Keeling CD, Chin JFS, Whorf TP (1996) Nature 382:146-149], suggesting that the increase in the MLO CO(2) amplitude is dominated by enhanced photosynthetic drawdown in North America and enhanced respiration in Eurasia. In contrast, the recent decline in the CO(2) amplitude is attributed to reductions in carbon sequestration over North America associated with severe droughts from 1998 to 2003 and changes in atmospheric circulation leading to decreased influence of Eurasian air masses. With the return of rains to the U.S. in 2004, both the normalized difference vegetation index and the MLO amplitude sharply increased, suggesting a return of the North American carbon sink to more normal levels. These findings indicate that atmospheric CO(2) measurements at remote sites can continue to play an important role in documenting changes in land carbon flux, including those related to widespread drought, which may continue to worsen as a result of global warming.

  19. The changing carbon cycle at Mauna Loa Observatory

    PubMed Central

    Buermann, Wolfgang; Lintner, Benjamin R.; Koven, Charles D.; Angert, Alon; Pinzon, Jorge E.; Tucker, Compton J.; Fung, Inez Y.

    2007-01-01

    The amplitude of the CO2 seasonal cycle at the Mauna Loa Observatory (MLO) increased from the early 1970s to the early 1990s but decreased thereafter despite continued warming over northern continents. Because of its location relative to the large-scale atmospheric circulation, the MLO receives mainly Eurasian air masses in the northern hemisphere (NH) winter but relatively more North American air masses in NH summer. Consistent with this seasonal footprint, our findings indicate that the MLO amplitude registers North American net carbon uptake during the warm season and Eurasian net carbon release as well as anomalies in atmospheric circulation during the cold season. From the early 1970s to the early 1990s, our analysis was consistent with that of Keeling et al. [Keeling CD, Chin JFS, Whorf TP (1996) Nature 382:146–149], suggesting that the increase in the MLO CO2 amplitude is dominated by enhanced photosynthetic drawdown in North America and enhanced respiration in Eurasia. In contrast, the recent decline in the CO2 amplitude is attributed to reductions in carbon sequestration over North America associated with severe droughts from 1998 to 2003 and changes in atmospheric circulation leading to decreased influence of Eurasian air masses. With the return of rains to the U.S. in 2004, both the normalized difference vegetation index and the MLO amplitude sharply increased, suggesting a return of the North American carbon sink to more normal levels. These findings indicate that atmospheric CO2 measurements at remote sites can continue to play an important role in documenting changes in land carbon flux, including those related to widespread drought, which may continue to worsen as a result of global warming. PMID:17360510

  20. Crystallization history of the 1984 Mauna Loa lava flow

    NASA Technical Reports Server (NTRS)

    Crisp, Joe; Cashman, Katharine V.; Bonini, Jennifer A.; Hougen, Sarah B.; Pieri, David C.

    1994-01-01

    During a 3-week eruption in 1984, Mauna Loa produced vent lavas that increased in crystallinity from less than 1 to 30%, and 27-km-long flows that increased in crystallinity as they moved downstream. We examined the crystallization history of these lavas using crystal size distribution (CSD) analysis to study the rates of crystallization, viscosity increase, and latent heating. Typical average growth and nucleation rates were 5 x 10(exp -9) cm/s and 5/cu cm/s for microphenocrysts (20- to 500-micron size crystals nucleated in the rift zone) and 5 x 10(exp -8) cm/s and 5 x 10(exp 4)/cu cm/s for microlites (1- to 20-micron size crystals nucleated in the channel). These crystallization rates are high compared with those found in other CSD studies of igneous rocks, probably due to highly nonequilibrium conditions brought on by rapid degassing in the rift zone and cooling in the lava channel. Growth and nucleation rates decreased with time at the vent and with distance downstream. The maximum downstream total crystallinity measured is 39% (25% microlites, 14% microphenocrysts) in a quenched sample 14 km from the vent. Growth and nucleation rates cannot be calculated for postemplacement samples, but they place upper limits of 53-58% on the amount of crystallization in the channel 9-20 km from the vent. Crystallization could have been mostly responsible for the 10(exp 5)-fold downstream increase in apparent viscosity, although degassing and increasing incorporation of solid lava fragments also contributed. Another effect of crystallization on the lava flow was the sizeable latent heating (0.01 J/g/s over the first half of the flow length, if the crystallinity of downstream quench samples is representative of the hot fluid core), which may have been counteracted by entrainment of cooler material. Measurements of crystallization are shown to be crucial in the study of lava flow emplacement dynamics.

  1. Crystallization history of the 1984 Mauna Loa lava flow

    NASA Technical Reports Server (NTRS)

    Crisp, Joe; Cashman, Katharine V.; Bonini, Jennifer A.; Hougen, Sarah B.; Pieri, David C.

    1994-01-01

    During a 3-week eruption in 1984, Mauna Loa produced vent lavas that increased in crystallinity from less than 1 to 30%, and 27-km-long flows that increased in crystallinity as they moved downstream. We examined the crystallization history of these lavas using crystal size distribution (CSD) analysis to study the rates of crystallization, viscosity increase, and latent heating. Typical average growth and nucleation rates were 5 x 10(exp -9) cm/s and 5/cu cm/s for microphenocrysts (20- to 500-micron size crystals nucleated in the rift zone) and 5 x 10(exp -8) cm/s and 5 x 10(exp 4)/cu cm/s for microlites (1- to 20-micron size crystals nucleated in the channel). These crystallization rates are high compared with those found in other CSD studies of igneous rocks, probably due to highly nonequilibrium conditions brought on by rapid degassing in the rift zone and cooling in the lava channel. Growth and nucleation rates decreased with time at the vent and with distance downstream. The maximum downstream total crystallinity measured is 39% (25% microlites, 14% microphenocrysts) in a quenched sample 14 km from the vent. Growth and nucleation rates cannot be calculated for postemplacement samples, but they place upper limits of 53-58% on the amount of crystallization in the channel 9-20 km from the vent. Crystallization could have been mostly responsible for the 10(exp 5)-fold downstream increase in apparent viscosity, although degassing and increasing incorporation of solid lava fragments also contributed. Another effect of crystallization on the lava flow was the sizeable latent heating (0.01 J/g/s over the first half of the flow length, if the crystallinity of downstream quench samples is representative of the hot fluid core), which may have been counteracted by entrainment of cooler material. Measurements of crystallization are shown to be crucial in the study of lava flow emplacement dynamics.

  2. Automatic near-real-time detection of CMEs in Mauna Loa K-Cor coronagraph images

    NASA Astrophysics Data System (ADS)

    Thompson, William T.; St. Cyr, Orville Chris; Burkepile, Joan; Posner, Arik

    2017-08-01

    A simple algorithm has been developed to detect the onset of coronal mass ejections (CMEs), together with an estimate of their speed, in near-real-time using images of the linearly polarized white-light solar corona taken by the K-Cor telescope at the Mauna Loa Solar Observatory (MLSO). The algorithm used is a variation on the Solar Eruptive Event Detection System (SEEDS) developed at George Mason University. The algorithm was tested against K-Cor data taken between 29 April 2014 and 20 February 2017, on days which the MLSO website marked as containing CMEs. This resulted in testing of 139 days worth of data containing 171 CMEs. The detection rate varied from close to 80% in 2014-2015 when solar activity was high, down to as low as 20-30% in 2017 when activity was low. The difference in effectiveness with solar cycle is attributed to the difference in relative prevalance of strong CMEs between active and quiet periods. There were also twelve false detections during this time period, leading to an average false detection rate of 8.6% on any given day. However, half of the false detections were clustered into two short periods of a few days each when special conditions prevailed to increase the false detection rate. The K-Cor data were also compared with major Solar Energetic Particle (SEP) storms during this time period. There were three SEP events detected either at Earth or at one of the two STEREO spacecraft where K-Cor was observing during the relevant time period. The K-Cor CME detection algorithm successfully generated alerts for two of these events, with lead times of 1-3 hours before the SEP onset at 1 AU. The third event was not detected by the automatic algorithm because of the unusually broad width of the CME in position angle.

  3. Piggyback tectonics: Long-term growth of Kilauea on the south flank of Mauna Loa

    USGS Publications Warehouse

    Lipman, Peter W.; Sisson, Thomas W.; Coombs, Michelle L.; Calvert, Andrew T.; Kimura, Jun-Ichi

    2006-01-01

    Present-day Kilauea is the more dynamic edifice, but prior to inception of Kilauea and during its early growth, Mauna Loa is inferred to have undergone intense volcano spreading, involving the Kaoiki–Honuapo fault system (considered a geometric analog of the Hilina system on Kilauea). Cumulative deformation of Mauna Loa's south flank during growth of Kilauea since 200–300 ka is estimated to have involved > 10 km of seaward spreading, displacing the rift zones of Kīlauea while its deep plumbing system and summit magma reservoir remained nearly fixed in space. Kilauea's rift zones, rather than migrating southward with time solely due to dike emplacement preferentially on the mobile seaward side, alternatively are interpreted to have been transported passively southward, “piggyback” style, during shield-stage growth of Kilauea as a blister on the still-mobile south flank of Mauna Loa. Such an evolution of Kilauea accounts for the arcuate geometry of the present-day rift zones, proximity of the summit magma supply to the exposed flank of Mauna Loa, initial submarine growth of the ancestral edifice, and present-day location of Mauna Loa rocks at shallow depth beneath the south flank of Kilauea.

  4. Volcanically related secular trends in atmospheric transmission at mauna loa observatory, hawaii.

    PubMed

    Mendonca, B G; Hanson, K J; Deluisi, J J

    1978-11-03

    Twenty years of atmospheric transmission data from Mauna Loa Observatory show secular decreases at irregular intervals. In addition, a regular annual variation is present during unperturbed as well as perturbed periods. These variations in transmission can be measured to a few tenths of a percent from the data record. Transient decreases in transmission are strongly correlated with explosive volcanic eruptions that inject effluent into the stratosphere. Recovery from these ejections takes as much as 8 years and the recovery curve is linear. Observations in 1977 at Mauna Loa show that, for the first time since the Mount Agung eruption in 1963, the atmospheric transmission of direct-incidence solar irradiation at Mauna Loa returned to values measured in 1958 to 1962.

  5. Submarine radial vents on Mauna Loa Volcano, Hawaìi

    NASA Astrophysics Data System (ADS)

    Wanless, V. Dorsey; Garcia, M. O.; Trusdell, F. A.; Rhodes, J. M.; Norman, M. D.; Weis, Dominique; Fornari, D. J.; Kurz, M. D.; Guillou, Hervé

    2006-05-01

    A 2002 multibeam sonar survey of Mauna Loa's western flank revealed ten submarine radial vents and three submarine lava flows. Only one submarine radial vent was known previously. The ages of these vents are constrained by eyewitness accounts, geologic relationships, Mn-Fe coatings, and geochemical stratigraphy; they range from 128 years B.P. to possibly 47 ka. Eight of the radial vents produced degassed lavas despite eruption in water depths sufficient to inhibit sulfur degassing. These vents formed truncated cones and short lava flows. Two vents produced undegassed lavas that created "irregular" cones and longer lava flows. Compositionally and isotopically, the submarine radial vent lavas are typical of Mauna Loa lavas, except two cones that erupted alkalic lavas. He-Sr isotopes for the radial vent lavas follow Mauna Loa's evolutionary trend. The compositional and isotopic heterogeneity of these lavas indicates most had distinct parental magmas. Bathymetry and acoustic backscatter results, along with photography and sampling during four JASON2 dives, are used to produce a detailed geologic map to evaluate Mauna Loa's submarine geologic history. The new map shows that the 1877 submarine eruption was much larger than previously thought, resulting in a 10% increase for recent volcanism. Furthermore, although alkalic lavas were found at two radial vents, there is no systematic increase in alkalinity among these or other Mauna Loa lavas as expected for a dying volcano. These results refute an interpretation that Mauna Loa's volcanism is waning. The submarine radial vents and flows cover 29 km2 of seafloor and comprise a total volume of ˜2 × 109 m3 of lava, reinforcing the idea that submarine lava eruptions are important in the growth of oceanic island volcanoes even after they emerged above sea level.

  6. Role of CYP1B1, MYOC, OPTN and OPTC genes in adult-onset primary open-angle glaucoma: predominance of CYP1B1 mutations in Indian patients

    PubMed Central

    Basavaraj, Manjunath G.; Gupta, Santosh K.; Qamar, Imteyaz; Ali, Abdullah Mahmood; Bajaj, Vineeta; Ramesh, T.K.; Prakash, D. Ravi; Shetty, Jyoti S.; Dorairaj, Syril K.

    2007-01-01

    Purpose Mutations in the CYP1B1, MYOC, OPTN, and WDR36 genes result in glaucoma. Given its expression in the optic nerve, it is likely a mutation in the OPTC gene is also involved in initiating glaucoma. This study was designed to evaluate the involvement of the CYP1B1, MYOC, OPTN, and OPTC genes in the etiology of adult-onset primary open-angle glaucoma (POAG) found in 251 Indian patients. Methods Blood samples were obtained from individuals for DNA isolation. A combination of polymerase chain reaction-single strand conformation polymorphism, allele-specific PCR, and DNA sequencing techniques were used to detect mutations in four genes. Four microsatellite markers from the CYP1B1 candidate region and three intragenic CYP1B1 single nucleotide polymorphisms (SNPs) were used to determine the origin of the most common CYP1B1 mutations. Results Three previously known mutations (Pro193Leu, Glu229Lys, and Arg368His) and one novel (Met292Lys) mutation were found in the CYP1B1 gene. Frequencies of the most common mutations, Glu229Lys and Arg368His, in patients were 5.12% and 3.98%, respectively. The Glu229Lys and Arg368His mutations were also found in normal controls at frequencies of 5% and 2%, respectively, suggesting that these mutations might be polymorphic variants in our population. The absence of allele sharing for D2S177, D2S1346, D2S2974, and D2S2331 markers and three intragenic CYP1B1 SNPs in patients suggested multiple origins for the Glu229Lys and Arg368His variants. Two of 251 (0.8%) patients had the Gln48His mutation in MYOC. There was no difference in the frequency of a MYOC -83G>A promoter polymorphism between patients and controls. A novel OPTN mutation, Thr202Arg, was detected in one of 251 (0.4%) patients. The OPTN variant Met98Lys was detected in similar frequencies in patients and controls. No mutation was detected in OPTC. Taken together, 3.59% (9/251) of our POAG patients had mutations in the CYP1B1, MYOC, and OPTN genes. Conclusions This is the

  7. Disruption of the mauna loa magma system by the 1868 Hawaiian earthquake: Geochemical evidence

    USGS Publications Warehouse

    Tilling, R.I.; Michael, Rhodes J.; Sparks, J.W.; Lockwood, J.P.; Lipman, P.W.

    1987-01-01

    To test whether a catastrophic earthquake could affect an active magma system, mean abundances (adjusted for "olivine control") of titanium, potassium, phosphorus, strontium, zirconium, and niobium of historic lavas erupted from Mauna Loa Volcano, Hawaii, after 1868 were analyzed and were found to decrease sharply relative to lavas erupted before 1868. This abrupt change in lava chemistry, accompanied by a halved lava-production rate for Mauna Loa after 1877, is interpreted to reflect the disruptive effects of a magnitude 7.5 earthquake in 1868. This interpretation represents a documentable case of changes in magmatic chemical variations initiated or accelerated by a major tectonic event.

  8. Disruption of the Mauna Loa magma system by the 1868 Hawaiian earthquake - Geochemical evidence

    NASA Technical Reports Server (NTRS)

    Tilling, Robert I.; Rhodes, J. Michael; Sparks, Joel W.; Lockwood, John P.; Lipman, Peter W.

    1987-01-01

    To test whether a catastrophic earthquake could affect an active magma system, mean abundances (adjusted for 'olivine control') of titanium, potassium, phosphorus, strontium, zirconium, and niobium of historic lavas erupted from Mauna Loa Volcano, Hawaii, after 1868 were analyzed and were found to decrease sharply relative to lavas erupted before 1868. This abrupt change in lava chemistry, accompanied by a halved lava-production rate for Mauna Loa after 1877, is interpreted to reflect the disruptive effects of a magnitude 7.5 earthquake in 1868. This interpretation represents a documentable case of changes in magmatic chemical variations initiated or accelerated by a major tectonic event.

  9. Determination of Total Ozone over Mauna Loa Using Very High Resolution Infrared Solar Spectra

    NASA Technical Reports Server (NTRS)

    David, Shelle J.; Beaton, Sheryl A.; Anderberg, Mary H.; Murcray, Frank J.

    1993-01-01

    A very high resolution infrared Fourier transform spectrometer has been used to record solar spectra at the Mauna Loa Observatory in Hawaii. Spectra are normally taken one day a week at sunrise. These spectra have been analyzed for ozone and N2O total columns, and the ozone column compared with the value reported by tile Mauna Loa Dobson spectrophotometer. Aside from the FTIR reporting about 5% lower values than the Dobson (which may be due to a systematic difference in the treatment of tropospheric ozone), the FTIR and Dobson agree to within 2.7% (RMS) during this period.

  10. The geochemical components that distinguish Loa- and Kea-trend Hawaiian shield lavas

    NASA Astrophysics Data System (ADS)

    Frey, Frederick A.; Huang, Shichun; Xu, Guangping; Jochum, Klaus P.

    2016-07-01

    Recent (<5 Ma) Hawaiian volcanoes define two sub-parallel spatial trends, Loa and Kea. Despite the short distance (∼30 km) between adjacent volcanoes on these trends, most of the Loa-trend shield lavas are geochemically distinct from most of the Kea-trend shield lavas. These geochemical differences arise from small amounts of the LOA component in the source of Loa-trend shield lavas. This component is most prominent in the uppermost shield lavas of Koolau, Lanai and Kahoolawe volcanoes. Correlations between abundance ratios of incompatible elements and isotopic ratios of Sr, Nd, Hf and Pb in Hawaiian shield lavas indicate that the LOA component consists of three geochemically distinct materials formed by diverse processes. A gabbroic adcumulate (i.e. no trapped melt) with abundant cumulus plagioclase is responsible for the high Sr/Nd, La/Th and La/Nb in Loa-trend shield lavas relative to Kea-trend shield lavas. Also it has relatively low 206Pb/204Pb and high 208Pb/204Pb at a given 206Pb/204Pb, consistent with the low U/Pb and Th/Pb that are characteristic of plagioclase; these distinctive Pb isotope ratios require a long-time interval, ∼3 Ga, to develop. This material is most abundant in the uppermost shield lavas of Koolau volcano. Possible origins of adcumulate gabbros with abundant cumulus plagioclase are the lower oceanic and continental crust. A second material in the LOA component is distinctive because it is offset from the linear trend of 176Hf/177Hf versus 143Nd/144Nd, known as the terrestrial array, to high 176Hf/177Hf at low 143Nd/144Nd. This offset requires an ancient material with high Lu/Hf. It is equally abundant in the shield lavas at Koolau, Lanai and Kahoolawe volcanoes. Possible origins of this material are ancient pelagic sediment or ancient depleted lithosphere. A third material in the LOA component is characterized by relatively high 87Sr/86Sr, but the Rb/Sr of this material is too low to explain the high 87Sr/86Sr in 4.5 Ga. A relatively

  11. Determination of Total Ozone over Mauna Loa Using Very High Resolution Infrared Solar Spectra

    NASA Technical Reports Server (NTRS)

    David, Shelle J.; Beaton, Sheryl A.; Anderberg, Mary H.; Murcray, Frank J.

    1993-01-01

    A very high resolution infrared Fourier transform spectrometer has been used to record solar spectra at the Mauna Loa Observatory in Hawaii. Spectra are normally taken one day a week at sunrise. These spectra have been analyzed for ozone and N2O total columns, and the ozone column compared with the value reported by tile Mauna Loa Dobson spectrophotometer. Aside from the FTIR reporting about 5% lower values than the Dobson (which may be due to a systematic difference in the treatment of tropospheric ozone), the FTIR and Dobson agree to within 2.7% (RMS) during this period.

  12. Disruption of the mauna loa magma system by the 1868 hawaiian earthquake: geochemical evidence.

    PubMed

    Tilling, R I; Rhodes, J M; Sparks, J W; Lockwood, J P; Lipman, P W

    1987-01-09

    To test whether a catastrophic earthquake could affect an active magma system, mean abundances (adjusted for "olivine control") of titanium, potassium, phosphorus, strontium, zirconium, and niobium of historic lavas erupted from Mauna Loa Volcano, Hawaii, after 1868 were analyzed and were found to decrease sharply relative to lavas erupted before 1868. This abrupt change in lava chemistry, accompanied by a halved lava-production rate for Mauna Loa after 1877, is interpreted to reflect the disruptive effects of a magnitude 7.5 earthquake in 1868. This interpretation represents a documentable case of changes in magmatic chemical variations initiated or accelerated by a major tectonic event.

  13. Infrared measurements of atmospheric gases above Mauna Loa, Hawaii, in February 1987

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Goldman, A.; Murcray, F. J.; Murcray, F. H.; Blatherwick, R. D.

    1988-01-01

    The IR absorptions spectra of 13 minor and trace atmospheric gases, recorded by the NOAA's Geophysical Monitoring for Climate Change (GMCC) program station at Mauna Loa, Hawaii, for four days in February 1987, were analyzed to determine simultaneous total vertical column amounts for these gases. Comparisons with other data indicate that the NOAA GMCC surface volume mixing ratios are good measures of the mean volume mixing ratios of these gases in the troposphere and that Mauna Loa is a favorable site for IR monitoring of atmospheric gases. The ozone total columns deduced from the IR spectra agreed with the correlative Umkehr observations.

  14. Loa loa encephalopathy temporally related to ivermectin administration reported from onchocerciasis mass treatment programs from 1989 to 2001: implications for the future

    PubMed Central

    Twum-Danso, Nana AY

    2003-01-01

    Of the 207 Serious Adverse Events (SAEs) following treatment with Mectizan® (ivermectin, Merck, Sharpe & Dohme) that were reported from 1989 to 2001 through the passive SAE surveillance system required of all onchocerciasis mass treatment programs, 65 were cases of 'Probable' or 'Possible' Loa loa Encephalopathy temporally Related to treatment with Mectizan® (PLERM). A retrospective analysis of these 65 PLERM cases revealed that 97% were from southern Cameroon, 85% were male and 93% were being treated with ivermectin for the first time. The mean time to onset of symptoms was 1.7 days (95% CI: 1.3, 2.2) but the mean time to receiving medical attention after the onset of symptoms was 2.0 days (95% CI: 1.5, 2.6). Hospitalization was reported in 53 cases with a mean duration of 27.5 days (95% CI: 13.3, 41.6, n = 35). Clinical outcome was reported in 34 cases: 64.7% recovered fully, 11.8% had partial neurologic deficit and 23.5% died. For the 32 cases where quantitative L. loa data were reported, the arithmetic means with 95% confidence intervals were for 1) peripheral blood: pre-treatment – 164,250 mf/ml (79,537, 248,963; n = 4); post-treatment within 1 month – 3926 mf/ml (2,128, 5,725; n = 21) and within 5 to 6 months – 7800 mf/ml (3417, 12,183; n = 7); and for 2) cerebrospinal fluid: 32 mf/ml (7, 37; n = 10) within 1 month post-treatment. Pending further research on practical methods to exclude individuals with high intensity L. loa infection from onchocerciasis mass treatment programs, more emphasis should be placed on surveillance and monitoring to ensure early recognition, referral and management of SAEs, during the first 2 years when majority of the population is presumably naïve to ivermectin. PMID:14975064

  15. Coupling at Mauna Loa and Kīlauea by stress transfer in an asthenospheric melt layer

    USGS Publications Warehouse

    Gonnermann, Helge M.; Foster, James H.; Poland, Michael; Wolfe, Cecily J.; Brooks, Benjamin A.; Miklius, Asta

    2012-01-01

    The eruptive activity at the neighbouring Hawaiian volcanoes, Kīlauea and Mauna Loa, is thought to be linked despite both having separate lithospheric magmatic plumbing systems. Over the past century, activity at the two volcanoes has been anti-correlated, which could reflect a competition for the same magma supply. Yet, during the past decade Kīlauea and Mauna Loa have inflated simultaneously. Linked activity between adjacent volcanoes in general remains controversial. Here we present a numerical model for the dynamical interaction between Kīlauea and Mauna Loa, where both volcanoes are coupled by pore-pressure diffusion, occurring within a common, asthenospheric magma supply system. The model is constrained by measurements of gas emission rates indicative of eruptive activity, and it is calibrated to match geodetic measurements of surface deformation at both volcanoes, inferred to reflect changes in shallow magma storage. Although an increase in the asthenospheric magma supply can cause simultaneous inflation of Kīlauea and Mauna Loa, we find that eruptive activity at one volcano may inhibit eruptions of the adjacent volcano, if there is no concurrent increase in magma supply. We conclude that dynamic stress transfer by asthenospheric pore pressure is a viable mechanism for volcano coupling at Hawai‘i, and perhaps for adjacent volcanoes elsewhere.

  16. Sea surface temperature variation linked to elemental mercury concentrations measured on Mauna Loa

    EPA Science Inventory

    The Hg0 time series recorded at the Mauna Loa Observatory (MLO) in Hawaii between 2002 and 2009 has been analyzed using Empirical Mode Decomposition. This technique has been used in numerous contexts in order to identify periodical variations in time series data. The periodicitie...

  17. Geochemical evidence for invasion of Kilauea's plumbing system by Mauna Loa magma

    USGS Publications Warehouse

    Rhodes, J.M.; Wenz, K.P.; Neal, C.A.; Sparks, J.W.; Lockwood, J.P.

    1989-01-01

    From the beginning of the study of Hawaiian volcanism there has been controversy over possible relationships between the neighbouring active volcanoes Mauna Loa and Kilauea1-5. Seismic activity, thought to reflect upward migration of magma, reveals that the magmatic plumbing systems apparently converge at depth to form a broad funnel within the mantle6. Although on rare occasions they have erupted concurrently, the brief historical eruptive record appears to show that when Kilauea is most active, Mauna Loa is in repose and vice versa, suggesting that they may be competing for the same magma supply5,7. Petrological, geochemical and isotope data, however, require a diametrically opposite conclusion. Distinct differences in major-element, trace-element and isotope compositions of lavas are regarded as compelling evidence that the two volcanoes have separate magmatic plumbing systems, supplied by parental magmas from physically and geochemically distinct mantle sources8-13. Here we present preliminary geochemical data which show that in the past 2,000 years Kilauea has erupted a spectrum of lava compositions resembling historical Kilauea lavas at one end and Mauna Loa lavas at the other. We discuss the cause of this diversity, and speculate that magma from Mauna Loa may have invaded Kilauea's 'high-level' magmatic plumbing system. ?? 1989 Nature Publishing Group.

  18. Sea surface temperature variation linked to elemental mercury concentrations measured on Mauna Loa

    EPA Science Inventory

    The Hg0 time series recorded at the Mauna Loa Observatory (MLO) in Hawaii between 2002 and 2009 has been analyzed using Empirical Mode Decomposition. This technique has been used in numerous contexts in order to identify periodical variations in time series data. The periodicitie...

  19. Filariasis due to Loa loa and Mansonella perstans: distribution in the region of Okondja, Haut-Ogooué Province, Gabon, with parasitological and serological follow-up over one year.

    PubMed

    Van Hoegaerden, M; Chabaud, B; Akue, J P; Ivanoff, B

    1987-01-01

    The prevalence of Loa loa and Mansonella perstans filariasis has been determined in 6 rural villages in eastern Gabon. Between 18.9 and 27.2% of people carry L. loa microfilariae with an overall microfilarial rate of 25.1%. The microfilarial rate for M. perstans was more variable, between 33.3 and 62.2% (average 49.1%). No significant difference was seen in the microfilarial rate with age over 15 years for either parasite, but men were infected more frequently than women. Anti-L. loa antibody titres were measured, using a homologous microfilarial antigen in ELISA. Taking the parasitological and immunological evaluations together, only 10% of the sample population appear to be free of these filarial infections. L. loa and M. perstans microfilaraemia and corresponding serology were also investigated twice in 150 people at a one-year interval. 99.1% of the cases who had no circulating L. loa microfilaria in March 1984 still did not show any 12 months later. Similarly, 97.1% of the untreated, microfilaraemic cases still harboured this parasite a year later. The same was not observed for M. perstans, since microfilariae appeared or disappeared in 26.7% of the cases. This suggests different dynamics for the two filarial infections. Variation in individual anti-L. loa antibody titres was low. The possibility of a genetic influence on the expression of loiasis is discussed.

  20. Fissure distribution at Mauna Loa (Hawaii) as an example to understand shallow magma transfer at volcanoes

    NASA Astrophysics Data System (ADS)

    La Marra, Daniele; Acocella, Valerio; Trusdell, Frank

    2016-04-01

    Mauna Loa (Hawaii) is the largest active shield volcano on the Island of Hawai'i, covering more than half of it and rising to 4,169 meters above sea level. The volcano hosts the Moku'aweoweo summit caldera, from which two elongated rift zones depart: the Northeast Rift Zone (NERZ) and the Southwest Rift Zone (SWRZ). Most of Mauna Loa's eruptions begin with lava fountains from a series of fissure vents in the summit region and then often migrate to vents down either rift zone. Mauna Loa volcano shows a distinctive feature, being characterized by minor radial eruptive fissures (not related to the two main rifts) on the NW flank only. This study tries to explain such a selective distribution of vents, and thus of shallow magma transfer. To this aim, we run numerical models with different amount of opening of the two rift zones of Mauna Loa, as well as different amount of slip on its SE flank. Our results suggest that the selective occurrence of the radial fissures may be explained by the competition between two processes: a) rift intrusion (especially along the NERZ), promoting the development of radial dikes along the NW flank; b) flank slip, inhibiting the development of the radial dikes on the SE flank. The opening of the two non-parallel main rift zones of Mauna Loa promotes the local extension necessary to develop the radial dikes on the NW flank. A general model for the development of a third branch of radial rift, which may be also applied to Mt. Etna and some volcanoes on the Canary Islands, is proposed.

  1. The Ninole Basalt - Implications for the structural evolution of Mauna Loa volcano, Hawaii

    USGS Publications Warehouse

    Lipman, P.W.; Rhodes, J.M.; Dalrymple, G.B.

    1990-01-01

    Lava flows of the Ninole Basalt, the oldest rocks exposed on the south side of the island of Hawaii, provide age and compositional constraints on the evolution of Mauna Loa volcano and the southeastward age progression of Hawaiian volcanism. Although the tholeiitic Ninole Basalt differs from historic lavas of Mauna Loa volcano in most major-element contents (e.g., variably lower K, Na, Si; higher Al, Fe, Ti, Ca), REE and other relatively immobile minor elements are similar to historic and prehistoric Mauna Loa lavas, and the present major-element differences are mainly due to incipient weathering in the tropical environment. New K-Ar whole-rock ages, from relatively fresh roadcut samples, suggest that the age of the Ninole Basalt is approximately 0.1-0.2 Ma, although resolution is poor because of low contents of K and radiogenic Ar. Originally considered the remnants of a separate volcano, the Ninole Hills are here interpreted as faulted remnants of the old south flank of Mauna Loa. Deep canyons in the Ninole Hills, eroded after massive landslide failure of flanks of the southwest rift zone, have been preserved from burial by younger lava due to westward migration of the rift zone. Landslide-induced depressurization of the southwest rift zone may also have induced phreatomagmatic eruptions that could have deposited widespread Basaltic ash that overlies the Ninole Basalt. Subaerial presence of the Ninole Basalt documents that the southern part of Hawaii Island had grown to much of its present size above sea level by 0.1-0.2 Ma, and places significant limits on subsequent enlargement of the south flank of Mauna Loa. ?? 1990 Springer-Verlag.

  2. Swarms of similar long-period earthquakes in the mantle beneath Mauna Loa Volcano

    USGS Publications Warehouse

    Okubo, P.G.; Wolfe, C.J.

    2008-01-01

    We present analyses of two swarms of long-period (LP) earthquakes at > 30??km depth that accompanied the geodetically observed 2002-2005 Mauna Loa intrusion. The first LP earthquake swarm in 2002 consisted of 31 events that were precursory and preceded the start of Mauna Loa inflation; the second LP swarm of two thousand events occurred from 2004-2005. The rate of LP earthquakes slowed significantly coincident with the occurrence of the December 26, 2004 Mw 9.3 Sumatra earthquake, suggesting that the seismic waves from this great earthquake may have had a dynamic triggering effect on the behavior of Mauna Loa's deep magma system. Using waveform cross correlation and double difference relocation, we find that a large number of earthquakes in each swarm are weakly similar and can be classified into two families. The relocated hypocenters for each family collapse to compact point source regions almost directly beneath the Mauna Loa intrusion. We suggest that the observed waveform characteristics are compatible with each family being associated with the resonance of a single fluid filled vertical crack of fixed geometry, with differences in waveforms between events being produced by slight variations in the trigger mechanism. If these LP earthquakes are part of the primary magma system that fed the 2002-2005 intrusion, as indicated by the spatial and temporal associations between mantle seismicity and surface deformation, then our results raise the possibility that this magma system may be quite focused at these depths as opposed to being a diffuse network. It is likely that only a few locations of Mauna Loa's deep magma system met the geometric and fluid dynamic conditions for generating LP earthquakes that were large enough to be recorded at the surface, and that much of the deep magma transfer associated with the 2002-2005 intrusion occurred aseismically. ?? 2008 Elsevier B.V.

  3. Ivermectin treatment of Loa loa hyper-microfilaraemic baboons (Papio anubis): Assessment of microfilarial load reduction, haematological and biochemical parameters and histopathological changes following treatment

    PubMed Central

    Wanji, Samuel; Eyong, Ebanga-Echi J.; Tendongfor, Nicholas; Ngwa, Che J.; Esuka, Elive N.; Kengne-Ouafo, Arnaud J.; Datchoua-Poutcheu, Fabrice R.; Enyong, Peter; Agnew, Dalen; Eversole, Rob R.; Hopkins, Adrian

    2017-01-01

    Background Individuals with high intensity of Loa loa are at risk of developing serious adverse events (SAEs) post treatment with ivermectin. These SAEs have remained unclear and a programmatic impediment to the advancement of community directed treatment with ivermectin. The pathogenesis of these SAEs following ivermectin has never been investigated experimentally. The Loa/baboon (Papio anubis) model can be used to investigate the pathogenesis of Loa-associated encephalopathy following ivermectin treatment in humans. Methods 12 baboons with microfilarial loads > 8,000mf/mL of blood were randomised into four groups: Group 1 (control group receiving no drug), Group 2 receiving ivermectin (IVM) alone, Group 3 receiving ivermectin plus aspirin (IVM + ASA), and Group 4 receiving ivermectin plus prednisone (IVM + PSE). Blood samples collected before treatment and at Day 5, 7 or 10 post treatment, were analysed for parasitological, hematological and biochemical parameters using standard techniques. Clinical monitoring of animals for side effects took place every 6 hours post treatment until autopsy. At autopsy free fluids and a large number of standard organs were collected, examined and tissues fixed in 10% buffered formalin and processed for standard haematoxylin-eosin staining and specific immunocytochemical staining. Results Mf counts dropped significantly (p<0.05) in all animals following ivermectin treatment with reductions as high as (89.9%) recorded; while no significant drop was observed in the control animals. Apart from haemoglobin (Hb) levels which recorded a significant (p = 0.028) drop post treatment, all other haematological and biochemical parameters did not show any significant changes (p>0.05). All animals became withdrawn 48 hours after IVM administration. All treated animals recorded clinical manifestations including rashes, itching, diarrhoea, conjunctival haemorrhages, lymph node enlargement, pinkish ears, swollen face and restlessness; one animal

  4. Macrofilaricidal Activity after Doxycycline Only Treatment of Onchocerca volvulus in an Area of Loa loa Co-Endemicity: A Randomized Controlled Trial

    PubMed Central

    Turner, Joseph D.; Tendongfor, Nicholas; Esum, Mathias; Johnston, Kelly L.; Langley, R. Stuart; Ford, Louise; Faragher, Brian; Specht, Sabine; Mand, Sabine; Hoerauf, Achim; Enyong, Peter; Wanji, Samuel; Taylor, Mark J.

    2010-01-01

    Background The risk of severe adverse events following treatment of onchocerciasis with ivermectin in areas co-endemic with loiasis currently compromises the development of control programmes and the treatment of co-infected individuals. We therefore assessed whether doxycycline treatment could be used without subsequent ivermectin administration to effectively deliver sustained effects on Onchocerca volvulus microfilaridermia and adult viability. Furthermore we assessed the safety of doxycycline treatment prior to ivermectin administration in a subset of onchocerciasis individuals co-infected with low to moderate intensities of Loa loa microfilaraemia. Methods A double-blind, randomized, field trial was conducted of 6 weeks of doxycycline (200 mg/day) alone, doxycycline in combination with ivermectin (150 µg/kg) at +4 months or placebo matching doxycycline + ivermectin at +4 months in 150 individuals infected with Onchocerca volvulus. A further 22 individuals infected with O. volvulus and low to moderate intensities of Loa loa infection were administered with a course of 6 weeks doxycycline with ivermectin at +4 months. Treatment efficacy was determined at 4, 12 and 21 months after the start of doxycycline treatment together with the frequency and severity of adverse events. Results One hundred and four (60.5%) participants completed all treatment allocations and follow up assessments over the 21-month trial period. At 12 months, doxycycline/ivermectin treated individuals had lower levels of microfilaridermia and higher frequency of amicrofilaridermia compared with ivermectin or doxycycline only groups. At 21 months, microfilaridermia in doxycycline/ivermectin and doxycycline only groups was significantly reduced compared to the ivermectin only group. 89% of the doxycycline/ivermectin group and 67% of the doxycycline only group were amicrofilaridermic, compared with 21% in the ivermectin only group. O. volvulus from doxycycline groups were depleted of Wolbachia

  5. Ivermectin treatment of Loa loa hyper-microfilaraemic baboons (Papio anubis): Assessment of microfilarial load reduction, haematological and biochemical parameters and histopathological changes following treatment.

    PubMed

    Wanji, Samuel; Eyong, Ebanga-Echi J; Tendongfor, Nicholas; Ngwa, Che J; Esuka, Elive N; Kengne-Ouafo, Arnaud J; Datchoua-Poutcheu, Fabrice R; Enyong, Peter; Agnew, Dalen; Eversole, Rob R; Hopkins, Adrian; Mackenzie, Charles D

    2017-07-01

    Individuals with high intensity of Loa loa are at risk of developing serious adverse events (SAEs) post treatment with ivermectin. These SAEs have remained unclear and a programmatic impediment to the advancement of community directed treatment with ivermectin. The pathogenesis of these SAEs following ivermectin has never been investigated experimentally. The Loa/baboon (Papio anubis) model can be used to investigate the pathogenesis of Loa-associated encephalopathy following ivermectin treatment in humans. 12 baboons with microfilarial loads > 8,000mf/mL of blood were randomised into four groups: Group 1 (control group receiving no drug), Group 2 receiving ivermectin (IVM) alone, Group 3 receiving ivermectin plus aspirin (IVM + ASA), and Group 4 receiving ivermectin plus prednisone (IVM + PSE). Blood samples collected before treatment and at Day 5, 7 or 10 post treatment, were analysed for parasitological, hematological and biochemical parameters using standard techniques. Clinical monitoring of animals for side effects took place every 6 hours post treatment until autopsy. At autopsy free fluids and a large number of standard organs were collected, examined and tissues fixed in 10% buffered formalin and processed for standard haematoxylin-eosin staining and specific immunocytochemical staining. Mf counts dropped significantly (p<0.05) in all animals following ivermectin treatment with reductions as high as (89.9%) recorded; while no significant drop was observed in the control animals. Apart from haemoglobin (Hb) levels which recorded a significant (p = 0.028) drop post treatment, all other haematological and biochemical parameters did not show any significant changes (p>0.05). All animals became withdrawn 48 hours after IVM administration. All treated animals recorded clinical manifestations including rashes, itching, diarrhoea, conjunctival haemorrhages, lymph node enlargement, pinkish ears, swollen face and restlessness; one animal died 5 hours after IVM

  6. Effect of Two or Six Doses 800 mg of Albendazole Every Two Months on Loa loa Microfilaraemia: A Double Blind, Randomized, Placebo-Controlled Trial

    PubMed Central

    Kamgno, Joseph; Nguipdop-Djomo, Patrick; Gounoue, Raceline; Téjiokem, Mathurin; Kuesel, Annette C.

    2016-01-01

    Background Loiasis is a parasitic infection endemic in the African rain forest caused by the filarial nematode Loa loa. Loiasis can be co-endemic with onchocerciasis and/or lymphatic filariasis. Ivermectin, the drug used in the control of these diseases, can induce serious adverse reactions in patients with high L loa microfilaraemia (LLM). A drug is needed which can lower LLM below the level that represents a risk so that ivermectin mass treatment to support onchocerciasis and lymphatic filariasis elimination can be implemented safely. Methodology Sixty men and women from a loiasis endemic area in Cameroon were randomized after stratification by screening LLM (≤30000, 30001–50000, >50000) to three treatment arms: two doses albendazole followed by 4 doses matching placebo (n = 20), six doses albendazole (n = 20) albendazole or 6 doses matching placebo (n = 20) administered every two months. LLM was measured before each treatment and 14, 18, 21 and 24 months after the first treatment. Monitoring for adverse events occurred three and seven days as well as 2 months after each treatment. Principal Findings None of the adverse events recorded were considered treatment related. The percentages of participants with ≥ 50% decrease in LLM from pre-treatment for ≥ 4 months were 53%, 17% and 11% in the 6-dose, 2-dose and placebo treatment arms, respectively. The difference between the 6-dose and the placebo arm was significant (p = 0.01). The percentages of participants with LLM < 8100 mf/ml for ≥4 months were 21%, 11% and 0% in the 6-dose, 2-dose and placebo treatment arms, respectively. Conclusions/ Significance The 6-dose regimen reduced LLM significantly, but the reduction was insufficient to eliminate the risk of severe and/or serious adverse reactions during ivermectin mass drug administration in loiasis co-endemic areas. PMID:26967331

  7. Effect of Two or Six Doses 800 mg of Albendazole Every Two Months on Loa loa Microfilaraemia: A Double Blind, Randomized, Placebo-Controlled Trial.

    PubMed

    Kamgno, Joseph; Nguipdop-Djomo, Patrick; Gounoue, Raceline; Téjiokem, Mathurin; Kuesel, Annette C

    2016-03-01

    Loiasis is a parasitic infection endemic in the African rain forest caused by the filarial nematode Loa loa. Loiasis can be co-endemic with onchocerciasis and/or lymphatic filariasis. Ivermectin, the drug used in the control of these diseases, can induce serious adverse reactions in patients with high L loa microfilaraemia (LLM). A drug is needed which can lower LLM below the level that represents a risk so that ivermectin mass treatment to support onchocerciasis and lymphatic filariasis elimination can be implemented safely. Sixty men and women from a loiasis endemic area in Cameroon were randomized after stratification by screening LLM (≤ 30000, 30001-50000, >50000) to three treatment arms: two doses albendazole followed by 4 doses matching placebo (n = 20), six doses albendazole (n = 20) albendazole or 6 doses matching placebo (n = 20) administered every two months. LLM was measured before each treatment and 14, 18, 21 and 24 months after the first treatment. Monitoring for adverse events occurred three and seven days as well as 2 months after each treatment. None of the adverse events recorded were considered treatment related. The percentages of participants with ≥ 50% decrease in LLM from pre-treatment for ≥ 4 months were 53%, 17% and 11% in the 6-dose, 2-dose and placebo treatment arms, respectively. The difference between the 6-dose and the placebo arm was significant (p = 0.01). The percentages of participants with LLM < 8100 mf/ml for ≥ 4 months were 21%, 11% and 0% in the 6-dose, 2-dose and placebo treatment arms, respectively. The 6-dose regimen reduced LLM significantly, but the reduction was insufficient to eliminate the risk of severe and/or serious adverse reactions during ivermectin mass drug administration in loiasis co-endemic areas.

  8. Innovative tools for assessing risks for severe adverse events in areas of overlapping Loa loa and other filarial distributions: the application of micro-stratification mapping

    PubMed Central

    2014-01-01

    Background The wide distribution of Loa loa infection (loiasis) throughout the Democratic Republic of Congo (DRC) is a major obstacle to the plans to eliminate onchocerciasis and lymphatic filariasis (LF) because the standard drug regime is dependent on ivermectin, which cannot be used in co-endemic areas due to the risk of severe adverse events (SAEs). A better understanding of the micro-epidemiology, overlapping low and high risk areas, and how they relate to SAEs is critical to ensure safe and effective treatment. Findings Based on published data from the Bas Congo Province in DRC, this study used geographical information systems (GIS) to re-map and analyse onchocerciasis and loiasis prevalence (<20%, 20 to 40%, >40%) at 144 sites in relation to health district areas reporting SAEs. The new maps highlighted the contrasting patterns of the high prevalence sites, and significant geographical overlap between low onchocerciasis and high loiasis sites. Statistical analyses found that sites with medium to high loiasis prevalence were 10 to 16 times more likely to be in a SAE area than those with low prevalence of loiasis. Sites where both onchocerciasis and loiasis prevalence was >20% were also associated with SAE areas. Conclusions Collaborative efforts between the national onchocerciasis and LF programmes are critical as plans to scale interventions are moving forward and thus, alternative strategies needed in loiasis co-endemic areas which may include the new L. loa test and treat strategy using the Cellscope, or interventions such as integrated vector management, or anti Wolbachia therapy using doxycycline. PMID:24992829

  9. Isotopic Study of the Mauna Loa Southwest Rift Mile High Section: Hawaiian Mantle Plume Components

    NASA Astrophysics Data System (ADS)

    Weis, D.; Rhodes, J. M.; Garcia, M. O.

    2003-12-01

    The new JASON2 ROV was employed to collect 51 samples from a 1.8 km thick submarine landslide scarp along the crest of the southwest rift zone of the Mauna Loa volcano to investigate the nature and history of Hawaiian mantle plume components. The rift zone section records about 400,000 years of eruptive activity, 50% of the volcano's total lifetime, which is comparable to the time-period sampled by the Hawaiian Scientific Drilling Project (HSPD2). Sr, Nd, Pb and Hf isotopes have been analyzed on 14 samples from the "Mile High" section. The range of variation observed falls typically within literature data for the Mauna Loa volcano with 87Sr/86Sr from 0.70368 to 0.70378 and 206Pb/204Pb from 18.16 to 18.26, and is somewhat more radiogenic than most Mauna Loa prehistoric (<31 ka) lavas. In the section, there is a distinct increase in Pb and Sr isotopes, which is also recorded by major and trace element data, at a depth of 1353 m. Isotope ratios continue to increase to the bottom of the section at 2290 m. High precision Pb-Pb isotopic systematics for Mauna Loa lavas do not show the binary mixing trends as also observed in the upper part of the HSDPI pilot hole and contrary to Mauna Kea lavas (Abouchami et al., Chemical Geology 2000). This might imply that the Mauna Loa plume source is more thoroughly mixed than the Mauna Kea source. Most of Mauna Loa isotopic compositions cluster at 18.15-18.20 for 206Pb/204Pb and ˜0.70370 for 87Sr/86Sr, which could be a ubiquitous refractory component in the Hawaiian mantle plume (Rhodes and Weis, Fall AGU 2001). Nevertheless, a more radiogenic plume component with higher 208Pb/204Pb and 208Pb*/206Pb* is clearly present in the lower part of the Mile High section and might be comparable to the Kilauea-like component observed in Mauna Kea lavas in HSDP2 (Blichert-Toft et al., G3 2003). Team members also include: D. Wanless and K. Kolysko, University of Hawaii; H. Guillou, CEA/CNRS, France; M. Kurz and D. Fornari, WHOI; M. Norman and V

  10. The Mauna Loa carbon dioxide record: lessons for long-term Earth observations

    USGS Publications Warehouse

    Sundquist, Eric T.; Keeling, Ralph F.

    2009-01-01

    The Mauna Loa carbon dioxide record is an iconic symbol of the human capacity to alter the planet. Yet this record would not have been possible without the remarkable work of one man, Charles David Keeling. We describe three emergent themes that characterized his work: (1) his desire to study and understand the processes that control atmospheric CO2 and the global carbon cycle, (2) his campaign to identify and minimize systematic measurement error, and (3) his tenacious efforts to maintain continuous funding despite changing government priorities and institutions. In many ways, the story of the Mauna Loa record demonstrates that distinctions between research and “routine” measurements are not very useful in long-term monitoring of Earth properties and processes.

  11. A study of the photochemistry and ozone budget during the Mauna Loa Observatory Photochemistry Experiment

    NASA Astrophysics Data System (ADS)

    Liu, S. C.; Trainer, M.; Carroll, M. A.; Huebler, G.; Montzka, D. D.; Norton, R. B.; Ridley, B. A.; Walega, J. G.; Atlas, E. L.; Heikes, B. G.

    1992-06-01

    Extensive measurements of trace species and parameters that are important to the photochemical production and loss of ozone have been made at Mauna Loa during the Mauna Loa Observatory Photochemistry Experiment. These measurements are used as inputs as well as constraints in a model study of the photochemical budgets of ozone and five other trace species (CH2O, CH3OOH, H2O2, NO, and NO(x)) that are closely coupled to the photochemical production and loss of ozone. The study shows that there are significant discrepancies in the photochemical budgets of these trace species in this region and suggests that some important uncertainties exist in the current understanding of the odd hydrogen photochemical processes.

  12. Summary of solar activity observed at the Mauna Loa Solar Observatory: 1980-1983. Technical note

    SciTech Connect

    Rock, K.; Fisher, R.; Garcia, C.; Yasukawa, E.

    1983-11-01

    The following technical note summarizes solar activity observed during the first four years operation of the experiment systems of the Coronal Dynamics Project, which are located at the Mauna Loa Solar Observatory. This short report has been produced with the general aim of providing users of Mauna Loa observations with a summary of data for specific events. So that this table might be as useful as possible, a comprehensive review of three sources was performed. The plain language logs, identified as the so-called observer's logs, the now-discontinued activity logs, and the prominence monitor quality control logs were the sources from which the information in the following tables was obtained. It is expected that this review will be of particular use to those investigators who intend to use both the K-coronameter data base and the SMM Coronagraph-Polarimeter data for the study of coronal transient events.

  13. SBAS-InSAR analysis of surface deformation at Mauna Loa and Kilauea volcanoes in Hawaii

    USGS Publications Warehouse

    Casu, F.; Lanari, Riccardo; Sansosti, E.; Solaro, G.; Tizzani, Pietro; Poland, M.; Miklius, Asta

    2009-01-01

    We investigate the deformation of Mauna Loa and K??lauea volcanoes, Hawai'i, by exploiting the advanced differential Synthetic Aperture Radar Interferometry (InSAR) technique referred to as the Small BAseline Subset (SBAS) algorithm. In particular, we present time series of line-of-sight (LOS) displacements derived from SAR data acquired by the ASAR instrument, on board the ENVISAT satellite, from the ascending (track 93) and descending (track 429) orbits between 2003 and 2008. For each coherent pixel of the radar images we compute time-dependent surface displacements as well as the average LOS deformation rate. Our results quantify, in space and time, the complex deformation of Mauna Loa and K??lauea volcanoes. The derived InSAR measurements are compared to continuous GPS data to asses the quality of the SBAS-InSAR products. ??2009 IEEE.

  14. Mauna Loa--history, hazards and risk of living with the world's largest volcano

    USGS Publications Warehouse

    Trusdell, Frank A.

    2012-01-01

    Mauna Loa on the Island Hawaiʻi is the world’s largest volcano. People residing on its flanks face many hazards that come with living on or near an active volcano, including lava flows, explosive eruptions, volcanic smog, damaging earthquakes, and local tsunami (giant seawaves). The County of Hawaiʻi (Island of Hawaiʻi) is the fastest growing County in the State of Hawaii. Its expanding population and increasing development mean that risk from volcano hazards will continue to grow. U.S. Geological Survey (USGS) scientists at the Hawaiian Volcano Observatory (HVO) closely monitor and study Mauna Loa Volcano to enable timely warning of hazardous activity and help protect lives and property.

  15. A user's guide to Mauna Loa Solar Observatory's coronal data system

    NASA Astrophysics Data System (ADS)

    Rock, K.; Seagraves, P.

    1982-09-01

    The seven data products available from the Mark III K-coronameter are described. One of these is a real time product (CORONA), four are available in near real time (1MAP, 1DATA, ACTIVITY, and DIMAGE), and two others are useful for trying to visualize the three dimensional distribution of coronal material (SHELL and HISTORY). Sufficient information for the intepretation of Mauna Loa Solar Observatory data by users outside the High Altitude Observatory's Coronal Dynamics Project is provided.

  16. Unattended spectrometer and lidar for measuring atmospheric radiation at Mauna Loa, Hawaii

    NASA Astrophysics Data System (ADS)

    Shaw, Joseph A.; Bates, John J.; Alvarez, Raul J., II; Bravo, Hector E.; Intrieri, Janet M.; McCarty, Brandi; Sandberg, Scott; Strow, L. Larrabee

    2002-09-01

    A combined active-passive remote sensing system has been developed to study atmospheric radiation and cirrus cloud radiative properties at the NOAA Mauna Loa Observatory on the island of Hawaii. The active portion of this system is an eye-safe, dual-polarization lidar, while the passive portion is a Fourier transform spectro-radiometer operating in emission mode. The combined system allows unattended, remote measurements of infrared atmospheric emission and clouds with depolarization discrimination of ice and liquid.

  17. Biological perspectives on Mauna Loa Volcano: A model system for ecological research

    NASA Astrophysics Data System (ADS)

    Vitousek, Peter M.; Aplet, Gregory H.; Raich, James W.; Lockwood, John P.

    As a result of evaluations of volcanic hazards, most of the surface lava flows of Mauna Loa have been mapped and dated. Each of these flows represents a valuable resource for ecological studies—a single-age, single-substrate transect reaching from near the summit towards the sea, often spanning a range of nearly 20°C in mean annual temperature. The set of flows on a particular flank of the mountain represents an age sequence of parallel transects, and the influence of precipitation can be assessed separately by examining flows of comparable age on different aspects of Mauna Loa. We evaluated the development of plant communities and the functioning of ecosystems across portions of the age-elevation-precipitation matrix on Mauna Loa. On the wet east flank, plant communities develop more slowly at high elevation, although the composition of the vegetation of young flows is similar at all elevations. However, rainforest ultimately develops on older flows below 1800 m elevation, while open woodlands dominate old flows at higher elevations. Rates of both plant production and decomposition increase with decreasing elevation (increasing temperature) on a given flow—but production increases linearly while decomposition increases exponentially. Consequently, soil carbon turnover and rates of nutrient cycling increase progressively from high to low elevation. These examples of ecological research illustrate how the relative simplicity of the biological systems on Mauna Loa, in combination with their relatively well-understood geology, allow us to evaluate processes that are difficult to study in more complex continental ecosystems.

  18. Fully automated chemiluminescence detection using an electrified-Lab-on-a-Disc (eLoaD) platform.

    PubMed

    Delgado, Saraí M Torres; Kinahan, David J; Sandoval, Fralett Suárez; Julius, Lourdes Albina Nirupa; Kilcawley, Niamh A; Ducrée, Jens; Mager, Dario

    2016-10-05

    Typical Lab-on-a-Disc (LoaD) platforms cannot make a continuous measurement while the disc is spinning; this drawback means that the disc usually must be stopped and aligned with a sensor. This can result in measurement errors in time-dependent assays along with inaccuracies due to liquid displacement and bubble formation in the absence of a stabilising centrifugal field. This paper presents a novel concept for a wirelessly electrified-Lab-on-a-Disc (eLoaD) platform that allows continuous measurement of experimental parameters while the disc is spinning. This platform incorporates all the components needed for measurement within the rotating frame of reference, and bidirectional transmission of data outside this reference frame, thus allowing for online measurement independent of the rotation of the disc. The eLoaD platform is conceived in a modular manner whereby an interchangeable and non-disposable 'Application Disc' can be fitted to the eLoaD platform and so the system can be adapted for a range of optical, electrochemical and other measurement types. As an application example, optical readout, using the Application Disc fitted with a silicon photomultiplier, is demonstrated using a tagged chemiluminescent antibody, which is commonly used, for instance, in ELISA assays. The precision of the eLoaD platform is >94%, while its accuracy, when compared to a commercial benchtop luminometer, is higher than 96%. The modular design of this platform will permit extension of this technology to many other LoaD applications.

  19. Prevalence of L. loa and M. perstans filariasis in southern Cameroon.

    PubMed

    Mommers, E C; Dekker, H S; Richard, P; Garica, A; Chippaux, J P

    1995-01-01

    The prevalence and microfilarial density of Loa loa and Mansonella perstans filariasis have been determined in three successive surveys in one village in the dense rainforest of Southern Cameroon. The prevalence of L. loa microfilaraemia was 30.9% with a geometric mean density of 81.4 microfilariae/30 microliter blood. There was no difference between men and women. The prevalence increased with age from 14.5% at 0-9 years to 52.9% at 40-49 years, whereafter it stablized. The microfilarial density increased until the age of 30-39 years. The highest densities have been found around noon, although the difference was not significant. The prevalence of M. perstans microfilaraemia was 26.6% with a median density of 2.0 microfilariae/30 microliter blood. Both prevalence and density were increasing with age and were higher for men than for women. The time of day that the blood sample was taken had no influence on the microfilarial density of M. perstans.

  20. Tholeiitic basalt magmatism of Kilauea and Mauna Loa volcanoes of Hawaii

    USGS Publications Warehouse

    Murata, K.J.

    1970-01-01

    The primitive magmas of Kilauca and Mauna Loa are generated by partial melting of mantle peridotite at depths of -60 km or more. Results of high-pressure melting experiments indicate that the primitive melt must contain at least 20% MgO in order to have olivine as a liquidus mineral. The least fractionated lavas of both volcanoes have olivine (Fa13) on the liquidus at 1 atmosphere, suggesting that the only substance lost from the primitive melt, during a rather rapid ascent to the surface, is olivine. This relation allows the primitive composition to be computed by adding olivine to the composition of an erupted lava until total MgO is at least 20 percent. Although roughly similar, historic lavas of the two volcanoes show a consistent difference in composition. The primitive melt of Mauna Loa contains 20% more dissolved orthopyroxene, a high-temperature melting phase in the mantle, and is deficient in elements such as potassium, uranium, and niobium, which presumably occur in minor low-melting phases. Mauna Loa appears to be the older volcano, deriving its magma at higher temperature and greater depth from a more depleted source rock. ?? 1970 Springer-Verlag.

  1. DYNC1H1 mutation alters transport kinetics and ERK1/2-cFos signalling in a mouse model of distal spinal muscular atrophy.

    PubMed

    Garrett, Caroline A; Barri, Muruj; Kuta, Anna; Soura, Violetta; Deng, Wenhan; Fisher, Elizabeth M C; Schiavo, Giampietro; Hafezparast, Majid

    2014-07-01

    Mutations in the gene encoding the heavy chain subunit (DYNC1H1) of cytoplasmic dynein cause spinal muscular atrophy with lower extremity predominance, Charcot-Marie-Tooth disease and intellectual disability. We used the legs at odd angles (Loa) (DYNC1H1(F580Y)) mouse model for spinal muscular atrophy with lower extremity predominance and a combination of live-cell imaging and biochemical assays to show that the velocity of dynein-dependent microtubule minus-end (towards the nucleus) movement of EGF and BDNF induced signalling endosomes is significantly reduced in Loa embryonic fibroblasts and motor neurons. At the same time, the number of the plus-end (towards the cell periphery) moving endosomes is increased in the mutant cells. As a result, the extracellular signal-regulated kinases (ERK) 1/2 activation and c-Fos expression are altered in both mutant cell types, but the motor neurons exhibit a strikingly abnormal ERK1/2 and c-Fos response to serum-starvation induced stress. These data highlight the cell-type specific ERK1/2 response as a possible contributory factor in the neuropathological nature of Dync1h1 mutations, despite generic aberrant kinetics in both cell types, providing an explanation for how mutations in the ubiquitously expressed DYNC1H1 cause neuron-specific disease. © The Author (2014). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. 40Ar/39Ar geochronology of submarine Mauna Loa volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Jicha, Brian R.; Rhodes, J. Michael; Singer, Brad S.; Garcia, Michael O.

    2012-09-01

    New geochronologic constraints refine the growth history of Mauna Loa volcano and enhance interpretations of the petrologic, geochemical, and isotopic evolution of Hawaiian magmatism. We report results of 40Ar/39Ar incremental heating experiments on low-K, tholeiitic lavas from the 1.6 km high Kahuku landslide scarp cutting Mauna Loa's submarine southwest rift zone, and from lavas in a deeper section of the rift. Obtaining precise40Ar/39Ar ages from young, tholeiitic lavas containing only 0.2-0.3 wt.% K2O is challenging due to their extremely low radiogenic 40Ar contents. Analyses of groundmass from 45 lavas yield 14 new age determinations (31% success rate) with plateau and isochron ages that agree with stratigraphic constraints. Lavas collected from a 1250 m thick section in the landslide scarp headwall were all erupted around 470 ± 10 ka, implying an extraordinary period of accumulation of ˜25 mm/yr, possibly correlating with the peak of the shield-building stage. This rate is three times higher than the estimated vertical lava accumulation rate for shield-building at Mauna Kea (8.6 ± 3.1 mm/yr) based on results from the Hawaii Scientific Drilling Project. Between ˜470 and 273 ka, the lava accumulation rate along the southwest rift zone decreased dramatically to ˜1 mm/yr. We propose that the marked reduction in lava accumulation rate does not mark the onset of post-shield volcanism as previously suggested, but rather indicates the upward migration of the magma system as Mauna Loa evolved from a submarine stage of growth to one that is predominantly subaerial, thereby cutting off supply to the distal rift zone. Prior to ˜250 ka, lavas with Loihi-like isotopic signatures were erupted along with lavas having typical Mauna Loa values, implying greater heterogeneity in the plume source earlier in Mauna Loa's growth. In addition to refining accumulation rates and the isotopic evolution of the lavas erupted along the southwest rift zone, our new40Ar/39Ar results

  3. Perception of Lava Flow Hazards and Risk at Mauna Loa and Hualalai Volcanoes, Kona, Hawaii

    NASA Astrophysics Data System (ADS)

    Gregg, C. E.; Houghton, B. F.; Johnston, D. M.; Paton, D.; Swanson, D. A.

    2001-12-01

    The island of Hawaii is composed of five sub-aerially exposed volcanoes, three of which have been active since 1801 (Kilauea, Mauna Loa, Hualalai). Hawaii has the fastest population growth in the state and the local economy in the Kona districts (i.e., western portion of the island) is driven by tourism. Kona is directly vulnerable to future lava flows from Mauna Loa and Hualalai volcanoes, as well as indirectly from the effects of lava flows elsewhere that may sever the few roads that connect Kona to other vital areas on the island. A number of factors such as steep slopes, high volume eruptions, and high effusion rates, combine to mean that lava flows from Hualalai and Mauna Loa can be fast-moving and hence unusually hazardous. The proximity of lifelines and structures to potential eruptive sources exacerbates societies' risk to future lava flows. Approximately \\$2.3 billion has been invested on the flanks of Mauna Loa since its last eruption in 1984 (Trusdell 1995). An equivalent figure has not yet been determined for Hualalai, but an international airport, several large resort complexes, and Kailua-Kona, the second largest town on the island, are down-slope and within 15km of potential eruptive Hualalai vents. Public and perhaps official understanding of specific lava flow hazards and the perceptions of risk from renewed volcanism at each volcano are proportional to the time lapsed since the most recent eruption that impacted Kona, rather than a quantitative assessment of risk that takes into account recent growth patterns. Lava flows from Mauna Loa and Hualalai last directly impacted upon Kona during the notorious 1950 and circa 1801 eruptions, respectively. Various non-profit organizations; local, state and federal government entities; and academic institutions have disseminated natural hazard information in Kona but despite the intuitive appeal that increased hazard understanding and risk perception results in increased hazard adjustment adoption, this

  4. Randomized, controlled, double-blind trial with ivermectin on Loa loa microfilaraemia: efficacy of a low dose (approximately 25 microg/kg) versus current standard dose (150 microg/kg).

    PubMed

    Kamgno, Joseph; Pion, Sébastien D S; Tejiokem, Mathurin C; Twum-Danso, Nana A Y; Thylefors, Björn; Boussinesq, Michel

    2007-08-01

    Neurological serious adverse events (SAEs) following ivermectin treatment may occur in individuals harbouring high Loa loa microfilarial densities and are of major concern in the context of mass ivermectin distributions organized in Africa for onchocerciasis and lymphatic filariasis control. As those SAEs are induced by the rapid and massive microfilaricidal effect of a standard dose of ivermectin (150 microg/kg), we performed a randomized, controlled, double-blind trial to determine whether ivermectin given as: (a) a single low dose of 1.5mg (i.e. 25 microg/kg for a 60 kg person); or (b) two doses of 1.5mg given at a 2 week interval leads to a more progressive decrease in Loa microfilarial loads compared with the standard dosage. A low dose of ivermectin brought about a significantly smaller decrease in Loa microfilaraemia than the standard dose. However, this decrease was not sufficiently different from that obtained after the standard dose to be acceptable to public health programmes, which require a wide safety margin. A second low dose of ivermectin given 15 days after the first dose did not lead to a further decrease in Loa microfilaraemia. Lastly, the variability in the response observed in the group treated with 25 microg/kg suggests that even lower doses would have no effect on a significant number of patients. Ivermectin given at a low dose (

  5. The Kea- and Loa- trends and magma genesis in the Hawaiian mantle plume

    NASA Astrophysics Data System (ADS)

    Ren, Z.; Ingle, S.; Takahashi, E.; Hirano, N.; Hirata, T.; Tatsumi, Y.

    2005-12-01

    The Hawaiian-Emperor volcanic island and seamount chain has been created by a hot mantle plume located beneath the Pacific lithosphere. The shield volcanoes of the Hawaiian islands are distributed in two curvilinear parallel trends, termed _eKea_Eand _eLoa_E(Jackson et al., 1972). Lavas from these two trends are commonly believed to have different geochemical characteristics (Tatsumoto, 1978; Frey et al., 1994; Hauri, 1996; Lassiter et al., 1996; Abouchami et al., 2005). The Kea- and Loa- geochemical trends within the Hawaiian shield volcanoes have been interpreted to reflect melting above a compositionally concentrically zoned (Hauri, 1996; Lassiter et al., 1996; Kurz et al., 1996; DePaolo et al., 2001) or compositionally left-right asymmetrically zoned mantle plume (Abouchami et al., 2005). In order to evaluate the homogeneity of the mantle plume source sampled by the Kea- and Loa- trends, we analyzed major and trace element compositions of olivine-hosted melt inclusions from Hawaiian shield lavas, using EPMA and Laser ICP-MS. We selected lava samples form submarine Hana Ridge, Haleakala volcano (Kea trend) and submarine exposures of the Makapuu stage, Koolau volcano (Loa trend), respectively. We found both Kea- and Loa-like major and trace element compositions from olivine-hosted melt inclusions in individual, shield-stage Hawaiian volcanoes, even within single rock samples. We infer from these data that although one mantle source component may dominate a single lava flow, the two (or more) mantle source components are consistently represented to some extent in all lavas, regardless of the specific geographic location of the volcano. On the basis of whole rock geochemical characteristics (Ren et al., J. pet., 2004; 2005) combined with the melt inclusion data (Ren et al., 2005, Nature), we propose a Hawaiian mantle plume characterized by more random heterogeneity than would be present in a simple compositionally zoned mantle plume. The geochemical differences in

  6. What do Kauai's dikes tell us about the Loa and Kea trends?

    NASA Astrophysics Data System (ADS)

    Utami, S.; Weis, D.; Garcia, M. O.

    2013-12-01

    Kauai, the northernmost of the main Hawaiian Islands, is dominated (>98%) by shield stage volcanism, which is predominantly exposed on its western and northern flanks. Surface exposures of shield stage volcanism (Waimea Canyon Basalts, WCB) on Kauai have been dated from 5.1 to 4.0 Ma [1]. Numerous steeply dipping dikes cut the Napali Member of the WCB along the Waimea Canyon and Napali Coast [2]. We present results of major and trace element, and Pb-Sr-Nd-Hf isotopic characterization of 11 whole-rocks and 13 glasses from WCB dikes. All rocks and glasses are tholeiitic basalts. Major element compositions reflect mostly olivine fractionation and accumulation. Trace element patterns for the samples are typical of ocean island basalts (OIB), with moderate enrichment in high field strength and large ion lithophile elements. C1 chondrite normalized (La/Yb)n vary from 2.76 to 4.75. Dikes plot comparably with shield stage Kauai lavas on the Nb-Zr-Y plot, with Nb/Y = 0.373-0.713 and Zr/Y = 3.93-6.18 [1,3]. Hence dikes plot above and along the lower boundary of the Iceland array [4] with other Hawaiian shield lavas [1,5]. Pb isotopic ratios are intermediate (206Pb/204Pb = 37.99-38.02; 207Pb/204Pb = 15.45-15.47; 208Pb/204Pb = 37.86-38.10) and straddle along the Kea and Loa boundary [6,7] with 208Pb*/206Pb* = 0.9428-0.9492 i.e. non-diagnostic of either trend. Sr, Nd and Hf isotopic compositions are also intermediate, even in binary plots, and fall at the intersection of the Loa and Kea fields. Variations in Zr/Nb and 208Pb*/206Pb* show apparent eastward enrichment from Kauai towards the younger West Kaena Ridge [5]. These observations appear to suggest the presence of the Loa enriched signature until the emergence of Waianae, which has a Kea signature [6]. These results confirm the re-emergence of the Loa component in Hawaiian lavas (previously found in a few south Kauai lavas [1] and in two lavas from the Daikakuji Seamount [8] located just south of the Bend in the Hawaiian

  7. Application of Earthquake Subspace Detectors at Kilauea and Mauna Loa Volcanoes, Hawai`i

    NASA Astrophysics Data System (ADS)

    Okubo, P.; Benz, H.; Yeck, W.

    2016-12-01

    Recent studies have demonstrated the capabilities of earthquake subspace detectors for detailed cataloging and tracking of seismicity in a number of regions and settings. We are exploring the application of subspace detectors at the United States Geological Survey's Hawaiian Volcano Observatory (HVO) to analyze seismicity at Kilauea and Mauna Loa volcanoes. Elevated levels of microseismicity and occasional swarms of earthquakes associated with active volcanism here present cataloging challenges due the sheer numbers of earthquakes and an intrinsically low signal-to-noise environment featuring oceanic microseism and volcanic tremor in the ambient seismic background. With high-quality continuous recording of seismic data at HVO, we apply subspace detectors (Harris and Dodge, 2011, Bull. Seismol. Soc. Am., doi: 10.1785/0120100103) during intervals of noteworthy seismicity. Waveform templates are drawn from Magnitude 2 and larger earthquakes within clusters of earthquakes cataloged in the HVO seismic database. At Kilauea, we focus on seismic swarms in the summit caldera region where, despite continuing eruptions from vents in the summit region and in the east rift zone, geodetic measurements reflect a relatively inflated volcanic state. We also focus on seismicity beneath and adjacent to Mauna Loa's summit caldera that appears to be associated with geodetic expressions of gradual volcanic inflation, and where precursory seismicity clustered prior to both Mauna Loa's most recent eruptions in 1975 and 1984. We recover several times more earthquakes with the subspace detectors - down to roughly 2 magnitude units below the templates, based on relative amplitudes - compared to the numbers of cataloged earthquakes. The increased numbers of detected earthquakes in these clusters, and the ability to associate and locate them, allow us to infer details of the spatial and temporal distributions and possible variations in stresses within these key regions of the volcanoes.

  8. Temporal helium isotopic variations within Hawaiian volcanoes: Basalts from Mauna Loa and Haleakala

    SciTech Connect

    Kurz, M.D.; O'Brien, P.A. ); Garcia, M.O. ); Frey, F.A. )

    1987-11-01

    Helium isotope ratios in basalts spanning the subaerial eruptive history of Mauna Loa and Haleakala vary systematically with eruption age. In both volcanoes, olivine mineral separates from the oldest samples have the highest {sup 3}He/{sup 4}he ratios. The Haleakala samples studied range in age from roughly one million years to historic time, while the Mauna Loa samples are radiocarbon dated flows younger than 30,000 years old. The Honomanu tholeiites are the oldest samples from Haleakala and have {sup 3}He/{sup 4}he ratios that range from 13 to 16.8X atmospheric, while the younger Kula and Hana series alkali basalts all have {sup 3}He/{sup 4}He close to 8X atmospheric. A similar range is observed on Manua Loa; the oldest samples have {sup 3}He/{sup 4}He ratios of 15 to 20X atmospheric, with a relatively smooth decrease to 8X atmospheric with decreasing age. The consistent trend of decreasing {sup 3}He/{sup 4}he ratio with time in both volcanoes, coherence between the helium and Sr and Nd isotopes (for Haleakala), and the similarity of {sup 3}He/{sup 4}He in the late stage basalts to depleted mid-ocean ridge basalt (MORB) helium, argue against the decrease being the result of radiogenic ingrowth of {sup 4}He. The data strongly suggest an undegassed mantle source for the early shield building stages of Hawaiian volcanism, and are consistent with the hotspot/mantle plume model. The data are difficult to reconcile with models for Hawaiian volcanism that require recycled oceanic crust or derivation from a MORB-related upper mantle source. The authors interpret the decrease in {sup 3}He/{sup 4}He with volcano evolution to result from an increasing involvement of depleted mantle and/or lithosphere during the late stages of Hawaiian volcanism.

  9. Tropospheric ozone trends at Mauna Loa Observatory tied to decadal climate variability

    NASA Astrophysics Data System (ADS)

    Lin, Meiyun; Horowitz, Larry W.; Oltmans, Samuel J.; Fiore, Arlene M.; Fan, Songmiao

    2014-02-01

    A potent greenhouse gas and biological irritant, tropospheric ozone is also the primary source of atmospheric hydroxyl radicals, which remove numerous hazardous trace gases from the atmosphere. Tropospheric ozone levels have increased in spring at remote sites in the mid-latitudes of the Northern Hemisphere over the past few decades; this increase has been attributed to a growth in Asian precursor emissions. In contrast, 40 years of continuous measurements at Mauna Loa Observatory in Hawaii reveal little change in tropospheric ozone levels during spring (March-April), but a rise in autumn (September-October). Here we examine the contribution of decadal shifts in atmospheric circulation patterns to decadal variability in tropospheric ozone levels at Mauna Loa using a suite of chemistry-climate model simulations. We show that the flow of ozone-rich air from Eurasia towards Hawaii during spring weakened in the 2000s as a result of La-Niña-like decadal cooling in the eastern equatorial Pacific Ocean. During autumn, in contrast, the flow of ozone-rich air from Eurasia to Hawaii strengthened in the mid-1990s onwards, coincident with the positive phase of the Pacific-North American pattern. We suggest that these shifts in atmospheric circulation patterns can reconcile observed trends in tropospheric ozone levels at Mauna Loa and the northern mid-latitudes in recent decades. We conclude that decadal variability in atmospheric circulation patterns needs to be considered when attributing observed changes in tropospheric ozone levels to human-induced trends in precursor emissions.

  10. The effect of the Mt. Pinatubo aerosol on the NHO3 column over Mauna Loa, Hawaii

    NASA Technical Reports Server (NTRS)

    David, Shelle J.; Murcray, Frank J.; Goldman, Aaron; Rinsland, Curtis P.; Murcray, David G.

    1994-01-01

    A very high resolution infrared solar spectrometer system for the Network for Detection of Stratospheric Change has been routinely operated at the Mauna Loa Observatory in Hawaii since November, 1991. Solar absorption spectra are normally taken one day a week at sunrise. We report the analysis of these spectra for the vertical column amount of nitric acid (HNO3) vapor. The observations began four months after the arrival of volcanic aerosols from Mt. Pinatubo over the site. Although quite variable, total HNO3 columns were initially about 7 x 10(exp 15) molecules/sq cm and have decreased about 30% in the following two years.

  11. Aerosol absorption measurements at Barrow, Mauna Loa and the south pole

    NASA Astrophysics Data System (ADS)

    Bodhaine, Barry A.

    1995-05-01

    Aerosol absorption (σap) has been measured continuously using aethalometers at Barrow, Alaska (1986 to present); Mauna Loa, Hawaii (1990 to present); and south pole, Antarctica (1987-1990). These three stations are part of a network of baseline monitoring stations operated by the Climate Monitoring and Diagnostics Laboratory (CMDL) of the National Oceanic and Atmospheric Administration (NOAA). Condensation nucleus (CN) concentration and multiwavelength aerosol scattering (σsp) have also been measured continuously for many years at these stations. Aethalometer measurements are usually reported in terms of atmospheric black carbon aerosol (BC) concentration using the calibration suggested by the manufacturer. Here we deduce the in situ σap(550 nm) from aethalometer measurements by assuming that the aerosol absorption on the aethalometer filter is enhanced by a factor of 1.9 over that in the atmosphere. This is consistent with using 19 m2 g-1 for the specific absorption of BC on the aethalometer filter and 10 m2 g-1 for the in situ specific absorption of BC in the atmosphere (the ratio of the two specific absorptions is 1.9). Although these values of specific absorption may vary significantly for different environments, the ratio might be expected to be relatively constant. The single-scattering albedo, defined by ω = σsp/(σsp + σap), has been estimated from the simultaneous measurements of σap and σsp. Furthermore, assuming a 1/λ dependence for σap in the 450 to 700-nm wavelength region, multiwavelength σsp measurements allow the estimation of the wavelength dependence of ω. Each station shows a considerable annual cycle in σap, σsp, and ω. The maximum in the Barrow annual cycle is caused primarily by the springtime Arctic haze phenomenon; the maximum in the Mauna Loa annual cycle is caused by the springtime Asian dust transport; and the maximum in the south pole annual cycle is caused by late winter transport from southern midlatitudes. It was found

  12. Interannual variation in the seasonal cycle of carbon dioxide concentration at Mauna Loa

    SciTech Connect

    Enting, I.G.

    1987-05-20

    A band-pass filter is used to obtain an estimate of the seasonal CO/sub 2/ cycle at Mauna Loa from monthly mean concentration data. The signal that is extracted shows interannual variations in the amplitude with, as has frequently been noted, a preponderance of larger amplitudes in recent years. An interesting feature of the signal is that abnormally small amplitude peaks in the (northern) spring are almost always followed by small-amplitude troughs in the following fall but that there is no similar correlation between the amplitudes of peaks in fall and the following spring. This suggests that the amplitude variations reflect changes in individual northern growth seasons.

  13. Stress control of deep rift intrusion at Mauna Loa volcano, Hawaii.

    PubMed

    Amelung, Falk; Yun, Sang-Ho; Walter, Thomas R; Segall, Paul; Kim, Sang-Wan

    2007-05-18

    Mauna Loa volcano, Hawaii, deforms by a combination of shallow dike intrusions in the rift zones and earthquakes along the base of the volcano, but it is not known how the spreading is accommodated in the lower part of the volcanic edifice. We present evidence from interferometric synthetic aperture radar data for secular inflation of a dike-like magma body at intermediate depth in the southwest rift zone during 2002 to 2005. Magma accumulation occurred in a section of the rift zone that was unclamped by previous dikes and earthquakes, suggesting that stress transfer plays an important role in controlling subsurface magma accumulation.

  14. IR Temperatures of Mauna Loa Caldera Obtained with Multispectral Thermal Imager

    SciTech Connect

    Kurzeja, R.J.

    2001-07-18

    A survey of surface temperatures of the Mauna Loa caldera during 7/14/00 and 7/15/00 was made by SRTC in conjunction with a MTI satellite image collection. The general variation of surface temperature appears quite predictable responding to solar heating. The analysis of detailed times series of temperature indicates systematic variations in temperature of 5 C corresponding to time scales of 3-5 minutes and space scales of 10-20 m. The average temperature patterns are consistent with those predicted by the Regional Atmospheric Modeling System (RAMS).

  15. Cross-Reactivity of Filariais ICT Cards in Areas of Contrasting Endemicity of Loa loa and Mansonella perstans in Cameroon: Implications for Shrinking of the Lymphatic Filariasis Map in the Central African Region

    PubMed Central

    Wanji, Samuel; Koudou, Benjamin; Chounna Ndongmo, Patrick W.; Kengne-Ouafo, Jonas A.; Datchoua-Poutcheu, Fabrice R.; Fovennso, Bridget Adzemye; Tayong, Dizzle Bita; Fombad, Fanny Fri; Fischer, Peter U.; Enyong, Peter I.; Bockarie, Moses

    2015-01-01

    Background Immunochromatographic card test (ICT) is a tool to map the distribution of Wuchereria bancrofti. In areas highly endemic for loaisis in DRC and Cameroon, a relationship has been envisaged between high L. loa microfilaria (Mf) loads and ICT positivity. However, similar associations have not been demonstrated from other areas with contrasting levels of L. loa endemicity. This study investigated the cross-reactivity of ICT when mapping lymphatic filariasis (LF) in areas with contrasting endemicity levels of loiasis and mansonellosis in Cameroon. Methodology/Principal Findings A cross-sectional study to assess the prevalence and intensity of W. bancrofti, L. loa and M. perstans was carried out in 42 villages across three regions (East, North-west and South-west) of the Cameroon rainforest domain. Diurnal blood was collected from participants for the detection of circulating filarial antigen (CFA) by ICT and assessment of Mf using a thick blood smear. Clinical manifestations of LF were also assessed. ICT positives and patients clinically diagnosed with lymphoedema were further subjected to night blood collection for the detection of W. bancrofti Mf. Overall, 2190 individuals took part in the study. Overall, 24 individuals residing in 14 communities were tested positive by ICT, with prevalence rates ranging from 0% in the South-west to 2.1% in the North-west. Lymphoedema were diagnosed in 20 individuals with the majority of cases found in the North-west (11/20), and none of them were tested positive by ICT. No Mf of W. bancrofti were found in the night blood of any individual with a positive ICT result or clinical lymphoedema. Positive ICT results were strongly associated with high L. loa Mf intensity with 21 subjects having more than 8,000 L. loa Mf ml/blood (Odds ratio = 15.4; 95%CI: 6.1–39.0; p < 0.001). Similarly, a strong positive association (Spearman’s rho = 0.900; p = 0.037) was observed between the prevalence of L. loa and ICT positivity by area

  16. Cross-Reactivity of Filariais ICT Cards in Areas of Contrasting Endemicity of Loa loa and Mansonella perstans in Cameroon: Implications for Shrinking of the Lymphatic Filariasis Map in the Central African Region.

    PubMed

    Wanji, Samuel; Amvongo-Adjia, Nathalie; Koudou, Benjamin; Njouendou, Abdel Jelil; Chounna Ndongmo, Patrick W; Kengne-Ouafo, Jonas A; Datchoua-Poutcheu, Fabrice R; Fovennso, Bridget Adzemye; Tayong, Dizzle Bita; Fombad, Fanny Fri; Fischer, Peter U; Enyong, Peter I; Bockarie, Moses

    2015-11-01

    Immunochromatographic card test (ICT) is a tool to map the distribution of Wuchereria bancrofti. In areas highly endemic for loaisis in DRC and Cameroon, a relationship has been envisaged between high L. loa microfilaria (Mf) loads and ICT positivity. However, similar associations have not been demonstrated from other areas with contrasting levels of L. loa endemicity. This study investigated the cross-reactivity of ICT when mapping lymphatic filariasis (LF) in areas with contrasting endemicity levels of loiasis and mansonellosis in Cameroon. A cross-sectional study to assess the prevalence and intensity of W. bancrofti, L. loa and M. perstans was carried out in 42 villages across three regions (East, North-west and South-west) of the Cameroon rainforest domain. Diurnal blood was collected from participants for the detection of circulating filarial antigen (CFA) by ICT and assessment of Mf using a thick blood smear. Clinical manifestations of LF were also assessed. ICT positives and patients clinically diagnosed with lymphoedema were further subjected to night blood collection for the detection of W. bancrofti Mf. Overall, 2190 individuals took part in the study. Overall, 24 individuals residing in 14 communities were tested positive by ICT, with prevalence rates ranging from 0% in the South-west to 2.1% in the North-west. Lymphoedema were diagnosed in 20 individuals with the majority of cases found in the North-west (11/20), and none of them were tested positive by ICT. No Mf of W. bancrofti were found in the night blood of any individual with a positive ICT result or clinical lymphoedema. Positive ICT results were strongly associated with high L. loa Mf intensity with 21 subjects having more than 8,000 L. loa Mf ml/blood (Odds ratio = 15.4; 95%CI: 6.1-39.0; p < 0.001). Similarly, a strong positive association (Spearman's rho = 0.900; p = 0.037) was observed between the prevalence of L. loa and ICT positivity by area: a rate of 1% or more of positive ICT results

  17. The origin of Mauna Loa's Nīnole Hills: Evidence of rift zone reorganization

    USGS Publications Warehouse

    Zurek, Jeffrey; Williams-Jones, Glyn; Trusdell, Frank A.; Martin, Simon

    2015-01-01

    In order to identify the origin of Mauna Loa volcano's Nīnole Hills, Bouguer gravity was used to delineate density contrasts within the edifice. Our survey identified two residual anomalies beneath the Southwest Rift Zone (SWRZ) and the Nīnole Hills. The Nīnole Hills anomaly is elongated, striking northeast, and in inversions both anomalies merge at approximately −7 km above sea level. The positive anomaly, modeled as a rock volume of ~1200 km3 beneath the Nīnole Hills, is associated with old eruptive vents. Based on the geologic and geophysical data, we propose that the gravity anomaly under the Nīnole Hills records an early SWRZ orientation, now abandoned due to geologically rapid rift-zone reorganization. Catastrophic submarine landslides from Mauna Loa's western flank are the most likely cause for the concurrent abandonment of the Nīnole Hills section of the SWRZ. Rift zone reorganization induced by mass wasting is likely more common than currently recognized.

  18. Amplified temperature dependence in ecosystems developing on the lava flows of Mauna Loa, Hawai'i

    PubMed Central

    Anderson-Teixeira, Kristina J.; Vitousek, Peter M.; Brown, James H.

    2008-01-01

    Through its effect on individual metabolism, temperature drives biologically controlled fluxes and transformations of energy and materials in ecological systems. Because primary succession involves feedbacks among multiple biological and abiotic processes, we expected it to exhibit complex dynamics and unusual temperature dependence. We present a model based on first principles of chemical kinetics to explain how biologically mediated temperature dependence of “reactant” concentrations can inflate the effective temperature dependence of such processes. We then apply this model to test the hypothesis that the temperature dependence of early primary succession is amplified due to more rapid accumulation of reactants at higher temperatures. Using previously published data from the lava flows of Mauna Loa, HI, we show that rates of vegetation and soil accumulation as well as rates of community compositional change all display amplified temperature dependence (Q10 values of ≈7–50, compared with typical Q10 values of 1.5–3 for the constituent biological processes). Additionally, in young ecosystems, resource concentrations increase with temperature, resulting in inflated temperature responses of biogeochemical fluxes. Mauna Loa's developing ecosystems exemplify how temperature-driven, biologically mediated gradients in resource availability can alter the effective temperature dependence of ecological processes. This mechanistic theory should contribute to understanding the complex effects of temperature on the structure and dynamics of ecological systems in a world where regional and global temperatures are changing rapidly. PMID:18156366

  19. Atmospheric CO{sub 2} concentrations -- Mauna Loa Observatory, Hawaii 1958--1986

    SciTech Connect

    Boden, T.A.

    1986-09-01

    Since 1958, CO{sub 2} concentrations at Mauna Loa Observatory have been obtained using a nondispersive, dual detector, infrared gas analyzer. Air samples are obtained from air intakes at the top of four 7m towers and one 27m tower. Those involved in the monitoring project have attempted to improving sampling techniques, reduce possible contamination sources, and adjust data to represent uncontaminated, true conditions throughout the twenty-eight year sampling period. The gas analyzer is calibrated by standardized CO{sub 2}-in-nitrogen reference gases twice daily. Flask samples are taken twice a month for comparison to the data recorded using the infrared gas analyzer. Data are scrutinized daily for possible contamination and archived on magnetic tape for further scrutiny and adjustment. Daily, monthly, and annual averages are computed for the Mauna Loa data after deletion of contaminated samples and readjustment of the data. These averages have shown a steady rise in annual average concentration from 316 parts per million by volume (ppmv) in 1959 to 346 ppmv in 1986.

  20. The origin of Mauna Loa's Nīnole Hills: Evidence of rift zone reorganization

    NASA Astrophysics Data System (ADS)

    Zurek, Jeffrey; Williams-Jones, Glyn; Trusdell, Frank; Martin, Simon

    2015-10-01

    In order to identify the origin of Mauna Loa volcano's Nīnole Hills, Bouguer gravity was used to delineate density contrasts within the edifice. Our survey identified two residual anomalies beneath the Southwest Rift Zone (SWRZ) and the Nīnole Hills. The Nīnole Hills anomaly is elongated, striking northeast, and in inversions both anomalies merge at approximately -7 km above sea level. The positive anomaly, modeled as a rock volume of ~1200 km3 beneath the Nīnole Hills, is associated with old eruptive vents. Based on the geologic and geophysical data, we propose that the gravity anomaly under the Nīnole Hills records an early SWRZ orientation, now abandoned due to geologically rapid rift-zone reorganization. Catastrophic submarine landslides from Mauna Loa's western flank are the most likely cause for the concurrent abandonment of the Nīnole Hills section of the SWRZ. Rift zone reorganization induced by mass wasting is likely more common than currently recognized.

  1. "The upper limits of vegetation on Mauna Loa, Hawaii": a 50th-anniversary reassessment.

    PubMed

    Juvik, James O; Rodomsky, Brett T; Price, Jonathan P; Hansen, Eric W; Kueffer, Christoph

    2011-02-01

    In January 1958, a survey of alpine flora was conducted along a recently constructed access road across the upper volcanic slopes of Mauna Loa, Hawaii (2525-3397 m). Only five native Hawaiian species were encountered on sparsely vegetated historic and prehistoric lava flows adjacent to the roadway. A resurvey of roadside flora in 2008 yielded a more than fourfold increase to 22 species, including nine native species not previously recorded. Eight new alien species have now invaded this alpine environment, although exclusively limited to a few individuals in ruderal habitat along the roadway. Alternative explanations for species invasion and altitudinal change over the past 50 years are evaluated: (1) changes related to continuing primary succession on ameliorating (weathering) young lava substrates; (2) local climate change; and (3) road improvements and increased vehicular access which promote enhanced car-borne dispersal of alien species derived from the expanding pool of potential colonizers naturalized on the island in recent decades. Unlike alpine environments in temperate latitudes, the energy component (warming) in climate change on Mauna Loa does not appear to be the unequivocal driver of plant invasion and range extension. Warming may be offset by other climate change factors including rainfall and evapotranspiration.

  2. Amplified temperature dependence in ecosystems developing on the lava flows of Mauna Loa, Hawai'i.

    PubMed

    Anderson-Teixeira, Kristina J; Vitousek, Peter M; Brown, James H

    2008-01-08

    Through its effect on individual metabolism, temperature drives biologically controlled fluxes and transformations of energy and materials in ecological systems. Because primary succession involves feedbacks among multiple biological and abiotic processes, we expected it to exhibit complex dynamics and unusual temperature dependence. We present a model based on first principles of chemical kinetics to explain how biologically mediated temperature dependence of "reactant" concentrations can inflate the effective temperature dependence of such processes. We then apply this model to test the hypothesis that the temperature dependence of early primary succession is amplified due to more rapid accumulation of reactants at higher temperatures. Using previously published data from the lava flows of Mauna Loa, HI, we show that rates of vegetation and soil accumulation as well as rates of community compositional change all display amplified temperature dependence (Q(10) values of approximately 7-50, compared with typical Q(10) values of 1.5-3 for the constituent biological processes). Additionally, in young ecosystems, resource concentrations increase with temperature, resulting in inflated temperature responses of biogeochemical fluxes. Mauna Loa's developing ecosystems exemplify how temperature-driven, biologically mediated gradients in resource availability can alter the effective temperature dependence of ecological processes. This mechanistic theory should contribute to understanding the complex effects of temperature on the structure and dynamics of ecological systems in a world where regional and global temperatures are changing rapidly.

  3. Differential arsenic binding in the sediments of two sites in Chile's lower Loa River basin.

    PubMed

    Bugueño, Manuel P; Acevedo, Sara E; Bonilla, Carlos A; Pizarro, Gonzalo E; Pasten, Pablo A

    2014-01-01

    Fluvial sediments from two lower Loa River basin sites in northern Chile were compared in order to probe the effects of vegetation and organic matter (OM) on As accumulation in fluvial environments. The two sites were the Sloman dam, which lacks macrophytes and has a low OM content (2.4%) in sediments, and the Quillagua Oasis, which is 23 km downstream from the Sloman site and has a higher OM (6.2%) in sediments and abundant aquatic plant life. The Quillagua site had preferential As enrichment with a co-occurrence pattern that differed from that of the Sloman site, which had a lower As concentration (1528 vs. 262 mg/kg d.w., respectively). At the Quillagua site, As concentration was strongly correlated with Mn and OM (r = 0.91 and 0.85, respectively); while at the Sloman site, As concentration in sediments was significantly correlated with Ca and Sr (r = 0.63 and 0.54, respectively). Sequential extraction analyses showed that the Sloman site had higher percentage of easily exchangeable As within the surface sediment (12%, 45 mg/kg d.w.) compared with the Quillagua site (3%, 40 mg/kg d.w.). These contrasting results suggest that both vegetation and OM control the immobilization and accumulation of As in the arid Loa River basin.

  4. Imaging the crustal magma sources beneath Mauna Loa and Kilauea volcanoes, Hawaii

    USGS Publications Warehouse

    Okubo, P.G.; Benz, H.M.; Chouet, B.A.

    1997-01-01

    Three-dimensional seismic P-wave traveltime tomography is used to image the magma sources beneath Mauna Loa and Kilauea volcanoes, Hawaii. High-velocity bodies (>6.4 km/s) in the upper 9 km of the crust beneath the summits and rift zones of the volcanoes correlate with zones of high magnetic intensities and are interpreted as solidified gabbro-ultramafic cumulates from which the surface volcanism is derived. The proximity of these high-velocity features to the rift zones is consistent with a ridge-spreading model of the volcanic flank. Southeast of the Hilina fault zone, along the south flank of Kilauea, low-velocity material (<6.0 km/s) is observed extending to depths of 9-11 km, indicating that the Hilina fault may extend possibly as deep as the basal decollement. Along the southeast flank of Mauna Loa, a similar low -velocity zone associated with the Kaoiki fault zone is observed extending to depths of 6-8 km. These two upper crustal low-velocity zones suggest common stages in the evolution of the Hawaiian shield volcanoes in which these fault systems are formed as a result of upper crustal deformation in response to magma injection within the volcanic edifice.

  5. Absence of an Association Between Plasmodium falciparum Infection and Post-Ivermectin Loa-Related Non-Neurologic Serious Adverse Events

    PubMed Central

    Fokom-Domgue, Joël; Pion, Sébastien D.; Gounoue, Raceline; Akame, Julie; Nguipdop-Djomo, Patrick; Twum-Danso, Nana A. Y.; Thylefors, Björn; Boussinesq, Michel; Kamgno, Joseph

    2014-01-01

    Although ivermectin treatment can induce serious adverse events (SAEs) in individuals harboring high Loa loa microfilaremia (mf), not all patients with high mf levels develop such reactions, suggesting that cofactors may be involved. A study was conducted in Cameroon to investigate the possible role of Plasmodium coinfection at the time of ivermectin treatment in the development of SAEs. Before their first ivermectin treatment, thick smears were obtained from 4,175 individuals to determine the burden of Plasmodium sp., L. loa, and Mansonella perstans. After treatment, 18 (4.3 per 1,000) patients developed a non-neurologic SAE. Logistic regression analysis, adjusting for age, sex, P. falciparum infection, and M. perstans infection intensities, confirmed that L. loa mf was the main risk factor for SAEs. We found no evidence that coinfection with P. falciparum at the time of ivermectin treatment was associated with the occurrence of Loa-related SAEs in this population. PMID:24420781

  6. Diversion of lava flows by aerial bombing — lessons from Mauna Loa volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Lockwood, J. P.; Torgerson, F. A.

    1980-12-01

    Lava flows from Mauna Loa volcano can travel the long distances from source vents to populated areas of east Hawaii only if heat-insulating supply conduits (lava channels and/or lava tubes) are constructed and maintained, so as to channelize the flow and prevent heat loss during transport. Lava is commonly directed into such conduits by horseshoe-or lyre-shaped spatter cones-loose accumulations of partially welded scoria formed around principal vents during periods of high fountaining. These conduit systems commonly develop fragile areas amenable to artificial disruption by explosives during typical eruptions. If these conduits can be broken or blocked, lava supply to the threatening flow fronts will be cut off or reduced. Explosives were first suggested as a means to divert lava flows threatening Hilo, Hawaii during the eruption of 1881. They were first used in 1935, without significant success, when the Army Air Force bombed an active pahoehoe channel and tube system on Mauna Loa’s north flank. Channel walls of a Mauna Loa flow were also bombed in 1942, but again there were no significant effects. The locations of the 1935 and 1942 bomb impact areas were determined and are shown for the first time, and the bombing effects are documented. Three days after the 1942 bombing the spatter cone surrounding the principal vent partially collapsed by natural processes, and caused the main flow advancing on Hilo to cease movement. This suggested that spatter cones might be a suitable target for future lava diversion attempts. Because ordnance, tactics, and aircraft delivery systems have changed dramatically since 1942, the U.S. Air Force conducted extensive testing of large aerial bombs (to 900 kg) on prehistoric Mauna Loa lavas in 1975 and 1976, to evaluate applicability of the new systems to lava diversion. Thirty-six bombs were dropped on lava tubes, channels, and a spatter cone in the tests, and it was verified that spatter cones are especially fragile. Bomb crater

  7. MULTISCALE THERMAL-INFRARED MEASUREMENTS OF THE MAUNA LOA CALDERA, HAWAII

    SciTech Connect

    L. BALICK; A. GILLESPIE; ET AL

    2001-03-01

    Until recently, most thermal infrared measurements of natural scenes have been made at disparate scales, typically 10{sup {minus}3}-10{sup {minus}2} m (spectra) and 10{sup 2}-10{sup 3} m (satellite images), with occasional airborne images (10{sup 1} m) filling the gap. Temperature and emissivity fields are spatially heterogeneous over a similar range of scales, depending on scene composition. A common problem for the land surface, therefore, has been relating field spectral and temperature measurements to satellite data, yet in many cases this is necessary if satellite data are to be interpreted to yield meaningful information about the land surface. Recently, three new satellites with thermal imaging capability at the 10{sup 1}-10{sup 2} m scale have been launched: MTI, TERRA, and Landsat 7. MTI acquires multispectral images in the mid-infrared (3-5{micro}m) and longwave infrared (8-10{micro}m) with 20m resolution. ASTER and MODIS aboard TERRA acquire multispectral longwave images at 90m and 500-1000m, respectively, and MODIS also acquires multispectral mid-infrared images. Landsat 7 acquires broadband longwave images at 60m. As part of an experiment to validate the temperature and thermal emissivity values calculated from MTI and ASTER images, we have targeted the summit region of Mauna Loa for field characterization and near-simultaneous satellite imaging, both on daytime and nighttime overpasses, and compare the results to previously acquired 10{sup {minus}1} m airborne images, ground-level multispectral FLIR images, and the field spectra. Mauna Loa was chosen in large part because the 4x6km summit caldera, flooded with fresh basalt in 1984, appears to be spectrally homogeneous at scales between 10{sup {minus}1} and 10{sup 2} m, facilitating the comparison of sensed temperature. The validation results suggest that, with careful atmospheric compensation, it is possible to match ground measurements with measurements from space, and to use the Mauna Loa validation

  8. Lidar Observations of the Middle Atmospheric Thermal Tides at Mauna Loa (19.5 Comparison with HRDI and GSWM

    NASA Technical Reports Server (NTRS)

    McDermid, I.; Leblanc, T.; Ortland, D.

    1998-01-01

    The tidal signature in the middle atmospheric thermal structure (15-95 km) at Mauna Loa, Hawaii, (19.5is investigated using more than 145 hours of nighttime lidar measurements obtained during October 3-16, 1996 and October 2-11, 1997.

  9. Atmospheric carbon dioxide at Mauna Loa Observatory 2. Analysis of the NOAA GMCC data, 1974--1985

    SciTech Connect

    Thoning, K. W.; Tans, P. P.; Komhyr, W. D.

    1989-06-20

    The first 12 years (1974--1985) of continuous atmospheric CO/sub 2/ measurements from the NOAA GMCC programs at the Mauna Loa Observatory in Hawaii are analyzed. Hourly and daily variations in the concentration of CO/sub 2/ due to local sources and sinks are described, with subsequent selection of data representing background concentrations. A digital filtering technique using the fast Fourier transform and low-pass filters was used to smooth the selected data and to separate the seasonal cycle from the long-term increase in CO/sub 2/. The amplitude of the seasonal cycle was found to be increasing at a rate of 0.05/plus minus/0.02 ppm yr/sup /minus/1/. The average growth rate of CO/sub 2/ was 1.42/plus minus/0.02 ppm yr/sup /minus/1/, and the fraction of CO/sub 2/ remaining in the atmosphere from fossil fuel combustion was 59%. A comparison between the Mauna Loa continuous CO/sub 2/ data and the CO/sub 2/ flask sample data from the sea level site at Cape Kumukahi, Hawaii, showed that the amplitude of the seasonal cycle at Cape Kumakahi was 23% larger than at Mauna Loa, with the phase of the cycle at Mauna Loa lagging the cycle at Cape Kumukahi by about 1-2 weeks. /copyright/ American Geophysical Union 1989

  10. Long, paired A'A/Pahoehoe flows of Mauna Loa: Volcanological significance and insights they provide into volcano plumbing systems

    NASA Technical Reports Server (NTRS)

    Rowland, Scott K.; Walker, George P. L.

    1987-01-01

    The long lava flows of Mauna Loa, Hawaii have been cited as Earth's closed analogs to the large Martian flows. It is therefore important to understand the flow mechanics and characteristics of the Mauna Loa flows and to make use of these in an attempt to gain insights into Martian eruptive processes. Two fundamentally different kinds of long lava flows can be distinguished on Hawaiian volcanoes as in Martian flows. The two kinds may have identical initial viscosities, chemical compositions, flow lengths, and flow volumes, but their flow mechanisms and thermal energy budgets are radically different. One travels a distance set by the discharge rate as envisaged by Walker and Wadge, and the other travels a distance set mainly by the eruption duration and ground slope. In the Mauna Loa lavas, yield strength becomes an important flow morphology control only in the distal part of a'a lavas. The occurrence of paired flows on Mauna Loa yields insights into the internal plumbing systems of the volcano, and it is significant that all of the volume of the a'a flow must be stored in a magma chamber before eruption, while none of the volume of the pahoehoe needs to be so stored. Differentiation between the two kinds of flows on images of Martian volcanoes is possible and hence an improved understanding of these huge structures is acquired.

  11. Results of a Longer Term NDACC Measurements Comparison Campaign at Mauna Loa Observatory

    NASA Astrophysics Data System (ADS)

    McGee, Thomas J.; Twigg, Laurence W.; Sumnicht, Grant K.; Leblanc, Thierry; Barnes, John

    2016-06-01

    Between November, 2015 and January, 2015, the Goddard Space Flight Center operated a pair of lidar instruments at the NOAA facility at Mauna Loa on the Big Island of Hawaii (Lat. 19.5N, Lon. 155.5 W, Altitude 3.397 km). Measurements were made during six different four week periods during this time period by both the NASA GSFC Stratospheric Ozone Lidar (STROZ) and the Aerosol and Temperature (ATL) lidar. Also making measurements were the JPL Stratospheric Ozone Lidar and the NOAA Aerosol and Water Vapor Lidar. All instruments participate and archive data with the Network for the Detection of Atmospheric Composition Change. Measurement comparisons were made among various instruments in accordance with the standard intercomparison protocols of the NDACC.

  12. Utilization of SAGE aerosol profiles in the analysis of Mauna Loa stratospheric lidar data

    NASA Technical Reports Server (NTRS)

    Fernald, F. G.; Murcray, D. G.

    1984-01-01

    A systematic approach to analyzing lidar data collected at NOAA's Mauna Loa Observatory (MLO) was developed which relies on parameters derived from SAGE satellite extinction profile measurements to verify boundary conditions applied to analysis. The approach also provides a means of assessing the uncertainties associated with the various inputs, so that the accuracy of the analysis of the MLO lidar data is available. The stratosphere during the 1980 to 1981 period was only mildly perturbed and could be easily represented by the SAMII/SAGE background aerosol model. The MLO lidar observations collected during this period provided stratospheric optical depths with uncertainties ranging between 15% and 25%. Uncertainties in the aerosol optical model contribute errors of 3% to 4% in the computed optical depths. Most of the optical depth uncertainty is associated with the calibration assumption in which no marked improvement can be expected.

  13. The Mauna Loa sulfur flow as an analog to secondary sulfur flows on Io

    NASA Technical Reports Server (NTRS)

    Greeley, R.; Theilig, E.; Christensen, P.

    1984-01-01

    Independent evidence suggests that both sulfur and silicate materials exist on the surface of Io. Spectral data indicate the presence of sulfur compounds, some of which are suggested to be of fumarolic origin. Morphological evidence and inferences of the physical properties of some land-forms suggest that silicate volcanism has occurred, which would involve temperatures 650 C or greater. Because the liquidus of sulfur is only about 115 C, it is likely that sulfur in close proximity to 'hot spots' or to active silicate volcanic areas on Io would be melted and mobilized as flows. The Mauna Loa sulfur flow may serve as an analog for such flows, as it consists of fumarolic sulfur that was melted as a consequence of a basaltic eruption and produced a small flow superimposed on silicate lavas.

  14. Sea surface temperature variation linked to elemental mercury concentrations measured on Mauna Loa

    NASA Astrophysics Data System (ADS)

    Carbone, F.; Landis, M. S.; Gencarelli, C. N.; Naccarato, A.; Sprovieri, F.; De Simone, F.; Hedgecock, I. M.; Pirrone, N.

    2016-07-01

    The Hg0 time series recorded at the Mauna Loa Observatory (MLO) in Hawaii between 2002 and 2009 has been analyzed using Empirical Mode Decomposition. This technique has been used in numerous contexts in order to identify periodical variations in time series data. The periodicities observed in the tropical Pacific sea surface temperature (SST), through the data collected from five buoys, are also observed in Hg0 concentrations and the relative humidity measured at the MLO. The lag times in the observed periodicities are related to the position of the buoys with respect to the measurement site. This demonstrates a direct link between climatological phenomena, in this case SST, and measured Hg0 and reflects the influence of ocean SST on Hg0 evasion. This is the first long-term experimental evidence of such a direct effect on Hg0 evasion from the oceanic surface driven by temperature.

  15. Orographic cloud over the eastern slopes of Mauna Loa volcano, Hawaii, related to insolation and wind

    SciTech Connect

    Garrett, A.J.

    1980-07-01

    During the period 1 to 11 June 1978, solar radiation and other meteorological data were gathered at eight stations arranged in a nearly linear transection extending from the coast at Hilo, Hawaii to Mauna Loa Observatory, 60 km inland and 3400 m higher. Solar radiation distributions followed climatological rainfall patterns; the driest areas were sunniest. At the wettest sites, underneath the orographic cloud, measured global solar radiation was only 50% of clear-sky potential, and the diffuse component probably accounted for more than 50% of the global radiation. The orographic cloud developed during the day in upslope winds, and sharply reduced afternoon solar radiation at all sites. Total cloudiness, and hence insolation, varied greatly from day to day due to the passage of trade wind cloud masses and jet stream cirrus.

  16. Effects of surface reflectance on skylight polarization measurements at the Mauna Loa Observatory.

    PubMed

    Dahlberg, Andrew R; Pust, Nathan J; Shaw, Joseph A

    2011-08-15

    An all-sky imaging polarimeter was deployed in summer 2008 to the Mauna Loa Observatory in Hawaii to study clear-sky atmospheric skylight polarization. The imager operates in five wavebands in the visible and near infrared spectrum and has a fisheye lens for all-sky viewing. This paper describes the deployment and presents comparisons of the degree of skylight polarization observed to similar data observed by Coulson with a principal-plane scanning polarimeter in the late 1970s. In general, the results compared favorably to those of Coulson. In addition, we present quantitative results correlating a variation of the maximum degree of polarization over a range of 70-85% to fluctuation in underlying surface reflectance and upwelling radiance data from the GOES satellite.

  17. Infrared Measurements of Atmospheric Gases Above Mauna Loa, Hawaii, in February 1987

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Goldman, A.; Murcray, F. J.; Murcray, F. H.; Blatherwick, R. D.; Murcray, D. G.

    1988-01-01

    Infrared solar absorption spectra recorded at 0.02/ cm resolution from the National Oceanic and Atmospheric Administration (NOAA) Geophysical Monitoring for Climate Change (GMCC) program station at Mauna Loa, Hawaii (latitude 19.5 deg N, longitude 155.6 deg W, elevation 3.40 km), in February 1997 have been analyzed to determine simultaneous total vertical column amounts for 13 atmospheric gases. Average tropospheric concentrations of CO2, N2O, CH4, and CHCIF2 and the daytime diurnal variations or the total columns of NO and NO2 have also been inferred. The retrieved total columns (in molecules /sq cm) of the nondiurnally varying gases are 1.6 +/- 0.2 x 10(exp 15) for HCl, 5.9 +/- 1.2 x 10(exp 15) for HNO3, 2.0 +/- 0.2 x 10(exp 21) for H2O16, 4.4 +/- 0.7 x 10(exp 18) for H2O18, 2.7 +/- 0.1 x 10(exp 17) for HDO, 2.3 +/- 0.2 x 10(exp 19) for CH4, 5.0 +/- 0.5 x 10(exp 21) for CO2, 6.7 +/- 0.8 x 10(exp 18) for O3, 4.3 +/- 0.4 x 10(exp 18) for N2O, 1.0 +/- 0.2 x 10(exp 16) for C2H6, and 9.7 +/- 2.5 x 10(exp 14) for CHClF2. We compare the total column measurements of HCl and HNO3 with previously reported ground-based, aircraft, and satellite measurements. The results for HCl are or particular interest because of the expected temporal increase in the concentration of this gas in the stratosphere. However, systematic differences among stratospheric HCl total column measurements from 1978 to 1980 and the absence of observations of free tropospheric HCl above Mauna Loa make it impossible to obtain a reliable estimate of the trend in the total burden of HCl. The measured HNO3 total column is consistent with aircraft measurements from approx. 12 km altitude. The O3 total column deduced from the IR spectra agrees with correlative Mauna Loa Umkehr measurements within the estimated error limits. The column-averaged D/H ratio of water vapor is (68 +/- 9) x- 10(exp -6), which is 0.44 +/- 0.06 times the reference value of 155.76 x 10(exp -6) for standard mean ocean water (SMOW). This

  18. Differentiation in the cumulates from a Mauna Loa, Hawaii magma chamber

    SciTech Connect

    Schwindinger, K.R.; Anderson, A.F.

    1985-01-01

    The interstitial glass in cognate nodules from Mauna Loa, has by chemical diffusion or convective fluid transport, remained in equilibrium with the overlying magma. The glass bearing nodules were collected from Damona Cone on the southwest rift zone of Mauna Loas. The nodules have approximately 15% olivine, 40% orthopyroxene plus clinopyroxene (3-20%), and 85% plagioclase plus vescicular glass (2-25%). Olivine norites have anhedral olivine mantled with anhedral orthopyroxene, subhedral to euhedral pyroxene, anhedral plagioclase, and 20 to 25% glass. Olivine gabbros have anhedral olivine, subequant, anhedral to subhedral pyroxene and plagioclase and less than 10% glass. The bulk composition of greater than 15%, MgO, with the textures, indicate the nodules are an accumulative origin. Thus these nodules are partially solidified pieces of crystal/liquid accumulative mush. The compositions of the olivines are Fa 18 to 25 mole percent, of the plagioclases are An 70 to 80 mole percent. The composition of the orthopyroxene is En76 Fs19 Wo5, and of the clinopyroxene is En50 Fall Wo30. The composition of the interstitial glasses is: SiO2 52.54, TiO2 2.04, Al2O3 14.39, FeO 11.47, MgO 7.15, CaO 10.28, Na20 1.42, K2O 0.39, P2O5 0.21. The low Na2O is from two nodules that may have experienced high temperature alteration. The uniformity of the glass composition, in contrast to its large variation in the mode, suggests the interstitial liquid in the mush has remained in equilibrium with some large reservoir of MgO rich liquid, such as the magma above the mush. Two possible mechanisms of cation exchange between the magma and the interstitial liquid of the mush are chemical diffusion and convective fluid transport.

  19. Angle detector

    NASA Technical Reports Server (NTRS)

    Parra, G. T. (Inventor)

    1978-01-01

    An angle detector for determining a transducer's angular disposition to a capacitive pickup element is described. The transducer comprises a pendulum mounted inductive element moving past the capacitive pickup element. The capacitive pickup element divides the inductive element into two parts L sub 1 and L sub 2 which form the arms of one side of an a-c bridge. Two networks R sub 1 and R sub 2 having a plurality of binary weighted resistors and an equal number of digitally controlled switches for removing resistors from the networks form the arms of the other side of the a-c bridge. A binary counter, controlled by a phase detector, balances the bridge by adjusting the resistance of R sub 1 and R sub 2. The binary output of the counter is representative of the angle.

  20. Geologic map of the northeast flank of Mauna Loa volcano, Island of Hawai'i, Hawaii

    USGS Publications Warehouse

    Trusdell, Frank A.; Lockwood, John P.

    2017-05-01

    SummaryMauna Loa, the largest volcano on Earth, has erupted 33 times since written descriptions became available in 1832. Some eruptions were preceded by only brief seismic unrest, while others followed several months to a year of increased seismicity.The majority of the eruptions of Mauna Loa began in the summit area (>12,000-ft elevation; Lockwood and Lipman, 1987); yet the Northeast Rift Zone (NERZ) was the source of eight flank eruptions since 1843 (table 1). This zone extends from the 13,680-ft-high summit towards Hilo (population ~60,000), the second largest city in the State of Hawaii. Although most of the source vents are farther than 30 km away, the 1880 flow from one of the vents extends into Hilo, nearly reaching Hilo Bay. The city is built entirely on flows erupted from the NERZ, most older than that erupted in 1843.Once underway, Mauna Loa's eruptions can produce lava flows that reach the sea in less than 24 hours, severing roads and utilities in their path. For example, lava flows erupted from the Southwest Rift Zone (SWRZ) in 1950 advanced at an average rate of 9.3 km per hour, and all three lobes reached the ocean within approximately 24 hours (Finch and Macdonald, 1953). The flows near the eruptive vents must have traveled even faster.In terms of eruption frequency, pre-eruption warning, and rapid flow emplacement, Mauna Loa poses an enormous volcanic-hazard threat to the Island of Hawai‘i. By documenting past activity and by alerting the public and local government officials of our findings, we can anticipate the volcanic hazards and substantially mitigate the risks associated with an eruption of this massive edifice.From the geologic record, we can deduce several generalized facts about the geologic history of the NERZ. The middle to the uppermost section of the rift zone were more active in the past 4,000 years than the lower part, perhaps due to buttressing of the lower east rift zone by Mauna Kea and Kīlauea volcanoes. The historical flows

  1. Clinical picture, epidemiology and outcome of Loa-associated serious adverse events related to mass ivermectin treatment of onchocerciasis in Cameroon

    PubMed Central

    Boussinesq, Michel; Gardon, Jacques; Gardon-Wendel, Nathalie; Chippaux, Jean-Philippe

    2003-01-01

    In August 2002, 65 cases of Loa-associated neurological Serious Adverse Events were reported after ivermectin treatment. The first signs, occurring within the 12–24 hours following treatment, included fatigue, generalized arthralgia, and sometimes agitation, mutism, and incontinence. Disorders of consciousness, including coma, generally appeared between 24 and 72 hours, and showed a rapid variation with time. The most frequent objective neurological signs were extrapyramidal. The patients presented with haemorrhages of the conjunctiva and of the retina. Biological examinations showed a massive Loa microfilaruria, the passage of Loa microfilariae into the cerebrospinal fluid, haematuria, and an increase in the C-reactive protein, all of which have been correlated with the high intensity of the initial Loa microfilaraemia. Eosinophil counts decreased dramatically within the first 24 hours, and then rose again rapidly. Electroencephalograms suggested the existence of a diffuse pathological process within the first weeks; the abnormalities disappearing after 3–6 months. Death may occur when patients are not properly managed, i.e. in the absence of good nursing. However, some patients who recovered showed sequelae such as aphasia, episodic amnesia, or extrapyramidal signs. The main risk factor for these encephalopathies is the intensity of the initial Loa microfilaraemia. The disorders of consciousness may occur when there are >50,000 Loa microfilariae per ml. The possible roles of co-factors, such as Loa strains, genetic predisposition of individuals, co-infestations with other parasites, or alcohol consumption, seem to be minor but they should be considered. The mechanisms of the post-ivermectin Loa-related encephalopathies should be investigated to improve the management of patients developing the condition. PMID:14975061

  2. Condensation nuclei and aerosol-scattering extinction measurements at Mauna Loa Observatory: 1974-1985. Data report

    SciTech Connect

    Massey, D.M.; Quakenbush, T.K.; Bodhaine, B.A.

    1987-07-01

    The observatory at Mauna Loa, Hawaii measures the characteristics of surface aerosols under background conditions. The instruments provide data that are representative of the background-aerosol climatology at Mauna Loa. These data can also be used to identify potential local contamination periods. The nephelometer's light-scattering measurements show an annual cycle: a maximum in April and a minimum in November, with a variation of a factor of 5.5. The Condensation Nucleus (CN) counter shows a much smaller annual cycle: a maximum in September and a minimum in March, with a variation of a factor of 1.5. A local decrease in CN concentration occurs in August. The Angstrom exponent minimum occurs in May. This indicates larger aerosol particles within the month as compared with the remainder of the year.

  3. Trace element abundances of high-MgO glasses from Kilauea, Mauna Loa and Haleakala volcanoes, Hawaii

    USGS Publications Warehouse

    Wagner, T.P.; Clague, D.A.; Hauri, E.H.; Grove, T.L.

    1998-01-01

    We performed an ion-microprobe study of eleven high-MgO (6.7-14.8 wt%) tholeiite glasses from the Hawaiian volcanoes Kilauea, Mauna Loa and Haleakala. We determined the rare earth (RE), high field strength, and other selected trace element abundances of these glasses, and used the data to establish their relationship to typical Hawaiian shield tholeiite and to infer characteristics of their source. The glasses have trace element abundance characteristics generally similar to those of typical shield tholeiites, e.g. L(light)REE/H(heavy)REE(C1) > 1. The Kilauea and Mauna Loa glasses, however, display trace and major element characteristics that cross geochemical discriminants observed between Kilauea and Mauna Loa shield lavas. The glasses contain a blend of these discriminating chemical characteristics, and are not exactly like the typical shield lavas from either volcano. The production of these hybrid magmas likely requires a complexly zoned source, rather than two unique sources. When corrected for olivine fractionation, the glass data show correlations between CaO concentration and incompatible trace element abundances, indicating that CaO may behave incompatibly during melting of the tholeiite source. Furthermore, the tholeiite source must contain residual garnet and clinopyroxene to account for the variation in trace element abundances of the Kilauea glasses. Inversion modeling indicates that the Kilauea source is flat relative to C1 chondrites, and has a higher bulk distribution coefficient for the HREE than the LREE.

  4. LoaP is a broadly conserved antiterminator protein that regulates antibiotic gene clusters in Bacillus amyloliquefaciens.

    PubMed

    Goodson, Jonathan R; Klupt, Steven; Zhang, Chengxi; Straight, Paul; Winkler, Wade C

    2017-02-13

    A valuable resource available in the search for new natural products is the diverse microbial life that spans the planet. A large subset of these microorganisms synthesize complex specialized metabolites exhibiting biomedically important activities. A limiting step to the characterization of these compounds is an elucidation of the genetic regulatory mechanisms that oversee their production. Although proteins that control transcription initiation of specialized metabolite gene clusters have been identified, those affecting transcription elongation have not been broadly investigated. In this study, we analysed the phylogenetic distribution of the large, widespread NusG family of transcription elongation proteins and found that it includes a cohesive outgroup of paralogues (herein coined LoaP), which are often positioned adjacent or within gene clusters for specialized metabolites. We established Bacillus amyloliquefaciens LoaP as a paradigm for this protein subgroup and showed that it regulated the transcriptional readthrough of termination sites located within two different antibiotic biosynthesis operons. Both of these antibiotics have been implicated in plant-protective activities, demonstrating that LoaP controls an important regulon of specialized metabolite genes for this microorganism. These data therefore reveal transcription elongation as a point of regulatory control for specialized metabolite pathways and introduce a subgroup of NusG proteins for this purpose.

  5. COR1 Engineering Test Unit Measurements at the Mauna Loa Solar Observatory, September 2003

    NASA Technical Reports Server (NTRS)

    Thompson, William; Reginald, Nelson; Streander, Kim

    2003-01-01

    The COR1 Engineering Test Unit (ETU), which had been previously tested at the NCAR/HAO and NRL test facilities, was modified into an instrument capable of observing the Sun. It was then taken to the Mauna Loa Solar Observatory to observe the corona. The changes made to observe the Sun were as follows: 1. The plate scale was changed to accommodate the smaller Apogee camera. This change had already been made for the NRL tests. 2. The previous Oriel polarizer was replaced with a commercial Polarcor polarizer from Newport to be more flight-like. However, because of cost and availability considerations, this polarizer was smaller than those which will be used for flight. 3. A structure was placed around the back section of the instrument, to protect it from stray light. 4. A pointing spar borrowed from HAO was used to track the Sun. A few days into the test, it became evident that some artifacts were appearing in the data, and these artifacts were changing as the polarizer was rotated. It was decided to test two other polarizers, the Oriel polarizer which had been used in the previous tests at HAO and NRL, and a Nikon polarizer which was borrowed from a camera belonging to one of the observatory staff members. These three polarizers had much different qualities are shown.

  6. Variation of free tropospheric total nitrate at Mauna Loa Observatory, Hawaii

    SciTech Connect

    Lee, G.; Merrill, J.T.; Huebert, B.J. |

    1994-06-01

    We measured total nitrate (TN) concentrations (defined as nitric acid vapor plus nitrate aerosol) nightly at the Mauna Loa Observatory (MLO) from September 1988 to September 1991. Using three meteorological criteria, (condensation nuclei, wind direction, and dew point) we selected samples that represented the free troposphere. The 3-year mean and median of TN mixing ratios were 113 parts per trillion by volume (pptv) and 93 pptv, respectively. Each year the TN concentrations at MLO during the spring and summer were larger by more than a factor of 2 than those during the fall and winter. The springtime peak TN corresponded to incidents of increased Asian dust over the northern Pacific Ocean. Isentropic back trajectories confirmed that spring air masses with high TN originated over the Asian continent. Back trajectories also indicated that the North American continent was often the source of high TN during the summer. Air mass source regions and flow patterns to MLO were classified into five distinct groups of trajectories by cluster analysis. Despite the different source regions for each of the clusters the distributions of TN were very similar. This suggests that the source region may be less important for determining TN at MLO than such factors as the degree of vertical mixing over source regions, stratospheric injection, and wet removal rates.

  7. Footprints of decadal climate variability in ozone at Mauna Loa Observatory

    NASA Astrophysics Data System (ADS)

    Lin, M.; Horowitz, L. W.; Oltmans, S. J.; Fiore, A. M.; Fan, S.

    2013-12-01

    Ozone is a greenhouse gas that plays a central role in tropospheric chemistry. A 40-year ozone record at Mauna Loa Observatory (MLO, 3.4 km altitude) reveals strikingly different seasonality of ozone trends from those observed at northern mid-latitudes: increasing in fall at MLO but in spring at northern midlatitude remote sites. These changes in seasonal ozone are well reproduced by a chemistry-climate model. We find that the seasonal ozone changes at MLO cannot be accounted for by trends in ozone precursor emissions alone, but reflect decadal shifts in circulation regimes. Specifically, airflow from Eurasia towards Hawaii weakened in spring but strengthened in fall. In spring, the long-term tropical expansion, combined with an early-2000s shift in the Pacific Decadal Oscillation (PDO) towards fewer El Niño events, offsets ozone increases that otherwise would have occurred due to rising Asian emissions. In fall, transport of midlatitude pollution events to MLO has occurred more frequently since the mid-1990s, corresponding with a period of predominantly positive Pacific-North American (PNA) pattern. Our findings highlight the potential for atmospheric ozone measurements at remote sites to document interannual to decadal changes in atmospheric circulation. Decadal shifts in circulation regimes must be considered when attributing ozone changes observed at remote sites to trends in precursor emissions.

  8. Results from the 1995 Stratospheric Ozone Profile Intercomparison at Mauna Loa (MLO3)

    NASA Technical Reports Server (NTRS)

    McPeters, R. D.; Hofmann, D. J.; Clark, M.; Flynn, L.; Froidevaux, L.; Gross, M.; Johnson, B.; Koenig, G.; Liu, X.; McDermid, S.; hide

    1998-01-01

    In August 1995 multiple instruments that measure the stratospheric ozone vertical distribution were intercompared at the Mauna Loa Observatory, Hawaii, under the auspices of the Network for the Detection of Stratospheric Change. The instruments included two UV lidar systems, one from JPL and the other from Goddard Space Flight Center, ECC balloon-sondes, a ground-based microwave instrument, Umkehr measurements, and a new ground-based FTIR instrument. The MLS instrument on the UARS satellite provided correlative profiles of ozone, and there was one close overpass of the SAGE II instrument. The results show that much better consistency among instruments is being achieved than even a few years ago, usually to within the instrument uncertainties. The different measurement techniques in this comparison agree to within +/-10% at almost all altitudes, and in the 20 km to 45 km region most agreed within +/-5%. The results show that the current generation of lidars are capable of accurate measurement of the ozone profile to a maximum altitude of 50 km. SAGE agreed well with both lidar and balloon-sonde down to at least 17 km. The ground-based microwave measurement agreed with other measurements from 22 km to above 50 km. One minor source of disagreement continues to be the pressure-altitude conversion needed to compare a measurement of ozone density versus altitude with a measurement of ozone mixing ratio versus pressure.

  9. Reef growth and volcanism on the submarine southwest rift zone of Mauna Loa, Hawaii

    USGS Publications Warehouse

    Moore, J.G.; Normark, W.R.; Szabo, B. J.

    1990-01-01

    A marine sampling program, utilizing the PISCES-5 submersible operated by the Hawaii Undersea Research Laboratory (NOAA), has confirmed the presence of a major submerged coral reef offshore from Ka Lae (South Point), Hawaii. The top of the reef is now 150-160 m below sea level. Radiocarbon and Useries dating indicates that it drowned about 13.9 ka by the combined effects of island subsidence (2.5 mm/year) and the rapid rise of sea level at the end of the last glaciation so that the relative submergence rate of more than 10 mm/year exceeded the upward growth rate of the reef. The submerged reef caps the offshore part of the southwest rift-zone ridge of Mauna Loa, which has apparently undergone little volcanic activity offshore since 170 ka, and possibly since 270 ka. This fact suggests that rift zone activity is becoming increasingly restricted toward the upper part of the volcano, a condition possibly heralding the end of the shield-building stage. ?? 1990 Springer-Verlag.

  10. A descriptive atmospheric transport climatology for the Mauna Loa observatory, using clustered trajectories

    NASA Astrophysics Data System (ADS)

    Harris, Joyce M.; Kahl, Jonathan D.

    1990-08-01

    The climatology of long-range atmospheric transport to the Mauna Loa Observatory (MLO) is examined through an analysis of 10-day isobaric back trajectories for the period 1981-1988, computed using the National Meteorological Center's analyzed gridded winds. The trajectories are classified into distinct transport patterns through the use of cluster analysis, a procedure that avoids the somewhat arbitrary classification by compass sector and instead searches for meaningful groupings within the data themselves. The clustering procedure is performed separately for yearly and monthly sets of 500- and 700-hPa trajectories to examine both year-to-year and month-to-month variability in flow characteristics. The dominant transport features are quite similar from year to year, and include frequent summertime easterly flow associated with the trade winds and strong, wintertime westerly flow close to the mean axis of the subtropical jet stream. Veering westerly patterns that approach MLO from the north and northeast dominate during winter/summer transition periods. Other noteworthy features include recurring air mass transport from Saharan and Asian desert regions, infrequent interhemisphere flow from as far as 10°S, and occasional flow from high northern latitudes. Ten-day back trajectories that pass over anthropogenic pollution source regions in western North America are rare.

  11. Spectroradiometer with wedge interference filters (SWIF): measurements of the spectral optical depths at Mauna Loa Observatory.

    PubMed

    Vasilyev, O B; Leyva, A; Muhila, A; Valdes, M; Peralta, R; Kovalenko, A P; Welch, R M; Berendes, T A; Isakov, V Y; Kulikovskiy, Y P; Sokolov, S S; Strepanov, N N; Gulidov, S S; von Hoyningen-Huene, W

    1995-07-20

    A spectroradiometer with wedge interference filters (SWIF) (the filters were produced by Carl Zeiss, Jena, Germany) and a CCD matrix (which was of Russian production) that functions as the sensor has been designed and built for use in ground-based optical sensing of the atmosphere and the Earth's surface in the spectral range of 0.35-1.15 µm. Absolute calibration of this instrument was performed through a series of observations of direct solar radiation at Mauna Loa Observatory (MLO) in Hawaii in May and June 1993. Spectral optical depth (SOD) measurements that were made during these field experiments provided detailed spectral information about both aerosol extinction (scattering plus absorption) and molecular absorption in the atmosphere above the site at MLO. The aerosol-SOD measurements were compared with narrow-band radiometer measurements at wavelengths of 380, 500, and 778 nm The SWIF and narrow-band radiometer measurements are in agreement to within the experimental error. At a wavelength of 500 nm, the aerosol SOD was found to be approximately 0.045. Adescription of the SWIF instrument, its absolute calibration, and the determination of atmospheric SOD's at MLO are presented.

  12. A descriptive atmospheric transport climatology for the Mauna Loa Observatory, using clustered trajectories

    SciTech Connect

    Harris, J.M.; Kahl, J.D. )

    1990-08-20

    The climatology of long-range atmospheric transport to the Mauna Loa Observatory (MLO) is examined through an analysis of 10-day isobaric back trajectories for the period 1981-1988, computed using the National Meteorological Centers analyzed gridded winds. The trajectories are classified into distinct transport patterns through the use of cluster analysis, a procedure that avoids the somewhat arbitrary classification by compass sector and instead searches for meaningful groupings within the data themselves. The clustering procedure is performed separately for yearly and monthly sets of 500- and 700-hPa trajectories to examine both year-to-year and month-to-month variability in flow characteristics. The dominant transport features are quite similar from year to year, and include frequent summertime easterly flow associated with the trade winds and strong, wintertime westerly flow close to the mean axis of the subtropical jet stream. Veering westerly patterns that approach MLO from the north and northeast dominate during winter/summer transition periods. Other noteworthy features include recurring air mass transport from Saharan and Asian desert regions, infrequent interhemispheric flow from as far as 10{degree}S, and occasional flow from high northern latitudes. Ten-day back trajectories that pass over anthropogenic pollution source regions in western North America are rare.

  13. Population structure in the endangered Mauna Loa silversword, Argyroxiphium kauense (Asteraceae), and its bearing on reintroduction.

    PubMed

    Friar, E A; Boose, D L; LaDoux, T; Roalson, E H; Robichaux, R H

    2001-07-01

    Reintroduction of populations of endangered species is a challenging task, involving a number of environmental, demographic and genetic factors. Genetic parameters of interest include historical patterns of genetic structure and gene flow. Care must be taken during reintroduction to balance the contrasting risks of inbreeding and outbreeding depression. The Mauna Loa silversword, Argyroxiphium kauense, has experienced a severe decline in population size and distribution in the recent past. Currently, three populations with a total of fewer than 1000 individuals remain. We measured genetic variation within and among the remnant populations using seven microsatellite loci. We found significant genetic variation remaining within all populations, probably related to the recent nature of the population impact, the longevity of the plants, and their apparent self-incompatibility. We also found significant genetic differentiation among the populations, reinforcing previous observations of ecological and morphological differentiation. With respect to reintroduction, the results suggest that, in the absence of additional data to the contrary, inbreeding depression may not be a substantial risk as long as propagules for the founding of new populations are adequately sampled from within each source population before additional inbreeding takes place. The results further suggest that if mixing of propagules from different source populations is not required to increase within-population genetic variation in the reintroduced populations, it may best be avoided.

  14. Coronal evolution during the sunspot cycle: Coronal holes observed with the Mauna Loa K-coronameters

    SciTech Connect

    Hundhausen, A.J.; Hansen, R.T.; Hansen, S.F.

    1981-04-01

    The white-light corona was observed regularly at the Mauna Loa Observatory during the years 1965--1967 and 1969--1978. Display of the measured polarization brightness in the form of synoptic maps permits the identification of large coronal holes and the study of their slow evolution during the sunspot cycle. The polar coronal holes were clearly seen to shrink in size during the ascending phase of cycle 20 (1965--1967), to be absent during a two-year period (1969--1970) just after sunspot maximum, to reappear near the end of 1970, and to remain as prominent features of the corona for the years 1971--1978. During the sunspot maximum epoch the corona was dominated by 'mid-latitude' holes, elongated in the direction parallel to the solar equator. Large equatorial holes or equatorward extensions of the polar holes were observed during the ascending, maximum, and descending phases of cycle 20 and appear to be sources of solar wind streams with maximum speeds over 600 km s/sup -1/ at all of these epochs. The lifetimes of these holes and streams were greatest during the descending phase of the cycle, or in 1974--1975.

  15. Receptor modeling of globally circulating airborne particles collected at Mauna Loa Observatory, Hawaii

    SciTech Connect

    Hermann, D.M.

    1988-01-01

    Weekly airborne particle samples were collected at Mauna Loa Observatory (MLO), Hawaii from February 1979 through May 1985. Receptor models were used to identify sources of airborne particles at MLO, determine compositions of particles from these sources, and assess the relative impacts of them. Major sources of ambient particles at MLO include Asian continental material, oceanic biological production of Se and SO{sub 4} species, marine particles, Asian anthropogenic material, local volcanic emissions, and basalt. Source composition profiles were developed for each component. The Asian continental component represents particles transported from Eastern Asia to the North Pacific, and the component consists of crustal material contaminated by anthropogenic emissions. To account for variations in the relative strengths of anthropogenic and crustal sources, a separate Asian anthropogenic component was also developed. During the dust season, Asian continental material accounts for 80% of total suspended particulate material (TSP) at MLO, oceanic productions of Se and SO{sub 4} 11%, marine particles 2.8%, basalt 1.9%, volcanic emissions 1.7%, and Asian anthropogenic material in excess of Asian continental material 3.2%. During the clean season, the oceanic biological production of Se and SO{sub 4} contributes 62% of TSP at MLO. Continental material contributes 22%, marine particles 6.4%, basalt 2.7%, volcanic emissions 2.4%, and anthropogenic materials in excess of continental material 4.3%.

  16. Composition and spectral characteristics of ambient aerosol at Mauna Loa Observatory

    SciTech Connect

    Johnson, S.A.; Kumar, R. )

    1991-03-20

    Ambient aerosol particles were sampled continuously with a time resolution of {approximately}4 hours for a period of 8 days at the Mauna Loa Observatory, Hawaii, in August 1986. The samples were analyzed on-site for their chemical composition by attenuated total internal reflection infrared spectroscopy. The infrared absorption spectra of the samples also provided data on aerosol light absorbance characteristics at 9.1 and 10.6 {mu}m - wavelengths of interest in determining aerosol backscatter coefficients for CO{sub 2} lidars. The chemical species in the ambient aerosol varied considerably during this 8-day period. The aerosol was acidic ((NH{sub 4}){sub 3}H(SO{sub 4}){sub 2},NH{sub 4}HSO{sub 4}, or H{sub 2}SO{sub 4}) rather than neutral ((NH{sub 4}){sub 2}SO{sub 4}) for a major fraction of the sampling time. The samples generally showed much higher absorbance at 9.1 {mu}m than at 10.6 {mu}m. Changes in the chemical composition between (NH{sub 4}){sub 2}SO{sub 4} and the more acidic forms were accompanied by substantial changes in the sample's absorbance at 9.1 {mu}m but lesser changes in the absorbance at 10.6 {mu}m. These variations could have a profound effect on backscatter coefficients of atmospheric aerosol particles at CO{sub 2} wavelengths.

  17. Chemistry of background atmospheric particles collected at Mauna Loa Observatory, Hawaii

    SciTech Connect

    Parrington, J.R.

    1984-01-01

    Mauna Loa Observatory, Hawaii, was selected as a remote northern hemisphere site from which to collect atmospheric particles for chemical analyses of background aerosols in the free troposphere of the northern hemisphere. An automatic digital sampling controller was designed and installed at this site to aid in the isolation of uncontaminated particles of the free troposphere, based on wind direction and speed, time-of-day and particle characteristics at the observatory. The three primary components measured on these background particles between 1979 and 1982 were sulfates, continentally derived crustal material and marine particles with average geometric mean concentrations of 240 ng/m/sup 3/, and 15 ng/m/sup 3/, respectively, during the months of July to mid-February. Other months showed a ten-fold increase in continental crustal material, geometric avg = 730 ng/m/sup 3/, (which has been traced to Asian deserts) and doubling of sulfate mass to 480 ng/m/sup 3/ while the marine mass showed no significant changes. The average geometric mean concentration of local basalt was determined to be 15 ng/m/sup 3/ in down-slope winds and, thus, does not represent a major interference to most studies at MLO as a majority of the crustal dust in the atmosphere, even in relatively clean periods, is transported over thousands of kilometers to the islands from continents surrounding the Pacific Ocean.

  18. Recycled oceanic crust observed in 'ghost plagioclase' within the source of Mauna Loa lavas

    PubMed

    Sobolev; Hofmann; Nikogosian

    2000-04-27

    The hypothesis that mantle plumes contain recycled oceanic crust is now widely accepted. Some specific source components of the Hawaiian plume have been inferred to represent recycled oceanic basalts, pelagic sediments or oceanic gabbros. Bulk lava compositions, however, retain the specific trace-element fingerprint of the original crustal component in only a highly attenuated form. Here we report the discovery of exotic, strontium-enriched melt inclusions in Mauna Loa olivines. Their complete trace-element patterns strongly resemble those of layered gabbros found in ophiolites, which are characterized by cumulus plagioclase with very high strontium abundances. The major-element compositions of these melts indicate that their composition cannot be the result of the assimilation of present-day oceanic crust through which the melts have travelled. Instead, the gabbro has been transformed into a (high-pressure) eclogite by subduction and recycling, and this eclogite has then been incorporated into the Hawaiian mantle plume. The trace-element signature of the original plagioclase is present only as a 'ghost' signature, which permits specific identification of the recycled rock type. The 'ghost plagioclase' trace-element signature demonstrates that the former gabbro can retain much of its original chemical identity through the convective cycle without completely mixing with other portions of the former oceanic crust.

  19. Groundmass Crystallization of A'a and Pahoehoe flows of Cerro Azul, Galapagos and Mauna Loa, Hawaii

    NASA Astrophysics Data System (ADS)

    Teasdale, R.; Geist, D.; Wanless, D.; Cashman, K.

    2001-12-01

    Crystallinities of 1998 lavas from Cerro Azul, Galapagos are distinguished from 1843 Mauna Loa, Hawaii lavas by higher modal proportions of groundmass plagioclase crystals. In both cases, a'a lava was erupted first, followed by emplacement of pahoehoe flows. The 1843 Mauna Loa eruption lasted 90 days and produced both a'a and inflated pahoehoe flows (1). The 1998 Galapagos flows were emplaced over the course of 37 days, and the transition from a'a to pahoehoe flow morphology corresponds with decreased eruption rate during the last week of the eruption. Samples were collected along the length of flows from both volcanoes. Modal groundmass plagioclase increases down-flow for each flow type from each volcano. A'a and pahoehoe flows of Cerro Azul consistently have higher crystallinities (41% and 14%) than equivalent flow types at Mauna Loa (29% and 7%). Whereas Cerro Azul groundmass crystals are exclusively plagioclase, the groundmass of Mauna Loa lavas consists of plagioclase and pyroxene crystals, similar to Kilauea lavas. Proportions of plagioclase crystals and flow morphologies are consistent with predictions that groundmass crystal morphology plays a significant role in the development of crystal networks and yield strength, which instigates the development of a'a flow morphology (2, 3). Galapagos volcanoes tend to have more a'a than their Hawaiian counterparts Mauna Loa and Kilauea. Volcano slopes do not appear to control the proportion of each flow type (4); rather, abundance of groundmass plagioclase appears to be the distinguishing factor. An important distinction between the two systems is that Galapagos lavas have consistently higher Al2O3 content than Hawaiian volcanoes. High Al203 results in a comparatively high abundance of groundmass plagioclase, and may partly explain the prevalence of a'a. We note that while the relative abundance of a'a and pahoehoe flow morphologies on other volcanoes is rarely quantified, Mount Etna is also distinguished by abundant

  20. Comparison of Inflation Processes at the 1859 Mauna Loa Flow, HI, and the McCartys Flow Field, NM

    NASA Technical Reports Server (NTRS)

    Bleacher, Jacob E.; Garry, W. Brent; Zimbelman, James R.; Crumpler, Larry S.

    2012-01-01

    Basaltic lavas typically form channels or tubes during flow emplacement. However, the importance of sheet flow in the development of basalt ic terrains received recognition over the last 15 years. George Walke r?s research on the 1859 Mauna Loa Flow was published posthumously in 2009. In this paper he discusses the concept of endogenous growth, or inflation, for the distal portion of this otherwise channeldominated lava flow. We used this work as a guide when visiting the 1859 flow to help us better interpret the inflation history of the McCartys flow field in NM. Both well preserved flows display similar clues about the process of inflation. The McCartys lava flow field is among the you ngest (approx.3000 yrs) basaltic lava flows in the continental United States. It was emplaced over slopes of <1 degree, which is similar to the location within the 1859 flow where inflation occurred. Although older than the 1859 flow, the McCartys is located in an arid environ ment and is among the most pristine examples of sheet flow morphologies. At the meter scale the flow surface typically forms smooth, undula ting swales that create a polygonal terrain. The literature for simil ar features includes multiple explanatory hypotheses, original breakouts from adjacent lobes, or inflation related upwarping of crust or sa gging along fractures that enable gas release. It is not clear which of these processes is responsible for polygonal terrains, and it is po ssible that one explanation is not the sole cause of this morphology between all inflated flows. Often, these smooth surfaces within an inflated sheet display lineated surfaces and occasional squeeze-ups alon g swale contacts. We interpret the lineations to preserve original fl ow direction and have begun mapping these orientations to better interpret the emplacement history. At the scale of 10s to 100s of meters t he flow comprises multiple topographic plateaus and depressions. Some depressions display level floors with

  1. Remote-controlled pan, tilt, zoom cameras at Kilauea and Mauna Loa Volcanoes, Hawai'i

    USGS Publications Warehouse

    Hoblitt, Richard P.; Orr, Tim R.; Castella, Frederic; Cervelli, Peter F.

    2008-01-01

    Lists of important volcano-monitoring disciplines usually include seismology, geodesy, and gas geochemistry. Visual monitoring - the essence of volcanology - is usually not mentioned. Yet, observations of the outward appearance of a volcano provide data that is equally as important as that provided by the other disciplines. The eye was almost certainly the first volcano monitoring-tool used by early man. Early volcanology was mostly descriptive and was based on careful visual observations of volcanoes. There is still no substitute for the eye of an experienced volcanologist. Today, scientific instruments replace or augment our senses as monitoring tools because instruments are faster and more sensitive, work tirelessly day and night, keep better records, operate in hazardous environments, do not generate lawsuits when damaged or destroyed, and in most cases are cheaper. Furthermore, instruments are capable of detecting phenomena that are outside the reach of our senses. The human eye is now augmented by the camera. Sequences of timed images provide a record of visual phenomena that occur on and above the surface of volcanoes. Photographic monitoring is a fundamental monitoring tool; image sequences can often provide the basis for interpreting other data streams. Monitoring data are most useful when they are generated and are available for analysis in real-time or near real-time. This report describes the current (as of 2006) system for real-time photograph acquisition and transmission from remote sites on Kilauea and Mauna Loa volcanoes to the U.S. Geological Survey Hawaiian Volcano Observatory (HVO). It also describes how the photographs are archived and analyzed. In addition to providing system documentation for HVO, we hope that the report will prove useful as a practical guide to the construction of a high-bandwidth network for the telemetry of real-time data from remote locations.

  2. Forecast, Measurement, and Modeling of an Unprecedented Polar Ozone Filament Event over Mauna Loa Observatory, Hawaii

    NASA Technical Reports Server (NTRS)

    Tripathi, Om Prakash; Leblanc, Thierry; McDermid, I. Stuart; Lefevre, Frank; Marchand, Marion; Hauchecorne, Alain

    2006-01-01

    In mid-March 2005 the northern lower stratospheric polar vortex experienced a severe stretching episode, bringing a large polar filament far south of Alaska toward Hawaii. This meridional intrusion of rare extent, coinciding with the polar vortex final warming and breakdown, was followed by a zonal stretching in the wake of the easterly propagating subtropical main flow. This caused polar air to remain over Hawaii for several days before diluting into the subtropics. After being successfully forecasted to pass over Hawaii by the high-resolution potential vorticity advection model Modele Isentrope du transport Meso-echelle de l'Ozone Stratospherique par Advection (MIMOSA), the filament was observed on isentropic surfaces between 415 K and 455 K (17-20 km) by the Jet Propulsion Laboratory stratospheric ozone lidar measurements at Mauna Loa Observatory, Hawaii, between 16 and 19 March 2005. It was materialized as a thin layer of enhanced ozone peaking at 1.6 ppmv in a region where the climatological values usually average 1.0 ppmv. These values were compared to those obtained by the three dimensional Chemistry-Transport Model MIMOSA-CHIM. Agreement between lidar and model was excellent, particularly in the similar appearance of the ozone peak near 435 K (18.5 km) on 16 March, and the persistence of this layer at higher isentropic levels for the following three days. Passive ozone, also modeled by MIMOSA-CHIM, was at about 3-4 ppmv inside the filament while above Hawaii. A detailed history of the modeled chemistry inside the filament suggests that the air mass was still polar ozone- depleted when passing over Hawaii. The filament quickly separated from the main vortex after its Hawaiian overpass. It never reconnected and, in less than 10 days, dispersed entirely in the subtropics.

  3. Atmospheric CO/sub 2/ concentrations Mauna Loa Observatory, Hawaii 1958-1983

    SciTech Connect

    Keeling, C.D.

    1984-09-01

    Carbon dioxide concentrations have been obtained throughout the sampling period using a nondispersive, dual detector, infrared gas analyzer. Air samples are obtained via air intakes at the top of 7m towers. Four of these towers exist, along with a 27m tower. The highest intake along with one of the lower intakes take four samples per hour. Air is sampled from one intake for 10 minutes, then from the second for 10 minutes, and then from a reference gas for 10 minutes. The intakes are actually maintained continuously, but are shunted when not being analyzed by the infrared gas analyzer. The air flow registers a voltage on the analyzer which then records the concentrations on a strip chart recorder. Two intakes are used to detect possible contamination. A sign of contamination, whether ambient or instrument, is evidenced by significant differences in CO/sub 2/ concentrations between the two paired intakes. Efforts to calibrate equipment, reduce the possibility of contamination, and to adjust data to represent uncontaminated, true conditions have been done and updated throughout the course of the project. Calibration of the gas analyzer by standardized CO/sub 2/-in-nitrogen reference gases is done twice daily. Flask samples are taken twice monthly to give a comparison to the data recorded using the infrared gas analyzer. Data is scrutinized daily for possible contamination and archived and magnetic tape for possible further scrutiny and adjustment. Daily, monthly, and annual averages are computed for the Mauna Loa data after deletion of con taminated samples and readjustment. These averages have shown a steady rise in the annual average concentration, from 316 ppmv in 1959 to 342 ppmv in 1983.

  4. Three-dimensional seismic velocity structure of Mauna Loa and Kilauea volcanoes in Hawaii from local seismic tomography

    USGS Publications Warehouse

    Lin, Guoqing; Shearer, Peter M.; Matoza, Robin S.; Okubo, Paul G.; Amelung, Falk

    2016-01-01

    We present a new three-dimensional seismic velocity model of the crustal and upper mantle structure for Mauna Loa and Kilauea volcanoes in Hawaii. Our model is derived from the first-arrival times of the compressional and shear waves from about 53,000 events on and near the Island of Hawaii between 1992 and 2009 recorded by the Hawaiian Volcano Observatory stations. The Vp model generally agrees with previous studies, showing high-velocity anomalies near the calderas and rift zones and low-velocity anomalies in the fault systems. The most significant difference from previous models is in Vp/Vs structure. The high-Vp and high-Vp/Vs anomalies below Mauna Loa caldera are interpreted as mafic magmatic cumulates. The observed low-Vp and high-Vp/Vs bodies in the Kaoiki seismic zone between 5 and 15 km depth are attributed to the underlying volcaniclastic sediments. The high-Vp and moderate- to low-Vp/Vs anomalies beneath Kilauea caldera can be explained by a combination of different mafic compositions, likely to be olivine-rich gabbro and dunite. The systematically low-Vp and low-Vp/Vs bodies in the southeast flank of Kilauea may be caused by the presence of volatiles. Another difference between this study and previous ones is the improved Vp model resolution in deeper layers, owing to the inclusion of events with large epicentral distances. The new velocity model is used to relocate the seismicity of Mauna Loa and Kilauea for improved absolute locations and ultimately to develop a high-precision earthquake catalog using waveform cross-correlation data.

  5. A Geochemical Study of Magmatic Processes and Evolution along the Submarine Southwest Rift zone of Mauna Loa Volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Rhodes, J. M.; Garcia, M. O.; Weis, D.; Trusdell, F. A.; Vollinger, M. J.

    2003-12-01

    Mauna Loa's southwest rift zone (SWR) extends for 102 km from its summit caldera, at an elevation of 4,170 m above sea level, to submarine depths of over 4,500 m. About 65% of the rift zone is subaerial and 35% submarine. Recent sampling with the Jason II submersible of the `mile-high' (1800 m) Ka Lae submarine landslide scarp and the deepest section of the rift zone, in conjunction with previous submersible and dredge-haul collecting, provides petrological and geochemical understanding of rift zone processes, as well as a record of Mauna Loa's eruptive history extending back about 400 ka. The major and trace element trends of the submarine lavas are remarkably similar to those of historical and young prehistoric lavas (<31 ka) erupted along the subaerial SWR. We take this to imply that magma-forming processes have remained relatively constant over much of the volcano's recorded eruptive history. However, the distribution of samples along these trends has varied, and is correlated with elevation. There are very few picrites (>12% MgO) among the subaerial lavas, and compositions tend to cluster around 6.8-8.0% MgO. In contrast, picritic lavas are extremely abundant in the submarine samples, increasing in frequency with depth, especially below 1200 m. These observations support earlier interpretations that the submarine lavas are derived directly from deeper levels in the magma column, and that magmas from a shallow, steady-state, magma reservoir are of uncommon at these depths. Isotopic ratios of Pb and Sr in the submarine lavas, in conjunction with Nb/Y and Zr/Nb ratios, extend from values that are identical with subaerial historical Mauna Loa lavas to lavas with markedly lower 87Sr/86Sr and higher 206Pb/204Pb isotopic ratios. As yet, we see no correlation with depth or age, but the implications are that, in the past, the plume source of Mauna Loa magmas was more variable than in the last 31 ka, and contained a greater proportion of the Kea component. *Team members

  6. Using an artificial neural network approach to estimate surface-layer optical turbulence at Mauna Loa, Hawaii.

    PubMed

    Wang, Yao; Basu, Sukanta

    2016-05-15

    In this Letter, an artificial neural network (ANN) approach is proposed for the estimation of optical turbulence (Cn2) in the atmospheric surface layer. Five routinely available meteorological variables are used as the inputs. Observed Cn2 data near the Mauna Loa Observatory, Hawaii are utilized for validation. The proposed approach has demonstrated its prowess by capturing the temporal evolution of Cn2 remarkably well. More interestingly, this ANN approach is found to outperform a widely used similarity theory-based conventional formulation for all the prevalent atmospheric conditions (including strongly stratified conditions).

  7. Electron Microanalysis of Aerosols Collected at Mauna Loa Observatory During an Asian Dust Storm Event

    NASA Astrophysics Data System (ADS)

    Conny, J. M.; Willis, R. D.; Ortiz-Montalvo, D. L.; Colton, A.

    2014-12-01

    Located in the remote marine free troposphere, the Mauna Loa Observatory (MLO) represents a clean airshed that can be used to study anthropogenic pollution influences and long-range transport of aerosol particles from the Asian mainland. Because of the global nature of Asian dust storms, the radiative properties of these particles transported long-range can significantly impact global climate. It has been proposed that aerosols transported to MLO during upslope wind conditions (typically daytime) are local in origin while aerosols transported during downslope conditions (typically nighttime) represent long-range transport in the free troposphere. Twelve PM10 samples (six daytime/nightime pairs) were collected on polycarbonate filters for 72 hours each between March 15 and April 26, 2011. Bulk samples of dust from local sources (road dust, parking lot, lava fields) were collected as well in order to assess the PM10 contribution from local dusts. On March 19-20 the Korea Meteorological Administration documented a significant dust event over the Korean peninsula. Back-trajectory analyses from MLO coupled with local wind speed and wind direction data suggest that this dust event may have been captured during the MLO sampling campaign. MLO samples were analyzed by computer-controlled scanning electron microscopy (CCSEM) coupled with energy-dispersive X-ray spectrometry (EDX) and particles were sorted into compositionally-distinct particle types which were then compared across the sample set. Concentrations of particle types expected to be associated with Asian dust were observed to peak in one pair of daytime/nighttime samples collected between March 22 and March 28. Manual microscopic characterization of suspected Asian dust particles and local dust particles was carried out using electron backscatter diffraction (EBSD) in conjunction with EDX and focussed ion beam SEM (FIB-SEM) in an effort to characterize differences in physicochemical or radiative properties of

  8. Using Mauna Loa Atmospheric CO2 Data in Large General Education Geoscience Courses

    NASA Astrophysics Data System (ADS)

    Richardson, R. M.; Kapp, J. L.

    2007-12-01

    We have been using the Mauna Loa atmospheric CO2 dataset (http://scrippsco2.ucsd.edu/data/in_situ_co2/monthly_mlo.csv) in a large (up to 300) General Education Geoscience course, primarily in small breakout groups (30 students). The exercise is designed to address quantitative literacy including percentages, slopes and linear trends, issues of data completeness and bias, quality of extrapolations, as well as implications for climate change. We are significantly revising the course, which serves 600 students a semester, with help from a curriculum grant. A major goal is to improve student learning by incorporating inquiry based activities in the large lecture setting. Lectures now incorporate several activities throughout a given class period, in which students are asked to use critical thinking skills such as interpreting patterns in data and graphs, analyzing a scientific hypothesis for its coherence with the scientific method, and answering higher order synthesis questions in both verbal and written form. This differs from our past format where class periods were dominated by lecture, with a single short activity done individually about every other lecture. To test the effectiveness of the new course format we will give students the same atmospheric CO2 exercise in the lecture setting that they were given previously in breakout groups. Students will work in small groups in lecture after receiving a short introduction to the exercise by the instructor. They will plot CO2 concentrations, make extrapolations, and interpret patterns in the data. We will compare scores on the exercise with previous semesters. We expect that students will do better having had more experience with interpreting scientific data and practicing higher order thinking skills. We also expect working in small groups will foster better learning through peer teaching and discussion. We will incorporate responses from students who took part in the exercises from current and previous semesters. We

  9. Aerosol size distribution, composition, and CO sub 2 backscatter at Mauna Loa Observatory

    SciTech Connect

    Clarke, A.D.; Porter, J.N. )

    1991-03-20

    Continuous measurements of aerosol size distributions were obtained during Jan-Mar and Nov-Dec periods of 1988 at Mauna Loa Observatory, Hawaii. These periods were chosen in order to characterize aerosol physiochemistry during periods representative of low-dust atmospheric conditions and periods associated with appreciable Asian dust transport to that site. Size distributions for particles with diameters between 0.15 and 7.6 {mu}m were accumulated in 256 size bins of a laser optical particle counter for 3-hour intervals during most of the period. The aerosol sample stream was heated to selected temperatures in order to provide size-discriminated measurements of aerosol volatility. Resulting data were used to assess the variability in aerosol concentrations and properties related to aerosol backscatter values at a wavelength of 10.6 {mu}m, {beta}{sub CO{sub 2}}, in the mid-troposphere. Low aerosol concentrations, considered representative of mid-tropospheric air, occurred in downslope flow between midnight and sunrise. Measurements for these time periods suggest that {beta}{sub CO{sub 2}} varied from a low of about 5 {times} 10{sup {minus}12}m{sup {minus}1}sr{sup {minus}1} to a high of 5 {times} 10{sup {minus}8}m{sup {minus}1}sr{sup {minus}1}. Coarse particles with diameters between 1.0 and 5.0 {mu}m account for most of the derived values of {beta}{sub CO{sub 2}} at all but the highest and lowest aerosol mass concentrations. Volatile aerosol appears to dominate aerosol mass during the cleanest periods but was a small fraction of the total during dust events. The authors estimate that minimum values for {beta}{sub CO{sub 2}} at about 8 km should usually fall in the range of 1-3 {times} 10{sup {minus}12}m{sup {minus}1}sr{sup {minus}1} and be dominated by a sulfate aerosol.

  10. Asian Dust at Mauna Loa Observatory: Analysis and Modeling of Individual Atmospheric Particles

    NASA Astrophysics Data System (ADS)

    Conny, J. M.; Willis, R. D.; Ortiz-Montalvo, D. L.

    2015-12-01

    Springtime Asian dust storms events, typically originating in the Gobi Desert or Taklamakan Desert, produce particles that can be carried aloft eastward for thousands of miles. As a result, the radiative properties of these particles can significantly affect global climate. Here, we determine the optical properties of particles identified as Asian dust at Mauna Loa Observatory, Hawaii, (MLO) based on the composition and actual shapes of individual particles. Samples of particulate material <10 μm in size were collected at MLO, between March 15 and April 26, 2011. Air mass back trajectories and satellite imagery showed that a subset of the aerosol sampled during this period likely originated from the Asian mainland while most of the aerosol probably did not. Samples were first analyzed by automated scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry, whereby particles were sorted into compositionally-distinct particle types. Two particle types, identified as dolomite and calcite were determined to have originated from Asia. A third type, anhydrite, also aloft in the free troposphere, was not associated with Asian dust. Individual particles were analyzed compositionally and their shapes modeled spatially using focused ion-beam (FIB) SEM and FIB tomography. Particle 3-D representations were then input to the discrete dipole approximation method to determine their optical properties for 589 nm light. Calculations revealed that the single scattering albedo (SSA) for the Asian dust particles (0.79 to 0.94) straddled the critical SSA for cooling vs. warming (0.86), with the lowest SSA (0.79) attributed to a small amount of soot (1.7 % by volume) attached to a dolomite particle. SSA for the free troposphere anhydrite particles (0.90 to 0.93) was well above the critical SSA. For the three particle types, SSA for the actual-shaped particles was higher than equivalently-sized spheres, cubes, or tetrahedra. For the fraction of backscattered light from

  11. Ups and downs on spreading flanks of ocean-island volcanoes: evidence from Mauna Loa and Kīlauea

    USGS Publications Warehouse

    Lipman, Peter W.; Eakins, Barry W.; Yokose, Hisayoshi

    2003-01-01

    Submarine-flank deposits of Hawaiian volcanoes are widely recognized to have formed largely by gravitationally driven volcano spreading and associated landsliding. Observations from submersibles show that prominent benches at middepths on flanks of Mauna Loa and Kilauea consist of volcaniclastic debris derived by landsliding from nearby shallow submarine and subaerial flanks of the same edifice. Massive slide breccias from the mature subaerial tholeiitic shield of Mauna Loa underlie the frontal scarp of its South Kona bench. In contrast, coarse volcaniclastic sediments derived largely from submarine-erupted preshield alkalic and transitional basalts of ancestral Kilauea underlie its Hilina bench. Both midslope benches record the same general processes of slope failure, followed by modest compression during continued volcano spreading, even though they record development during different stages of edifice growth. The dive results suggest that volcaniclastic rocks at the north end of the Kona bench, interpreted by others as distal sediments from older volcanoes that were offscraped, uplifted, and accreted to the island by far-traveled thrusts, alternatively are a largely coherent stratigraphic assemblage deposited in a basin behind the South Kona bench.

  12. Implications of historical eruptive-vent migration on the northeast rift zone of Mauna Loa Volcano, Hawaii

    SciTech Connect

    Lockwood, J.P. )

    1990-07-01

    Five times within the past 138 yr (1852, 1855-1856, 1880-1881, 1942, and 1984), lava flows from vents on the northeast rift zone of Mauna Loa Volcano have reached within a few kilometres of Hilo (the largest city on the Island of Hawaii). Most lavas erupted on this right zone in historical time have traveled northeastward (toward Hilo), because their eruptive vents have been concentrated north of the rift zone's broad topographic axis. However, with few exceptions each successive historical eruption on the northeast rift zone has occurred farther southeast than the preceding one. Had the 1984 eruptive vents (the most southeasterly yet) opened less than 200 m farther southeast, the bulk of the 1984 lavas would have flowed away from Hilo. If this historical vent-migration pattern continues, the next eruption on the northeast rift zone could send lavas to the southeast, toward less populated areas. The historical Mauna Loa vent-migration patterns mimic southeastern younging of the Hawaiian-Emperor volcanic chain and may be cryptically related to northwestward movement of the Pacific plate. Systematic temporal-spatial vent-migration patterns may characterize eruptive activity at other volcanoes with flank activity and should be considered as an aid to long-term prediction of eruption sites.

  13. Increase in background stratospheric aerosol observed with lidar at Mauna Loa Observatory and Boulder, Colorado - article no. L15808

    SciTech Connect

    Hofmann, D.; Barnes, J.; O'Neill, M.; Trudeau, M.; Neely, R.

    2009-08-15

    The stratospheric aerosol layer has been monitored with lidars at Mauna Loa Observatory in Hawaii and Boulder in Colorado since 1975 and 2000, respectively. Following the Pinatubo volcanic eruption in June 1991, the global stratosphere has not been perturbed by a major volcanic eruption providing an unprecedented opportunity to study the background aerosol. Since about 2000, an increase of 4-7% per year in the aerosol backscatter in the altitude range 20-30 km has been detected at both Mauna Loa and Boulder. This increase is superimposed on a seasonal cycle with a winter maximum that is modulated by the quasi-biennial oscillation (QBO) in tropical winds. Of the three major causes for a stratospheric aerosol increase: volcanic emissions to the stratosphere, increased tropical upwelling, and an increase in anthropogenic sulfur gas emissions in the troposphere, it appears that a large increase in coal burning since 2002, mainly in China, is the likely source of sulfur dioxide that ultimately ends up as the sulfate aerosol responsible for the increased backscatter from the stratospheric aerosol layer. The results are consistent with 0.6-0.8% of tropospheric sulfur entering the stratosphere.

  14. Ground Water in Kilauea Volcano and Adjacent Areas of Mauna Loa Volcano, Island of Hawaii

    USGS Publications Warehouse

    Takasaki, Kiyoshi J.

    1993-01-01

    About 1,000 million gallons of water per day moves toward or into ground-water bodies of Kilauea Volcano from the lavas of Mauna Loa Volcano. This movement continues only to the northern boundaries of the east and southwest rift zones of Kilauea, where a substantial quantity of ground water is deflected downslope to other ground-water bodies or to the ocean. In the western part of Kilauea, the kaoiki fault system, which parallels the southwest rift zone, may be the main barrier to ground-water movement. The diversion of the ground water is manifested in the western part of Kilauea by the presence of large springs at the shore end of the Kaoiki fault system, and in the eastern part by the apparently large flow of unheated basal ground water north of the east rift zone. Thus, recharge to ground water in the rift zones of Kilauea and to the areas to the south of the rift zones may be largely by local rainfall. Recharge from rainfall for all of Kilauea is about 1,250 million gallons per day. Beneath the upper slopes of the Kilauea rift zones, ground-water levels are 2,000 feet or more above mean sea level, or more than 1,000 feet below land surface. Ground-water levels are at these high altitudes because numerous and closely spaced dikes at depth in the upper slopes impound the ground water. In the lower slopes, because the number of dikes decreases toward the surface, the presence of a sufficient number of dikes capable of impounding ground water at altitudes substantially above sea level is unlikely. In surrounding basal ground-water reservoirs, fresh basal ground water floats on seawater and, through a transition zone of mixed freshwater and seawater, discharges into the sea. The hydraulic conductivity of the dike-free lavas ranges from about 3,000 to about 7,000 feet per day. The conductivity in the upper slopes of the rift ranges from about 5 to 30 feet per day and that of the lower slopes of the east rift zone was calculated at about 7,000 feet per day. The

  15. Lidar Observations of the Middle Atmospheric Thermal Tides and Comparison with HRDI and GSWM. Part II: October Observations at Mauna Loa (19.5 degrees North)

    NASA Technical Reports Server (NTRS)

    Leblanc, T.; McDermid, I. S.; Ortland, D. A.

    1998-01-01

    Using more than 145 hours of nighttime lidar measurements obtained during October 1-16, 1996 and October 2-11, 1997, the tidal signature in the middle atmopheric thermal structure (15-95 km) at Mauna Loa, Hawaii, is investigated.

  16. Eosinophil-Associated Processes Underlie Differences in Clinical Presentation of Loiasis Between Temporary Residents and Those Indigenous to Loa-Endemic Areas

    PubMed Central

    Herrick, Jesica A.; Metenou, Simon; Makiya, Michelle A.; Taylar-Williams, Cheryl A.; Law, Melissa A.; Klion, Amy D.; Nutman, Thomas B.

    2015-01-01

    Background. Loa loa has emerged as an important public health problem due to the occurrence of immune-mediated severe posttreatment reactions following ivermectin distribution. Also thought to be immune-mediated are the dramatic differences seen in clinical presentation between infected temporary residents (TR) and individuals native to endemic regions (END). Methods. All patients diagnosed with loiasis at the National Institutes of Health between 1976 and 2012 were included. Patients enrolled in the study underwent a baseline clinical and laboratory evaluation and had serum collected and stored. Stored pretreatment serum was used to measure filaria-specific antibody responses, eosinophil-related cytokines, and eosinophil granule proteins. Results. Loa loa infection in TR was characterized by the presence of Calabar swelling (in 82% of subjects), markedly elevated eosinophil counts, and increased filaria-specific immunoglobulin G (IgG) levels; these findings were thought to reflect an unmodulated immune response. In contrast, END showed strong evidence for immune tolerance to the parasite, with high levels of circulating microfilariae, few clinical symptoms, and diminished filaria-specific IgG. The striking elevation in eosinophil counts among the TR group was accompanied by increased eosinophil granule protein levels (associated with eosinophil activation and degranulation) as well as elevated levels of eosinophil-associated cytokines. Conclusions. These data support the hypothesis that differing eosinophil-associated responses to the parasite may be responsible for the marked differences in clinical presentations between TR and END populations with loiasis. PMID:25234520

  17. A new angle on the Euler angles

    NASA Technical Reports Server (NTRS)

    Markley, F. Landis; Shuster, Malcolm D.

    1995-01-01

    We present a generalization of the Euler angles to axes beyond the twelve conventional sets. The generalized Euler axes must satisfy the constraint that the first and the third are orthogonal to the second; but the angle between the first and third is arbitrary, rather than being restricted to the values 0 and pi/2, as in the conventional sets. This is the broadest generalization of the Euler angles that provides a representation of an arbitrary rotation matrix. The kinematics of the generalized Euler angles and their relation to the attitude matrix are presented. As a side benefit, the equations for the generalized Euler angles are universal in that they incorporate the equations for the twelve conventional sets of Euler angles in a natural way.

  18. Inflation Features of the Distal Pahoehoe Portion of the 1859 Mauna Loa Flow, Hawaii; Implications for Evaluating Planetary Lava Flows

    NASA Technical Reports Server (NTRS)

    Zimbelman, J. R.; Garry, W. B.; Bleacher, Jacob E.; Crumpler, L S.

    2011-01-01

    The 1859 eruption of Mauna Loa, Hawaii, resulted in the longest subaerial lava flow on the Big Island. Detailed descriptions were made of the eruption both from ships and following hikes by groups of observers; the first three weeks of the eruption produced an `a`a flow that reached the ocean, and the following 10 months produced a pahoehoe flow that also eventually reached the ocean. The distal portion of the 1859 pahoehoe flow component includes many distinctive features indicative of flow inflation. Field work was conducted on the distal 1859 pahoehoe flow during 2/09 and 3/10, which allowed us to document several inflation features, in or-der evaluate how well inflated landforms might be detected in remote sensing data of lava flows on other planets.

  19. Perspectives on basaltic magma crystallization and differentiation: Lava-lake blocks erupted at Mauna Loa volcano summit, Hawaii

    USGS Publications Warehouse

    McCarter, Renee L.; Fodor, R.V.; Trusdell, Frank A.

    2006-01-01

    Explosive eruptions at Mauna Loa summit ejected coarse-grained blocks (free of lava coatings) from Moku'aweoweo caldera. Most are gabbronorites and gabbros that have 0–26 vol.% olivine and 1–29 vol.% oikocrystic orthopyroxene. Some blocks are ferrogabbros and diorites with micrographic matrices, and diorite veins (≤2 cm) cross-cut some gabbronorites and gabbros. One block is an open-textured dunite.The MgO of the gabbronorites and gabbros ranges ∼ 7–21 wt.%. Those with MgO >10 wt.% have some incompatible-element abundances (Zr, Y, REE; positive Eu anomalies) lower than those in Mauna Loa lavas of comparable MgO; gabbros (MgO <10 wt.%) generally overlap lava compositions. Olivines range Fo83–58, clinopyroxenes have Mg#s ∼83–62, and orthopyroxene Mg#s are 84–63 — all evolved beyond the mineral-Mg#s of Mauna Loa lavas. Plagioclase is An75–50. Ferrogabbro and diorite blocks have ∼ 3–5 wt.% MgO (TiO2 3.2–5.4%; K2O 0.8–1.3%; La 16–27 ppm), and a diorite vein is the most evolved (SiO2 59%, K2O 1.5%, La 38 ppm). They have clinopyroxene Mg#s 67–46, and plagioclase An57–40. The open-textured dunite has olivine ∼ Fo83.5. Seven isotope ratios are 87Sr/86Sr 0.70394–0.70374 and 143Nd/144Nd 0.51293–0.51286, and identify the suite as belonging to the Mauna Loa system.Gabbronorites and gabbros originated in solidification zones of Moku'aweoweo lava lakes where they acquired orthocumulate textures and incompatible-element depletions. These features suggest deeper and slower cooling lakes than the lava lake paradigm, Kilauea Iki, which is basalt and picrite. Clinopyroxene geobarometry suggests crystallization at <1 kbar P. Highly evolved mineral Mg#s, <75, are largely explained by cumulus phases exposed to evolving intercumulus liquids causing compositional ‘shifts.’ Ferrogabbro and diorite represent segregation veins from differentiated intercumulus liquids filter pressed into rigid zones of cooling lakes. Clinopyroxene

  20. Seasonal amplitude increase in atmospheric CO/sub 2/ concentration at Mauna Loa, Hawaii, 1959-1982

    SciTech Connect

    Bacastow, R.B.; Keeling, C.D.; Whorf, T.P.

    1985-10-20

    The concentration of atmospheric carbon dioxide at Mauna Loa Observatory exhibits a seasonal pattern that repeats with striking regularity from year to year. The amplitude of this seasonal signal, expressed either by peak-to-peak changes in concentration or as a series of harmonic terms, increased at an average rate of about 0.7% per year from 1958 to 1982. The estimated standard error in the linear coefficient of increase is 0.09%. Thus the increase appears to be highly significant statistically. A detailed examination of methods of calibration and of data analysis during this long record do not reveal any inconsistencies large enough to be responsible for the increase. Because the seasonal cycle of CO/sub 2/ in the northern hemisphere is thought to be due principally to the metabolic activity of terrestrial vegetation, it is likely that at least part of the increase is a result of increasing plant activity.

  1. Marine and terrestrial influences on interannual CO{sub 2} variations at Mauna Loa and the South Pole

    SciTech Connect

    Dettinger, M.D.; Ghil, M.

    1997-11-01

    Data are presented and very briefly discussed regarding interannual variations of atmospheric carbon dioxide (CO{sub 2}) concentrations. Interannual variations are isolated from monthly concentrations by using singular-spectrum analysis of CO{sub 2} and atmospheric carbon isotopic ratios at Mauna Loa, Hawaii, United States and at the South Pole. Interannual variations are shared at the two sites, and can be used to differentiate between marine and land-surface responses to different interannual climate variations on global scales. Two time-scales are compared: (1) quasi-quadrennial (QQ) and (2) 3-year. Phase relations indicate that QQ variations are dominated by terrestrial influences, whereas the 3-year variations reflect marine (upwelling) influences in the eastern Pacific. The contrasting CO{sub 2} responses on these two time scales thus provide a useful measure of differences in global climate responses, and especially in terrestrial-ecosystem responses to different tropical forcings. 1 fig.

  2. The effect of the Mt. Pinatubo aerosol on the HNO{sub 3} column over Mauna Loa, Hawaii

    SciTech Connect

    David, S.J.; Murcray, F.J.; Goldman, A.; Murcray, D.G.; Rinsland, C.P.

    1994-06-01

    A very high resolution infrared solar spectrometer system for the Network for Detection of Stratospheric Change has been routinely operated at the Mauna Loa Observatory in Hawaii since November, 1991. Solar absorption spectra are normally taken one day a week at sunrise. The authors report the analysis of these spectra for the vertical column amount of nitric acid (HNO{sub 3}) vapor. The observations began four months after the arrival of volcanic aerosols from Mt. Pinatubo over the site. Although quite variable, total HNO{sub 3} columns were initially about 7{times}10{sup 15} molecules/cm{sup 2} and have decreased about 30% in the following two years. 23 refs., 2 figs.

  3. Comparison of airborne CO2 flask samples and measurements from the Mauna Loa Observatory during the HAMEC Project (June 1980)

    NASA Astrophysics Data System (ADS)

    Herbert, G. A.; Harris, T. B.; Chin, J. F. S.

    1983-08-01

    A P3 aircraft has been used to measure meteorological variables upwind and downwind of the island of Hawaii in order to provide data for the evaluation of mesoscale models of airflow and cloud physics. An attempt was made to obtain flask samples upwind of the island which might confirm that the CO2 values gathered at the Mauna Loa Observatory (MLO) are representative of the free air at comparable altitudes. CO2 flask samples exposed aboard the aircraft at the altitude of the observatory and immediately above the trade inversion yielded flask pairs which were in reasonable agreement. The average difference between the aircraft measurements at the observatory altitude and the continuous CO2 record from the observatory over the same period was 0.8 mole fraction in ppm. Attention is given to measurement differences in light of prevailing meteorological conditions.

  4. Immunogenicity of a DNA and Recombinant Protein Vaccine Combining LipL32 and Loa22 for Leptospirosis Using Chitosan as a Delivery System.

    PubMed

    Umthong, Supawadee; Buaklin, Arun; Jacquet, Alain; Sangjun, Noppadol; Kerdkaew, Ruthairat; Patarakul, Kanitha; Palaga, Tanapat

    2015-04-01

    Leptospirosis is a worldwide zoonotic disease caused by pathogenic Leptospira, a genus of which more than 250 serovars have been identified. Commercial bacterin vaccines are limited in that they lack both cross-protection against heterologous serovars and long-term protection. This study investigated in mice the immunogenicity of an anti-leptospirosis vaccine, using the outer membrane proteins LipL32 and Loa22 as antigens. The immunogenicity of this vaccine formulation was compared with those induced by vaccines based on LipL32 or Loa22 alone. A DNA-encapsulated chitosan nanoparticle was used for in vivo DNA delivery. Using a unique DNA plasmid expressing both lipL32 and loa22 for vaccination, higher antibody responses were induced than when combining plasmids harboring each gene separately. Therefore, this formulation was used to test the immunogenicity when administered by a heterologous prime (DNA)-boost (protein) immunization regimen. The specific antibody responses against LipL32 (total IgG and IgG1) and Loa22 (IgG1) were higher in mice receiving two antigens in combination than in those vaccinated with a single antigen alone. Although no significant difference in splenic CD4+ T cell proliferation was observed among all groups of vaccinated mice, splenocytes from mice vaccinated with two antigens exhibited higher interferon-γ and IL-2 production than when using single antigens alone upon in vitro restimulation. Taken together, the immunogenicity induced by LipL32 and Loa22 antigens in a heterologous primeboost immunization regimen using chitosan as a DNA delivery system induces higher immune response, and may be useful for developing a better vaccine for leptospirosis.

  5. Pinatubo and pre-Pinatubo optical-depth spectra: Mauna Loa measurements, comparisons, inferred particle size distributions, radiative effects, and relationship to lidar data

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Livingston, J. M.; Dutton, E. G.; Pueschel, R. F.; Reagan, J. A.; Defoor, T. E.; Box, M. A.; Allen, D.; Pilewskie, P.; Herman, B. M.

    1993-01-01

    The Ames airborne tracking sunphotometer was operated at the National Oceanic and Atmospheric Administration (NOAA) Mauna Loa Observatory (MLO) in 1991 and 1992 along with the NOAA Climate Monitoring and Diagnostics Laboratory (CMDL) automated tracking sunphotometer and lidar. June 1991 measurements provided calibrations, optical-depth spectra, and intercomparisons under relatively clean conditions; later measurements provided spectra and comparisons for the Pinatubo cloud plus calibration checks. June 1991 results are similar to previous MLO springtime measurements, with midvisible particle optical depth at the near-background level of 0.012 +/- 0.006 and no significant wavelength dependence in the measured range (lambda = 0.38 to 1.06 micrometers). The arrival of the Pinatubo cloud in July 1991 increased midvisible particle optical depth by more than an order of magnitude and changed the spectral shape of to an approximate power law with an exponent of about -1.4. By clearly September 1991, the spectrum was broadly peaked near 0.5 micrometers, and by July 1992, it was peaked near 0.8 micrometers. Our optical-depth spectra include corrections for diffuse light. NOAA- and Ames Research Center (ARC)-measured spectra are in good agreement. Columnar size distributions inverted from the spectra show that the initial (July 1991) post-Pinatubo cloud was relatively rich in small particles (r less than 0.25 micrometers), which were progressively depleted in the August-September 1991 and July 1992 periods. Conversely, both of the later periods had more of the optically efficient medium-sized particles (0.25 less than r less than 1 micrometers) than did the fresh July 1991 cloud. These changes are consistent with particle growth by condensation and coagulation. Photometer-inferred column backscatter values agree with those measured by the CMDL lidar on nearby nights. Combining lidar-measured backscatter profiles with photometer-derived backscatter-to-area ratios gives peak

  6. Pinatubo and pre-Pinatubo optical-depth spectra: Mauna Loa measurements, comparisons, inferred particle size distributions, radiative effects, and relationship to lidar data

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Livingston, J. M.; Dutton, E. G.; Pueschel, R. F.; Reagan, J. A.; Defoor, T. E.; Box, M. A.; Allen, D.; Pilewskie, P.; Herman, B. M.

    1993-01-01

    The Ames airborne tracking sunphotometer was operated at the National Oceanic and Atmospheric Administration (NOAA) Mauna Loa Observatory (MLO) in 1991 and 1992 along with the NOAA Climate Monitoring and Diagnostics Laboratory (CMDL) automated tracking sunphotometer and lidar. June 1991 measurements provided calibrations, optical-depth spectra, and intercomparisons under relatively clean conditions; later measurements provided spectra and comparisons for the Pinatubo cloud plus calibration checks. June 1991 results are similar to previous MLO springtime measurements, with midvisible particle optical depth at the near-background level of 0.012 +/- 0.006 and no significant wavelength dependence in the measured range (lambda = 0.38 to 1.06 micrometers). The arrival of the Pinatubo cloud in July 1991 increased midvisible particle optical depth by more than an order of magnitude and changed the spectral shape of to an approximate power law with an exponent of about -1.4. By clearly September 1991, the spectrum was broadly peaked near 0.5 micrometers, and by July 1992, it was peaked near 0.8 micrometers. Our optical-depth spectra include corrections for diffuse light. NOAA- and Ames Research Center (ARC)-measured spectra are in good agreement. Columnar size distributions inverted from the spectra show that the initial (July 1991) post-Pinatubo cloud was relatively rich in small particles (r less than 0.25 micrometers), which were progressively depleted in the August-September 1991 and July 1992 periods. Conversely, both of the later periods had more of the optically efficient medium-sized particles (0.25 less than r less than 1 micrometers) than did the fresh July 1991 cloud. These changes are consistent with particle growth by condensation and coagulation. Photometer-inferred column backscatter values agree with those measured by the CMDL lidar on nearby nights. Combining lidar-measured backscatter profiles with photometer-derived backscatter-to-area ratios gives peak

  7. Mauna Loa lava accumulation rates at the Hilo drill site: Formation of lava deltas during a period of declining overall volcanic growth

    USGS Publications Warehouse

    Lipman, P.W.; Moore, J.G.

    1996-01-01

    Accumulation rates for lava flows erupted from Mauna Loa, as sampled in the uppermost 280 m of the Hilo drill hole, vary widely for short time intervals (several thousand years), but overall are broadly similar to those documented elsewhere on this volcano since 100 ka. Thickness variations and accumulation rates for Mauna Loa lavas at the Hilo drill site have been strongly affected by local paleotopography, including funneling and ponding between Mauna Kea and Kilauea. In addition, gentle submerged slopes of Mauna Kea in Hilo Bay have permitted large shoreline displacements by Mauna Loa flows. Ages of eruptive intervals have been determined from published isotopic data and from eustatic sea level curves modified to include the isostatic subsidence of the island of Hawaii at 2.2-2.6 mm/yr. Prior to 10 ka, rates of Mauna Loa lava accumulation at the drill site varied from 0.6 to 4.3 mm/yr for dateable intervals, with an overall rate of 1.8 mm/yr. Major eruptive pulses at about 1.3 and 10 ka, each probably representing a single long-lived eruption based on lack of weathering between flow units, increase the overall accumulation rate to 2.4 mm/yr. The higher rate since 10 ka reflects construction of thick near-shoreline lava deltas as postglacial sea levels rose rapidly. Large lava deltas form only along coastal segments where initially subaerial slopes have been submerged by the combined effects of eustatic sea level rise, isostatic subsidence, or spreading of volcano flanks. Overall accumulation of 239 m of lava at the drill site since 100-120 ka closely balances submergence of the Hilo area, suggesting that processes of coastal lava deposition have been modulated by rise in sea level. The Hilo accumulation rate is slightly higher than average rates of 1-2 mm/yr determined elsewhere along the Mauna Loa coast, based on rates of shoreline coverage and dated sea cliff and fault scarp exposures. Low rates of coastal lava accumulation since 100 ka, near or below the rate

  8. Community preparedness for lava flows from Mauna Loa and Hualālai volcanoes, Kona, Hawai'i

    USGS Publications Warehouse

    Gregg, Chris E.; Houghton, Bruce F; Paton, Douglas; Swanson, Donald A.; Johnston, David M.

    2004-01-01

    Lava flows from Mauna Loa and Huala??lai volcanoes are a major volcanic hazard that could impact the western portion of the island of Hawai'i (e.g., Kona). The most recent eruptions of these two volcanoes to affect Kona occurred in A.D. 1950 and ca. 1800, respectively. In contrast, in eastern Hawai'i, eruptions of neighboring Ki??lauea volcano have occurred frequently since 1955, and therefore have been the focus for hazard mitigation. Official preparedness and response measures are therefore modeled on typical eruptions of Ki??lauea. The combinations of short-lived precursory activity (e.g., volcanic tremor) at Mauna Loa, the potential for fast-moving lava flows, and the proximity of Kona communities to potential vents represent significant emergency management concerns in Kona. Less is known about past eruptions of Huala??lai, but similar concerns exist. Future lava flows present an increased threat to personal safety because of the short times that may be available for responding. Mitigation must address not only the specific characteristics of volcanic hazards in Kona, but also the manner in which the hazards relate to the communities likely to be affected. This paper describes the first steps in developing effective mitigation plans: measuring the current state of people's knowledge of eruption parameters and the implications for their safety. We present results of a questionnaire survey administered to 462 high school students and adults in Kona. The rationale for this study was the long lapsed time since the last Kona eruption, and the high population growth and expansion of infrastructure over this time interval. Anticipated future growth in social and economic infrastructure in this area provides additional justification for this work. The residents of Kona have received little or no specific information about how to react to future volcanic eruptions or warnings, and short-term preparedness levels are low. Respondents appear uncertain about how to respond

  9. The Perception of Volcanic Risk in Kona Communities from Mauna Loa and Hualalai Volcanoes, Hawai`i

    NASA Astrophysics Data System (ADS)

    Gregg, C. E.; Houghton, B. F.; Johnston, D. M.; Paton, D.; Swanson, D. A.

    2002-12-01

    Hawai`i's coastal communities are becoming increasingly vulnerable to natural hazards as a consequence of increasing population and infrastructure. Volcanic hazards in Kona (i.e., western side of the island) stem primarily from Mauna Loa and Hualalai volcanoes. The former has erupted thirty-nine times since 1832. Lava flows were emplaced in Kona during six of these, but last impacted Kona in 1950. Hualalai last erupted in c. 1800. The most recent eruptions at each volcano were damaging to society, but future eruptions would exact much greater impacts. The second largest city on the island, several resort complexes, and an international airport are located within 15 km of vents. Society's proximity to potential eruptive sources, a potential for relatively fast moving lavas, and the relatively long time intervals since the last eruptions in Kona, are the stimuli for this study of risk perception. Target populations were high school students and their parents, and the greater adult public (n=462). Using this data, we discuss threat knowledge as an influence on risk perception and perceptions as a driving mechanism for preparedness. Threat knowledge and perception of risk were found to be low to moderate. On average less than two-thirds of residents were aware of the most recent eruptions that impacted Kona and a minority felt that Mauna Loa and Hualalai could erupt again. Furthermore, only about one-third were aware that lava flows could reach the coast in Kona in under three hours. Lava flows and ash fall were perceived to be among the least likely hazards to affect the respondent's community. Not unexpectedly, individual preparedness measures were found to be limited to simple tasks, while measures specific to infrequent hazard events such as volcanic eruptions and earthquakes were seldom adopted. Respondents exhibit an "unrealistic optimism bias" and infer that responsibility for community preparedness for future eruptions rests primarily with officials. Hazard

  10. Measurements of solar radiation at Mauna Loa Observatory, 1978-1985, with emphasis on the effects of the eruption of El Chichon. Data report

    SciTech Connect

    Dutton, E.G.; DeLuisi, J.J.; Austring, A.P.

    1987-07-01

    Results from three different projects that involved either absolute or relative measurement of solar radiation at the NOAA Mauna Loa Observatory are reported. Included are measurements, in summary form, of broadband solar irradiance, spectral aerosol optical depth, and spectral diffuse-sky irradiance. Each data set includes the influence of the stratospheric debris from the eruption of El Chichon. Procedures that were used to acquire and finalize the observational records are documented.

  11. Steepest-descent lines for Kīlauea, Mauna Loa, Hualālai, and Mauna Kea Volcanoes, Hawaiʻi

    USGS Publications Warehouse

    Kauahikaua, James P.; Orr, Tim; Patrick, Matthew R.; Trusdell, Frank

    2016-01-01

    This USGS data release includes two ESRI polyline shapefiles (file_names.shp) describing the describing the steepest-descent lines calculated at two levels of detail (See Process Step for explanation). To increase access to these data, KMZ (Compressed Keyhole Markup Language) versions of the polyline feature layers are included in this release (file_names.kmz). In addition to these data layers, two supplementary data layers from the Big Island Mapping Project (BIMP) showing lava flows originating on Mauna Loa and Kilauea volcanoes, originally published in Trusdell, Wolfe, and Morris (2006), are included for context and reference. Both ESRI polygon shapefiles and KMZ versions of these files are included, naming conventions are identical as the files in this release. This metadata file provides information for the GIS data files unique to this data release. Below are the files that comprise this release, including the metadata files: Steepest-Descent_lines_3M_m2.shp Steepest-Descent_lines_750K_m2.shp Steepest-Descent_lines_3M_m2.KMZ Steepest-Descent_lines_750K_m2.KMZ Kilauea1983-1996_from_BIMP.shp ML1984_from_BIMP.shp Kilauea1983-1996_from_BIMP.kmz ML1984_from_BIMP.kmz mauna_loa_steepest_descent_lines_FGDC.xml mauna_loa_steepest_descent_lines_FGDC.txt

  12. Seasonal and interannual variability of gravity wave activity revealed by long-term lidar observations over Mauna Loa Observatory, Hawaii

    NASA Astrophysics Data System (ADS)

    Li, Tao; Leblanc, Thierry; McDermid, I. Stuart; Wu, Dong L.; Dou, Xiankang; Wang, Shui

    2010-07-01

    The seasonal and interannual variability of gravity wave (GW) variance in the upper stratosphere (35-50 km) and lower mesosphere (48-63 km) has been studied using 10.5 years (January 1997 to June 2007) of temperature profile results obtained with the Jet Propulsion Laboratory Rayleigh lidar at Mauna Loa Observatory, Hawaii (19.5°N, 155.6°W). Seasonal variability with a maximum in winter and a minimum in summer was observed in the upper stratosphere, suggesting dominance of the annual oscillation. In the lower mesosphere the seasonal oscillations of GW variance were dominated by a semiannual oscillation (SAO), likely due to the selective filtering of GWs by the tropical upper stratospheric SAO wind. Modulation of GW variance by the quasi-biennial oscillation was clearly present only for the long vertical wavelength band in the upper stratosphere, and not in the lower mesosphere. The United Kingdom Met Office zonal mean zonal wind further supports that enhanced GW activity in the upper stratosphere corresponds to the westerly shear phase of the zonal wind at 10 hPa (˜30 km), and suppressed activity corresponds to the easterly shear phase. During the strong El Niño event in the winter of 1997-1998, enhanced GW activity was observed only in the lower mesosphere, and not in the upper stratosphere. Additional enhancement of GW variance, especially clear in the upper stratosphere, was also found during 2001-2002 and winter 2005-2006.

  13. Infrared spectroscopic measurements of the ethane (C2H6) total column abundance above Mauna Loa, Hawaii -- seasonal variations

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Goldman, A.; Murcray, F. J.; David, S. J.; Blatherwick, R. D.; Murcray, D. G.

    1994-01-01

    About 200 i.r. solar spectra recorded at 0.01/cm resolution on 71 days between November 1991 and July 1993 at the Network for the Detection of Stratospheric Change (NDSC) station at Mauna Loa, Hawaii (latitude 19.53 deg N, longitude 155.58 deg W, elevation 3.459 km) have been analyzed with a nonlinear least-squares spectral fitting technique to study temporal variations in the total column of atmospheric ethane (C2H6) above the site. The results were derived from the analysis of the unresolved nu(sub 7) band (P)Q(sub 3) subbranch at 2976.8/cm. A distinct seasonal cycle is observed with a factor of 2 variation, a maximum total column of 1.16 x 10(exp 16) mol/sq cm at the end of winter, and a minimum total column of 0.53 x 10(exp 16) mol/sq cm at the end of summer. Our measurements are compared with previous observations and model predictions.

  14. Infrared Spectroscopic Measurements of the Ethane (C2H6) Total Column Abundance Above Mauna Loa, Hawaii: Seasonal Variations

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Goldman, A.; Murcray, F. J.; David, S. J.; Blatherwick, R. D.; Murcray, D. G.

    1994-01-01

    About 200 i.r. solar spectra recorded at 0.01/ cm resolution on 71 days between November 1991 and July 1993 at the Network for the Detection of Stratospheric Change (NDSC) station at Mauna Loa, Hawaii (latitude 19.53 deg N, longitude 155.58 deg W, elevation 3.459 km) have been analyzed with a nonlinear least-squares spectral fitting technique to study temporal variations in the total column of atmospheric ethane (C2H6) above the site. The results were derived from the analysis of the unresolved nu(sub 7) band (sup P)Q(sub 3) subbranch at 2976.8/cm. A distinct seasonal cycle is observed with a factor of 2 variation, a maximum total column of 1.1 6 x 10(exp 16) mol /sq cm at the end of winter, and a minimum total column of 0.53 x 10(exp 16) mol/sq cm at the end of summer. Our measurements are compared with previous observations and model predictions.

  15. Applications of GIS to the estimation of lava flow hazards on Mauna Loa Volcano, Hawai'i

    NASA Astrophysics Data System (ADS)

    Kauahikaua, Jim; Margriter, Sandy; Lockwood, Jack; Trusdell, Frank

    Vector-based GIS computer software is used with preliminary digital geologic maps of the active volcano Mauna Loa, Hawai'i to assess the probability that lava flows from this volcano might adversely affect certain areas more than others. A few possible GIS strategies are explored with the maps completed thus far. Traditional coverage rates and probabilities of lava flow occurrence are calculated for target regions of different sizes and shapes. Probability of lava flow occurrence is the probability that one lava flow will enter the target region within the target time period. Probability of coverage is the probability that a particular point will be covered by one or more lava flows within the target time period. The results show that the two approaches yield similar results, with the occurrence of lava flows in a predefined region being more probable than coverage by lava flows. The probabilities of lava flow occurrence reflect all effects of lava flows, whereas the coverage rate estimates reflect only the most serious effect, that of coverage by lava flows.

  16. Pinatubo and Pre-Pinatubo Optical-Depth Spectra: Mauna Loa Measurements, Comparisons, Inferred Particle Size Distributions, Radiative Effects, and Relationship to Lidar Data

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Livingston, J. M.; Dutton, E. G.; Pueschel, R. F.; Reagan, J. A.; DeFoor, T. E.; Box, M. A.; Pilewskie, P.; Herman, B. M.; Kinne, S. A.; Hofmann, D. J.

    1993-01-01

    The Ames airborne tracking sunphotometer was operated at the National Oceanic and Atmospheric Administration (NOAA) Mauna Loa Observatory (MLO) in 1991 and 1992 along with the NOAA Climate Monitoring and Diagnostics Laboratory (CMDL) automated tracking sunphotometer and lidar. June 1991 measurements provided calibrations, optical-depth spectra, and intercomparisons under relatively clean conditions; later measurements provided spectra and comparisons for the Pinatubo cloud plus calibration checks. June 1991 results are similar to previous MLO springtime measurements, with midvisible particle optical depth tau(sub p)(lambda = 0.526 microns) at the near-background level of 0.012 +/- 0.006 and no significant wavelength dependence in the measured range (lambda = 0.38 to 1.06 microns). The arrival of the Pinatubo cloud in July 1991 increased midvisible particle optical depth by more than an order of magnitude and changed the spectral shape of tau(sub p)(lambda) to an approximate power law with an exponent of about -1.4. By early September 1991, the spectrum was broadly peaked near 0.5 microns, and by July 1992, it was peaked near 0.8 microns. Our optical-depth spectra include corrections for diffuse light which increase postvolcanic midvisible tau(sub p) values by 1 to 3% (i.e., 0.0015 to 0.0023). NOAA- and Ames Research Center (ARC)-measured spectra are in good agreement. Columnar size distributions inverted from the spectra show that the initial (July 1991) post-Pinatubo cloud was relatively rich in small particles (r less than 0.25 microns), which were progressively depleted in the August-September 1991 and July 1992 periods. Conversely, both of the later periods had more of the optically efficient medium-sized particles (0.25 less than r less than 1 micron) than did the fresh July 1991 cloud. These changes are consistent with particle growth by condensation and coagulation. The effective, or area-weighted, radius increased from 0.22 +/- 0.06 micron in July 1991 to 0

  17. Pinatubo and Pre-Pinatubo Optical-Depth Spectra: Mauna Loa Measurements, Comparisons, Inferred Particle Size Distributions, Radiative Effects, and Relationship to Lidar Data

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Livingston, J. M.; Dutton, E. G.; Pueschel, R. F.; Reagan, J. A.; DeFoor, T. E.; Box, M. A.; Pilewskie, P.; Herman, B. M.; Kinne, S. A.; hide

    1993-01-01

    The Ames airborne tracking sunphotometer was operated at the National Oceanic and Atmospheric Administration (NOAA) Mauna Loa Observatory (MLO) in 1991 and 1992 along with the NOAA Climate Monitoring and Diagnostics Laboratory (CMDL) automated tracking sunphotometer and lidar. June 1991 measurements provided calibrations, optical-depth spectra, and intercomparisons under relatively clean conditions; later measurements provided spectra and comparisons for the Pinatubo cloud plus calibration checks. June 1991 results are similar to previous MLO springtime measurements, with midvisible particle optical depth tau(sub p)(lambda = 0.526 microns) at the near-background level of 0.012 +/- 0.006 and no significant wavelength dependence in the measured range (lambda = 0.38 to 1.06 microns). The arrival of the Pinatubo cloud in July 1991 increased midvisible particle optical depth by more than an order of magnitude and changed the spectral shape of tau(sub p)(lambda) to an approximate power law with an exponent of about -1.4. By early September 1991, the spectrum was broadly peaked near 0.5 microns, and by July 1992, it was peaked near 0.8 microns. Our optical-depth spectra include corrections for diffuse light which increase postvolcanic midvisible tau(sub p) values by 1 to 3% (i.e., 0.0015 to 0.0023). NOAA- and Ames Research Center (ARC)-measured spectra are in good agreement. Columnar size distributions inverted from the spectra show that the initial (July 1991) post-Pinatubo cloud was relatively rich in small particles (r less than 0.25 microns), which were progressively depleted in the August-September 1991 and July 1992 periods. Conversely, both of the later periods had more of the optically efficient medium-sized particles (0.25 less than r less than 1 micron) than did the fresh July 1991 cloud. These changes are consistent with particle growth by condensation and coagulation. The effective, or area-weighted, radius increased from 0.22 +/- 0.06 micron in July 1991 to 0

  18. Pinatubo and pre-Pinatubo optical-depth spectra: Mauna Loa measurements, comparisons, inferred particle size distributions, radiative effects, and relationship to lidar data

    NASA Astrophysics Data System (ADS)

    Russell, P. B.; Livingston, J. M.; Dutton, E. G.; Pueschel, R. F.; Reagan, J. A.; Defoor, T. E.; Box, M. A.; Allen, D.; Pilewskie, P.; Herman, B. M.; Kinne, S. A.; Hofmann, D. J.

    1993-12-01

    The Ames airborne tracking sunphotometer was operated at the National Oceanic and Atmospheric Administration (NOAA) Mauna Loa Observatory (MLO) in 1991 and 1992 along with the NOAA Climate Monitoring and Diagnostics Laboratory (CMDL) automated tracking sunphotometer and lidar. June 1991 measurements provided calibrations, optical-depth spectra, and intercomparisons under relatively clean conditions; later measurements provided spectra and comparisons for the Pinatubo cloud plus calibration checks. June 1991 results are similar to previous MLO springtime measurements, with midvisible particle optical depth τp(λ = 0.526μm) at the near-background level of 0.012 ± 0.006 and no significant wavelength dependence in the measured range (λ = 0.38 to 1.06μm). The arrival of the Pinatubo cloud in July 1991 increased midvisible particle optical depth by more than an order of magnitude and changed the spectral shape of τp(λ) to an approximate power law with an exponent of about -1.4. By early September 1991, the spectrum was broadly peaked near 0.5 μm, and by July 1992, it was peaked near 0.8 μm. Our optical-depth spectra include corrections for diffuse light which increase postvolcanic midvisible τp values by 1 to 3% (i.e., 0.0015 to 0.0023). NOAA- and Ames Research Center (ARC)-measured spectra are in good agreement. Columnar size distributions inverted from the spectra show that the initial (July 1991) post-Pinatubo cloud was relatively rich in small particles (r<0.25μm), which were progressively depleted in the August-September 1991 and July 1992 periods. Conversely, both of the later periods had more of the optically efficient medium-sized particles (0.25

  19. Reading Angles in Maps

    ERIC Educational Resources Information Center

    Izard, Véronique; O'Donnell, Evan; Spelke, Elizabeth S.

    2014-01-01

    Preschool children can navigate by simple geometric maps of the environment, but the nature of the geometric relations they use in map reading remains unclear. Here, children were tested specifically on their sensitivity to angle. Forty-eight children (age 47:15-53:30 months) were presented with fragments of geometric maps, in which angle sections…

  20. Reading Angles in Maps

    ERIC Educational Resources Information Center

    Izard, Véronique; O'Donnell, Evan; Spelke, Elizabeth S.

    2014-01-01

    Preschool children can navigate by simple geometric maps of the environment, but the nature of the geometric relations they use in map reading remains unclear. Here, children were tested specifically on their sensitivity to angle. Forty-eight children (age 47:15-53:30 months) were presented with fragments of geometric maps, in which angle sections…

  1. The perception of volcanic risk in Kona communities from Mauna Loa and Hualālai volcanoes, Hawai'i

    USGS Publications Warehouse

    Gregg, Chris E.; Houghton, B.F.; Johnston, David M.; Paton, Douglas; Swanson, D.A.

    2004-01-01

    Volcanic hazards in Kona (i.e. the western side of the island of Hawai'i) stem primarily from Mauna Loa and Huala??lai volcanoes. The former has erupted 39 times since 1832. Lava flows were emplaced in Kona during seven of these eruptions and last impacted Kona in 1950. Huala??lai last erupted in ca. 1800. Society's proximity to potential eruptive sources and the potential for relatively fast-moving lava flows, coupled with relatively long time intervals since the last eruptions in Kona, are the underlying stimuli for this study of risk perception. Target populations were high-school students and adults ( n =462). Using these data, we discuss threat knowledge as an influence on risk perception, and perception as a driving mechanism for preparedness. Threat knowledge and perception of risk were found to be low to moderate. On average, fewer than two-thirds of the residents were aware of the most recent eruptions that impacted Kona, and a minority felt that Mauna Loa and Huala??lai could ever erupt again. Furthermore, only about one-third were aware that lava flows could reach the coast in Kona in less than 3 h. Lava flows and ash fall were perceived to be among the least likely hazards to affect the respondent's community within the next 10 years, whereas vog (volcanic smog) was ranked the most likely. Less than 18% identified volcanic hazards as amongst the most likely hazards to affect them at home, school, or work. Not surprisingly, individual preparedness measures were found on average to be limited to simple tasks of value in frequently occurring domestic emergencies, whereas measures specific to infrequent hazard events such as volcanic eruptions were seldom adopted. Furthermore, our data show that respondents exhibit an 'unrealistic optimism bias' and infer that responsibility for community preparedness for future eruptions primarily rests with officials. We infer that these respondents may be less likely to attend to hazard information, react to warnings as

  2. A quantitative analysis of phenotypic variations of Metrosideros polymorpha within and across populations along environmental gradients on Mauna Loa, Hawaii.

    PubMed

    Tsujii, Yuki; Onoda, Yusuke; Izuno, Ayako; Isagi, Yuji; Kitayama, Kanehiro

    2016-04-01

    Metrosideros polymorpha, a dominant tree species in the Hawaiian Islands, shows an extreme phenotypic polymorphism both across gradients of climatic/edaphic conditions and within populations, making it a potentially useful model species for evolutionary study. In order to understand how the phenotypic diversity is maintained within populations as well as across populations, we examined the diversities of several leaf and stem functional traits across five elevations and two soil substrates on the volcanic mountain of Mauna Loa, on the island of Hawaii. Leaf dry mass per area (LMA), a key leaf functional trait, was particularly focused on and analyzed in relation to its underlying components-namely, tissue LMA and trichome LMA (LMA = tissue LMA + trichome LMA). Across populations, tissue LMA increased linearly with elevation while trichome LMA showed unimodal patterns with elevation, which were better correlated with temperature and rainfall, respectively. Substantial phenotypic variations were also found within populations. Interestingly, the variations of tissue LMA were often negatively correlated to trichome LMA within populations, which contrasts with the cross-populations pattern, where a strong positive correlation between tissue LMA and trichome LMA was found. This suggests that phenotypic variations within populations were substantially influenced by local ecological processes. Soil depth (an indicator of local water availability) and tree size (an indicator of colonized timing) modestly explained the within-population variations, implying other local environmental factors and/or random processes are also important in local phenotypic diversity. This study provides an insight about how phenotypic diversity of plant species is maintained from local to landscape levels.

  3. Identifying tropospheric baseline air masses at Mauna Loa Observatory between 2004 and 2010 using Radon-222 and back trajectories

    NASA Astrophysics Data System (ADS)

    Chambers, Scott D.; Zahorowski, Wlodek; Williams, Alastair G.; Crawford, Jagoda; Griffiths, Alan D.

    2013-01-01

    We use 7 years of hourly radon observations at Mauna Loa Observatory (MLO), together with 10-day back trajectories, to identify baseline air masses at the station. The amplitude of the annual MLO radon cycle, based on monthly means, was 98 mBq m-3 (39 -137 mBq m-3), with maximum values in February (90th percentile 330 mBq m-3) and minimum values in August (10th percentile 8.1 mBq m-3). The composite diurnal radon cycle (amplitude 49 mBq m-3) is discussed with reference to the influences of local flow features affecting the site, and a 3-hour diurnal sampling window (0730-1030 HST) is proposed for observing the least terrestrially influenced tropospheric air masses. A set of 763 baseline events is selected, using the proposed sampling window together with trajectory information, and presented along with measured radon concentrations as a supplement. This data set represents a resource for the selection of baseline events at MLO for use with a range of trace species. A reduced set of 196 "deep baseline" events occurring in the July-September window is also presented and discussed. The distribution (10th/50th/90th percentile) of radon in deep-baseline events (8.7/29.2/66.1 mBq m-3) was considerably lower than that for the overall set of 763 baseline events (12.3/40.8/104.1 mBq m-3). Results from a simple budget calculation, using sonde-derived mixing depths and literature-based estimates of oceanic radon flux and radon concentrations in the marine boundary layer, indicate that the main source of residual radon in the lower troposphere under baseline conditions at MLO is downward mixing from aged terrestrial air masses in the upper troposphere.

  4. Prevalence of pox-like lesions and malaria in forest bird communitites on leeward Mauna Loa volcano, Hawaii

    USGS Publications Warehouse

    Atkinson, C.T.; Lease, J.K.; Dusek, R.J.; Samuel, M.D.

    2005-01-01

    Introduced avian pox virus and malaria have had devastating impacts on native Hawaiian forest birds, yet little has been published about their prevalence and distribution in forest bird communities outside of windward Hawaii Island. We surveyed native and non-native forest birds for these two diseases at three different elevations on leeward Mauna Loa Volcano at the Kona Forest Unit of Hakalau Forest National Wildlife Refuge. Prevalence of malaria by both serology and microscopy varied by elevation and ranged from 28% at 710 m to 13% at 1830 m. Prevalence of pox-like lesions also varied by altitude, ranging in native species from 10% at 710 m to 2% at 1830 m. Native species at all elevations had the highest prevalence of malarial antibody and pox-like lesions. By contrast, pox-like lesions were not detected in individuals of four non-native species and only 5% of Japanese White-eye (Zosterops japonicus) was positive for malaria. A significantly high proportion of birds with pox-like lesions also had serological evidence of concurrent, chronic malarial infections, suggesting an interaction between these diseases, dual transmission of both diseases by the primary mosquito vector (Culex quinquefasciatus) or complete recovery of some pox-infected birds without loss of toes. Results from this study document high prevalence of malaria and pox at this refuge. Development of effective disease control strategies will be important for restoration of remnant populations of the endangered 'Akiapola'au (Hemignathus munroi), Hawaii Creeper (Oreomystis mana), and Hawaii 'Akepa (Loxops coccineus coccineus) that still occur on the refuge.

  5. Viewing angle changeable display

    NASA Astrophysics Data System (ADS)

    Leng, Jinbi; Huang, Ziqiang; Yang, Wenjun; Chen, Xiaoxi

    2010-10-01

    Viewing angle changeable display can change the display viewing angle as needed: In the public place the display could have a narrow viewing angle for privacy, while in the private place the displays could have a wide viewing angle for the convenience of the operation and better viewing experience. This article propose a novel adjustable optical transmission device to realize the viewing angle changes for LCD by using the principle of guest- host effect of liquid crystal. The major technology is to insert a special equipment between the backlight and the LCD, through which the backlight will display either parallel or scattered features to get an either narrow or wide viewing angle. The equipment is an adjustable transmission cell (ATC) which is actually a black G-H LC cell. This ATC is the main focus of our invention. The ATC consists of a polarizer sheet and a special guest-host liquid crystal device filled with the two-phase dye (called as GH-LC in this report), to achieve the viewing angle change in the LCD. When an electrical field charges to the ATC, only the so-called near-axis lights can pass through the ATC within a relatively small angle, while the other scattered lights are absorbed sequentially by GH-LC and the polarizer sheet. On the other hand, when there is no electrical charge to the ATC, the cell behaves like a normal polarizer; and the scattered light can pass through the cell and polarizer in a normal way. This paper describes the principle and structure of the device, applies the electric field on the sample to observe the electro-optical properties, combine the theoretical and experimental research, getting the viewing angle effects of the display.

  6. Photoelectric angle converter

    NASA Astrophysics Data System (ADS)

    Podzharenko, Volodymyr A.; Kulakov, Pavlo I.

    2001-06-01

    The photo-electric angle transmitter of rotation is offered, at which the output voltage is linear function of entering magnitude. In a transmitter the linear phototransducer is used on the basis of pair photo diode -- operating amplifier, which output voltage is linear function of the area of an illuminated photosensitive stratum, and modulator of a light stream of the special shape, which ensures a linear dependence of this area from an angle of rotation. The transmitter has good frequent properties and can be used for dynamic measurements of an angular velocity and angle of rotation, in systems of exact drives and systems of autocontrol.

  7. Meteorite incidence angles

    NASA Astrophysics Data System (ADS)

    Hughes, D. W.

    1993-06-01

    Think about an asteroid smashing into the surface of the Moon and excavating a crater; or hitting Earth and scattering meteorite fragments over a strewn field. Imagine a fragment of cometary dust burning out in the Earth's atmosphere and producing a meteor. These bodies have paths that are inclined at some angle to the vertical. But what is the predominant value of this angle of incidence, i? How does the number of incident bodies vary as a function of angle i? And how do both these affect the prevalence of non- circular lunar craters and the ellipticity of meteorite strewn fields?

  8. Radiocarbon dates for lava flows from northeast rift zone of Mauna Loa Volcano, Hilo 7 1/2 minute quadrangle, Island of Hawaii

    USGS Publications Warehouse

    Buchanan-Banks, J. M.; Lockwood, J.P.; Rubin, M.

    1989-01-01

    Twenty-eight 14C analyses are reported for carbonized roots and other plant material collected from beneath 15 prehistoric lava flows erupted from the northeast rift zone (NERZ) of Mauna Loa Volcano (ML). The new 14C dates establish ages for 13 previously undated lava flows, and correct or add to information previously reported. Limiting ages on other flows that lie either above or below the dated flows are also established. These dates help to unravel the eruptive history of ML's NERZ. -from Authors

  9. Angles, Time, and Proportion

    ERIC Educational Resources Information Center

    Pagni, David L.

    2005-01-01

    This article describes an investigation making connections between the time on an analog clock and the angle between the minute hand and the hour hand. It was posed by a middle school mathematics teacher. (Contains 8 tables and 6 figures.)

  10. 'Magic Angle Precession'

    SciTech Connect

    Binder, Bernd

    2008-01-21

    An advanced and exact geometric description of nonlinear precession dynamics modeling very accurately natural and artificial couplings showing Lorentz symmetry is derived. In the linear description it is usually ignored that the geometric phase of relativistic motion couples back to the orbital motion providing for a non-linear recursive precession dynamics. The high coupling strength in the nonlinear case is found to be a gravitomagnetic charge proportional to the precession angle and angular velocity generated by geometric phases, which are induced by high-speed relativistic rotations and are relevant to propulsion technologies but also to basic interactions. In the quantum range some magic precession angles indicating strong coupling in a phase-locked chaotic system are identified, emerging from a discrete time dynamical system known as the cosine map showing bifurcations at special precession angles relevant to heavy nuclei stability. The 'Magic Angle Precession' (MAP) dynamics can be simulated and visualized by cones rolling in or on each other, where the apex and precession angles are indexed by spin, charge or precession quantum numbers, and corresponding magic angles. The most extreme relativistic warping and twisting effect is given by the Dirac spinor half spin constellation with 'Hyperdiamond' MAP, which resembles quark confinement.

  11. Controls on Synoptic Scale Variability in Atmospheric Water Vapor Stable Isotopologues from Mauna Loa Observatory, Hawaii (Invited)

    NASA Astrophysics Data System (ADS)

    Hurley, J. V.; Galewsky, J.; Noone, D. C.; Worden, J.; Johnson, L. R.

    2010-12-01

    The Havaiki campaign, 9 October to 6 November, 2008, included continuous (6 seconds) in-situ measurement of water vapor stable isotopic ratios at the NOAA Mauna Loa Observatory (MLO), Hawaii. δD correlates with water vapor mixing ratios, and is characterized by both diurnal fluctuations and synoptic scale variability. Daily fluctuations are related to day-time lifting and night-time compression of the trade inversion. We focus on the synoptic variability of night-time δD values, which is more representative of the free troposphere. To do so, we determined last saturation conditions for air at MLO using both Lagrangian back-trajectory and Eulerian GCM-based techniques. Last saturation of air at MLO occurs primarily in the extra-tropical middle-upper troposphere, along mid-latitude baroclinic zones, and secondarily near Hawaii within mesoscale convective systems. Synoptic-scale periods of lower (elevated) δD values at MLO correspond to extra-tropical (near-Hawaii) last saturation. To assess the influence of mixing on water vapor δD at MLO, we reconstructed Havaiki humidity and δD values from both our Lagrangian and Eulerian last saturation model results. The Eulerian based reconstructions, which account for mixing, better represent the observed Havaiki δD values. The Lagrangian approach does not account for mixing and overestimates the observed variability. These results suggest that mixing plays a critical role in setting the water vapor δD of sub-saturated air in the subtropical free tropopshere. To weigh the influences that large-scale circulation or the pre-saturation water vapor δD values have on the observed synoptic variability of δD at MLO, we conducted δD reconstruction experiments. First, we held constant the pre-saturation water vapor δD, varied the last saturation distributions, and were able to reproduce the observed synoptic variability. In the second experiment, we held last saturation distributions constant, varied the pre-saturation

  12. Health hazard evaluation determination report no. HE 79-31-699, University Corporation for Atmospheric Research, Mauna Loa Observatory, Hilo, Hawaii 96720

    SciTech Connect

    Belanger, P.L.

    1980-06-01

    An environmental survey was conducted from September 24 to 26, 1979 at the Mauna Loa Observatory, Hawaii (SIC-8922). An authorized employer representative requested the evaluation to determine whether solar observers and engineers working at the observatory were exposed to toxic chemicals emanating from the Mauna Loa volcano five miles away. Personal breathing zone and area air samples were collected to measure concentrations of methyl chloride (74873), methyl iodide (74884), inorganic mercury (7439976), sulfur dioxide (7446095), hydrogen sulfide (7783064), and selenium (7782492) and other metals in the telescope control room and telescope room. Airborne concentrations of methyl iodide, mercury, sulfuric acid, trace metals and hydrogen sulfide were below the limits of detection. Airborne concentrations of methyl chloride ranged from 0.02 to 0.08 parts per million (ppm) and were well below the OSHA standard of 100ppm as an 8 hour time weighted average (TWA). Sulfur dioxide concentrations ranging from 0.30 to 0.05ppm were all below or equal to NIOSH recommended criterion of 0.50ppm. The authors conclude that no hazard existed from exposure to any of the compounds.

  13. An Iterative Angle Trisection

    ERIC Educational Resources Information Center

    Muench, Donald L.

    2007-01-01

    The problem of angle trisection continues to fascinate people even though it has long been known that it can't be done with straightedge and compass alone. However, for practical purposes, a good iterative procedure can get you as close as you want. In this note, we present such a procedure. Using only straightedge and compass, our procedure…

  14. Casting and Angling.

    ERIC Educational Resources Information Center

    Little, Mildred J.; Bunting, Camille

    The self-contained packet contains background information, lesson plans, 15 transparency and student handout masters, drills and games, 2 objective examinations, and references for teaching a 15-day unit on casting and angling to junior high and senior high school students, either as part of a regular physical education program or as a club…

  15. Casting and Angling.

    ERIC Educational Resources Information Center

    Smith, Julian W.

    As part of a series of books and pamphlets on outdoor education, this manual consists of easy-to-follow instructions for fishing activities dealing with casting and angling. The manual may be used as a part of the regular physical education program in schools and colleges or as a club activity for the accomplished weekend fisherman or the…

  16. The Rainbow Angle.

    ERIC Educational Resources Information Center

    Sims, B.

    1978-01-01

    Two articles in the "Scientific American" form the background of this note. The rainbow angle for the primary bow of a monochromatic Cartesian rainbow is calculated. Special projects for senior high school students could be patterned after this quantitative study. (MP)

  17. Casting and Angling.

    ERIC Educational Resources Information Center

    Little, Mildred J.; Bunting, Camille

    The self-contained packet contains background information, lesson plans, 15 transparency and student handout masters, drills and games, 2 objective examinations, and references for teaching a 15-day unit on casting and angling to junior high and senior high school students, either as part of a regular physical education program or as a club…

  18. Characterizing the influence of anthropogenic emissions and transport variability on sulfate aerosol concentrations at Mauna Loa Observatory

    NASA Astrophysics Data System (ADS)

    Potter, Lauren E.

    Sulfate aerosol in the atmosphere has substantial impacts on human health and environmental quality. Most notably, atmospheric sulfate has the potential to modify the earth's climate system through both direct and indirect radiative forcing mechanisms (Meehl et al., 2007). Emissions of sulfur dioxide, the primary precursor of sulfate aerosol, are now globally dominated by anthropogenic sources as a result of widespread fossil fuel combustion. Economic development in Asian countries since 1990 has contributed considerably to atmospheric sulfur loading, particularly China, which currently emits approximately 1/3 of global anthropogenic SO2 (Klimont et al., 2013). Observational and modeling studies have confirmed that anthropogenic pollutants from Asian sources can be transported long distances with important implications for future air quality and global climate change. Located in the remote Pacific Ocean (19.54°N, 155.58°W) at an elevation of 3.4 kilometers above sea level, Mauna Loa Observatory (MLO) is an ideal measurement site for ground-based, free tropospheric observations and is well situated to experience influence from springtime Asian outflow. This study makes use of a 14-year data set of aerosol ionic composition, obtained at MLO by the University of Hawaii at Manoa. Daily filter samples of total aerosol concentrations were made during nighttime downslope (free-tropospheric) transport conditions, from 1995 to 2008, and were analyzed for aerosol-phase concentrations of the following species: nitrate (NO3-), sulfate (SO42-), methanesulfonate (MSA), chloride (Cl-), oxalate, sodium (Na+), ammonium (NH 4+), potassium (K+), magnesium (Mg 2+), and calcium (Ca2+). An understanding of the factors controlling seasonal and interannual variations in aerosol speciation and concentrations at this site is complicated by the relatively short lifetimes of aerosols, compared with greenhouse gases which have also been sampled over long time periods at MLO. Aerosol filter

  19. A Different Angle on Perspective

    ERIC Educational Resources Information Center

    Frantz, Marc

    2012-01-01

    When a plane figure is photographed from different viewpoints, lengths and angles appear distorted. Hence it is often assumed that lengths, angles, protractors, and compasses have no place in projective geometry. Here we describe a sense in which certain angles are preserved by projective transformations. These angles can be constructed with…

  20. A Different Angle on Perspective

    ERIC Educational Resources Information Center

    Frantz, Marc

    2012-01-01

    When a plane figure is photographed from different viewpoints, lengths and angles appear distorted. Hence it is often assumed that lengths, angles, protractors, and compasses have no place in projective geometry. Here we describe a sense in which certain angles are preserved by projective transformations. These angles can be constructed with…

  1. Angles in the Sky?

    NASA Astrophysics Data System (ADS)

    Behr, Bradford

    2005-09-01

    Tycho Brahe lived and worked in the late 1500s before the telescope was invented. He made highly accurate observations of the positions of planets, stars, and comets using large angle-measuring devices of his own design. You can use his techniques to observe the sky as well. For example, the degree, a common unit of measurement in astronomy, can be measured by holding your fist at arm's length up to the sky. Open your fist and observe the distance across the sky covered by the width of your pinky fingernail. That is, roughly, a degree! After some practice, and knowing that one degree equals four minutes, you can measure elapsed time by measuring the angle of the distance that the Moon appears to have moved and multiplying that number by four. You can also figure distances and sizes of things. These are not precise measurements, but rough estimates that can give you a "close-enough" answer.

  2. Laser angle sensor

    NASA Technical Reports Server (NTRS)

    Pond, C. R.; Texeira, P. D.

    1985-01-01

    A laser angle measurement system was designed and fabricated for NASA Langley Research Center. The instrument is a fringe counting interferometer that monitors the pitch attitude of a model in a wind tunnel. A laser source and detector are mounted above the model. Interference fringes are generated by a small passive element on the model. The fringe count is accumulated and displayed by a processor in the wind tunnel control room. This report includes optical and electrical schematics, system maintenance and operation procedures.

  3. Contact angle hysteresis explained.

    PubMed

    Gao, Lichao; McCarthy, Thomas J

    2006-07-04

    A view of contact angle hysteresis from the perspectives of the three-phase contact line and of the kinetics of contact line motion is given. Arguments are made that advancing and receding are discrete events that have different activation energies. That hysteresis can be quantified as an activation energy by the changes in interfacial area is argued. That this is an appropriate way of viewing hysteresis is demonstrated with examples.

  4. Small Angle Neutron Scattering

    SciTech Connect

    Urban, Volker S

    2012-01-01

    Small Angle Neutron Scattering (SANS) probes structural details at the nanometer scale in a non-destructive way. This article gives an introduction to scientists who have no prior small-angle scattering knowledge, but who seek a technique that allows elucidating structural information in challenging situations that thwart approaches by other methods. SANS is applicable to a wide variety of materials including metals and alloys, ceramics, concrete, glasses, polymers, composites and biological materials. Isotope and magnetic interactions provide unique methods for labeling and contrast variation to highlight specific structural features of interest. In situ studies of a material s responses to temperature, pressure, shear, magnetic and electric fields, etc., are feasible as a result of the high penetrating power of neutrons. SANS provides statistical information on significant structural features averaged over the probed sample volume, and one can use SANS to quantify with high precision the structural details that are observed, for example, in electron microscopy. Neutron scattering is non-destructive; there is no need to cut specimens into thin sections, and neutrons penetrate deeply, providing information on the bulk material, free from surface effects. The basic principles of a SANS experiment are fairly simple, but the measurement, analysis and interpretation of small angle scattering data involves theoretical concepts that are unique to the technique and that are not widely known. This article includes a concise description of the basics, as well as practical know-how that is essential for a successful SANS experiment.

  5. Observation of the middle atmospheric thermal tides using lidar measurements over Mauna Loa Observatory (19.5 deg N, 155.6 deg W)

    NASA Technical Reports Server (NTRS)

    Leblanc, Thierry; McDermid, I. Stuart

    1998-01-01

    Temperature measurements in the middle atmosphere using Rayleigh lidars have been performed for several decades now. The high accuracy and vertical resolution provided by lidars allow to study the temperature variability at various scales with high confidence levels. One of the numerous applications is the study of the middle atmospheric thermal tides. Although Rayleigh lidar measurements are basically possible only at nighttime, diurnal and semidiurnal components can often be extracted if the results are taken with care and correctly interpreted. Using results from more than 200 hours of nighttime measurements obtained by lidar in October 1996 and 1997 at Mauna Loa Observatory, Hawaii, a study of the middle atmospheric (25-90 km) thermal tides is presented in this paper. The amplitudes and phases of the diurnal and semidiurnal components were calculated for some altitudes where the fits converged significantly, and compared to that of the Global Scale Wave Model (GSWM).

  6. Assessing individual and organizational response to volcanic crisis and unrest at Kīlauea and Mauna Loa volcanoes, Hawai'i

    NASA Astrophysics Data System (ADS)

    Reeves, Ashleigh; Gregg, Chris; Lindell, Michael; Prater, Carla; Joyner, Timothy; Eggert, Sarah

    2017-04-01

    This study describes response to and preparedness for eruption and unrest at Kīlauea and Mauna Loa volcanoes, respectively. The on-going 1983-present eruption of Kīlauea's East Rift Zone (ERZ) has generated a series of lava flow crises, the latest occurring in 2014 and 2015 when lava from a new vent flowed northeast and into the perimeter of developed areas in the lower Puna District, some 20km distant. It took ca. 2 months for the June 27 lava flow to advance a distance to which scientists reported it might be a concern to people downslope, but this prompted widespread formal and informal responses and culminated in improvements to infrastructure, voluntary evacuations of residents and businesses and closure of schools. Unlike Kīlauea, which has had frequent crises since the mid-20th century, the last eruption of nearby Mauna Loa occurred in 1984 and the last eruption and crisis on its Southwest Rift Zone (SWZ) was in 1950, so residents there are less familiar with eruptions than in Puna. In September 2015, the US Geological Survey, Hawaiian Volcano Observatory upgraded Mauna Loa's Alert Level from Normal to Advisory due to increases in unrest above known background levels. A crisis on Mauna Loa's SWZ would likely be much different than the recent 2014-15 crisis at Kīlauea as steep topography downslope of the SWZ and typical high discharge rates mean lava flows move fast, posing increased risk to areas downslope. Typically, volcanic eruptions have significant economic consequences out of proportion with their magnitudes. Furthermore, uncertainties regarding the physical and organizational communication of risk information amplify these economic losses. One significant impediment to risk communication is limited knowledge about the most effective ways to verbally, numerically and graphically communicate scientific uncertainty. This was a challenge in the recent lava flow crisis on Kīlauea. The public's demand for near-real time information updates, including

  7. An application of the lottery competition model to a montane rainforest community of two canopy trees, ohia (Metrosideros polymorpha) and koa (Acacia koa) on Mauna Loa, Hawaii

    USGS Publications Warehouse

    Hatfield, J.S.; Link, W.A.; Dawson, D.K.; Lindquist, E.L.

    1992-01-01

    This rainforest occurs on Mauna Loa at 1500-2000 m elevation. Earthwatch volunteers, studying the habitat of 8 native forest bird species (3 endangered), identified 2382 living canopy trees, and 99 dead trees, on 68 study plots, 400 m2 each. Ohia made up 88% of the canopy; koa was 12%. The two-species lottery competition model, a stochastic model in which coexistence of species results from variation in recruitment and death rates, predicts a quadratic-beta distribution for the proportion of space occupied by one species. A discrete version was fit to the live tree data and a likelihood ratio test (p=0.02) was used to test if the mean death rates were equal. This test was corroborated by a contingency table analysis (p=0.03) based on dead trees. Parameter estimates from the two analyses were similar.

  8. Impact of Asian emissions on the remote North Pacific atmosphere: Interpretation of CO data from Shemya, Guam, Midway and Mauna Loa

    NASA Astrophysics Data System (ADS)

    Jaffe, Daniel; Mahura, Alexander; Kelley, Jennifer; Atkins, John; Novelli, Paul C.; Merrill, John

    1997-12-01

    In this study we look at the concentration of CO at four remote stations in the North Pacific to evaluate the impact of Asian industrial emissions on the remote atmosphere. Using a locally weighted smoothing technique to identify individual data outliers from the seasonal cycle, we have identified 22-92 outliers or "events" (greater than 5 ppbv above the seasonal cycle) at each site for the 3-6 year data records. Using isentropic back trajectories, we identify a possible source region for each event and present a distribution of the trajectory types. For the events at Midway, Mauna Loa, Guam, and Shemya, we are able to identify a source region for the elevated CO in 82, 72, 65, and 50% of the events, respectively. At Mauna Loa and Midway a majority of the events occur during spring and are usually associated with transport from Asia. These events bring the highest CO mixing ratios observed at any time during the year to these sites, with CO enhancements up to 46 ppb. At Guam, easterly trade winds are the norm, but occasionally synoptic events bring Asian emissions to the island, generally during late summer and fall, from either East Asia or Southeast Asia (e.g., Indonesia). These events bring with them the largest CO enhancements of any of the four sites considered in this paper, up to 58 ppb. Finally, to examine the robustness of our conclusions, we redo our analysis using the more stringent definition that an event must be either 10 or 15 ppb above the seasonal cycle. Although this reduces the number of events identified at each site, it does not significantly change the fraction of events which can be attributed to a known source.

  9. Water vapor isotopes measurements at Mauna Loa, Hawaii: Comparison of laser spectroscopy and remote sensing with traditional methods, and the need for ongoing monitoring

    NASA Astrophysics Data System (ADS)

    Galewsky, J.; Noone, D.; Sharp, Z.; Worden, J.

    2009-04-01

    The isotopic composition of water vapor (2H/1H and 18O/16 ratios) provides unique information on the transport pathways that link water sources to regional sinks, and thus proves useful in understanding large scale atmospheric humidity budgets. Recent advances in measurement technology allow the monitoring of water vapor isotope composition in ways which has can revolutionize investigations of atmospheric hydrology. Traditional measurement of isotopic composition requires trapping of samples with either large volume vacuum flasks or by trapping liquid samples with cryogens for later analyses using mass spectrometry, and are laborious and seldom span more than just short dedicated observational periods. On the other hand, laser absorption spectroscopy can provide almost continuous and autonomous in situ measurements of isotope abundances with precision almost that of traditional mass spectrometry, and observations from spacecraft can make almost daily maps of the global isotope distributions. In October of 2008 three laser based spectrometers were deployed at the Mauna Loa Laboratory in Hawaii to make continuous measurement of the 2H and 18O abundance of free tropospheric water vapor. These results are compared with traditional measurements and with measurements from two satellite platforms. While providing field validation of the new methodologies, the data show variability which captures the transport processes in the region. The data are used to characterize the role of large scale mixing of dry air, the influence of the boundary layer and the importance of moist convection in controlling the low humidity of subtropical air near Hawaii. Although the record is short, it demonstrates the usefulness of using robust isotope measurements to understand the budgets of the most important greenhouse gas. This work motivates establishing a continuous record of isotopes measurement at baseline sites, like Mauna Loa, such that the changes in water cycle can be understood and

  10. Water vapor isotopes measurements at Mauna Loa, Hawaii: Comparison of laser spectroscopy and remote sensing with traditional methods, and the need for ongoing monitoring

    NASA Astrophysics Data System (ADS)

    Noone, D.; Galewsky, J.; Sharp, Z.; Worden, J.

    2008-12-01

    The isotopic composition of water vapor (2H/1H and 18O/16 ratios) provides unique information on the transport pathways that link the water sources to regional sinks, and thus proves useful in understanding the large scale humidity budgets. Recent advances in measurement technology allow the monitoring of water vapor isotope composition in ways which has can revolutionize investigations of atmospheric hydrology. Traditional measurement of isotopic composition requires trapping of samples with either large volume vacuum flasks or by trapping liquid samples with cryogens for later analyses using mass spectrometry, and are laborious and seldom span more than just short dedicated observational periods. On the other hand, laser absorption spectroscopy can provide almost continuous and autonomous in situ measurements of isotope abundances with precision almost that of traditional mass spectrometry, and observations from spacecraft can make almost daily maps of the global isotope distributions. In October of 2008 three laser based spectrometers were deployed at the Mauna Loa Laboratory in Hawaii to make continuous measurement of the 2H and 18O abundance of free tropospheric water vapor. These results are compared with traditional measurements and with measurements from two satellite platforms. While providing field validation of the new methodologies, the data show variability which captures the transport processes in the region. The data are used to characterize the role of large scale mixing of dry air, the influence of the boundary layer and the importance of moist convection in controlling the low humidity of subtropical air near Hawaii. Although the record is short, it demonstrates the usefulness of using robust isotope measurements to understand the budgets of the most important greenhouse gas. This work motivates establishing a continuous record of isotopes measurement at baseline sites, like Mauna Loa, such that the changes in water cycle can be understood and

  11. Near-real time infrared observations of acidic sulfates in /open quotes/clean/close quotes/ air at Mauna Loa, Hawaii

    SciTech Connect

    Johnson, S.A.; Kumar, R.

    1988-01-01

    Sulfuric acid and its partially or completely neutralized salts with ammonia are believed to result from the oxidation of sulfur dioxide in cloud water and in other heterogeneous media present in the atmosphere. Due to the natural abundance of ammonia and the ubiquitous presence of sulfur in the atmosphere, (NH/sub 4/)/sub 2/SO/sub 4/ is commonly the dominant chemical species in the ambient aerosol. The amounts of ammonium sulfates are expected to be very low in areas far removed from anthropogenic emissions of sulfur dioxide. The chemical composition of submicrometer aerosol particles was determined at the Mauna Loa Observatory (MLO) on Mauna Loa in Hawaii during an eight-day period in August 1986. The MLO site was selected for this measurement because it is the only ground-based aerosol observatory in the remote Pacific Ocean that allows extended sampling of aerosols in the free troposphere. Measurements were made using an attenuated total internal reflection (ATR) impactor system. The impactor collects size-fractionated submicrometer particles for analysis by ATR infrared spectroscopy. The collected samples were analyzed using an on-site Perkin Elmer dispersive infrared spectrophotometer. Infrared absorption spectra (4000 to 250 cm/sup /minus/1/) of the samples were obtained within minutes after the ATR substrates were removed from the impactor. Absorbances were measured for sulfate, nitrate, and ammonium. Acidic sulfate showed infrared absorbances at 600 cm/sup /minus/1/ and 1210 cm/sup /minus/1/ in addition. Results showed that ammonium sulfate was the dominant chemical species in the submicrometer particles. Over half of the nearly 40 samples collected showed an acidic sulfate component. Consecutive samples were found to change from completely neutralized ammonium sulfate to acidic ammonium sulfates in a two-hour time interval. 5 refs., 1 tab.

  12. Project Ahupua'a: solar meteorological field measurements on the Island of Hawaii, Summer 1978. 5. Southern flank of Mauna Loa

    SciTech Connect

    Ekern, P.C.; Becker, R.J.

    1982-10-01

    Between 12-21 June 1978, four instrumented vans were deployed in a nearly linear transect above Na'alehu, along the steep southeastern slope of Mauna Loa. The transect, traversing a pronounced rainfall and insolation gradient, was designed to monitor sunlight and other meteorological variables related to solar energy. Surprisingly, many locations here receive more insolation during winter than during summer. Stronger than normal trade wind conditions prevailed during the period. A minor distrubance moved eastward to the north of the Island of Hawaii on 20 June, weakened the trade winds for nearly 24 h, and offered the opportunity to examine the development of island-generated circulations unhindered by the large scale flow. The amount of insolation recieved at the transect stations was less than the long-term mean. Persistent cloudiness attenuated insolation. Orographic cloud limited morning insolation while a sea breeze-anabatic cloud depleted afternoon insolation. Peak sunlight values were recorded during the mid-morning transition. This pattern occurred on all nine trade wind days. On 20 June, no orographic cloud formed and maximum values of insolation were received at three of the four transect sites. Strong gusty surface winds recorded along the transect may have been associated with a low level jet stream with Mauna Loa acting as a western boundary to the trade wind current. All transect stations experienced nocturnal wind pulses. Wind speed fluctuations, occasionally exceeding 5 m s/sup -1/, occurred with pronounced changes in wind direction. Increasing winds veered toward the prevailing trade wind direction, decreasing winds backed. Low level jet stream instabilities were a likely cause of these fluctuations.

  13. Wide Angle Movie

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This brief movie illustrates the passage of the Moon through the Saturn-bound Cassini spacecraft's wide-angle camera field of view as the spacecraft passed by the Moon on the way to its closest approach with Earth on August 17, 1999. From beginning to end of the sequence, 25 wide-angle images (with a spatial image scale of about 14 miles per pixel (about 23 kilometers)were taken over the course of 7 and 1/2 minutes through a series of narrow and broadband spectral filters and polarizers, ranging from the violet to the near-infrared regions of the spectrum, to calibrate the spectral response of the wide-angle camera. The exposure times range from 5 milliseconds to 1.5 seconds. Two of the exposures were smeared and have been discarded and replaced with nearby images to make a smooth movie sequence. All images were scaled so that the brightness of Crisium basin, the dark circular region in the upper right, is approximately the same in every image. The imaging data were processed and released by the Cassini Imaging Central Laboratory for Operations (CICLOPS)at the University of Arizona's Lunar and Planetary Laboratory, Tucson, AZ.

    Photo Credit: NASA/JPL/Cassini Imaging Team/University of Arizona

    Cassini, launched in 1997, is a joint mission of NASA, the European Space Agency and Italian Space Agency. The mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  14. Laser angle measurement system

    NASA Technical Reports Server (NTRS)

    Pond, C. R.; Texeira, P. D.; Wilbert, R. E.

    1980-01-01

    The design and fabrication of a laser angle measurement system is described. The instrument is a fringe counting interferometer that monitors the pitch attitude of a model in a wind tunnel. A laser source and detector are mounted above the mode. Interference fringes are generated by a small passive element on the model. The fringe count is accumulated and displayed by a processor in the wind tunnel control room. Optical and electrical schematics, system maintenance and operation procedures are included, and the results of a demonstration test are given.

  15. Measures on mixing angles

    SciTech Connect

    Gibbons, Gary W.; Gielen, Steffen; Pope, C. N.; Turok, Neil

    2009-01-01

    We address the problem of the apparently very small magnitude of CP violation in the standard model, measured by the Jarlskog invariant J. In order to make statements about probabilities for certain values of J, we seek to find a natural measure on the space of Kobayashi-Maskawa matrices, the double quotient U(1){sup 2}/SU(3)/U(1){sup 2}. We review several possible, geometrically motivated choices of the measure, and compute expectation values for powers of J for these measures. We find that different choices of the measure generically make the observed magnitude of CP violation appear finely tuned. Since the quark masses and the mixing angles are determined by the same set of Yukawa couplings, we then do a second calculation in which we take the known quark mass hierarchy into account. We construct the simplest measure on the space of 3x3 Hermitian matrices which reproduces this known hierarchy. Calculating expectation values for powers of J in this second approach, we find that values of J close to the observed value are now rather likely, and there does not seem to be any fine-tuning. Our results suggest that the choice of Kobayashi-Maskawa angles is closely linked to the observed mass hierarchy. We close by discussing the corresponding case of neutrinos.

  16. Variable angle correlation spectroscopy

    SciTech Connect

    Lee, Young Kyo

    1994-05-01

    In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with 13C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system.

  17. A model for column angle evolution during oblique angle deposition

    NASA Astrophysics Data System (ADS)

    Tanto, B.; Ten Eyck, G.; Lu, T.-M.

    2010-07-01

    We present a semiempirical model based on the shadowing effect to describe quantitatively the aggregation of columnar structure during physical vapor condensation onto a surface with an array of line seeds and a flat surface. Specifically, we predict the relationship between the column angle and the incident flux angle and how this relationship changes with processing conditions and materials. The model uses one input parameter, the fan angle generated at normal incident flux. The model describes well our experimental data on the Ge column angle evolution as a function of a wide range of incident flux angles.

  18. Enhanced backscattering at grazing angles.

    PubMed

    Gu, Zu-Han; Fuks, I M; Ciftan, Mikael

    2002-12-02

    Backscattering signals at small grazing angles are important for space vehicle atmospheric reentrance and subsurface radar sensing applications. They are also useful in Fourier-transform infrared grazing-angle microscopy. Recently we performed an experimental study of far-field scattering at small grazing angles, in particular, of enhanced backscattering at grazing angles. For a randomly weak rough dielectric film upon a reflecting metal substrate, a large enhanced backscattering peak was measured. Experimental results are compared with small perturbation theoretical predictions.

  19. Heterodyne Interferometer Angle Metrology

    NASA Technical Reports Server (NTRS)

    Hahn, Inseob; Weilert, Mark A.; Wang, Xu; Goullioud, Renaud

    2010-01-01

    A compact, high-resolution angle measurement instrument has been developed that is based on a heterodyne interferometer. The common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer setup, an optical mask is used to sample the measurement laser beam reflecting back from a target surface. Angular rotations, around two orthogonal axes in a plane perpendicular to the measurement- beam propagation direction, are determined simultaneously from the relative displacement measurement of the target surface. The device is used in a tracking telescope system where pitch and yaw measurements of a flat mirror were simultaneously performed with a sensitivity of 0.1 nrad, per second, and a measuring range of 0.15 mrad at a working distance of an order of a meter. The nonlinearity of the device is also measured less than one percent over the measurement range.

  20. Cerebellopontine Angle Lipoma

    PubMed Central

    Schuhmann, Martin U.; Lüdemann, Wolf O.; Schreiber, Hartwig; Samii, Madjid

    1997-01-01

    Intracranial lipomas in an infratentorial and extra-axial location are extremely rare. The presented case of an extensive lipoma of the cerebellopontine angle (CPA) represents 0.05% of all CPA tumors operated on in our department from 1978 to 1996. The lipoma constitutes an important differential diagnosis because the clinical management differs significantly from other CPA lesions. The clinical presentation and management of the presented case are analyzed in comparison to all previously described cases of CPA lipomas. The etiology and the radiological features of CPA lipomas are reviewed and discussed. CPA lipomas are maldevelopmental lesions that may cause slowly progressive symptoms. Neuroradiology enables a reliable preoperative diagnosis. Attempts of complete lipoma resection usually result in severe neurological deficits. Therefore, we recommend a conservative approach in managing these patients. Limited surgery is indicated if the patient has an associated vascular compression syndrome or suffers from disabling vertigo. ImagesFigure 1Figure 2Figure 3Figure 4 PMID:17171031

  1. Narrow Angle movie

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This brief three-frame movie of the Moon was made from three Cassini narrow-angle images as the spacecraft passed by the Moon on the way to its closest approach with Earth on August 17, 1999. The purpose of this particular set of images was to calibrate the spectral response of the narrow-angle camera and to test its 'on-chip summing mode' data compression technique in flight. From left to right, they show the Moon in the green, blue and ultraviolet regions of the spectrum in 40, 60 and 80 millisecond exposures, respectively. All three images have been scaled so that the brightness of Crisium basin, the dark circular region in the upper right, is the same in each image. The spatial scale in the blue and ultraviolet images is 1.4 miles per pixel (2.3 kilometers). The original scale in the green image (which was captured in the usual manner and then reduced in size by 2x2 pixel summing within the camera system) was 2.8 miles per pixel (4.6 kilometers). It has been enlarged for display to the same scale as the other two. The imaging data were processed and released by the Cassini Imaging Central Laboratory for Operations (CICLOPS) at the University of Arizona's Lunar and Planetary Laboratory, Tucson, AZ.

    Photo Credit: NASA/JPL/Cassini Imaging Team/University of Arizona

    Cassini, launched in 1997, is a joint mission of NASA, the European Space Agency and Italian Space Agency. The mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  2. Mutation and the environment

    SciTech Connect

    Mendelsohn, M.L. ); Albertini, R.J. )

    1990-01-01

    This book is covered under the following topics: Somatic Mutation: Animal Model; Somatic Mutation: Human; Heritable Mutation: Animal Model; Heritable Mutation: Approaches to Human Induction Rates; Heritable Mutation: Human Risk; Epidemiology: Population Studies on Genotoxicity; and Epidemiology: Workplace Studies of Genotoxicity.

  3. Equilibrium contact angle or the most-stable contact angle?

    PubMed

    Montes Ruiz-Cabello, F J; Rodríguez-Valverde, M A; Cabrerizo-Vílchez, M A

    2014-04-01

    It is well-established that the equilibrium contact angle in a thermodynamic framework is an "unattainable" contact angle. Instead, the most-stable contact angle obtained from mechanical stimuli of the system is indeed experimentally accessible. Monitoring the susceptibility of a sessile drop to a mechanical stimulus enables to identify the most stable drop configuration within the practical range of contact angle hysteresis. Two different stimuli may be used with sessile drops: mechanical vibration and tilting. The most stable drop against vibration should reveal the changeless contact angle but against the gravity force, it should reveal the highest resistance to slide down. After the corresponding mechanical stimulus, once the excited drop configuration is examined, the focus will be on the contact angle of the initial drop configuration. This methodology needs to map significantly the static drop configurations with different stable contact angles. The most-stable contact angle, together with the advancing and receding contact angles, completes the description of physically realizable configurations of a solid-liquid system. Since the most-stable contact angle is energetically significant, it may be used in the Wenzel, Cassie or Cassie-Baxter equations accordingly or for the surface energy evaluation.

  4. Mutation rates and mutational loads in man

    SciTech Connect

    Cavalli-Sforza, L.L.

    1984-01-01

    The following areas of research are discussed: (1) the study of human mutation rates; (2) geography of human genes and its relevance to mutation; (3) sociocultural studies correlated with population genetics; (4) consanguineous marriages; and (5) surnames. (ACR)

  5. Diurnal variations of stratospheric ozone measured by ground-based microwave remote sensing at the Mauna Loa NDACC site: measurement validation and GEOSCCM model comparison

    NASA Astrophysics Data System (ADS)

    Parrish, A.; Boyd, I. S.; Nedoluha, G. E.; Bhartia, P. K.; Frith, S. M.; Kramarova, N. A.; Connor, B. J.; Bodeker, G. E.; Froidevaux, L.; Shiotani, M.; Sakazaki, T.

    2014-07-01

    There is presently renewed interest in diurnal variations of stratospheric and mesospheric ozone for the purpose of supporting homogenization of records of various ozone measurements that are limited by the technique employed to being made at certain times of day. We have made such measurements for 19 years using a passive microwave remote sensing technique at the Mauna Loa Observatory (MLO) in Hawaii, which is a primary station in the Network for Detection of Atmospheric Composition Change (NDACC). We have recently reprocessed these data with hourly time resolution to study diurnal variations. We inspected differences between pairs of the ozone spectra (e.g., day and night) from which the ozone profiles are derived to determine the extent to which they may be contaminated by diurnally varying systematic instrumental or measurement effects. These are small, and we have reduced them further by selecting data that meet certain criteria that we established. We have calculated differences between profiles measured at different times: morning-night, afternoon-night, and morning-afternoon and have intercompared these with like profiles derived from the Aura Microwave Limb Sounder (Aura-MLS), the Upper Atmosphere Research Satellite Microwave Limb Sounder (UARS-MLS), the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES), and Solar Backscatter Ultraviolet version 2 (SBUV/2) measurements. Differences between averages of coincident profiles are typically < 1.5% of typical nighttime values over most of the covered altitude range with some exceptions. We calculated averages of ozone values for each hour from the Mauna Loa microwave data, and normalized these to the average for the first hour after midnight for comparison with corresponding values calculated with the Goddard Earth Observing System Chemistry Climate Model (GEOSCCM). We found that the measurements and model output mostly agree to better than 1.5% of the midnight value, with one noteworthy exception

  6. Generalization of the Euler Angles

    NASA Technical Reports Server (NTRS)

    Bauer, Frank H. (Technical Monitor); Shuster, Malcolm D.; Markley, F. Landis

    2002-01-01

    It is shown that the Euler angles can be generalized to axes other than members of an orthonormal triad. As first shown by Davenport, the three generalized Euler axes, hereafter: Davenport axes, must still satisfy the constraint that the first two and the last two axes be mutually perpendicular if these axes are to define a universal set of attitude parameters. Expressions are given which relate the generalized Euler angles, hereafter: Davenport angles, to the 3-1-3 Euler angles of an associated direction-cosine matrix. The computation of the Davenport angles from the attitude matrix and their kinematic equation are presented. The present work offers a more direct development of the Davenport angles than Davenport's original publication and offers additional results.

  7. Small angle neutron scattering

    NASA Astrophysics Data System (ADS)

    Cousin, Fabrice

    2015-10-01

    Small Angle Neutron Scattering (SANS) is a technique that enables to probe the 3-D structure of materials on a typical size range lying from ˜ 1 nm up to ˜ a few 100 nm, the obtained information being statistically averaged on a sample whose volume is ˜ 1 cm3. This very rich technique enables to make a full structural characterization of a given object of nanometric dimensions (radius of gyration, shape, volume or mass, fractal dimension, specific area…) through the determination of the form factor as well as the determination of the way objects are organized within in a continuous media, and therefore to describe interactions between them, through the determination of the structure factor. The specific properties of neutrons (possibility of tuning the scattering intensity by using the isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons) make it particularly interesting in the fields of soft matter, biophysics, magnetic materials and metallurgy. In particular, the contrast variation methods allow to extract some informations that cannot be obtained by any other experimental techniques. This course is divided in two parts. The first one is devoted to the description of the principle of SANS: basics (formalism, coherent scattering/incoherent scattering, notion of elementary scatterer), form factor analysis (I(q→0), Guinier regime, intermediate regime, Porod regime, polydisperse system), structure factor analysis (2nd Virial coefficient, integral equations, characterization of aggregates), and contrast variation methods (how to create contrast in an homogeneous system, matching in ternary systems, extrapolation to zero concentration, Zero Averaged Contrast). It is illustrated by some representative examples. The second one describes the experimental aspects of SANS to guide user in its future experiments: description of SANS spectrometer, resolution of the spectrometer, optimization of spectrometer

  8. Angle Performance on Optima XE

    SciTech Connect

    David, Jonathan; Satoh, Shu

    2011-01-07

    Angle control on high energy implanters is important due to shrinking device dimensions, and sensitivity to channeling at high beam energies. On Optima XE, beam-to-wafer angles are controlled in both the horizontal and vertical directions. In the horizontal direction, the beam angle is measured through a series of narrow slits, and any angle adjustment is made by steering the beam with the corrector magnet. In the vertical direction, the beam angle is measured through a high aspect ratio mask, and any angle adjustment is made by slightly tilting the wafer platen during implant.Using a sensitive channeling condition, we were able to quantify the angle repeatability of Optima XE. By quantifying the sheet resistance sensitivity to both horizontal and vertical angle variation, the total angle variation was calculated as 0.04 deg. (1{sigma}). Implants were run over a five week period, with all of the wafers selected from a single boule, in order to control for any crystal cut variation.

  9. The Critical Angle Can Override the Brewster Angle

    ERIC Educational Resources Information Center

    Froehle, Peter H.

    2009-01-01

    As a culminating activity in their study of optics, my students investigate polarized light and the Brewster angle. In this exercise they encounter a situation in which it is impossible to measure the Brewster angle for light reflecting from a particular surface. This paper describes the activity and explains the students' observations.

  10. The Critical Angle Can Override the Brewster Angle

    ERIC Educational Resources Information Center

    Froehle, Peter H.

    2009-01-01

    As a culminating activity in their study of optics, my students investigate polarized light and the Brewster angle. In this exercise they encounter a situation in which it is impossible to measure the Brewster angle for light reflecting from a particular surface. This paper describes the activity and explains the students' observations.

  11. Shifts in bryophyte carbon isotope ratio across an elevation × soil age matrix on Mauna Loa, Hawaii: do bryophytes behave like vascular plants?

    PubMed

    Waite, Mashuri; Sack, Lawren

    2011-05-01

    The carbon isotope ratio (δ(13)C) of vascular plant leaf tissue is determined by isotope discrimination, primarily mediated by stomatal and mesophyll diffusion resistances and by photosynthetic rate. These effects lead to predictable trends in leaf δ(13)C across natural gradients of elevation, irradiance and nutrient supply. Less is known about shifts in δ(13)C for bryophytes at landscape scale, as bryophytes lack stomata in the dominant gametophyte phase, and thus lack active control over CO(2) diffusion. Twelve bryophyte species were sampled across a matrix of elevation and soil ages on Mauna Loa, Hawaii Island. We tested hypotheses based on previous findings for vascular plants, which tend to have less negative δ(13)C at higher elevations or irradiances, and for leaves with higher leaf mass per area (LMA). Across the matrix, bryophytes spanned the range of δ(13)C values typical of C(3) vascular plants. Bryophytes were remarkably similar to vascular plants in exhibiting less negative δ(13)C with increasing elevation, and with lower overstory cover; additionally δ(13)C was related to bryophyte canopy projected mass per area, a trait analogous to LMA in vascular plants, also correlated negatively with overstory cover. The similarity of responses of δ(13)C in bryophytes and vascular plants to environmental factors, despite differing morphologies and diffusion pathways, points to a strong direct role of photosynthetic rate in determining δ(13)C variation at the landscape scale.

  12. Channel overflows of the Pōhue Bay flow, Mauna Loa, Hawai'i: examples of the contrast between surface and interior lava

    NASA Astrophysics Data System (ADS)

    Jurado-Chichay, Zinzuni; Rowland, Scott K.

    1995-04-01

    A number of overflows from a large lava channel and tube system on the southwest rift zone of Mauna Loa were studied. Initial overflows were very low viscosity gas-rich pāhoehoe evidenced by flow-unit aspect ratios and vesicle sizes and contents. Calculated volumetric flow-rates in the channel range between 80 and 890 m3/s, and those of the overflows between 35 and 110 m3/s. After traveling tens to hundreds of meters the tops of these sheet-like overflows were disrupted into a surface composed of clinker and pāhoehoe fragments. After these 'a'ā overflows came to rest, lava from the interiors was able to break out on to the surface as pāhoehoe. The surface structure of a lava flow records the interaction between the differential shear rate (usually correlated with the volumetric flow-rate) and viscosity-induced resistance to flow. However, the interior of a flow, being better insulated, may react differently or record a later set of emplacement conditions. Clefts of toothpaste lava occurring within fields of clinker on proximal-type 'a'ā flows also record different shear rates during different times of flow emplacement. The interplay between viscosity and shear rate determines the final morphological lava type, and although no specific portion of lava ever makes a transition from 'a'ā back to pāhoehoe, parts of a flow can appear to do so.

  13. A Comparison of Aircraft and Ground-Based Measurements at Mauna Loa Observatory, Hawaii, During GTE PEM-West and MLOPEX 2

    NASA Technical Reports Server (NTRS)

    Atlas, E.; Ridley, B.; Walega, J.; Greenberg, J.; Kok, G.; Staffelbach, T.; Schauffler, S.; Lind, J.; Huebler, G.; Norton, R.

    1996-01-01

    During October 19-20, 1991, one flight of the NASA Global Tropospheric Experiment (GTE) Pacific Exploratory Mission (PEM-West A) mission was conducted near Hawaii as an intercomparison with ground-based measurements of the Mauna Loa Observatory Photochemistry Experiment (MLOPEX 2) and the NOAA Climate Modeling and Diagnostics Laboratory (CMDL). Ozone, reactive nitrogen species, peroxides, hydrocarbons, and halogenated hydrocarbons were measured by investigators aboard the DC-8 aircraft and at the ground site. Lidar cross sections of ozone revealed a complex air mass structure near the island of Hawaii which was evidenced by large variation in some trace gas mixing ratios. This variation limited the time and spatial scales for direct measurement intercomparisons. Where differences occurred between measurements in the same air masses, the intercomparison suggested that biases for some trace gases was due to different calibration scales or, in some cases, instrumental or sampling biases. Relatively large uncertainties were associated with those trace gases present in the low parts per trillion by volume range. Trace gas correlations were used to expand the scope of the intercomparison to identify consistent trends between the different data sets.

  14. sup 222 Rn, sup 222 Rn progeny and sup 220 Rn progeny as atmospheric tracers of air masses at the Mauno Loa Observatory

    SciTech Connect

    Hutter, A.R.; George, A.C.; Maiello, M.L.; Fisenne, I.M.; Larsen, R.J.; Beck, H.L.; Wilson, F.C.

    1990-03-01

    {sup 222}Rn, {sup 222}Rn progeny and {sup 220}Rn progeny concentrations in air were measured at the Mauna Loa Observatory (MLO) in Hawaii during March 1989 in order to investigate the feasibility of using them as atmospheric tracers to help determine local air mass flow patterns. Charcoal traps, cooled to dry ice temperatures, were used to collect {sup 222}Rn, which was subsequently measured in pulse ionization chambers at the Environmental Measurements Laboratory (EML). {sup 222}Rn progeny and {sup 220}Rn progeny for 37 samples were measured at the Observatory by sampling high volumes of air through filters, which were counted for up to 11 h in alpha scintillation counters. Individual progeny concentrations were calculated using both least squares and maximum likelihood techniques. In general, {sup 222}Rn progeny and {sup 220}Rn progeny concentrations were low when free tropospheric air was present (downslope and tradewind conditions), and consistently higher when surface air from the island broke through the trade wind inversion layer (upslope conditions). The data suggest that {sup 222}Rn, {sup 222}Rn progeny, or {sup 220}Rn progeny monitoring may provide new and useful information to help indicate the different air flow patterns present at MLO. 17 refs., 5 figs., 2 tabs.

  15. Strong Saharan Dust Event Detected at Lalinet LOA-UNAL Station, over Medellín, Colombia by Active and Passive Remote Sensing

    NASA Astrophysics Data System (ADS)

    Bedoya, Andrés; Nisperuza, Daniel; Alegría, Dairo; Múnera, Mauricio; Guerrero-Rascado, Juan Luis; Zapata, Carmen E.; Jiménez, Jose F.; Landulfo, Eduardo; Bastidas, Álvaro

    2016-06-01

    Passive and active remote sensing techniques are well used for understanding optical and microphysical characteristics of aerosol layers. Lidar has the ability to resolve stratifications of the complex vertical structures in the atmosphere and determine the existence of aerosols which has been transported for long-ranges through the evaluation of the optical properties such as particle backscatter and extinction coefficients, among others. CIMEL sunphotometer data (AERONET network) give information about optical properties such as Aerosol Optical Depth (AOD), Single Scattering Albedo (SSA), and Angström Exponent (AE) and microphysical properties such as size distribution. The LOA-UNAL lidar station as part of the LALINET (Latin American LIdar NETwork) [1], involves an elastic coaxial system operating in zenith mode used for monitoring the atmosphere at Medellín-Colombia (6.26°N, 75.58°W, 1470 m asl). This work presents a Saharan dust even over Medellín, Colombia, 27th June, 2014, observed simultaneously with lidar, sun-photometer and complementary global mass transport model HYSPLIT.

  16. Comparison of airborne CO/sub 2/ flask samples and measurements from the Mauna Loa Observatory during the HAMEC project (June 1980)

    SciTech Connect

    Herbert, G.A.; Harris, T.B.; Chin, J.F.S.

    1983-08-20

    During June 1980, the Hawaii Mesoscale Energy and Climate Project (HAMEC) field program was conducted in the vicinity of the island of Hawaii. The objective of the program was to use the NOAA P3 aircraft to measure meteorological variables upwind and downwind of the island to provide data to evaluate mesoscale models of airflow and cloud physics. One specific objective was to obtain flask samples upwind of the island to confirm that the CO/sub 2/ values observed at the Mauna Loa Observatory (MLO) are representative of the free air at comparable altitudes. On 2 days, carbon dioxide flask samples were exposed aboard the aircraft at the altitude of the observatory and immediately above the trade inversion. Flask pairs in reasonable agreement were obtained on both occasions. During the same period the sampling conditions at MLO were free of obvious local contamination. The average difference between the aircraft measurements at the altitude of the observatory and the continuous CO/sub 2/ record from the observatory over the same period of time was 0.8 mole fraction in ppM. Differences in the individual measurements are discussed with respect to prevailing meteorological conditions. 11 references, 2 figures, 2 tables.

  17. Estimate of the biotic contribution to the atmospheric CO/sub 2/ increase based on direct measurements at Mauna Loa Observatory

    SciTech Connect

    Elliott, W.P.; Machta, L.; Keeling, C.D.

    1985-04-20

    The CO/sub 2/ concentrations recorded at Mauna Loa Observatory from 1958-1983 were examined to detect the existence of any significant sources of CO/sub 2/ other than fossil fuel combustion. The observed annual CO/sub 2/ concentrations were compared with concentrations calculated assuming a number of hypothetical constant, nonfossil fuel emission scenarios added to the fossil fuel emissions. It was found that constant nonfossil fuel sources must have been 10% or less of the fossil fuel sources. This conclusion assumes that a constant fraction of the total emissions went into the oceans and that the nonfossil fuel emissions were invariant from year to year. When this latter restriction was relaxed, almost any nonfossil fuel source was possible if its history closely matched that of the fossil fuel emissions. We conclude that it is unlikely that biotic or other nonfossil fuel sources could have exceeded about 0.5 GT of carbon per year except in the unlikely event that they grew at a rate close to that of the fossil fuel emissions.

  18. Atmospheric carbon dioxide at Mauna Loa Observatory 1. NOAA global monitoring for climatic change measurements with a nondispersive infrared analyzer, 1974--1985

    SciTech Connect

    Komhyr, W. D.; Harris, T. B.; Waterman, L. S.; Chin, J. F. S.; Thoning, K. W.

    1989-06-20

    Atmospheric CO/sub 2/ measurements made with a nondispersive infrared analyzer during 1974--1985 at Mauna Lao Observatory, Hawaii, are described, with emphasis on the measurement methodology, calibrations, and data accuracy. Monthly mean CO/sub 2/ data, representative of global background conditions, are presented for the period of record. The monthly means were derived from an all-data base of CO/sub 2/ hourly averged archived at the National Oceanic and Atmospheric Administration (NOAA) Geophysical Monitoring for Climatic Change (GMCC) facility in Boulder, Colorado; at the Carbon Dioxide Information Analysis Center (CDIAC) in Oak Ridge, Tennessee; and in the microfiche version of this paper. Flags in the all-data base identify CO/sub 2/ hourly averages that have been deemed unreliable because of sampling and analysis problems or that are unrepresentative of clean background air because of influences of the local environment, for example, CO/sub 2/ uptake by nearby vegetation or contamination and pollution effects. The select NOAA GMCC monthly mean data are compared with similar data obtained independently at Mauna Loa Observatory by the Scripps Institution of Oceanography. The averge difference of corresponding monthly mean CO/sub 2/ values for the two data sets is 0.15/plus minus/0.18 ppm, where the indicated variability is the standard deviation. Careful scrutiny of the NOAA GMCC measurement, calibration, and data processing procedures that might have caused the small bias in the data has revealed no unusual errors. /copyright/ American Geophysical Union 1989

  19. Deformation history of Mauna Loa (Hawaii) from 2003 to 2014 through InSAR data: understanding the shorter-term processes

    NASA Astrophysics Data System (ADS)

    La Marra, Daniele; Poland, Michael P.; Acocella, Valerio; Battaglia, Maurizio; Miklius, Asta

    2016-04-01

    Geodesy allows detecting the deformation of volcanoes, thus understanding magmatic processes. This becomes particularly efficient when time series are available and volcanoes can be monitored on the mean-term (decades), and not only during a specific event. Here we exploit the SBAS technique, using SAR images from ENVISAT (descending and ascending orbits; 2003 - 2010) and COSMO-SkyMed (descending and ascending orbits; 2012 - 2014), to study a decade of deformation at Mauna Loa (Hawaii). These data are merged time series data from 24 continuously operating GPS stations, which allows us to calibrate the InSAR time series. Our results show a long-term inflation of the volcano from 2003 to 2014, reaching a peak of ~11 cm/yr on the summit area between mid-2004 to mid-2005 and then slowing down. Within this frame, we were able to identify five main periods with approximately linear deformation behavior. The inversion of the deformation data in the first four periods suggests the repeated, though not constant, intrusion of one or more dikes below the summit caldera and the upper Southwest Rift Zone. Moreover, the dike intrusion coincides with minor acceleration of flank slip. Such a behavior is distinctive and, with the exception of the nearby Kilauea, has not been observed at any other volcano on the mean term. It is proposed that continuous, even though not constant flank instability of the SE flank may promote semi-continuous intrusions in a volcano with a ready magma supply.

  20. Spinning angle optical calibration apparatus

    DOEpatents

    Beer, Stephen K.; Pratt, II, Harold R.

    1991-01-01

    An optical calibration apparatus is provided for calibrating and reproducing spinning angles in cross-polarization, nuclear magnetic resonance spectroscopy. An illuminated magnifying apparatus enables optical setting an accurate reproducing of spinning "magic angles" in cross-polarization, nuclear magnetic resonance spectroscopy experiments. A reference mark scribed on an edge of a spinning angle test sample holder is illuminated by a light source and viewed through a magnifying scope. When the "magic angle" of a sample material used as a standard is attained by varying the angular position of the sample holder, the coordinate position of the reference mark relative to a graduation or graduations on a reticle in the magnifying scope is noted. Thereafter, the spinning "magic angle" of a test material having similar nuclear properties to the standard is attained by returning the sample holder back to the originally noted coordinate position.

  1. Angle closure in younger patients.

    PubMed Central

    Chang, Brian M; Liebmann, Jeffrey M; Ritch, Robert

    2002-01-01

    PURPOSE: Angle-closure glaucoma is rare in children and young adults. Only scattered cases associated with specific clinical entities have been reported. We evaluated the findings in patients in our database aged 40 or younger with angle closure. METHODS: Our database was searched for patients with angle closure who were 40 years old or younger. Data recorded included age at initial consultation; age at the time of diagnosis; gender; results of slit-lamp examination, gonioscopy, and ultrasound biomicroscopy (from 1993 onward); clinical diagnosis; and therapy. Patients with previous incisional surgery were excluded, as were patients with anterior chamber proliferative mechanisms leading to angle closure. RESULTS: Sixty-seven patients (49 females, 18 males) met entry criteria. Mean age (+/- SD) at the time of consultation was 34.4 +/- 9.4 years (range, 3-68 years). Diagnoses included plateau iris syndrome (35 patients), iridociliary cysts (8 patients), retinopathy of prematurity (7 patients), uveitis (5 patients), isolated nanophthalmos (3 patients), relative pupillary block (2 patients), Weill-Marchesani syndrome (3 patients), and 1 patient each with Marfan syndrome, miotic-induced angle closure, persistent hyperplastic primary vitreous, and idiopathic lens subluxation. CONCLUSION: The etiology of angle closure in young persons is different from that in the older population and is typically associated with structural or developmental ocular anomalies rather than relative pupillary block. Following laser iridotomy, these eyes should be monitored for recurrent angle closure and the need for additional laser or incisional surgical intervention. PMID:12545694

  2. Hysteresis during contact angles measurement.

    PubMed

    Diaz, M Elena; Fuentes, Javier; Cerro, Ramon L; Savage, Michael D

    2010-03-15

    A theory, based on the presence of an adsorbed film in the vicinity of the triple contact line, provides a molecular interpretation of intrinsic hysteresis during the measurement of static contact angles. Static contact angles are measured by placing a sessile drop on top of a flat solid surface. If the solid surface has not been previously in contact with a vapor phase saturated with the molecules of the liquid phase, the solid surface is free of adsorbed liquid molecules. In the absence of an adsorbed film, molecular forces configure an advancing contact angle larger than the static contact angle. After some time, due to an evaporation/adsorption process, the interface of the drop coexists with an adsorbed film of liquid molecules as part of the equilibrium configuration, denoted as the static contact angle. This equilibrium configuration is metastable because the droplet has a larger vapor pressure than the surrounding flat film. As the drop evaporates, the vapor/liquid interface contracts and the apparent contact line moves towards the center of the drop. During this process, the film left behind is thicker than the adsorbed film and molecular attraction results in a receding contact angle, smaller than the equilibrium contact angle. 2009 Elsevier Inc. All rights reserved.

  3. Ring magnet firing angle control

    DOEpatents

    Knott, M.J.; Lewis, L.G.; Rabe, H.H.

    1975-10-21

    A device is provided for controlling the firing angles of thyratrons (rectifiers) in a ring magnet power supply. A phase lock loop develops a smooth ac signal of frequency equal to and in phase with the frequency of the voltage wave developed by the main generator of the power supply. A counter that counts from zero to a particular number each cycle of the main generator voltage wave is synchronized with the smooth AC signal of the phase lock loop. Gates compare the number in the counter with predetermined desired firing angles for each thyratron and with coincidence the proper thyratron is fired at the predetermined firing angle.

  4. Hydrogen isotope correction for laser instrument measurement bias at low water vapor concentration using conventional isotope analyses: application to measurements from Mauna Loa Observatory, Hawaii.

    PubMed

    Johnson, L R; Sharp, Z D; Galewsky, J; Strong, M; Van Pelt, A D; Dong, F; Noone, D

    2011-03-15

    The hydrogen and oxygen isotope ratios of water vapor can be measured with commercially available laser spectroscopy analyzers in real time. Operation of the laser systems in relatively dry air is difficult because measurements are non-linear as a function of humidity at low water concentrations. Here we use field-based sampling coupled with traditional mass spectrometry techniques for assessing linearity and calibrating laser spectroscopy systems at low water vapor concentrations. Air samples are collected in an evacuated 2 L glass flask and the water is separated from the non-condensable gases cryogenically. Approximately 2 µL of water are reduced to H(2) gas and measured on an isotope ratio mass spectrometer. In a field experiment at the Mauna Loa Observatory (MLO), we ran Picarro and Los Gatos Research (LGR) laser analyzers for a period of 25 days in addition to periodic sample collection in evacuated flasks. When the two laser systems are corrected to the flask data, they are strongly coincident over the entire 25 days. The δ(2)H values were found to change by over 200‰ over 2.5 min as the boundary layer elevation changed relative to MLO. The δ(2)H values ranged from -106 to -332‰, and the δ(18)O values (uncorrected) ranged from -12 to -50‰. Raw data from laser analyzers in environments with low water vapor concentrations can be normalized to the international V-SMOW scale by calibration to the flask data measured conventionally. Bias correction is especially critical for the accurate determination of deuterium excess in dry air.

  5. Physical Properties of a Coronal Hole from a Coronal Diagnostics Spectrometer, Mauna Loa Coronagraph, and LASCO Observations during the Whole Sun Month

    NASA Technical Reports Server (NTRS)

    Guhathakurta, M.; Fludra, A.; Gibson, S. E.; Biesecker, D.; Fisher, R.

    2004-01-01

    Until recently, inference of electron density distribution in the solar corona was limited by the field of view of white-light coronagraphs (typically out to 6 Rs). Now, for the first time we have a series of white- light coronagraphs (SOHO/LASCO) whose combined field of view extends from 1.1 - 30 Rs. Quantitative information on electron density distribution of coronal hole and coronal plumes/rays are estimated by using white-light, polarized brightness (pB) observations from the SOHO/LASCO/C2 and C3 and HAO/Mauna Loa Mark III coronagraphs from 1.15 to 8.0 Rs. Morphological information on the boundary of the polar coronal hole and streamer interface is determined from the white-light observations in a manner similar to the Skylab polar coronal hole boundary estimate. The average coronal hole electron density in the region 1 - 1.15 Rs is estimated from the density-sensitive EUV line ratios of Si IX 3501342 A observed by the SOHO/coronal diagnostic spectrometer (CDS). We combine these numbers with the estimate from white-light (WL) observations to obtain a density profile from 1 to 8 Rs for the plumes and the polar coronal hole. We find that white light and spectral analysis produce consistent density information. Extrapolated densities inferred from SOHO observations are compared to Ulysses in situ observations of density. Like the density inferred from the Spartan 201-03 coronagraph, the current SOHO density profiles suggest that the acceleration of the fast solar wind takes place very close to the Sun, within 10-15 Rs. The density information is used to put constraints on solar wind flow velocities and effective temperatures. Finally, these results are compared to the recent analysis of the Spartan 201-03 white-light observations.

  6. Study of extreme-ultraviolet emission and properties of a coronal streamer from PROBA2/SWAP, HINODE/EIS and Mauna Loa Mk4 observations

    SciTech Connect

    Goryaev, F.; Slemzin, V.; Vainshtein, L.; Williams, David R.

    2014-02-01

    Wide-field extreme-ultraviolet (EUV) telescopes imaging in spectral bands sensitive to 1 MK plasma on the Sun often observe extended, ray-like coronal structures stretching radially from active regions to distances of 1.5-2 R {sub ☉}, which represent the EUV counterparts of white-light streamers. To explain this phenomenon, we investigated the properties of a streamer observed on 2010 October 20 and 21, by the PROBA2/SWAP EUV telescope together with the Hinode/EIS (HOP 165) and the Mauna Loa Mk4 white-light coronagraph. In the SWAP 174 Å band comprising the Fe IX-Fe XI lines, the streamer was detected to a distance of 2 R {sub ☉}. We assume that the EUV emission is dominated by collisional excitation and resonant scattering of monochromatic radiation coming from the underlying corona. Below 1.2 R {sub ☉}, the plasma density and temperature were derived from the Hinode/EIS data by a line-ratio method. Plasma conditions in the streamer and in the background corona above 1.2 R {sub ☉} from the disk center were determined by forward-modeling the emission that best fit the observational data in both EUV and white light. It was found that the plasma in the streamer above 1.2 R {sub ☉} is nearly isothermal, with a temperature of T = 1.43 ± 0.08 MK. The hydrostatic scale-height temperature determined from the evaluated density distribution was significantly higher (1.72 ± 0.08 MK), which suggests the existence of outward plasma flow along the streamer. We conclude that, inside the streamer, collisional excitation provided more than 90% of the observed EUV emission, whereas, in the background corona, the contribution of resonance scattering became comparable with that of collisions at R ≳ 2 R {sub ☉}.

  7. Two Comments on Bond Angles

    NASA Astrophysics Data System (ADS)

    Glaister, P.

    1997-09-01

    Tetrahedral Bond Angle from Elementary Trigonometry The alternative approach of using the scalar (or dot) product of vectors enables the determination of the bond angle in a tetrahedral molecule in a simple way. There is, of course, an even more straightforward derivation suitable for students who are unfamiliar with vectors, or products thereof, but who do know some elementary trigonometry. The starting point is the figure showing triangle OAB. The point O is the center of a cube, and A and B are at opposite corners of a face of that cube in which fits a regular tetrahedron. The required bond angle alpha = AÔB; and using Pythagoras' theorem, AB = 2(square root 2) is the diagonal of a face of the cube. Hence from right-angled triangle OEB, tan(alpha/2) = (square root 2) and therefore alpha = 2tan-1(square root 2) is approx. 109° 28' (see Fig. 1).

  8. Relativistic Transformation of Solid Angle.

    ERIC Educational Resources Information Center

    McKinley, John M.

    1980-01-01

    Rederives the relativistic transformations of light intensity from compact sources (stars) to show where and how the transformation of a solid angle contributes. Discusses astrophysical and other applications of the transformations. (Author/CS)

  9. Angles of multivariable root loci

    NASA Technical Reports Server (NTRS)

    Thompson, P. M.; Stein, G.; Laub, A. J.

    1982-01-01

    A generalized eigenvalue problem is demonstrated to be useful for computing the multivariable root locus, particularly when obtaining the arrival angles to finite transmission zeros. The multivariable root loci are found for a linear, time-invariant output feedback problem. The problem is then employed to compute a closed-loop eigenstructure. The method of computing angles on the root locus is demonstrated, and the method is extended to a multivariable optimal root locus.

  10. The Semiotic and Conceptual Genesis of Angle

    ERIC Educational Resources Information Center

    Tanguay, Denis; Venant, Fabienne

    2016-01-01

    In the present study, we try to understand how students at the end of primary school conceive of angle: Is an angle a magnitude for them or a geometric figure, and how do they manage to coordinate the two aspects in their understanding of the concepts of angle and of angle measurement? With the aim of better grasping the way "angle" is…

  11. The Semiotic and Conceptual Genesis of Angle

    ERIC Educational Resources Information Center

    Tanguay, Denis; Venant, Fabienne

    2016-01-01

    In the present study, we try to understand how students at the end of primary school conceive of angle: Is an angle a magnitude for them or a geometric figure, and how do they manage to coordinate the two aspects in their understanding of the concepts of angle and of angle measurement? With the aim of better grasping the way "angle" is…

  12. Mechanisms of viral mutation.

    PubMed

    Sanjuán, Rafael; Domingo-Calap, Pilar

    2016-12-01

    The remarkable capacity of some viruses to adapt to new hosts and environments is highly dependent on their ability to generate de novo diversity in a short period of time. Rates of spontaneous mutation vary amply among viruses. RNA viruses mutate faster than DNA viruses, single-stranded viruses mutate faster than double-strand virus, and genome size appears to correlate negatively with mutation rate. Viral mutation rates are modulated at different levels, including polymerase fidelity, sequence context, template secondary structure, cellular microenvironment, replication mechanisms, proofreading, and access to post-replicative repair. Additionally, massive numbers of mutations can be introduced by some virus-encoded diversity-generating elements, as well as by host-encoded cytidine/adenine deaminases. Our current knowledge of viral mutation rates indicates that viral genetic diversity is determined by multiple virus- and host-dependent processes, and that viral mutation rates can evolve in response to specific selective pressures.

  13. CF Mutation Panel

    MedlinePlus

    ... AACC products and services. Advertising & Sponsorship: Policy | Opportunities CF Gene Mutations Testing Share this page: Was this page helpful? Also known as: Cystic Fibrosis Genotyping; CF DNA Analysis; CF Gene Mutation Panel; ...

  14. Low phosphate alters lateral root setpoint angle and gravitropism.

    PubMed

    Bai, Hanwen; Murali, Bhavna; Barber, Kevin; Wolverton, Chris

    2013-01-01

    Lateral roots, responsible for water and nutrient uptake, maintain nonvertical angles throughout development. Soil phosphate is one limiting nutrient for plant growth that is known to induce changes to root system architecture, such as increased lateral root formation. This study seeks to determine whether phosphate concentration affects lateral root orientation in addition to its previously described influences on root architecture. Images of intact Arabidopsis root systems were recorded for 24 h, and lateral root tip angles were measured for wild-type and mutant pgm-1 and pin3-1 roots on a full or low phosphate medium. Setpoint angles of unstimulated root systems were determined, as were gravitropic responses of lateral roots over time. The root system setpoint angles of wild-type and mutant pin3-1 roots showed a shift toward a more vertical orientation on low orthophosphate (Pi) medium. The gravitropic responses of both pgm-1 and pin3-1 roots on low Pi medium was elevated relative to control Pi medium. Mutations in two phosphate transporters with high levels of expression in the root showed a gravitropic response similar to wild-type roots grown on low Pi, supporting a role for Pi status in regulating lateral root gravitropism. Lateral root orientation and gravitropism are affected by Pi status and may provide an important additional parameter for describing root responses to low Pi. The data also support the conclusion that gravitropic setpoint angle reacts to nutrient status and is under dynamic regulation.

  15. Critical rolling angle of microparticles

    NASA Astrophysics Data System (ADS)

    Farzi, Bahman; Vallabh, Chaitanya K. P.; Stephens, James D.; Cetinkaya, Cetin

    2016-03-01

    At the micrometer-scale and below, particle adhesion becomes particularly relevant as van der Waals force often dominates volume and surface proportional forces. The rolling resistance of microparticles and their critical rolling angles prior to the initiation of free-rolling and/or complete detachment are critical in numerous industrial processes and natural phenomenon involving particle adhesion and granular dynamics. The current work describes a non-contact measurement approach for determining the critical rolling angle of a single microparticle under the influence of a contact-point base-excitation generated by a transient displacement field of a prescribed surface acoustic wave pulse and reports the critical rolling angle data for a set of polystyrene latex microparticles.

  16. A new angle on the Angle of Louis.

    PubMed

    Ramana, Ravi K; Sanagala, Thriveni; Lichtenberg, Robert

    2006-01-01

    Previous literature has stated that the center of the right atrium lies approximately 5 cm below the sternal angle regardless of body position. Our objective was to measure the distance from the Angle of Louis to various locations in the right atrium and determine whether these distances vary with patients' body habitus. The authors conducted a cross-sectional study with 52 consecutive patients who underwent computed tomography. The Angle of Louis was measured to various right atrial anatomic locations and was correlated with patients' body habitus characteristics. There was a positive correlation between patients' weight or body mass index and the distance of the Angle of Louis to right atrial locations. Therefore, using the traditional 5 cm in an obese patient can and usually will result in an underestimation of right atrial pressure. The authors suggest that in patients with body mass index > 35 kg/m2 (body surface area > 2.5 m2), a jugular venous column height at the clavicle is likely to indicate significantly elevated jugular venous pressure and should be considered abnormal. Therefore, further clinical assessment and subsequent therapeutic decisions of these morbidly obese patients with abnormal jugular venous pressures should be made accordingly.

  17. Cydonia: Wide Angle Color Image

    NASA Technical Reports Server (NTRS)

    2000-01-01

    [figure removed for brevity, see original site]

    Although the resolution of the MOC wide angle cameras is too low to tell much about the geomorphology of the Cydonia region, the images from the red and blue wide angle cameras provide us with two types of information that is of interest in their own right: color and stereoscopic data. Above are a color view and a stereoscopic anaglyph rendition of Geodesy Campaign images acquired by MGS MOC in May 1999. To view the stereo image, you need red/blue '3-D' glasses.

  18. Tiny incident light angle sensor

    NASA Astrophysics Data System (ADS)

    Mitrenga, D.; Schädel, M.; Winzer, A. T.; Völlmeke, S.; Preuß, K. D.; Freitag, J.; Brodersen, O.

    2017-05-01

    A novel device for detecting the intensity and the angles of incoming light is presented. The silicon chip with 1 mm edge length comprises a segmented photo diode with four active areas within the inclined surfaces of a deep etched cavity. Simple signal difference analysis of these signals allow for accurate azimuth and inclination measurement in the range of 0 to 360° and 0 to 55°, respectively. Using an artificial neural network (ANN) calibration strategy the operation range of inclination can be increased up to 85° with typical angle errors below 2°. In this report we present details on design, fabrication, signal analysis and calibration strategies.

  19. UV Signature Mutations

    PubMed Central

    2014-01-01

    Sequencing complete tumor genomes and exomes has sparked the cancer field's interest in mutation signatures for identifying the tumor's carcinogen. This review and meta-analysis discusses signatures and their proper use. We first distinguish between a mutagen's canonical mutations – deviations from a random distribution of base changes to create a pattern typical of that mutagen – and the subset of signature mutations, which are unique to that mutagen and permit inference backward from mutations to mutagen. To verify UV signature mutations, we assembled literature datasets on cells exposed to UVC, UVB, UVA, or solar simulator light (SSL) and tested canonical UV mutation features as criteria for clustering datasets. A confirmed UV signature was: ≥60% of mutations are C→T at a dipyrimidine site, with ≥5% CC→TT. Other canonical features such as a bias for mutations on the non-transcribed strand or at the 3' pyrimidine had limited application. The most robust classifier combined these features with criteria for the rarity of non-UV canonical mutations. In addition, several signatures proposed for specific UV wavelengths were limited to specific genes or species; non-signature mutations induced by UV may cause melanoma BRAF mutations; and the mutagen for sunlight-related skin neoplasms may vary between continents. PMID:25354245

  20. Discovering the Inscribed Angle Theorem

    ERIC Educational Resources Information Center

    Roscoe, Matt B.

    2012-01-01

    Learning to play tennis is difficult. It takes practice, but it also helps to have a coach--someone who gives tips and pointers but allows the freedom to play the game on one's own. Learning to act like a mathematician is a similar process. Students report that the process of proving the inscribed angle theorem is challenging and, at times,…

  1. Discovering the Inscribed Angle Theorem

    ERIC Educational Resources Information Center

    Roscoe, Matt B.

    2012-01-01

    Learning to play tennis is difficult. It takes practice, but it also helps to have a coach--someone who gives tips and pointers but allows the freedom to play the game on one's own. Learning to act like a mathematician is a similar process. Students report that the process of proving the inscribed angle theorem is challenging and, at times,…

  2. Effective Temperature of Mutations

    NASA Astrophysics Data System (ADS)

    Derényi, Imre; Szöllősi, Gergely J.

    2015-02-01

    Biological macromolecules experience two seemingly very different types of noise acting on different time scales: (i) point mutations corresponding to changes in molecular sequence and (ii) thermal fluctuations. Examining the secondary structures of a large number of microRNA precursor sequences and model lattice proteins, we show that the effects of single point mutations are statistically indistinguishable from those of an increase in temperature by a few tens of kelvins. The existence of such an effective mutational temperature establishes a quantitative connection between robustness to genetic (mutational) and environmental (thermal) perturbations.

  3. Supercritical Angle Fluorescence Correlation Spectroscopy

    PubMed Central

    Ries, Jonas; Ruckstuhl, Thomas; Verdes, Dorinel; Schwille, Petra

    2008-01-01

    We explore the potential of a supercritical angle (SA) objective for fluorescence correlation spectroscopy (FCS). This novel microscope objective combines tight focusing by an aspheric lens with strong axial confinement of supercritical angle fluorescence collection by a parabolic mirror lens, resulting in a small detection volume. The tiny axial extent of the detection volume features an excellent surface sensitivity, as is demonstrated by diffusion measurements in model membranes with an excess of free dye in solution. All SA-FCS measurements are directly compared to standard confocal FCS, demonstrating a clear advantage of SA-FCS, especially for diffusion measurements in membranes. We present an extensive theoretical framework that allows for accurate and quantitative evaluation of the SA-FCS correlation curves. PMID:17827221

  4. Angle interferometer cross axis errors

    NASA Astrophysics Data System (ADS)

    Bryan, J. B.; Carter, D. L.; Thompson, S. L.

    1994-01-01

    Angle interferometers are commonly used to measure surface plate flatness. An error can exist when the centerline of the double comer cube mirror assembly is not square to the surface plate and the guide bar for the mirror sled is curved. Typical errors can be one to two microns per meter. A similar error can exist in the calibration of rotary tables when the centerline of the double comer cube mirror assembly is not square to the axes of rotation of the angle calibrator and the calibrator axis is not parallel to the rotary table axis. Commercial double comer cube assemblies typically have non-parallelism errors of ten milli-radians between their centerlines and their sides and similar values for non-squareness between their centerlines and end surfaces. The authors have developed a simple method for measuring these errors and correcting them.

  5. Angle interferometer cross axis errors

    SciTech Connect

    Bryan, J.B.; Carter, D.L.; Thompson, S.L.

    1994-01-01

    Angle interferometers are commonly used to measure surface plate flatness. An error can exist when the centerline of the double comer cube mirror assembly is not square to the surface plate and the guide bar for the mirror sled is curved. Typical errors can be one to two microns per meter. A similar error can exist in the calibration of rotary tables when the centerline of the double comer cube mirror assembly is not square to the axes of rotation of the angle calibrator and the calibrator axis is not parallel to the rotary table axis. Commercial double comer cube assemblies typically have non-parallelism errors of ten milli-radians between their centerlines and their sides and similar values for non-squareness between their centerlines and end surfaces. The authors have developed a simple method for measuring these errors and correcting them by remachining the reference surfaces.

  6. High Angle of Attack Aerodynamics

    DTIC Science & Technology

    1979-01-01

    describe the behaviour of the air. The Symposium made it clear that the present state of knowledge in the area of high angle-of-attack aerodynamics...TESTING EXPERIENCE by C.W. Smith and C.A.Anderson S FOREBODY-WING VORTEX INTERACTIONS AND THEIR INFLUENCE ON DEPARTURE AND SPIN RESISTANCE by A.MSkow...Figure 6) caused by asymmetric flow conditions. ., s already mentioned, asymmetric flow occurs not only when an air- craft flies at non-zero sideslip

  7. Gaia basic angle monitoring system

    NASA Astrophysics Data System (ADS)

    Gielesen, W.; de Bruijn, D.; van den Dool, T.; Kamphues, F.; Mekking, J.; Calvel, B.; Laborie, A.; Coatantiec, C.; Touzeau, S.; Erdmann, M.; Gare, P.; Monteiro, D.

    2013-09-01

    The Gaia mission1 will create an extraordinarily precise three-dimensional map of more than one billion stars in our Galaxy. The Gaia spacecraft2, built by EADS Astrium, is part of ESA's Cosmic Vision programme and scheduled for launch in 2013. Gaia measures the position, distance and motion of stars with an accuracy of 24 micro-arcsec using two telescopes at a fixed mutual angle of 106.5°, named the `Basic Angle', at an operational temperature of 100 K. This accuracy requires ultra-high stability at cryogenic conditions, which can only be achieved by using Silicon Carbide for both the optical bench and the telescopes. TNO has developed, built and space qualified the Silicon carbide Basic Angle Monitoring (BAM) on-board metrology system3 for this mission, measuring the relative motion of Gaia's telescopes with accuracies in the range of 0.5 micro-arcsec. This is achieved by a system of two laser interferometers able to detect Optical Path Differences (OPD) as small as 1.5 picometer rms. Following a general introduction on Gaia and the use of Silicon Carbide as base material this paper addresses the specific challenges towards the cryogenic application of the Gaia BAM including design, integration and verification/qualification by testing.

  8. OPENING ANGLES OF COLLAPSAR JETS

    SciTech Connect

    Mizuta, Akira; Ioka, Kunihito

    2013-11-10

    We investigate the jet propagation and breakout from the stellar progenitor for gamma-ray burst (GRB) collapsars by performing two-dimensional relativistic hydrodynamic simulations and analytical modeling. We find that the jet opening angle is given by θ{sub j} ∼ 1/5Γ{sub 0} and infer the initial Lorentz factor of the jet at the central engine, Γ{sub 0}, is a few for existing observations of θ{sub j}. The jet keeps the Lorentz factor low inside the star by converging cylindrically via collimation shocks under the cocoon pressure and accelerates at jet breakout before the free expansion to a hollow-cone structure. In this new picture, the GRB duration is determined by the sound crossing time of the cocoon, after which the opening angle widens, reducing the apparent luminosity. Some bursts violating the maximum opening angle θ{sub j,{sub max}} ∼ 1/5 ∼ 12° imply the existence of a baryon-rich sheath or a long-acting jet. We can explain the slopes in both Amati and Yonetoku spectral relations using an off-centered photosphere model, if we make only one assumption that the total jet luminosity is proportional to the initial Lorentz factor of the jet. We also numerically calibrate the pre-breakout model (Bromberg et al.) for later use.

  9. TCP transcription factor, BRANCH ANGLE DEFECTIVE 1 (BAD1), is required for normal tassel branch angle formation in maize

    PubMed Central

    Bai, Fang; Reinheimer, Renata; Durantini, Diego; Kellogg, Elizabeth A.; Schmidt, Robert J.

    2012-01-01

    In grass inflorescences, a structure called the “pulvinus” is found between the inflorescence main stem and lateral branches. The size of the pulvinus affects the angle of the lateral branches that emerge from the main axis and therefore has a large impact on inflorescence architecture. Through EMS mutagenesis we have identified three complementation groups of recessive mutants in maize having defects in pulvinus formation. All mutants showed extremely acute tassel branch angles accompanied by a significant reduction in the size of the pulvinus compared with normal plants. Two of the complementation groups correspond to mutations in the previously identified genes, RAMOSA2 (RA2) and LIGULELESS1 (LG1). Mutants corresponding to a third group were cloned using mapped-based approaches and found to encode a new member of the plant-specific TCP (TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL NUCLEAR ANTIGEN FACTOR) family of DNA-binding proteins, BRANCH ANGLE DEFECTIVE 1 (BAD1). BAD1 is expressed in the developing pulvinus as well as in other developing tissues, including the tassels and juvenile leaves. Both molecular and genetics studies show that RA2 is upstream of BAD1, whereas LG1 may function in a separate pathway. Our findings demonstrate that BAD1 is a TCP class II gene that functions to promote cell proliferation in a lateral organ, the pulvinus, and influences inflorescence architecture by impacting the angle of lateral branch emergence. PMID:22773815

  10. Gestational mutations in radiation carcinogenesis

    NASA Astrophysics Data System (ADS)

    Meza, R.; Luebeck, G.; Moolgavkar, S.

    Mutations in critical genes during gestation could increase substantially the risk of cancer. We examine the consequences of such mutations using the Luebeck-Moolgavkar model for colorectal cancer and the Lea-Coulson modification of the Luria-Delbruck model for the accumulation of mutations during gestation. When gestational mutation rates are high, such mutations make a significant contribution to cancer risk even for adult tumors. Furthermore, gestational mutations ocurring at distinct times during emryonic developmemt lead to substantially different numbers of mutated cells at birth, with early mutations leading to a large number (jackpots) of mutated cells at birth and mutation occurring late leading to only a few mutated cells. Thus gestational mutations could confer considerable heterogeneity of the risk of cancer. If the fetus is exposed to an environmental mutagen, such as ionizing radiation, the gestational mutation rate would be expected to increase. We examine the consequences of such exposures during gestation on the subsequent development of cancer.

  11. Discrimination of geometric angles by adult humans.

    PubMed

    Reichert, James F; Kelly, Debbie M

    2012-03-01

    Men and women learned to discriminate between two different size angles presented to them as objects within a real-world task. During Experiment 1, participants in group 50 were trained to choose a 50° angle and participants in group 75 were trained to choose a 75° angle. During testing, both groups were provided with a choice between their training angle and one of a set of test angles that was either smaller or larger than the training angle. Results showed a generalized pattern of responding, with group 50 showing increased responding to test angles smaller than 50° and group 75 showing increased responding to test angles larger than 75°. Further analysis of the response patterns revealed that participants in group 50 showed evidence of absolute learning, whereas participants in group 75 showed evidence of relational learning. During Experiment 2, a third group of participants (group 25) trained to choose a smaller angle (25°) was included in addition to group 50 and group 75. Participants were trained with three angles present and tested with just two, one being their training angle and the other being one of a set of novel test angles. Similar to the participants from Experiment 1, group 75 showed evidence of relational learning. Group 50, for which no relational rule could be applied during training, showed an absolute learning pattern with no response shift to test angles smaller or larger than their training angle. Group 25 showed evidence of absolute responding that was more pronounced than that found for the smallest training angle during Experiment 1. These findings suggest differential learning of geometric angles based on amplitude with smaller angles perceived as more distinct and thus more resistant to broader generalization than larger angles. Implications of these results are that certain geometric properties may be subject to different learning processes based on the specific magnitude of that property.

  12. Mutation and premating isolation.

    PubMed

    Woodruff, R C; Thompson, J N

    2002-11-01

    While premating isolation might be traceable to different genetic mechanisms in different species, evidence supports the idea that as few as one or two genes may often be sufficient to initiate isolation. Thus, new mutation can theoretically play a key role in the process. But it has long been thought that a new isolation mutation would fail, because there would be no other individuals for the isolation-mutation-carrier to mate with. We now realize that premeiotic mutations are very common and will yield a cluster of progeny carrying the same new mutant allele. In this paper, we discuss the evidence for genetically simple premating isolation barriers and the role that clusters of an isolation mutation may play in initiating allopatric, and even sympatric, species divisions.

  13. Mutation and premating isolation

    NASA Technical Reports Server (NTRS)

    Woodruff, R. C.; Thompson, J. N. Jr

    2002-01-01

    While premating isolation might be traceable to different genetic mechanisms in different species, evidence supports the idea that as few as one or two genes may often be sufficient to initiate isolation. Thus, new mutation can theoretically play a key role in the process. But it has long been thought that a new isolation mutation would fail, because there would be no other individuals for the isolation-mutation-carrier to mate with. We now realize that premeiotic mutations are very common and will yield a cluster of progeny carrying the same new mutant allele. In this paper, we discuss the evidence for genetically simple premating isolation barriers and the role that clusters of an isolation mutation may play in initiating allopatric, and even sympatric, species divisions.

  14. Mutation and premating isolation

    NASA Technical Reports Server (NTRS)

    Woodruff, R. C.; Thompson, J. N. Jr

    2002-01-01

    While premating isolation might be traceable to different genetic mechanisms in different species, evidence supports the idea that as few as one or two genes may often be sufficient to initiate isolation. Thus, new mutation can theoretically play a key role in the process. But it has long been thought that a new isolation mutation would fail, because there would be no other individuals for the isolation-mutation-carrier to mate with. We now realize that premeiotic mutations are very common and will yield a cluster of progeny carrying the same new mutant allele. In this paper, we discuss the evidence for genetically simple premating isolation barriers and the role that clusters of an isolation mutation may play in initiating allopatric, and even sympatric, species divisions.

  15. Aircraft flight path angle display system

    NASA Technical Reports Server (NTRS)

    Lambregts, Antonius A. (Inventor)

    1991-01-01

    A display system for use in an aircraft control wheel steering system provides the pilot with a single, quickened flight path angle display to overcome poor handling qualities due to intrinsic flight path angle response lags, while avoiding multiple information display symbology. The control law for the flight path angle control system is designed such that the aircraft's actual flight path angle response lags the pilot's commanded flight path angle by a constant time lag .tau., independent of flight conditions. The synthesized display signal is produced as a predetermined function of the aircraft's actual flight path angle, the time lag .tau. and command inputs from the pilot's column.

  16. Management of Secondary Angle Closure Glaucoma.

    PubMed

    Parivadhini, Annadurai; Lingam, Vijaya

    2014-01-01

    Secondary angle closure glaucomas are a distinct entity from primary angle closure glaucoma (PACG). Unlike PACG, secondary angle closure glaucoma's have an identifable contributory factor/s for angle closure and obstruction of aqueous fow which is usually unrelieved by iridotomy. The treatment of each type of secondary angle closure glaucoma is varied, so identification of the primary cause aids in its effective management. How to cite this article: Annadurai P, Vijaya L. Management of Secondary Angle Closure Glaucoma. J Current Glau Prac 2014;8(1):25-32.

  17. Genetic screening in a large family with juvenile onset primary open angle glaucoma

    PubMed Central

    Booth, A.; Anwar, R.; Chen, H.; Churchill, A.; Jay, J.; Polansky, J.; Nguyen, T.; Markham, A.

    2000-01-01

    AIMS—A number of genetic loci have been implicated in the pathogenesis of primary open angle glaucoma (POAG). The aim of this study was to identify the genetic cause of POAG in a large Scottish family and, if possible, offer genetic screening and advice to family members.
METHODS—Family members were examined to determine their disease status. Base excision sequence scanning was carried out in order to test for the presence of a POAG causing mutation at known genetic loci. Direct DNA sequencing was performed in order to determine the mutation sequence.
RESULTS—All family members of known affected disease status and two family members of unknown disease status were found to have a mutation in the TIGR gene. The mutation resulted in the substitution of a glycine residue with an arginine residue at codon 252 (Gly252Arg). No other sequence variations were present in any members of the family.
CONCLUSION—The Gly252Arg mutation in the TIGR gene results in the development of POAG in this family. It was possible to identify younger, currently unaffected, members of the family who carry the mutation and who are therefore at a very high risk of developing POAG themselves. This is the first demonstration that Gly252Arg can be a disease causing mutation rather than a benign polymorphism. The possible pathogenic mechanisms and wider implications of the mutation are considered.

 PMID:10873982

  18. Theta angle in holographic QCD

    NASA Astrophysics Data System (ADS)

    Järvinen, Matti

    2017-03-01

    V-QCD is a class of effective holographic models for QCD which fully includes the backreaction of quarks to gluon dynamics. The physics of the θ-angle and the axial anomaly can be consistently included in these models. We analyze their phase diagrams over ranges of values of the quark mass, Nf/Nc, and θ, computing observables such as the topological susceptibility and the meson masses. At small quark mass, where effective chiral Lagrangians are reliable, they agree with the predictions of V-QCD.

  19. Primary Cerebellopontine Angle Melanocytoma: Review

    PubMed Central

    Phang, Isaac; Elashaal, Rahim; Ironside, James; Eljamel, Sam

    2012-01-01

    Introduction Primary cerebellopontine angle melanocytomas (PCPAMs) are very rare. Their natural history and prognosis are not fully understood. We reviewed the literature and add a new case to analyze PCPAM's presentation, radiological features, and outcome of treatment. Methods We performed a literature review using Medline, Embase, PubMed, and Cochrane databases. We searched for melanocytoma, melanoma, and pigmented tumors in the posterior cranial fossa and CPA to identify PCPAM. We have also searched our institution's neuro-oncology database. Results We identified 23 PCPAM from the literature and one case of our own. The mean age at presentation was 44.4 years with slight male preponderance. PCPAM presented with cerebellopontine angle (CPA) syndrome with or without hydrocephalus. Preoperative diagnosis was difficult; they appeared hyperintense on T1 and isointense on T2 magnetic resonance imaging (MRI) and enhanced with gadolinium. However, the final diagnosis was only made by immunohistochemical examination. Total surgical resection of PCPAM was associated with prolonged survival while subtotal excision was associated with frequent recurrence. Conclusion PCPAM are very rare and should be considered in the differential diagnosis of all CPA lesions that appear hyperintense on T1 and isointense on T2 MRI images. Patients with PCPAM should undergo total surgical resection to avoid fatal recurrences. PMID:23946922

  20. Gaia basic angle monitoring system

    NASA Astrophysics Data System (ADS)

    Gielesen, W.; de Bruijn, D.; van den Dool, T.; Kamphues, F.; Meijer, E.; Calvel, B.; Laborie, A.; Monteiro, D.; Coatantiec, C.; Touzeau, S.; Erdmann, M.; Gare, P.

    2012-09-01

    The Gaia mission will create an extraordinarily precise three-dimensional map of more than one billion stars in our Galaxy. The Gaia spacecraft, built by EADS Astrium, is part of ESA's Cosmic Vision programme and scheduled for launch in 2013. Gaia measures the position, distance and motion of stars with an accuracy of 24 micro-arcsec using two telescopes at a fixed mutual angle of 106.5°, named the ‘Basic Angle’. This accuracy requires ultra-high stability, which can only be achieved by using Silicon Carbide for both the optical bench and the telescopes. TNO has developed, built and space qualified the Silicon carbide Basic Angle Monitoring (BAM) on-board metrology system for this mission. The BAM measures the relative motion of Gaia’s telescopes with accuracies in the range of 0.5 micro-arcsec. This is achieved by a system of two laser interferometers able to measure Optical Path Differences (OPD) as small as 1.5 picometer rms. Following a general introduction to the Gaia mission, the Payload Module (PLM) and the use of Silicon Carbide as base material, this presentation will address an overview of the challenges towards the key requirements, design, integration and testing (including space-level qualification) of the Gaia BAM.

  1. Predictive models of large neutrino mixing angles

    SciTech Connect

    Barr, S.M.

    1997-02-01

    Several experimental results could be interpreted as evidence that certain neutrino mixing angles are large, of order unity. However, in the context of grand unified models the neutrino angles come out characteristically to be small, like the KM angles. It is shown how to construct simple grand-unified models in which neutrino angles are not only large but completely predicted with some precision. Six models are presented for illustration. {copyright} {ital 1997} {ital The American Physical Society}

  2. Bilarge neutrino mixing and the Cabibbo angle

    NASA Astrophysics Data System (ADS)

    Boucenna, S. M.; Morisi, S.; Tórtola, M.; Valle, J. W. F.

    2012-09-01

    Recent measurements of the neutrino mixing angles cast doubt on the validity of the so-far popular tribimaximal mixing Ansatz. We propose a parametrization for the neutrino mixing matrix where the reactor angle seeds the large solar and atmospheric mixing angles, equal to each other in first approximation. We suggest such a bilarge mixing pattern as a model-building standard, realized when the leading order value of θ13 equals the Cabibbo angle λC.

  3. Optoelectronic Shaft-Angle Encoder Tolerates Misalignments

    NASA Technical Reports Server (NTRS)

    Osborne, Eric P.

    1991-01-01

    Optoelectronic shaft-angle encoder measures angle of rotation of shaft with high precision while minimizing effects of eccentricity and other misalignments. Grooves on disk serve as reference marks to locate reading heads and measure increments of rotation of disk. Shaft-angle encoder, resembling optical compact-disk drive, includes two tracking heads illuminating grooves on disk and measures reflections from them.

  4. A new procedure for measuring contact angle

    SciTech Connect

    Concus, P.; Finn, R.

    1994-05-01

    Described here are some recent work regarding the mathematic design of apparatus that exploits microgravity conditions for accurate experimental determination of contact angle. The underlying motivation for the procedures rests on a discontinuous dependence of the capillary free surface interface S on the contact angle {gamma}, in a cylindrical capillary tube whose section (base) {Omega} contains a protruding corner with opening angle 2{alpha}.

  5. AIP mutations and gigantism.

    PubMed

    Rostomyan, Liliya; Potorac, Iulia; Beckers, Pablo; Daly, Adrian F; Beckers, Albert

    2017-06-01

    AIP mutations are rare in sporadic acromegaly but they are seen at a higher frequency among certain specific populations of pituitary adenoma patients (pituitary gigantism cases, familial isolated pituitary adenoma (FIPA) kindreds, and patients with macroadenomas who are diagnosed ≤30 years). AIP mutations are most prevalent in patients with pituitary gigantism (29% of this group were found to have mutations in AIP gene). These data support targeted genetic screening for AIP mutations/deletions in these groups of pituitary adenoma patients. Earlier diagnosis of AIP-related acromegaly-gigantism cases enables timely clinical evaluation and treatment, thereby improving outcomes in terms of excessive linear growth and acromegaly comorbidities. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  6. Primary open-angle glaucoma.

    PubMed

    Weinreb, Robert N; Khaw, Peng Tee

    2004-05-22

    Primary open-angle glaucoma is a progressive optic neuropathy and, perhaps, the most common form of glaucoma. Because the disease is treatable, and because the visual impairment caused by glaucoma is irreversible, early detection is essential. Early diagnosis depends on examination of the optic disc, retinal nerve fibre layer, and visual field. New imaging and psychophysical tests can improve both detection and monitoring of the progression of the disease. Recently completed long-term clinical trials provide convincing evidence that lowering intraocular pressure prevents progression at both the early and late stages of the disease. The degree of protection is related to the degree to which intraocular pressure is lowered. Improvements in therapy consist of more effective and better-tolerated drugs to lower intraocular pressure, and more effective surgical procedures. New treatments to directly treat and protect the retinal ganglion cells that are damaged in glaucoma are also in development.

  7. ATM mutations for surgeons.

    PubMed

    Mansfield, Sara A; Pilarski, Robert; Agnese, Doreen M

    2016-12-17

    The ataxia-telangiectasia mutated (ATM) gene encodes a protein kinase involved in DNA repair. Heterozygotic carriers are at an increased risk of developing breast cancer. As the use of genetic testing increases, identification of at-risk patients will also increase. The aim of this study is to review two cases of heterozygous ATM mutation carriers and review the literature to clarify the cancer risks and suggested management for breast surgeons who will be intimately involved in the care of these patients.

  8. Comparing Mutational Variabilities

    PubMed Central

    Houle, D.; Morikawa, B.; Lynch, M.

    1996-01-01

    We have reviewed the available data on V(M), the amount of genetic variation in phenotypic traits produced each generation by mutation. We use these data to make several qualitative tests of the mutation-selection balance hypothesis for the maintenance of genetic variance (MSB). To compare V(M) values, we use three dimensionless quantities: mutational heritability, V(M)/V(E); the mutational coefficient of variation, CV(M); and the ratio of the standing genetic variance to V(M), V(G)/V(M). Since genetic coefficients of variation for life history traits are larger than those for morphological traits, we predict that under MSB, life history traits should also have larger CV(M). This is confirmed; life history traits have a median CV(M) value more than six times higher than that for morphological traits. V(G)/V(M) approximates the persistence time of mutations under MSB in an infinite population. In order for MSB to hold, V(G)/V(M) must be small, substantially less than 1000, and life history traits should have smaller values than morphological traits. V(G)/V(M) averages about 50 generations for life history traits and 100 generations for morphological traits. These observations are all consistent with the predictions of a mutation-selection balance model. PMID:8807316

  9. Individualized optimal release angles in discus throwing.

    PubMed

    Leigh, Steve; Liu, Hui; Hubbard, Mont; Yu, Bing

    2010-02-10

    The purpose of this study was to determine individualized optimal release angles for elite discus throwers. Three-dimensional coordinate data were obtained for at least 10 competitive trials for each subject. Regression relationships between release speed and release angle, and between aerodynamic distance and release angle were determined for each subject. These relationships were linear with subject-specific characteristics. The subject-specific relationships between release speed and release angle may be due to subjects' technical and physical characteristics. The subject-specific relationships between aerodynamic distance and release angle may be due to interactions between the release angle, the angle of attack, and the aerodynamic distance. Optimal release angles were estimated for each subject using the regression relationships and equations of projectile motion. The estimated optimal release angle was different for different subjects, and ranged from 35 degrees to 44 degrees . The results of this study demonstrate that the optimal release angle for discus throwing is thrower-specific. The release angles used by elite discus throwers in competition are not necessarily optimal for all discus throwers, or even themselves. The results of this study provide significant information for understanding the biomechanics of discus throwing techniques.

  10. Wafer scale oblique angle plasma etching

    DOEpatents

    Burckel, David Bruce; Jarecki, Jr., Robert L.; Finnegan, Patrick Sean

    2017-05-23

    Wafer scale oblique angle etching of a semiconductor substrate is performed in a conventional plasma etch chamber by using a fixture that supports a multiple number of separate Faraday cages. Each cage is formed to include an angled grid surface and is positioned such that it will be positioned over a separate one of the die locations on the wafer surface when the fixture is placed over the wafer. The presence of the Faraday cages influences the local electric field surrounding each wafer die, re-shaping the local field to be disposed in alignment with the angled grid surface. The re-shaped plasma causes the reactive ions to follow a linear trajectory through the plasma sheath and angled grid surface, ultimately impinging the wafer surface at an angle. The selected geometry of the Faraday cage angled grid surface thus determines the angle at with the reactive ions will impinge the wafer.

  11. Angle illusion in a straight road.

    PubMed

    Osa, Atsushi; Nagata, Kazumi; Honda, Yousuke; Ichikawa, Makoto; Matsuda, Ken; Miike, Hidetoshi

    2011-01-01

    We report a new angle illusion observed when viewing a real scene involving a straight road. The scene portrays two white lines which outline a traffic lane on a road and converge to a vanishing point. In experiment 1, observers estimated the angle created by these converging lines in this scene or in its image projected onto a screen. Results showed strong underestimation of the angle, ie over 50% for observations of both the real scene and its projected image. Experiment 2 assessed how depth cues in projected images influence the angle illusion. Results showed that this angle illusion disappeared when scene information surrounding convergent lines was removed. In addition, the illusion was attenuated with projection of an inverted scene image. These findings are interpreted in terms of a misadoption of depth information in the processing of angle perception in a flat image; in turn, this induces a massive angle illusion.

  12. Assessment and predictability of ANB angle.

    PubMed

    Chandra, P K; Godfrey, K

    1990-03-01

    This cephalometric study consisting of thirty three orthodontic patients in the age group of 13 to 15 years was carried out to: 1. Evaluate the relationship between angle ANB and horizontal distance between jaws at the level of point A (r = 0.99); 2. Evaluate the relationship between angle ANB and Wits appraisal (r = 0.95 when mandibular plane angle is within normal limits of 32 +/- 5); 3. Predict angle ANB from Wits appraisal and vice versa (which was 90 percent correct in mesofacial type and obtained by the regression equation: angle ANB = 2.31 + 1.00 x Wits value; and 4. Evaluate the validity of angle ANB compared to other methods (angle ANB 78.5 percent in agreement with the standard followed by Wits 64.28 percent).

  13. Meningiomas of the cerebellopontine angle.

    PubMed

    Matthies, C; Carvalho, G; Tatagiba, M; Lima, M; Samii, M

    1996-01-01

    Meningiomas of the cerebellopontine angle (CPA) represent a clinically and surgically interesting entity. The opportunity of complete surgical excision and the incidence of impairment of nerval structures largely depend on the tumour biology that either leads to displacement of surrounding structures by an expansive type of growth or to an enveloping of nerval and vascular structures by an en plaque type of growth. As the origin and the direction of growth are very variable, the exact tumour extension in relation to the nerval structures and the tumour origin can be identified sometimes only at the time of surgery. Out of a series of 230 meningiomas of the posterior skull base operated between 1978 and 1993, data of 134 meningiomas involving the cerebellopontine angle are presented. There were 20% male and 80% female patients, age at the time of surgery ranging from 18 to 76 years, on the average 51 years. The clinical presentation was characterized by a predominant disturbance of the cranial nerves V (19%), VII (11%), VIII (67%) and the caudal cranial nerves (6%) and signs of ataxia (28%). 80% of the meningiomas were larger than 30 mm in diameter, 53% led to evident brainstem compression or dislocation and 85% extended anteriorly to the internal auditory canal. Using the lateral suboccipital approach in the majority of cases and a combined presigmoidal or combined suboccipital and subtemporal approaches in either sequence in 5%, complete tumour removal (Simpson I and II) was accomplished in 95% and subtotal tumour removal in 5%. Histologically the meningiotheliomatous type was most common (49%) followed by the mixed type (19%), fibroblastic (16%), psammomatous (7%), hemangioblastic (7%) and anaplastic (2%) types. Major post-operative complications were CSF leakage (8%) requiring surgical revision in 2% and hemorrhage (3%) requiring revision in 2%. While the majority of neurological disturbances showed signs of recovery, facial nerve paresis or paralysis was

  14. Foot Progression Angle Walking Test

    PubMed Central

    Ranawat, Anil S.; Gaudiani, Michael A.; Slullitel, Pablo A.; Satalich, James; Rebolledo, Brian J.

    2017-01-01

    Background: Determining an accurate clinical diagnosis for nonarthritic hip pain may be challenging, as symptoms related to femoroacetabular impingement (FAI) or hip instability can be difficult to elucidate with current testing methods. In addition, commonly utilized physical examination maneuvers are static and do not include a dynamic or weightbearing assessment to reproduce activity-related symptoms. Therefore, implementing a dynamic assessment for FAI and hip instability could help to improve diagnostic accuracy for routine clinical examinations of patients with nonarthritic hip pain. Purpose: To assess the efficacy of a novel diagnostic foot progression angle walking (FPAW) test for identifying hip pathology related to FAI or hip instability. Study Design: Prospective cohort study; Level of evidence, 3. Methods: This prospective study included 199 consecutive patients who were evaluated for unilateral hip pain and who underwent FPAW testing along with standard physical examination testing. Demographic data, including age, sex and hip laterality, were collected from each patient. FPAW testing was performed with directed internal and external foot progression angles from their baseline measurements, with a positive test reproducing pain and/or discomfort. Comparisons were then made with flexion adduction internal rotation (FADIR) and flexion abduction external rotation (FABER) tests as the designated diagnostic standard examinations for FAI and hip instability, respectively. Sensitivity and specificity, along with the McNemar chi-square test for group comparison, were used to generate summary statistics. In addition, areas under the combined receiver operating characteristic curves (AUC) of test performance were calculated for both FPAW and the designated standard examination tests (FADIR, FABER). Radiographic imaging was used subsequently to confirm the diagnosis. Results: The average age of the study cohort was 35.4 ± 11.8 years, with 114 patients being

  15. Dynamic contact angle measurements on superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Kim, Jeong-Hyun; Kavehpour, H. Pirouz; Rothstein, Jonathan P.

    2015-03-01

    In this paper, the dynamic advancing and receding contact angles of a series of aqueous solutions were measured on a number of hydrophobic and superhydrophobic surfaces using a modified Wilhelmy plate technique. Superhydrophobic surfaces are hydrophobic surfaces with micron or nanometer sized surface roughness. These surfaces have very large static advancing contact angles and little static contact angle hysteresis. In this study, the dynamic advancing and dynamic receding contact angles on superhydrophobic surfaces were measured as a function of plate velocity and capillary number. The dynamic contact angles measured on a smooth hydrophobic Teflon surface were found to obey the scaling with capillary number predicted by the Cox-Voinov-Tanner law, θD3 ∝ Ca. The response of the dynamic contact angle on the superhydrophobic surfaces, however, did not follow the same scaling law. The advancing contact angle was found to remain constant at θA = 160∘, independent of capillary number. The dynamic receding contact angle measurements on superhydrophobic surfaces were found to decrease with increasing capillary number; however, the presence of slip on the superhydrophobic surface was found to result in a shift in the onset of dynamic contact angle variation to larger capillary numbers. In addition, a much weaker dependence of the dynamic contact angle on capillary number was observed for some of the superhydrophobic surfaces tested.

  16. Large Angle Satellite Attitude Maneuvers

    NASA Technical Reports Server (NTRS)

    Cochran, J. E.; Junkins, J. L.

    1975-01-01

    Two methods are proposed for performing large angle reorientation maneuvers. The first method is based upon Euler's rotation theorem; an arbitrary reorientation is ideally accomplished by rotating the spacecraft about a line which is fixed in both the body and in space. This scheme has been found to be best suited for the case in which the initial and desired attitude states have small angular velocities. The second scheme is more general in that a general class of transition trajectories is introduced which, in principle, allows transfer between arbitrary orientation and angular velocity states. The method generates transition maneuvers in which the uncontrolled (free) initial and final states are matched in orientation and angular velocity. The forced transition trajectory is obtained by using a weighted average of the unforced forward integration of the initial state and the unforced backward integration of the desired state. The current effort is centered around practical validation of this second class of maneuvers. Of particular concern is enforcement of given control system constraints and methods for suboptimization by proper selection of maneuver initiation and termination times. Analogous reorientation strategies which force smooth transition in angular momentum and/or rotational energy are under consideration.

  17. A thermodynamic model of contact angle hysteresis

    NASA Astrophysics Data System (ADS)

    Makkonen, Lasse

    2017-08-01

    When a three-phase contact line moves along a solid surface, the contact angle no longer corresponds to the static equilibrium angle but is larger when the liquid is advancing and smaller when the liquid is receding. The difference between the advancing and receding contact angles, i.e., the contact angle hysteresis, is of paramount importance in wetting and capillarity. For example, it determines the magnitude of the external force that is required to make a drop slide on a solid surface. Until now, fundamental origin of the contact angle hysteresis has been controversial. Here, this origin is revealed and a quantitative theory is derived. The theory is corroborated by the available experimental data for a large number of solid-liquid combinations. The theory is applied in modelling the contact angle hysteresis on a textured surface, and these results are also in quantitative agreement with the experimental data.

  18. Dual-view angle backlight module design.

    PubMed

    Chen, Bo-Tsuen; Pan, Jui-Wen

    2015-10-01

    We propose a bilayer light guide plate (BLGP) with specially designed microstructures and two light source modules to achieve an adjustable viewing angle backlight for ecofriendly displays. The dual viewing angle backlight module has a thin, simple structure and a high optical efficiency. Comparison with the conventional edge-lit backlight module shows an improvement in the on-axis luminance of the narrow viewing angle mode of 4.3 times and a decrease in the half-luminance angle of 7° in the horizontal direction. When using the wide viewing angle mode, there is an improvement in the on-axis luminance of 1.8 times and an improvement in the half-luminance angle of 54° in the horizontal direction. The uniformity of illuminance can reach 80% in each mode. The backlight optical sheet number is reduced from 5 to 1.

  19. Contact angle measurement on rough surfaces.

    PubMed

    Meiron, Tammar S; Marmur, Abraham; Saguy, I Sam

    2004-06-15

    A new method for the measurement of apparent contact angles at the global energy minimum on real surfaces has been developed. The method consists of vibrating the surface, taking top-view pictures of the drop, monitoring the drop roundness, and calculating the contact angle from the drop diameter and weight. The use of the new method has been demonstrated for various rough surfaces, all having the same surface chemistry. In order to establish the optimal vibration conditions, the proper ranges for the system parameters (i.e., drop volume, vibration time, frequency of vibration, and amplitude of vibration) were determined. The reliability of the method has been demonstrated by the fact that the ideal contact angles of all surfaces, as calculated from the Wenzel equation using the measured apparent contact angles, came out to be practically identical. This ideal contact angle has been compared with three methods of calculation from values of advancing and receding contact angles.

  20. Signature extension for sun angle, volume 1

    NASA Technical Reports Server (NTRS)

    Smith, J. A. (Principal Investigator); Berry, J. K.; Heimes, F.

    1975-01-01

    The author has identified the following significant results. Within a restricted zenith sun angle range of 35 - 50 degrees, it was empirically observed that canopy reflectance is mainly Lambertian. Reflectance changes with crop stage were simple shifts in scale in the sun angle range. It was noted that sun angle variations depend on canopy characteristics. Effects of the vegetative canopy were most pronounced at the larger solar zenith angles (20 %). The linear sun angle correction coefficients demonstrate a dependency on both crop stage (15-20 %) and crop type (10-20 %). The use of canopy reflectance modeling allowed for the generation of a simulated data set over an extremely broad envelope of sun angles.

  1. A thermodynamic model of contact angle hysteresis.

    PubMed

    Makkonen, Lasse

    2017-08-14

    When a three-phase contact line moves along a solid surface, the contact angle no longer corresponds to the static equilibrium angle but is larger when the liquid is advancing and smaller when the liquid is receding. The difference between the advancing and receding contact angles, i.e., the contact angle hysteresis, is of paramount importance in wetting and capillarity. For example, it determines the magnitude of the external force that is required to make a drop slide on a solid surface. Until now, fundamental origin of the contact angle hysteresis has been controversial. Here, this origin is revealed and a quantitative theory is derived. The theory is corroborated by the available experimental data for a large number of solid-liquid combinations. The theory is applied in modelling the contact angle hysteresis on a textured surface, and these results are also in quantitative agreement with the experimental data.

  2. [Introduction of mutations in insulin molecule: positive and negative mutations].

    PubMed

    Ksenofontova, O I

    2014-01-01

    Introduction of mutations in an insulin molecule is one of the important approaches to drug development for treatment of diabetes mellitus. Generally, usage of mutations is aimed at activation of insulin and insulin receptor interaction. Such mutations can be considered as positive. Mutations that reduce the binding efficacy are negative. There are neutral mutations as well. This article considers both natural mutations that are typical for various members of the insulin superfamily and artificial ones which are introduced to improve the insulin pharmacological characteristics. Data presented here can be useful in developing new effective insulin analogues for treatment of diabetes mellitus.

  3. Mutations in Lettuce Improvement

    PubMed Central

    Mou, Beiquan

    2011-01-01

    Lettuce is a major vegetable in western countries. Mutations generated genetic variations and played an important role in the domestication of the crop. Many traits derived from natural and induced mutations, such as dwarfing, early flowering, male sterility, and chlorophyll deficiency, are useful in physiological and genetic studies. Mutants were also used to develop new lettuce products including miniature and herbicide-tolerant cultivars. Mutant analysis was critical in lettuce genomic studies including identification and cloning of disease-resistance genes. Mutagenesis combined with genomic technology may provide powerful tools for the discovery of novel gene alleles. In addition to radiation and chemical mutagens, unconventional approaches such as tissue or protoplast culture, transposable elements, and space flights have been utilized to generate mutants in lettuce. Since mutation breeding is considered nontransgenic, it is more acceptable to consumers and will be explored more in the future for lettuce improvement. PMID:22287955

  4. Contact angle measurements under thermodynamic equilibrium conditions.

    PubMed

    Lages, Carol; Méndez, Eduardo

    2007-08-01

    The precise control of the ambient humidity during contact angle measurements is needed to obtain stable and valid data. For a such purpose, a simple low-cost device was designed, and several modified surfaces relevant to biosensor design were studied. Static contact angle values for these surfaces are lower than advancing contact angles published for ambient conditions, indicating that thermodynamic equilibrium conditions are needed to avoid drop evaporation during the measurements.

  5. High angle of attack hypersonic aerodynamics

    NASA Technical Reports Server (NTRS)

    Harloff, Gary J.

    1987-01-01

    A new aerodynamics force model is presented which is based on modified Newtonian theory and empirical correlations. The algebraic model was developed for complete vehicles from take off to orbital speeds and for large angles of attack. Predictions are compared to results for a wind tunnel model at a Mach number of 20, and the full scale Shuttle Orbiter for Mach numbers from 0.25 to 20 for angles of attack from 0 to 50 deg. The maximum shuttle orbiter lift/drag at Mach 10 and 20 is 1.85 at 20-deg angle-of-attack. Aerodynamic force predictions are made for a transatmospheric vehicle, which is a derivative of the Shuttle Orbiter, for Mach numbers from 4 to 27 at angles of attack from 5 to 40 deg. Predicted aerodynamic force data indicate that lift/drag ratios of 5.2 at Mach number 10 and 3.6 at Mach number 26 are obtainable. Changes in force coefficients with changes in: nose angle, sweep angle, and (volume exp 2/3)/planform area are quantified for Mach numbers of 10 and 26. Lift/drag ratios increase with decreasing nose angle and (volume exp 2/3)/planform area and increasing wing sweep angle. Lift/drag ratios are independent of these variables for angles of attack in excess of 20 deg at Mach 10 and 30 deg at Mach 26.

  6. Pitch Angle Survey of GOODS Spiral Galaxies

    NASA Astrophysics Data System (ADS)

    Boe, Benjamin; Kennefick, Daniel; Arkansas Galaxy Evolution Survey, Arkansas CenterSpace; Planetary Sciences

    2015-01-01

    This research looks at how the pitch angles of galaxies change over scales of cosmic time. We measure the pitch angle, or tightness of spiral winding, using a new code, Spirality. We then compare the results to those obtained from established software, 2DFFT (2 Dimensional Fast Fourier Transform). We investigate any correlation between pitch angle and redshift, or distance from Earth. Previous research indicates that the pitch angle of a galaxy correlates with its central bulge mass and the mass of its central black hole. Thus any evolution in the distribution of pitch angles could ultimately prove to be indicative of evolution in the supermassive black hole mass function. Galaxies from the Hubble GOODS (Great Observatories Origins Deep Survey) North and South were measured. We found that there was strong agreement between Spirality and 2DFFT measurements. Spirality measured the pitch angle of the GOODS galaxies with a lower error than 2DFFT on average. With both software a correlation between pitch angle and redshift was found. Spirality observed a 6.150 increase in pitch per unit redshift. The increase in pitch angle with redshift suggests that in the past galaxies had higher pitch angles, which could be indicative of lower central black hole masses (or, more directly, central bulge masses).

  7. Best Angle to Orient Two Intersecting Lines

    SciTech Connect

    Awwal, A S; Ferguson, S W; Shull, P B

    2006-07-25

    Fiducials in the form of intersecting straight lines are used to align the target in the final target chamber of the National Ignition Facility of Lawrence Livermore National Laboratory. One of the techniques used to locate these lines is the Hough transform. When two lines intersect at a 90 degree angle, it is tempting to orient the lines to horizontal and vertical directions. There are other possible angles at which the lines may be oriented. One question that arises while designing the fiducials is whether there is a preferred angle or range of angles that leads to higher accuracy. This work attempts to answer this question through detailed computer simulation.

  8. Behavior of Tilted Angle Shear Connectors

    PubMed Central

    Khorramian, Koosha; Maleki, Shervin; Shariati, Mahdi; Ramli Sulong, N. H.

    2015-01-01

    According to recent researches, angle shear connectors are appropriate to transfer longitudinal shear forces across the steel-concrete interface. Angle steel profile has been used in different positions as L-shaped or C-shaped shear connectors. The application of angle shear connectors in tilted positions is of interest in this study. This study investigates the behaviour of tilted-shaped angle shear connectors under monotonic loading using experimental push out tests. Eight push-out specimens are tested to investigate the effects of different angle parameters on the ultimate load capacity of connectors. Two different tilted angles of 112.5 and 135 degrees between the angle leg and steel beam are considered. In addition, angle sizes and lengths are varied. Two different failure modes were observed consisting of concrete crushing-splitting and connector fracture. By increasing the size of connector, the maximum load increased for most cases. In general, the 135 degrees tilted angle shear connectors have a higher strength and stiffness than the 112.5 degrees type. PMID:26642193

  9. ALS2 mutations

    PubMed Central

    Schneider, Susanne A.; Carr, Lucinda; Deuschl, Guenther; Hopfner, Franziska; Stamelou, Maria; Wood, Nicholas W.; Bhatia, Kailash P.

    2014-01-01

    Objective: To determine the genetic etiology in 2 consanguineous families who presented a novel phenotype of autosomal recessive juvenile amyotrophic lateral sclerosis associated with generalized dystonia. Methods: A combination of homozygosity mapping and whole-exome sequencing in the first family and Sanger sequencing of candidate genes in the second family were used. Results: Both families were found to have homozygous loss-of-function mutations in the amyotrophic lateral sclerosis 2 (juvenile) (ALS2) gene. Conclusions: We report generalized dystonia and cerebellar signs in association with ALS2-related disease. We suggest that the ALS2 gene should be screened for mutations in patients who present with a similar phenotype. PMID:24562058

  10. The inheritance of juvenile onset primary open angle glaucoma.

    PubMed

    Gupta, V; Somarajan, B I; Gupta, S; Chaurasia, A K; Kumar, S; Dutta, P; Gupta, V; Sharma, A; Tayo, B O; Nischal, K

    2016-10-25

    Juvenile onset open angle glaucoma (JOAG) affects patients before 40 years of age, who present with high intraocular pressure and deep steep cupping of the optic nerve head. While it was considered to be inherited in an autosomal dominant fashion, recent studies have shown an autosomal recessive pattern as well as sporadic occurrence of the disease in several families. In this review, we analyze the genetic basis of the disease along with common mutations and their association with JOAG. We also analyzed the inheritance patterns in a large group of unrelated JOAG patients (n = 336) from Northern India wherein the prevalence of familial occurrence was assessed and segregation analysis performed, to determine the mode of inheritance.

  11. Contact angle hysteresis on fluoropolymer surfaces.

    PubMed

    Tavana, H; Jehnichen, D; Grundke, K; Hair, M L; Neumann, A W

    2007-10-31

    Contact angle hysteresis of liquids with different molecular and geometrical properties on high quality films of four fluoropolymers was studied. A number of different causes are identified for hysteresis. With n-alkanes as probe liquids, contact angle hysteresis is found to be strongly related to the configuration of polymer chains. The largest hysteresis is obtained with amorphous polymers whereas the smallest hysteresis occurs for polymers with ordered molecular chains. This is explained in terms of sorption of liquid by the solid and penetration of liquid into the polymer film. Correlation of contact angle hysteresis with the size of n-alkane molecules supports this conclusion. On the films of two amorphous fluoropolymers with different molecular configurations, contact angle hysteresis of one and the same liquid with "bulky" molecules is shown to be quite different. On the surfaces of Teflon AF 1600, with stiff molecular chains, the receding angles of the probe liquids are independent of contact time between solid and liquid and similar hysteresis is obtained for all the liquids. Retention of liquid molecules on the solid surface is proposed as the most likely cause of hysteresis in these systems. On the other hand, with EGC-1700 films that consist of flexible chains, the receding angles are strongly time-dependent and the hysteresis is large. Contact angle hysteresis increases even further when liquids with strong dipolar intermolecular forces are used. In this case, major reorganization of EGC-1700 chains due to contact with the test liquids is suggested as the cause. The effect of rate of motion of the three-phase line on the advancing and receding contact angles, and therefore contact angle hysteresis, is investigated. For low viscous liquids, contact angles are independent of the drop front velocity up to approximately 10 mm/min. This agrees with the results of an earlier study that showed that the rate-dependence of the contact angles is an issue only

  12. Msx1 Mutations

    PubMed Central

    Wang, Y.; Kong, H.; Mues, G.; D’Souza, R.

    2011-01-01

    Mutations in the transcription factors PAX9 and MSX1 cause selective tooth agenesis in humans. In tooth bud mesenchyme of mice, both proteins are required for the expression of Bmp4, which is the key signaling factor for progression to the next step of tooth development. We have previously shown that Pax9 can transactivate a 2.4-kb Bmp4 promoter construct, and that most tooth-agenesis-causing PAX9 mutations impair DNA binding and Bmp4 promoter activation. We also found that Msx1 by itself represses transcription from this proximal Bmp4 promoter, and that, in combination with Pax9, it acts as a potentiator of Pax9-induced Bmp4 transactivation. This synergism of Msx1 with Pax9 is significant, because it is currently the only documented mechanism for Msx1-mediated activation of Bmp4. In this study, we investigated whether the 5 known tooth-agenesis-causing MSX1 missense mutations disrupt this Pax9-potentiation effect, or if they lead to deficiencies in protein stability, protein-protein interactions, nuclear translocation, and DNA-binding. We found that none of the studied molecular mechanisms yielded a satisfactory explanation for the pathogenic effects of the Msx1 mutations, calling for an entirely different approach to the investigation of this step of odontogenesis on the molecular level. PMID:21297014

  13. The SU(2) action-angle variables

    NASA Technical Reports Server (NTRS)

    Ellinas, Demosthenes

    1993-01-01

    Operator angle-action variables are studied in the frame of the SU(2) algebra, and their eigenstates and coherent states are discussed. The quantum mechanical addition of action-angle variables is shown to lead to a noncommutative Hopf algebra. The group contraction is used to make the connection with the harmonic oscillator.

  14. [Clinical classification of variable angle exotrophy].

    PubMed

    Arroyo-Yllanes, María Estela; Osorio-González, Déborah Itzel; Pérez-Pérez, José Fernando

    2007-01-01

    Variable exotropia is determined by a series of mechanisms that provide different clinical characteristics to outline individual therapy. There is no specific categorization that can identify such an entity. A clinical classification is proposed that includes different clinical features in accordance with the mechanisms involved in the variability genesis of such exotropias. Patients with a diagnosis of variable angle exotropia without previous surgery were included. A complete ophthalmic and strabismus exploration was performed. Variability characteristics were studied and grouped by entries in the classification proposed. Ninety patients were examined from the Pediatric Ophthalmology and Strabismus Unit of the General Hospital of Mexico O.D., with a diagnosis of variable angle exotropia. The following forms of presentations were found: secondary variable angle exotropia due to neurological alteration in 32 cases (35.5%), secondary variable angle exotropia due to monocular bad vision in 19 cases (21.2%), dissociated horizontal deviation in 14 cases (15.5%), mixed variable angle exotropia in 22 cases (4.5%) and primary variable angle exotropia in 3 cases (3.33%). This classification allows categorization of all patients of variable angle exotropia into proposed categories. The most common mechanism responsible for variability is neurological alteration. Primary variable angle exotropias are rare and are present in a minimum percentage.

  15. A Climbing Class' Reinvention of Angles

    ERIC Educational Resources Information Center

    Fyhn, Anne Birgitte

    2008-01-01

    A previous study shows how a twelve-year-old girl discovers angles in her narrative from a climbing trip. Based on this research, the girl's class takes part in one day of climbing and half a day of follow-up work at school. The students mathematise their climbing with respect to angles and they express themselves in texts and drawings. Their…

  16. Nasolabial angle: a perception of treatment needs.

    PubMed

    Sukhia, Rashna Hoshang; Sukhia, Hoshang Rumi; Fida, Mubassar; Khan, Munizeh

    2012-01-01

    The nasolabial angle holds a very important position in the treatment planning process for an orthodontic case, especially in today's soft tissue paradigm. This study was therefore conducted to compare the mean preference scores for orthodontic treatment need considering the nasolabial angle among orthodontists, orthodontic patients and their parents.

  17. Effects Of Molecular Processes On Trim Angles

    NASA Technical Reports Server (NTRS)

    Park, Chul; Yoon, Seokkwan

    1991-01-01

    Report discusses preliminary calculations of effects of vibrational excitation and dissociation of air molecules on trim angle of attack on blunt body flying at suborbital speed. Intended as study of feasibility and utility of such calculations, motivated by fact that trim angle of attack at suborbital and higher speeds important aerodynamic parameter for spacecraft reentering atmosphere and for future hypersonic aerospace vehicles.

  18. Bilateral angle closure glaucoma following general anaesthesia.

    PubMed

    Raj, K Mohan; Reddy, P Arun Subhash; Kumar, Vikram Chella

    2015-04-01

    Angle closure glaucoma is one of the ophthalmic emergencies and treatment has to be given at the earliest. It is a rare complication of general anesthesia. A female patient underwent Hysterectomy under general anesthesia. Following this, patient developed bilateral angle closure glaucoma. This patient was treated with antiglaucoma medications followed by YAG laser iridotomy and patient regained vision.

  19. Classification procedure in limited angle tomography system

    SciTech Connect

    Chlewicki, W.; Baniukiewicz, P.; Chady, T.; Brykalski, A.

    2011-06-23

    In this work we propose the use of limited angle reconstruction algorithms combined with a procedure for defect detection and feature evaluation in three dimensions. The procedure consists of the following steps: acquisition of the X-ray projections, approximated limited angle 3D image reconstruction, and image preprocessing and classification.

  20. Mutations in galactosemia

    SciTech Connect

    Reichardt, J.K.V.

    1995-10-01

    This Letter raises four issues concerning two papers on galactosemia published in the March 1995 of the Journal. First, table 2 in the paper by Elsas et al. incorrectly attributes seven galactose-l-phosphate uridyl transferase (GALT) mutations (S135L, L195P, K285N, N314D, R333W, R333G, and K334R). The table also fails to mention that others have reported the same two findings attributed to {open_quotes}Leslie et al.; Elsas et al. and in press{close_quotes} and {open_quotes}Leslie et al.; Elsas et al.{close_quotes} The first finding on the prevalence of the Q188R galactosemia mutation in the G/G Caucasian population has also been described by Ng et al., and the second finding on the correlation of the N314D GALT mutation with the Duarte variant was reported by Lin et al. Second, Elsas et al. suggest that the E203K and N314D mutations may {open_quotes}produce intra-allelic complementation when in cis{close_quotes}. This speculation is supported by the activity data of individual III-2 but is inconsistent with the activities of three other individuals I-1, II-1, and III-1 of the same pedigree. The GALT activity measured in these three individuals suggests a dominant negative effect of E203K in E203K-N314D chromosomes, since they all have less than normal activity. Thus, the preponderance of the data in this paper is at odds with the authors speculation. It is worth recalling that Lin et al. also identified four N314D GALT mutations on 95 galactosemic chromosomes examined. A similar situation also appears to be the case in proband III-1 (with genotype E203K-N314D/IVSC) in the Elsas et al. paper. 9 refs.

  1. Apparent contact angle and contact angle hysteresis on liquid infused surfaces

    NASA Astrophysics Data System (ADS)

    Semprebon, Ciro; McHale, Glen; Kusumaatmaja, Halim

    We theoretically investigate the apparent contact angle and contact angle hysteresis of a droplet placed on a liquid infused surface. We show that the apparent contact angle is not uniquely defined by material parameters, but also has a strong dependence on the relative size between the droplet and its surrounding wetting ridge formed by the infusing liquid. We derive a closed form expression for the contact angle in the limit of vanishing wetting ridge, and compute the correction for small but finite ridge, which corresponds to an effective line tension term. We also predict contact angle hysteresis on liquid infused surfaces generated by the pinning of the contact lines by the surface corrugations. Our analytical expressions for both the apparent contact angle and contact angle hysteresis can be interpreted as `weighted sums' between the contact angles of the infusing liquid relative to the droplet and surrounding gas phases, where the weighting coefficients are given by ratios of the fluid surface tensions.

  2. Apparent contact angle and contact angle hysteresis on liquid infused surfaces.

    PubMed

    Semprebon, Ciro; McHale, Glen; Kusumaatmaja, Halim

    2016-12-21

    We theoretically investigate the apparent contact angle and contact angle hysteresis of a droplet placed on a liquid infused surface. We show that the apparent contact angle is not uniquely defined by material parameters, but also has a dependence on the relative size between the droplet and its surrounding wetting ridge formed by the infusing liquid. We derive a closed form expression for the contact angle in the limit of vanishing wetting ridge, and compute the correction for small but finite ridge, which corresponds to an effective line tension term. We also predict contact angle hysteresis on liquid infused surfaces generated by the pinning of the contact lines by the surface corrugations. Our analytical expressions for both the apparent contact angle and contact angle hysteresis can be interpreted as 'weighted sums' between the contact angles of the infusing liquid relative to the droplet and surrounding gas phases, where the weighting coefficients are given by ratios of the fluid surface tensions.

  3. Nanodrop contact angles from molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Ravipati, Srikanth; Aymard, Benjamin; Yatsyshin, Petr; Galindo, Amparo; Kalliadasis, Serafim

    2016-11-01

    The contact angle between three phases being in thermodynamic equilibrium is highly sensitive to the nature of the intermolecular forces as well as to various fluctuation effects. Determining the Young contact angle of a sessile drop sitting on a substrate from molecular dynamics (MD) simulations is a highly non-trivial task. Most commonly employed methods for finding droplet contact angles from MD simulation data either require large numbers of particles or are system-dependent. We propose a systematic geometry based methodology for extracting the contact angle from simulated sessile droplets by analysing an appropriately coarse-grained density field. To demonstrate the method, we consider Lennard-Jones (LJ) and SPC/E water nanodroplets of different sizes sitting on planar LJ walls. Our results are in good agreement with Young contact angle values computed employing test-area perturbation method.

  4. Investigation of Lightning Rod Shielding Angle

    NASA Astrophysics Data System (ADS)

    Nayel, Mohamed

    This paper studies those parameters affecting the shielding angle of the lightning rod (Franklin Rod) above very tall buildings. It was recommended that the shielding angle of the lightning rod is about 45°∼60°. The downward lightning leader is modeled by using discrete line charges to consider the exponential distribution of charges through the downward leader. The voltage condition used by Rizk is used to investigate the inception of the upward lightning leader. Different air conditions (relative air density and air humidity) are considered for more practical simulation. The influences of lightning parameters and lightning rod height on the shielding angle are studied. The results shows that, lightning leader parameters, lightning rod height and ground slope have series effects on the lightning rod shielding angle. Based on the results, a lightning rod shielding angle for shielding design is recommended to decrease the lightning stroke to the lightning rod.

  5. Reliable measurement of the receding contact angle.

    PubMed

    Korhonen, Juuso T; Huhtamäki, Tommi; Ikkala, Olli; Ras, Robin H A

    2013-03-26

    Surface wettability is usually evaluated by the contact angle between the perimeter of a water drop and the surface. However, this single measurement is not enough for proper characterization, and the so-called advancing and receding contact angles also need to be measured. Measuring the receding contact angle can be challenging, especially for extremely hydrophobic surfaces. We demonstrate a reliable procedure by using the common needle-in-the-sessile-drop method. Generally, the contact line movement needs to be followed, and true receding movement has to be distinguished from "pseudo-movement" occurring before the receding angle is reached. Depending on the contact angle hysteresis, the initial size of the drop may need to be surprisingly large to achieve a reliable result. Although our motivation for this work was the characterization of superhydrophobic surfaces, we also show that this method works universally ranging from hydrophilic to superhydrophobic surfaces.

  6. Contact angle hysteresis of microbead suspensions.

    PubMed

    Waghmare, Prashant R; Mitra, Sushanta K

    2010-11-16

    Microbead suspensions are often used in microfluidic devices for transporting biomolecules. An experimental investigation on the wettability of microbead suspension is presented in this study. The variation in the surface tension and the equilibrium contact angle with the change in the volume fraction of the microbead is presented here. The surface tension of the microbead suspension is measured with the pendant drop technique, whereas the dynamic contact angle measurements, i.e., advancing and receding contact angles, are measured with the sessile drop technique. An equilibrium contact angle of a suspension with particular volume fraction is determined by computing an average over the measured advancing and receding contact angles. It is observed that the surface tension and the equilibrium contact angle determined from advancing and receding contact angles vary with the magnitude of the microbeads volume fraction in the suspension. A decrease in the surface tension with an increase in the volume fraction of the microbead suspension is observed. The advancement and the recession in contact line for dynamic contact angle measurements are achieved with the motorized dosing mechanism. For microbead suspensions, the advancement of the contact line is faster as compared to the recession of the contact line for the same flow rate. The presence of microbeads assists in the advancement and the recession of the contact line of the suspension. A decrease in the equilibrium contact angles with an increase in the microbead suspension volume fraction is observed. Inclusion of microbeads in the suspension increases the wetting capability for the considered combination of the microbead suspension and substrate. Finally, empirical correlations for the surface tension and the contact angle of the suspension as a function of microbead volume fraction are proposed. Such correlations can readily be used to develop mechanistic models for the capillary transport of microbead

  7. Mutators in space: the dynamics of high-mutability clones in a two-patch model.

    PubMed Central

    Travis, E R; Travis, J M J

    2004-01-01

    Clones of bacteria possessing high-mutability rates (or mutators) are being observed in an increasing number of species. In a constant environment most mutations are deleterious, and hence the spontaneous mutation rate is generally low. However, mutators may play an important role in the adaptation of organisms to changing environments. To date, theoretical work has focused on temporal variability in the environment, implicitly assuming that environmental conditions are constant through space. Here, we develop a two-patch model to investigate how spatiotemporal environmental variability and dispersal might influence mutator dynamics. Environmental conditions in each patch fluctuate between two states; the rate of fluctuation varies in each patch at differing phase angles. We find that at low and intermediate rates of fluctuation, an increase in dispersal results in a decrease in the density of mutators. However, at high rates of environmental change, dispersal causes an increase in mutator density. For all frequencies of environmental fluctuation these trends are enhanced as the phase angle approaches 180 degrees. We argue that future work, both empirical and theoretical, is needed to improve our understanding of how spatiotemporal variability impacts on mutator densities and dynamics. PMID:15166173

  8. Survival and Growth of Cottonwood Clones After Angle Planting and Base Angle Treatments

    Treesearch

    W.K. Randall; Harvey E. Kennedy

    1976-01-01

    Presently, commercial cottonwood plantations in the lower Mississippi Valley are established using vertically planted, unrooted cuttings with a flat (90°) base. Neither survival nor first-year growth of a group of six Stoneville clones was improved by angle planting or cutting base angles diagonally. For one clone, survival was significantly better when base angle was...

  9. Investigation of the Booroola (FecB) and Inverdale (FecX(I)) mutations in 21 prolific breeds and strains of sheep sampled in 13 countries.

    PubMed

    Davis, G H; Balakrishnan, L; Ross, I K; Wilson, T; Galloway, S M; Lumsden, B M; Hanrahan, J P; Mullen, M; Mao, X Z; Wang, G L; Zhao, Z S; Zeng, Y Q; Robinson, J J; Mavrogenis, A P; Papachristoforou, C; Peter, C; Baumung, R; Cardyn, P; Boujenane, I; Cockett, N E; Eythorsdottir, E; Arranz, J J; Notter, D R

    2006-03-01

    Twenty-one of the world's prolific sheep breeds and strains were tested for the presence of the FecB mutation of BMPR1B and the FecX(I) mutation of BMP15. The breeds studied were Romanov (2 strains), Finn (2 strains), East Friesian, Teeswater, Blueface Leicester, Hu, Han, D'Man, Chios, Mountain Sheep (three breeds), German Whiteheaded Mutton, Lleyn, Loa, Galician, Barbados Blackbelly (pure and crossbred) and St. Croix. The FecB mutation was found in two breeds, Hu and Han from China, but not in any of the other breeds. The 12 Hu sheep sampled were all homozygous carriers of FecB (FecB(B)/FecB(B)) whereas the sample of 12 Han sheep included all three genotypes (FecB(B)/FecB(B), FecB(B)/FecB+, FecB+/FecB+) at frequencies of 0.33, 0.58 and 0.08, respectively. There was no evidence of FecX(I) in any of the breeds sampled.

  10. Analysis of factors affecting angle ANB.

    PubMed

    Hussels, W; Nanda, R S

    1984-05-01

    Cephalometric analyses based on angular and linear measurements have obvious fallacies, which have been discussed in detail by Moyers and Bookstein. However, the clinical application of such an analysis by the orthodontic profession in treatment planning is widely accepted. Variations of angle ANB are commonly used to determine relative jaw relationships in most of the cephalometric evaluations. Several authors, including points A and B influences angle ANB, as does rotational growth of the upper and lower jaws. In addition, the authors point out that growth in a vertical direction (distance N to B) and an increase of the dental height (distance A to B) may contribute to changes in angle ANB. For a Class I relation (Wits = 0 mm), a mathematical formula has been developed which enables the authors to study the geometric influence of angle ANB caused by the following four effects: (1) rotation of the jaws and/or occlusal plane relative to the anterior cranial base; (2) anteroposterior position of N relative to point B, (3) vertical growth (distance N to B); (4) increase in dental height (distance A to B). It was observed that, contrary to the common belief that an ANB angle of 2 +/- 3.0 degrees is considered normal for a skeletal Class I relation, the calculated values of angle ANB will vary widely with changes in these four controlling factors under the same skeletal Class I conditions (Wits = 0 mm). Therefore, in a case under consideration, angle ANB must be corrected for these geometric effects in order to get a proper perspective of the skeletal discrepancy. This is facilitated by comparing the measured ANB angle with the corresponding ANB angle calculated by a formula for a Class I relationship. The corresponding calculated angle ANB can be taken from the tables which are based upon the formula using the same values for SNB, omega (angle between occlusal plane and anterior cranial base), b (which is distance N to B) and a (dental height measured as perpendicular

  11. Asteroid photometry: Phase-angle effects

    NASA Astrophysics Data System (ADS)

    Belskaya, I.; Shevchenko, V.

    2014-07-01

    We review available observational data on magnitude phase-angle dependencies of asteroids. The number of asteroids, for which good quality phase curves were measured, increases very slowly. At present, the data-set on magnitude-phase dependencies with a good phase-angle coverage and small scatter includes less than one hundred asteroids. Most part of these data is related to the ground-based observations of main-belt asteroids and covered the phase-angle range from 0.3--0.5 deg to 20--25 deg. The phase curves in the wider phase-angle range up to 120--140 deg were measured for ten asteroids observed by space missions and for several near-Earth asteroids. Ground-based and space-based observations are generally mutually consistent. For most of the observed phase-angle ranges, asteroid magnitude phase curves are found to be linear with a noticeable deviation at phase angles smaller than 5--7 deg due to the opposition effect and at phase angles larger than 70-80 deg due to the influence of large-scale surface features. The differences in the phase curves at large phase angles and their influence on the phase integral have not yet been thoroughly investigated. The measured linear phase coefficients of asteroids are in the range of 0.02--0.05 mag/deg. The opposition-effect amplitudes determined relatively to the extrapolation of the linear part of the phase curve do not exceeds 0.4 mag. Relatively small variations of asteroid phase curve parameters require accurate photometric observations and thorough account for lightcurve amplitude to distinguish phase-angle effects. The measured magnitude phase dependencies revealed essential differences in magnitude phase-angle behavior for asteroids of different surface composition both in the linear part and in the opposition effect range (Harris et al. 1989, Belskaya and Shevchenko 2000, Shevchenko et al. 2012). Maximal amplitude of the opposition effect occurs for moderate-albedo S- and M-type asteroids. Low-albedo asteroids

  12. Synonymous mutations frequently act as driver mutations in human cancers.

    PubMed

    Supek, Fran; Miñana, Belén; Valcárcel, Juan; Gabaldón, Toni; Lehner, Ben

    2014-03-13

    Synonymous mutations change the sequence of a gene without directly altering the sequence of the encoded protein. Here, we present evidence that these "silent" mutations frequently contribute to human cancer. Selection on synonymous mutations in oncogenes is cancer-type specific, and although the functional consequences of cancer-associated synonymous mutations may be diverse, they recurrently alter exonic motifs that regulate splicing and are associated with changes in oncogene splicing in tumors. The p53 tumor suppressor (TP53) also has recurrent synonymous mutations, but, in contrast to those in oncogenes, these are adjacent to splice sites and inactivate them. We estimate that between one in two and one in five silent mutations in oncogenes have been selected, equating to ~6%- 8% of all selected single-nucleotide changes in these genes. In addition, our analyses suggest that dosage-sensitive oncogenes have selected mutations in their 3' UTRs.

  13. Creation of the π angle standard for the flat angle measurements

    NASA Astrophysics Data System (ADS)

    Giniotis, V.; Rybokas, M.

    2010-07-01

    Angle measurements are based mainly on multiangle prisms - polygons with autocollimators, rotary encoders fo high accuracy and circular scales as the standards of the flat angle. Traceability of angle measurements is based on the standard of the plane angle - prism (polygon) calibrated at an appropriate accuracy. Some metrological institutions have established their special test benches (comparators) equipped with circular scales or rotary encoders of high accuracy and polygons with autocollimators for angle calibration purposes. Nevertheless, the standard (etalon) of plane angle - polygon has many restrictions for the transfer of angle unit - radian (rad) and other units of angle. It depends on the number of angles formed by the flat sides of the polygon that is restricted by technological and metrological difficulties related to the production and accuracy determination of the polygon. A possibility to create the standard of the angle equal to π rad or half the circle or the full angle is proposed. It can be created by the circular scale with the rotation axis of very high accuracy and two precision reading instruments, usually, photoelectric microscopes (PM), placed on the opposite sides of the circular scale using the special alignment steps. A great variety of angle units and values can be measured and its traceability ensured by applying the third PM on the scale. Calibration of the circular scale itself and other scale or rotary encoder as well is possible using the proposed method with an implementation of π rad as the primary standard angle. The method proposed enables to assure a traceability of angle measurements at every laboratory having appropriate environment and reading instruments of appropriate accuracy together with a rotary table with the rotation axis of high accuracy - rotation trajectory (runout) being in the range of 0.05 μm. Short information about the multipurpose angle measurement test bench developed is presented.

  14. Stratospheric Ozone Climatology from Lidar Measurements at Table Mountain (34.0 deg N, 117.7 deg W) and Mauna Loa (19.5 deg N, 155.6 deg W)

    NASA Technical Reports Server (NTRS)

    Leblanc, T.; McDermid, I. S.

    2000-01-01

    Using more than 1600 nighttime profiles obtained by the JPL differential absorption lidars (DIAL) located at Table Mountain Facility (TMF, 34.4 N) and Mauna Loa Observatory (MLO, 19.5 N) is presented in this paper. These two systems have been providing high-resolution vertical profiles of ozone number density between 15-50 km, several nights a week since 1989 (TMF) and 1993 (MLO). The climatology presented here is typical of early night ozone values with only a small influence of the Pinatubo aerosols and the 11-year solar cycle. The observed seasonal and vertical structure of the ozone concentration at TMF is consistent with that typical of mid- to subtropical latitudes. A clear annual cycle in opposite phase below and above the ozone concentration peak is observed. The observed winter maximum below the ozone peak is associated with a maximum day-to-day variability, typical of a dynamically driven lower stratosphere. The maximum concentration observed in summer above the ozone peak emphasizes the more dominant role of photochemistry. Unlike TMF, the ozone concentration observed at MLO tends to be higher during the summer months and lower during the winter months throughout the entire stratospheric ozone layer. Only a weak signature of the extra-tropical latitudes is observed near 19-20 km, with a secondary maximum in late winter. The only large variability observed at MLO is associated with the natural variability of the tropical tropopause.

  15. Pitch angle variations in spiral galaxies

    NASA Astrophysics Data System (ADS)

    Savchenko, S. S.; Reshetnikov, V. P.

    2013-12-01

    We present a detailed photometric study and measurements of spiral arm pitch angles for a sample of 50 non-barred or weakly barred grand-design spiral galaxies selected from Sloan Digital Sky Survey. In order to find pitch angles, we used a new method based on the window Fourier analysis of their images. This method allows us not only to infer the average pitch angle, but to obtain its value as a function of galactocentric radius as well. Our main results are as follows: (1) Spiral arms of most galaxies cannot be described by a single value of the pitch angle. About 2/3 of galaxies demonstrate pitch angle variations exceeding 20 per cent. In most galaxies in the sample their pitch angle decreases by increasing the distance from the centre. (2) Pitch angle variations correlate with the properties of galaxies - with the shape of the surface brightness distribution (envelope-type or truncated disc), and with the sign of stellar disc colour gradient. (3) More luminous and bright bulges produce more tightly wound spiral arms, that is in agreement with current models for spiral arms formation.

  16. Contact angle hysteresis, adhesion, and marine biofouling.

    PubMed

    Schmidt, Donald L; Brady, Robert F; Lam, Karen; Schmidt, Dale C; Chaudhury, Manoj K

    2004-03-30

    Adhesive and marine biofouling release properties of coatings containing surface-oriented perfluoroalkyl groups were investigated. These coatings were prepared by cross-linking a copolymer of 1H,1H,2H,2H-heptadecafluorodecyl acrylate and acrylic acid with a copolymer of poly(2-isopropenyl-2-oxazoline) and methyl methacrylate at different molar ratios. The relationships between contact angle, contact angle hysteresis, adhesion, and marine biofouling were studied. Adhesion was determined by peel tests using pressure-sensitive adhesives. The chemical nature of the surfaces was studied by using X-ray photoelectron spectroscopy. Resistance to marine biofouling of an optimized coating was studied by immersion in seawater and compared to previous, less optimized coatings. The adhesive release properties of the coatings did not correlate well with the surface energies of the coatings estimated from the static and advancing contact angles nor with the amount of fluorine present on the surface. The adhesive properties of the surfaces, however, show a correlation with water receding contact angles and contact angle hysteresis (or wetting hysteresis) resulting from surface penetration and surface reconstruction. Coatings having the best release properties had both the highest cross-link density and the lowest contact angle hysteresis. An optimized coating exhibited unprecedented resistance to marine biofouling. Water contact angle hysteresis appears to correlate with marine biofouling resistance.

  17. Bayesian AVO inversion with consistent angle parameters

    NASA Astrophysics Data System (ADS)

    Li, Chao; Zhang, Jinmiao; Zhu, Zhenyu

    2017-04-01

    Amplitude versus offset (AVO) inversion has been extensively used in seismic exploration. Many different elastic parameters can be inverted by incorporating corresponding reflection coefficient approximations. Although efforts have been made to improve the accuracy of AVO inversions for years, there is still one problem that has long been ignored. In most methods, the angle in the approximation and the angle used in seismic angle gather extractions are not the same one. This inconsistency leads to inaccurate inversion results. In this paper, a Bayesian AVO inversion method with consistent angles is proposed to solve the problem and improve inversion accuracy. Firstly, a linearized P-wave reflection coefficient approximation with consistent angles is derived based on angle replacements. The equivalent form of the approximation in terms moduli and density is derived so that moduli can be inverted for reservoir characterization. Then, by convoluting it with seismic wavelets as the forward solver, a probabilistic prestack seismic inversion method with consistent angles is presented in a Bayesian scheme. The synthetic test proves that the accuracy of this method is higher than the traditional one. The real data example shows that the inversion result fits better with well log interpretation data, which verifies the feasibility of the proposed method.

  18. Globographic visualisation of three dimensional joint angles.

    PubMed

    Baker, Richard

    2011-07-07

    Three different methods for describing three dimensional joint angles are commonly used in biomechanics. The joint coordinate system and Cardan/Euler angles are conceptually quite different but are known to represent the same underlying mathematics. More recently the globographic method has been suggested as an alternative and this has proved particularly attractive for the shoulder joint. All three methods can be implemented in a number of ways leading to a choice of angle definitions. Very recently Rab has demonstrated that the globographic method is equivalent to one implementation of the joint coordinate system. This paper presents a rigorous analysis of the three different methods and proves their mathematical equivalence. The well known sequence dependence of Cardan/Euler is presented as equivalent to configuration dependence of the joint coordinate system and orientation dependence of globographic angles. The precise definition of different angle sets can be easily visualised using the globographic method using analogues of longitude, latitude and surface bearings with which most users will already be familiar. The method implicitly requires one axis of the moving segment to be identified as its principal axis and this can be extremely useful in helping define the most appropriate angle set to describe the orientation of any particular joint. Using this technique different angle sets are considered to be most appropriate for different joints and examples of this for the hip, knee, ankle, pelvis and axial skeleton are outlined.

  19. Why does acute primary angle closure happen? Potential risk factors for acute primary angle closure.

    PubMed

    Zhang, Xiulan; Liu, Yaoming; Wang, Wei; Chen, Shida; Li, Fei; Huang, Wenbin; Aung, Tin; Wang, Ningli

    Acute primary angle closure is an ocular emergency and requires immediate management to avoid blindness. Narrow anterior chamber angle, advanced age, female gender, and Asian ethnic background are considered risk factors for acute primary angle closure. The predictive power of these factors is, however, relatively poor, and many questions remain unanswered because acute primary angle closure eventually develops in only a relatively small proportion of anatomically predisposed eyes. We summarize the potential roles of various factors in the pathogenesis of acute primary angle closure. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Phase-angle controller for Stirling engines

    NASA Technical Reports Server (NTRS)

    Mcdougal, A. R. (Inventor)

    1980-01-01

    An actuator includes a restraint link adapted to be connected with a pivotal carrier arm for a force transfer gear interposed between the crankshaft for an expander portion of a Stirling engine and a crankshaft for the displacer portion of the engine. The restraint link is releasably trapped hydraulic fluid for selectively establishing a phase angle relationship between the crankshaft. A second embodiment incorporates a hydraulic coupler for use in varying the phase angle of gear-coupled crank fpr a Stirling engine whereby phase angle changes are obtainable.

  1. Wide-angle vision for road views

    NASA Astrophysics Data System (ADS)

    Huang, F.; Fehrs, K.-K.; Hartmann, G.; Klette, R.

    2013-03-01

    The field-of-view of a wide-angle image is greater than (say) 90 degrees, and so contains more information than available in a standard image. A wide field-of-view is more advantageous than standard input for understanding the geometry of 3D scenes, and for estimating the poses of panoramic sensors within such scenes. Thus, wide-angle imaging sensors and methodologies are commonly used in various road-safety, street surveillance, street virtual touring, or street 3D modelling applications. The paper reviews related wide-angle vision technologies by focusing on mathematical issues rather than on hardware.

  2. OXPHOS mutations and neurodegeneration

    PubMed Central

    Koopman, Werner J H; Distelmaier, Felix; Smeitink, Jan AM; Willems, Peter HGM

    2013-01-01

    Mitochondrial oxidative phosphorylation (OXPHOS) sustains organelle function and plays a central role in cellular energy metabolism. The OXPHOS system consists of 5 multisubunit complexes (CI–CV) that are built up of 92 different structural proteins encoded by the nuclear (nDNA) and mitochondrial DNA (mtDNA). Biogenesis of a functional OXPHOS system further requires the assistance of nDNA-encoded OXPHOS assembly factors, of which 35 are currently identified. In humans, mutations in both structural and assembly genes and in genes involved in mtDNA maintenance, replication, transcription, and translation induce ‘primary' OXPHOS disorders that are associated with neurodegenerative diseases including Leigh syndrome (LS), which is probably the most classical OXPHOS disease during early childhood. Here, we present the current insights regarding function, biogenesis, regulation, and supramolecular architecture of the OXPHOS system, as well as its genetic origin. Next, we provide an inventory of OXPHOS structural and assembly genes which, when mutated, induce human neurodegenerative disorders. Finally, we discuss the consequences of mutations in OXPHOS structural and assembly genes at the single cell level and how this information has advanced our understanding of the role of OXPHOS dysfunction in neurodegeneration. PMID:23149385

  3. Mutator and MULE Transposons.

    PubMed

    Lisch, Damon

    2015-04-01

    The Mutator system of transposable elements (TEs) is a highly mutagenic family of transposons in maize. Because they transpose at high rates and target genic regions, these transposons can rapidly generate large numbers of new mutants, which has made the Mutator system a favored tool for both forward and reverse mutagenesis in maize. Low copy number versions of this system have also proved to be excellent models for understanding the regulation and behavior of Class II transposons in plants. Notably, the availability of a naturally occurring locus that can heritably silence autonomous Mutator elements has provided insights into the means by which otherwise active transposons are recognized and silenced. This chapter will provide a review of the biology, regulation, evolution and uses of this remarkable transposon system, with an emphasis on recent developments in our understanding of the ways in which this TE system is recognized and epigenetically silenced as well as recent evidence that Mu-like elements (MULEs) have had a significant impact on the evolution of plant genomes.

  4. Crystallographic and mutational analyses of cystathionine β-synthase in the H2 S-synthetic gene cluster in Lactobacillus plantarum.

    PubMed

    Matoba, Yasuyuki; Yoshida, Tomoki; Izuhara-Kihara, Hisae; Noda, Masafumi; Sugiyama, Masanori

    2017-01-27

    Cystathionine β-synthase (CBS) catalyzes the formation of l-cystathionine from l-serine and l-homocysteine. The resulting l-cystathionine is decomposed into l-cysteine, ammonia, and α-ketobutylic acid by cystathionine γ-lyase (CGL). This reverse transsulfuration pathway, which is catalyzed by both enzymes, mainly occurs in eukaryotic cells. The eukaryotic CBS and CGL have recently been recognized as major physiological enzymes for the generation of hydrogen sulfide (H2 S). In some bacteria, including the plant-derived lactic acid bacterium Lactobacillus plantarum, the CBS- and CGL-encoding genes form a cluster in their genomes. Inactivation of these enzymes has been reported to suppress H2 S production in bacteria; interestingly, it has been shown that H2 S suppression increases their susceptibility to various antibiotics. In the present study, we characterized the enzymatic properties of the L. plantarum CBS, whose amino acid sequence displays a similarity with those of O-acetyl-l-serine sulfhydrylase (OASS) that catalyzes the generation of l-cysteine from O-acetyl-l-serine (l-OAS) and H2 S. The L. plantarum CBS shows l-OAS- and l-cysteine-dependent CBS activities together with OASS activity. Especially, it catalyzes the formation of H2 S in the presence of l-cysteine and l-homocysteine, together with the formation of l-cystathionine. The high affinity toward l-cysteine as a first substrate and tendency to use l-homocysteine as a second substrate might be associated with its enzymatic ability to generate H2 S. Crystallographic and mutational analyses of CBS indicate that the Ala70 and Glu223 residues at the substrate binding pocket are important for the H2 S-generating activity.

  5. Mutation Rates among RNA Viruses

    NASA Astrophysics Data System (ADS)

    Drake, John W.; Holland, John J.

    1999-11-01

    The rate of spontaneous mutation is a key parameter in modeling the genetic structure and evolution of populations. The impact of the accumulated load of mutations and the consequences of increasing the mutation rate are important in assessing the genetic health of populations. Mutation frequencies are among the more directly measurable population parameters, although the information needed to convert them into mutation rates is often lacking. A previous analysis of mutation rates in RNA viruses (specifically in riboviruses rather than retroviruses) was constrained by the quality and quantity of available measurements and by the lack of a specific theoretical framework for converting mutation frequencies into mutation rates in this group of organisms. Here, we describe a simple relation between ribovirus mutation frequencies and mutation rates, apply it to the best (albeit far from satisfactory) available data, and observe a central value for the mutation rate per genome per replication of μ g≈ 0.76. (The rate per round of cell infection is twice this value or about 1.5.) This value is so large, and ribovirus genomes are so informationally dense, that even a modest increase extinguishes the population.

  6. Septin Mutations in Human Cancers

    PubMed Central

    Angelis, Dimitrios; Spiliotis, Elias T.

    2016-01-01

    Septins are GTP-binding proteins that are evolutionarily and structurally related to the RAS oncogenes. Septin expression levels are altered in many cancers and new advances point to how abnormal septin expression may contribute to the progression of cancer. In contrast to the RAS GTPases, which are frequently mutated and actively promote tumorigenesis, little is known about the occurrence and role of septin mutations in human cancers. Here, we review septin missense mutations that are currently in the Catalog of Somatic Mutations in Cancer (COSMIC) database. The majority of septin mutations occur in tumors of the large intestine, skin, endometrium and stomach. Over 25% of the annotated mutations in SEPT2, SEPT4, and SEPT9 belong to large intestine tumors. From all septins, SEPT9 and SEPT14 exhibit the highest mutation frequencies in skin, stomach and large intestine cancers. While septin mutations occur with frequencies lower than 3%, recurring mutations in several invariant and highly conserved amino acids are found across different septin paralogs and tumor types. Interestingly, a significant number of these mutations occur in the GTP-binding pocket and septin dimerization interfaces. Future studies may determine how these somatic mutations affect septin structure and function, whether they contribute to the progression of specific cancers and if they could serve as tumor-specific biomarkers. PMID:27882315

  7. Estimation of spontaneous mutation rates.

    PubMed

    Natarajan, Loki; Berry, Charles C; Gasche, Christoph

    2003-09-01

    Spontaneous or randomly occurring mutations play a key role in cancer progression. Estimation of the mutation rate of cancer cells can provide useful information about the disease. To ascertain these mutation rates, we need mathematical models that describe the distribution of mutant cells. In this investigation, we develop a discrete time stochastic model for a mutational birth process. We assume that mutations occur concurrently with mitosis so that when a nonmutant parent cell splits into two progeny, one of these daughter cells could carry a mutation. We propose an estimator for the mutation rate and investigate its statistical properties via theory and simulations. A salient feature of this estimator is the ease with which it can be computed. The methods developed herein are applied to a human colorectal cancer cell line and compared to existing continuous time models.

  8. Mucopolysaccharidosis IVA mutations in Chinese patients: 16 novel mutations.

    PubMed

    Wang, Zheng; Zhang, Weimin; Wang, Yun; Meng, Yan; Su, Liang; Shi, Huiping; Huang, Shangzhi

    2010-08-01

    Mucopolysaccharidosis IVA (MPS IVA; Morquio A syndrome) is a lysosomal storage disease caused by deficiency of N-acetylgalactosamine-6-sulfatase (GALNS) and transmitted as an autosomal recessive trait. This is the first systematic mutation screen in Chinese MPS IVA patients. Mutation detections in 24 unrelated Chinese MPS IVA patients were performed by PCR and direct sequencing of exons or the mRNA of GALNS. A total of 42 mutant alleles were identified, belonging to 27 different mutations. Out of the 27 mutations, 16 were novel, including 2 splicing mutations (c.567-1G>T and c.634-1G>A), 2 nonsense mutations (p.W325X and p.Q422X) and 12 missense mutations (p.T88I, p.H142R, p.P163H, p.G168L, p.H236D, p.N289S, p.T312A, p.G316V, p.A324E, p.L366P, p.Q422K and p.F452L). p.G340D was found to be a common mutation in the Chinese MPS IVA patients, accounting for 16.7% of the total number of mutant alleles. The results show that the mutations in Chinese MPS IVA patients are also family specific but have a different mutation spectrum as compared to those of other populations.

  9. Calreticulin Mutations in Myeloproliferative Neoplasms

    PubMed Central

    Lavi, Noa

    2014-01-01

    With the discovery of the JAK2V617F mutation in patients with Philadelphia chromosome-negative (Ph−) myeloproliferative neoplasms (MPNs) in 2005, major advances have been made in the diagnosis of MPNs, in understanding of their pathogenesis involving the JAK/STAT pathway, and finally in the development of novel therapies targeting this pathway. Nevertheless, it remains unknown which mutations exist in approximately one-third of patients with non-mutated JAK2 or MPL essential thrombocythemia (ET) and primary myelofibrosis (PMF). At the end of 2013, two studies identified recurrent mutations in the gene encoding calreticulin (CALR) using whole-exome sequencing. These mutations were revealed in the majority of ET and PMF patients with non-mutated JAK2 or MPL but not in polycythemia vera patients. Somatic 52-bp deletions (type 1 mutations) and recurrent 5-bp insertions (type 2 mutations) in exon 9 of the CALR gene (the last exon encoding the C-terminal amino acids of the protein calreticulin) were detected and found always to generate frameshift mutations. All detected mutant calreticulin proteins shared a novel amino acid sequence at the C-terminal. Mutations in CALR are acquired early in the clonal history of the disease, and they cause activation of JAK/STAT signaling. The CALR mutations are the second most frequent mutations in Ph− MPN patients after the JAK2V617F mutation, and their detection has significantly improved the diagnostic approach for ET and PMF. The characteristics of the CALR mutations as well as their diagnostic, clinical, and pathogenesis implications are discussed in this review. PMID:25386351

  10. Reconditioning of Cassini Narrow-Angle Camera

    NASA Image and Video Library

    2002-07-23

    These five images of single stars, taken at different times with the narrow-angle camera on NASA Cassini spacecraft, show the effects of haze collecting on the camera optics, then successful removal of the haze by warming treatments.

  11. High angle conveyors climb to the top

    SciTech Connect

    Mitchell, J.J.

    1984-11-01

    A major objective in the design of a storage facility is to have the least handling over the shortest distances and to optimize land usage by attaining the highest tons-per-acre value. The advantages of high angle conveyors become apparent when the height of lift is compared with the surface area. High angle conveyors achieve high capacities in the least amount of space. Continental Conveyor and Equipment Co., has conducted several studies that evaluate the technical and economic feasibility of using high angle conveyors in conveyor systems. A few of the high angle conveying concepts reviewed are the bucket ladder or pocket belt, belts with partitions or fin belt, and the sandwich type belt conveyors.

  12. High angle conveyors climb to the top

    SciTech Connect

    Mitchell, J.J.

    1984-11-01

    Descriptions are presented of various types of high angle conveyors, including pocket belt, fin belt, sandwich belt, snake sandwich conveyor, mechanically pressed sandwich conveyor, and pneumatically pressed sandwich conveyors. 10 references.

  13. SOLARMAX/Electron Pitch Angle Anisotropy Distributions

    NASA Technical Reports Server (NTRS)

    McKenzie, David L.; Anderson, Phillip C.

    2002-01-01

    This final research report summarizes the scientific work performed by The Aerospace Corporation on SOLARMAX/Electron Pitch Angle Anisotropy Distributions. The period of performance was from June 1, 2000 to December 31, 2001.

  14. Angle measurement with laser feedback instrument.

    PubMed

    Chen, Wenxue; Zhang, Shulian; Long, Xingwu

    2013-04-08

    An instrument for angle measurement based on laser feedback has been designed. The measurement technique is based on the principle that when a wave plate placed into a feedback cavity rotates, its phase retardation varies. Phase retardation is a function of the rotating angle of the wave plate. Hence, the angle can be converted to phase retardation. The phase retardation is measured at certain characteristic points identified in the laser outputting curve that are then modulated by laser feedback. The angle of a rotating object can be measured if it is connected to the wave plate. The main advantages of this instrument are: high resolution, compact, flexible, low cost, effective power, and fast response.

  15. A Distance and Angle Similarity Measure Method.

    ERIC Educational Resources Information Center

    Zhang, Jin; Korfhage, Robert R.

    1999-01-01

    Discusses similarity measures that are used in information retrieval to improve precision and recall ratios and presents a combined vector-based distance and angle measure to make similarity measurement more scientific and accurate. Suggests directions for future research. (LRW)

  16. Low-angle optical vortex coronagraphic scatterometer.

    PubMed

    Wan, Lingyu; Ruane, Garreth J; Swartzlander, Grover A

    2016-11-01

    The important, but difficult-to-measure zero and low-angle scattering spectrum, as well as the broader angular spectrum, was obtained by use of an optical vortex coronagraphic scatterometer (patent pending). The experimental measurements agreed well with the predictions from the Mie scattering theory. High contrast discrimination allowed us to remove the unscattered coherent illumination, revealing a low-angle superimposed scattered signal.

  17. Eliminating Deadbands In Resistive Angle Sensors

    NASA Technical Reports Server (NTRS)

    Salomon, Phil M.; Allen, Russell O.; Marchetto, Carl A.

    1992-01-01

    Proposed shaft-angle-measuring circuit provides continuous indication of angle of rotation from 0 degree to 360 degrees. Sensing elements are two continuous-rotation potentiometers, and associated circuitry eliminates deadband that occurs when wiper contact of potentiometer crosses end contacts near 0 degree position of circular resistive element. Used in valve-position indicator or similar device in which long operating life and high angular precision not required.

  18. Solar Cell Angle of Incidence Corrections

    NASA Technical Reports Server (NTRS)

    Burger, Dale R.; Mueller, Robert L.

    1995-01-01

    The Mars Pathfinder mission has three different solar arrays each of which sees changes in incidence angle during normal operation. When solar array angle of incidence effects was researched little published data was found. The small amount of-published data created a need to obtain and evaluate such data. The donation of the needed data, which was taken in the fall of 1994, was a major factor in the preparation of this paper.

  19. Contact angle hysteresis on superhydrophobic stripes.

    PubMed

    Dubov, Alexander L; Mourran, Ahmed; Möller, Martin; Vinogradova, Olga I

    2014-08-21

    We study experimentally and discuss quantitatively the contact angle hysteresis on striped superhydrophobic surfaces as a function of a solid fraction, ϕS. It is shown that the receding regime is determined by a longitudinal sliding motion of the deformed contact line. Despite an anisotropy of the texture the receding contact angle remains isotropic, i.e., is practically the same in the longitudinal and transverse directions. The cosine of the receding angle grows nonlinearly with ϕS. To interpret this we develop a theoretical model, which shows that the value of the receding angle depends both on weak defects at smooth solid areas and on the strong defects due to the elastic energy of the deformed contact line, which scales as ϕS(2)lnϕS. The advancing contact angle was found to be anisotropic, except in a dilute regime, and its value is shown to be determined by the rolling motion of the drop. The cosine of the longitudinal advancing angle depends linearly on ϕS, but a satisfactory fit to the data can only be provided if we generalize the Cassie equation to account for weak defects. The cosine of the transverse advancing angle is much smaller and is maximized at ϕS ≃ 0.5. An explanation of its value can be obtained if we invoke an additional energy due to strong defects in this direction, which is shown to be caused by the adhesion of the drop on solid sectors and is proportional to ϕS(2). Finally, the contact angle hysteresis is found to be quite large and generally anisotropic, but it becomes isotropic when ϕS ≤ 0.2.

  20. Particle chaos and pitch angle scattering

    NASA Technical Reports Server (NTRS)

    Burkhart, G. R.; Dusenbery, P. B.; Speiser, T. W.

    1995-01-01

    Pitch angle scattering is a factor that helps determine the dawn-to-dusk current, controls particle energization, and it has also been used as a remote probe of the current sheet structure. Previous studies have interpreted their results under the exception that randomization will be greatest when the ratio of the two timescales of motion (gyration parallel to and perpendicular to the current sheet) is closet to one. Recently, the average expotential divergence rate (AEDR) has been calculated for particle motion in a hyperbolic current sheet (Chen, 1992). It is claimed that this AEDR measures the degree of chaos and therefore may be thought to measure the randomization. In contrast to previous expectations, the AEDR is not maximized when Kappa is approximately equal to 1 but instead increases with decreasing Kappa. Also contrary to previous expectations, the AEDR is dependent upon the parameter b(sub z). In response to the challenge to previous expectations that has been raised by this calculation of the AEDR, we have investigated the dependence of a measure of particle pitch angle scattering on both the parameters Kappa and b(sub z). We find that, as was previously expected, particle pitch angle scattering is maximized near Kappa = 1 provided that Kappa/b(sub z) greater than 1. In the opposite regime, Kappa/b(sub z) less than 1, we find that particle pitch angle scattering is still largest when the two timescales are equal, but the ratio of the timescales is proportional to b(sub z). In this second regime, particle pitch angle scattering is not due to randomization, but is instead due to a systematic pitch angle change. This result shows that particle pitch angle scattering need not be due to randomization and indicates how a measure of pitch angle scattering can exhibit a different behavior than a measure of chaos.

  1. Nucleation of small-angle boundaries

    SciTech Connect

    Nabarro, F.R.N. |; Wilsdorf, D.K.

    1996-12-01

    The internal stresses induced by the strain gradients in an array of lattice cells delineated by low-angle dislocation boundaries are partially relieved by the creation of new low-angle boundaries. This is shown to be a first-order transition, the new boundaries having finite misorientations. The calculated misorientations both of the new boundaries and of the existing boundaries which provoke the transition agree well with observations.

  2. Angle only tracking with particle flow filters

    NASA Astrophysics Data System (ADS)

    Daum, Fred; Huang, Jim

    2011-09-01

    We show the results of numerical experiments for tracking ballistic missiles using only angle measurements. We compare the performance of an extended Kalman filter with a new nonlinear filter using particle flow to compute Bayes' rule. For certain difficult geometries, the particle flow filter is an order of magnitude more accurate than the EKF. Angle only tracking is of interest in several different sensors; for example, passive optics and radars in which range and Doppler data are spoiled by jamming.

  3. Neutron spin echo scattering angle measurement (SESAME)

    SciTech Connect

    Pynn, R.; Fitzsimmons, M.R.; Fritzsche, H.; Gierlings, M.; Major, J.; Jason, A.

    2005-05-15

    We describe experiments in which the neutron spin echo technique is used to measure neutron scattering angles. We have implemented the technique, dubbed spin echo scattering angle measurement (SESAME), using thin films of Permalloy electrodeposited on silicon wafers as sources of the magnetic fields within which neutron spins precess. With 30-{mu}m-thick films we resolve neutron scattering angles to about 0.02 deg. with neutrons of 4.66 A wavelength. This allows us to probe correlation lengths up to 200 nm in an application to small angle neutron scattering. We also demonstrate that SESAME can be used to separate specular and diffuse neutron reflection from surfaces at grazing incidence. In both of these cases, SESAME can make measurements at higher neutron intensity than is available with conventional methods because the angular resolution achieved is independent of the divergence of the neutron beam. Finally, we discuss the conditions under which SESAME might be used to probe in-plane structure in thin films and show that the method has advantages for incident neutron angles close to the critical angle because multiple scattering is automatically accounted for.

  4. Harmonic phase angles used for nanoparticle sensing.

    PubMed

    Shi, Yipeng; Khurshid, Hafsa; Ness, Dylan B; Weaver, John B

    2017-10-04

    A series of techniques have been developed to use magnetic nanoparticles as biosensors to characterize their local microenvironment. Two approaches have been used to obtain quantitative information: model based approaches and scaling based approaches. We have favored scaling based approaches, because approximations made in models can lead to limitations in the accuracy. Currently all the scaling approaches use harmonic ratios to retrieve physical parameters like temperature, viscosity and relaxation time. In this work, we showed that the phase angle of the signal at a single harmonic frequency is an alternative to the ratio. The phase angle is nanoparticle density-independent, and can be used to improve sensitivity, enabling us to measure smaller biomedical effects. With the phase angle as an example, we showed that scaling methods are general and do not depend on specific approximations. We showed that the same scaling techniques can be used with both the phase angle and harmonic ratio because they both depend on the same combinations of physical parameters. Using the phase angle improves the precision and using the combination of phase angles and harmonic ratio provides the best precision.

  5. Pressure dependence of the contact angle.

    PubMed

    Wu, Jiyu; Farouk, T; Ward, C A

    2007-06-07

    When a liquid and its vapor contact a smooth, homogeneous surface, Gibbsian thermodynamics indicates that the contact angle depends on the pressure at the three-phase line of an isothermal system. When a recently proposed adsorption isotherm for a solid-vapor interface is combined with the equilibrium conditions and the system is assumed to be in a cylinder where the liquid-vapor interface can be approximated as spherical, the contact-angle-pressure relation can be made explicit. It indicates that a range of contact angles can be observed on a smooth homogeneous surface by changing the pressure at the three-phase line, but it also indicates that the adsorption at the solid-liquid interface is negative, and leads to the prediction that the contact angle increases with pressure. The predicted dependence of the contact angle on pressure is investigated experimentally in a system that has an independent mechanism for determining when thermodynamic equilibrium is reached. The predictions are in agreement with the measurements. The results provide a possible explanation for contact angle hysteresis.

  6. Does gallbladder angle affect gallstone formation?

    PubMed Central

    Sanal, Bekir; Korkmaz, Mehmet; Zeren, Sezgin; Can, Fatma; Elmali, Ferhan; Bayhan, Zulfu

    2016-01-01

    Introduction Morphology of gallbladder varies considerably from person to person. We believe that one of the morphological variations of gallbladder is the “gallbladder angle”. Gallbladder varies also in “angle”, which, to the best of our knowledge, has never been investigated before. The purpose of this study was to investigate the impact of gallbladder angle on gallstone formation. Methods in this study, 1075 abdominal computed tomography (CT) images were retrospectively examined. Patients with completely normal gallbladders were selected. Among these patients, those with both abdominal ultrasound and blood tests were identified in the hospital records and included in the study. Based on the findings of the ultrasound scans, patients were divided into two groups as patients with gallstones and patients without gallstones. Following the measurement of gallbladder angles on the CT images, the groups were statistically evaluated. Results The gallbladder angle was smaller in patients with gallstones (49 ± 21 degrees and 53 ± 19 degrees) and the gallbladder with larger angle was 1.015 (1/0.985) times lower the risk of gallstone formation. However, these were not statistically significant (p>0,05). Conclusion A more vertically positioned gallbladder does not affect gallstone formation. However, a smaller gallbladder angle may facilitate gallstone formation in patients with the risk factors. Gallstones perhaps more easily and earlier develop in gallbladders with a smaller angle. PMID:27795762

  7. Modelling PTB's spatial angle autocollimator calibrator

    NASA Astrophysics Data System (ADS)

    Kranz, Oliver; Geckeler, Ralf D.; Just, Andreas; Krause, Michael

    2013-05-01

    The accurate and traceable form measurement of optical surfaces has been greatly advanced by a new generation of surface profilometers which are based on the reflection of light at the surface and the measurement of the reflection angle. For this application, high-resolution electronic autocollimators provide accurate and traceable angle metrology. In recent years, great progress has been made at the Physikalisch-Technische Bundesanstalt (PTB) in autocollimator calibration. For an advanced autocollimator characterisation, a novel calibration device has been built up at PTB: the Spatial Angle Autocollimator Calibrator (SAAC). The system makes use of an innovative Cartesian arrangement of three autocollimators (two reference autocollimators and the autocollimator to be calibrated), which allows a precise measurement of the angular orientation of a reflector cube. Each reference autocollimator is sensitive primarily to changes in one of the two relevant tilt angles, whereas the autocollimator to be calibrated is sensitive to both. The distance between the reflector cube and the autocollimator to be calibrated can be varied flexibly. In this contribution, we present the SAAC and aspects of the mathematical modelling of the system for deriving analytical expressions for the autocollimators' angle responses. These efforts will allow advancing the form measurement substantially with autocollimator-based profilometers and approaching fundamental measurement limits. Additionally, they will help manufacturers of autocollimators to improve their instruments and will provide improved angle measurement methods for precision engineering.

  8. Management of Primary Angle-Closure Glaucoma.

    PubMed

    Lai, Jimmy; Choy, Bonnie N K; Shum, Jennifer W H

    2016-01-01

    Primary angle-closure glaucoma (PACG) is a progressive optic nerve degeneration and is defined as a glaucomatous optic neuropathy with associated characteristic enlargement of optic disc cupping and visual field loss that is secondary to ocular hypertension caused by closure of the drainage angle. Angle closure is caused by appositional approximation or adhesion between the iris and the trabecular meshwork. The main treatment strategy for PACG lies in the reduction of intraocular pressure, reopening of the closed angle, and possible prevention of further angle closure. There is no universally agreed best surgical treatment for PACG. Trabeculectomy, goniosynechialysis (GSL), glaucoma implant, and cyclodestructive procedures are effective surgical options. Each of them plays an important role in the management of PACG with its own pros and cons. Accumulating evidence is available to show the effectiveness of visually significant and visually nonsignificant cataract extraction in the treatment of PACG. Trabeculectomy and GSL are often combined with cataract extraction, which may offer additional pressure control benefits to patients with PACG. This review article will discuss laser peripheral iridotomy, argon laser peripheral iridoplasty, and surgeries such as GSL, phacoemulsification, and phaco plus glaucoma surgeries that lower intraocular pressure and also alter the anterior segment and/or drainage angle anatomy. Currently, glaucoma implants and cyclodestruction are mainly reserved for PACG patients who have failed previous filtering operations. Their role as initial surgical treatment for PACG will not be discussed.

  9. Sharper angle, higher risk? The effect of cutting angle on knee mechanics in invasion sport athletes.

    PubMed

    Schreurs, Mervin J; Benjaminse, Anne; Lemmink, Koen A P M

    2017-08-24

    Cutting is an important skill in team-sports, but unfortunately is also related to non-contact ACL injuries. The purpose was to examine knee kinetics and kinematics at different cutting angles. 13 males and 16 females performed cuts at different angles (45°, 90°, 135° and 180°) at maximum speed. 3D kinematics and kinetics were collected. To determine differences across cutting angles (45°, 90°, 135° and 180°) and sex (female, male), a 4×2 repeated measures ANOVA was conducted followed by post hoc comparisons (Bonferroni) with alpha level set at α≤0.05a priori. At all cutting angles, males showed greater knee flexion angles than females (p<0.01). Also, where males performed all cutting angles with no differences in the amount of knee flexion -42.53°±8.95°, females decreased their knee flexion angle from -40.6°±7.2° when cutting at 45° to -36.81°±9.10° when cutting at 90°, 135° and 180° (p<0.01). Knee flexion moment decreased for both sexes when cutting towards sharper angles (p<0.05). At 90°, 135° and 180°, males showed greater knee valgus moments than females. For both sexes, knee valgus moment increased towards the sharper cutting angles and then stabilized compared to the 45° cutting angle (p<0.01). Both females and males showed smaller vGRF when cutting to sharper angles (p<0.01). It can be concluded that different cutting angles demand different knee kinematics and kinetics. Sharper cutting angles place the knee more at risk. However, females and males handle this differently, which has implications for injury prevention. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Solar cell angle of incidence corrections

    NASA Technical Reports Server (NTRS)

    Burger, Dale R.; Mueller, Robert L.

    1995-01-01

    Literature on solar array angle of incidence corrections was found to be sparse and contained no tabular data for support. This lack along with recent data on 27 GaAs/Ge 4 cm by 4 cm cells initiated the analysis presented in this paper. The literature cites seven possible contributors to angle of incidence effects: cosine, optical front surface, edge, shadowing, UV degradation, particulate soiling, and background color. Only the first three are covered in this paper due to lack of sufficient data. The cosine correction is commonly used but is not sufficient when the incident angle is large. Fresnel reflection calculations require knowledge of the index of refraction of the coverglass front surface. The absolute index of refraction for the coverglass front surface was not known nor was it measured due to lack of funds. However, a value for the index of refraction was obtained by examining how the prediction errors varied with different assumed indices and selecting the best fit to the set of measured values. Corrections using front surface Fresnel reflection along with the cosine correction give very good predictive results when compared to measured data, except there is a definite trend away from predicted values at the larger incident angles. This trend could be related to edge effects and is illustrated by a use of a box plot of the errors and by plotting the deviation of the mean against incidence angle. The trend is for larger deviations at larger incidence angles and there may be a fourth order effect involved in the trend. A chi-squared test was used to determine if the measurement errors were normally distributed. At 10 degrees the chi-squared test failed, probably due to the very small numbers involved or a bias from the measurement procedure. All other angles showed a good fit to the normal distribution with increasing goodness-of-fit as the angles increased which reinforces the very small numbers hypothesis. The contributed data only went to 65 degrees

  11. Contact angle hysteresis: study by dynamic cycling contact angle measurements and variable angle spectroscopic ellipsometry on polyimide.

    PubMed

    Hennig, A; Eichhorn, K-J; Staudinger, U; Sahre, K; Rogalli, M; Stamm, M; Neumann, A W; Grundke, K

    2004-08-03

    The phenomenon of contact angle hysteresis was studied on smooth films of polyimide, a polymer type used in the microelectronic industry, by dynamic cycling contact angle measurements based on axisymmetric drop shape analysis-profile in combination with variable angle spectroscopic ellipsometry (VASE). It was found that both advancing and receding contact angles became smaller with increasing the number of cycles and are, therefore, not a property of the dry solid alone. The changes of the wetting behavior during these dynamic cycling contact angle measurements are attributed mainly to swelling and/or liquid retention. To reveal the water-induced changes of the polymer film, the polyimide surface was studied before and after the contact with a water droplet by VASE. Both the experimental ellipsometric spectrum for Delta and that for Psi as well as the corresponding simulations show characteristic shifts due to the contact with water. The so-called effective medium approximation was applied to recover information about the thickness and effective optical constants of the polymer layer from the ellipsometrically measured values of Delta and Psi. On the basis of these results, the swelling and retention behavior of the polyimide films in contact with water droplets were discussed.

  12. Contact angle of unset elastomeric impression materials.

    PubMed

    Menees, Timothy S; Radhakrishnan, Rashmi; Ramp, Lance C; Burgess, John O; Lawson, Nathaniel C

    2015-10-01

    Some elastomeric impression materials are hydrophobic, and it is often necessary to take definitive impressions of teeth coated with some saliva. New hydrophilic materials have been developed. The purpose of this in vitro study was to compare contact angles of water and saliva on 7 unset elastomeric impression materials at 5 time points from the start of mixing. Two traditional polyvinyl siloxane (PVS) (Aquasil, Take 1), 2 modified PVS (Imprint 4, Panasil), a polyether (Impregum), and 2 hybrid (Identium, EXA'lence) materials were compared. Each material was flattened to 2 mm and a 5 μL drop of distilled water or saliva was dropped on the surface at 25 seconds (t0) after the start of mix. Contact angle measurements were made with a digital microscope at initial contact (t0), t1=2 seconds, t2=5 seconds, t3=50% working time, and t4=95% working time. Data were analyzed with a generalized linear mixed model analysis, and individual 1-way ANOVA and Tukey HSD post hoc tests (α=.05). For water, materials grouped into 3 categories at all time-points: the modified PVS and one hybrid material (Identium) produced the lowest contact angles, the polyether material was intermediate, and the traditional PVS materials and the other hybrid (EXA'lence) produced the highest contact angles. For saliva, Identium, Impregum, and Imprint 4 were in the group with the lowest contact angle at most time points. Modified PVS materials and one of the hybrid materials are more hydrophilic than traditional PVS materials when measured with water. Saliva behaves differently than water in contact angle measurement on unset impression material and produces a lower contact angle on polyether based materials. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  13. Fractal Approach in Petrology: Combining Ultra-Small Angle (USANA) and Small Angle Neutron Scattering (SANS)

    SciTech Connect

    LoCelso, F.; Triolo, F.; Triolo, A.; Lin, J.S.; Lucido, G.; Triolo, R.

    1999-10-14

    Ultra small angle neutron scattering instruments have recently covered the gap between the size resolution available with conventional intermediate angle neutron scattering and small angle neutron scattering instruments on one side and optical microscopy on the other side. Rocks showing fractal behavior in over two decades of momentum transfer and seven orders of magnitude of intensity are examined and fractal parameters are extracted from the combined USANS and SANS curves.

  14. Ocular biometry in occludable angles and angle closure glaucoma: a population based survey.

    PubMed

    George, R; Paul, P G; Baskaran, M; Ramesh, S Ve; Raju, P; Arvind, H; McCarty, C; Vijaya, L

    2003-04-01

    To compare ocular biometric values in a population based sample of eyes with occludable angles, angle closure glaucoma, and normal subjects. 2850 subjects from a population based glaucoma prevalence study underwent complete ocular examination including indentation gonioscopy. Ocular biometry was performed in all subjects classified to have occludable angles (n = 143); angle closure glaucoma (n = 22), and a random subgroup of 419 normal subjects. Ocular biometry readings between the groups were compared and statistically analysed using "t," "z," and Mann-Whitney U tests. The mean age among subjects with occludable angles (54.43 (SD 9.53) years) and angle closure glaucoma (57.45 (8.5) years) was significantly higher (p<0.001) than normal subjects (49.95 (9.95) years). Axial length was shorter (p<0.001) in the occludable angle group (22.07 (0.69) mm) compared to the normal group (22.76 (0.78) mm). Anterior chamber depth (ACD) was shallower (p<0.001) among subjects with occludable angles (2.53 (0.26) mm) than normal subjects (3.00 (0.30) mm). Lens thickness (LT) was greater (p<0.001) in people with occludable angles (4.40 (0.53) mm) compared to normal subjects (4.31 (0.31) mm). No significant difference was noted in axial length, ACD (p = 0.451), and LT (p = 0.302) between angle closure glaucoma and occludable eyes. South Indian eyes with angle closure glaucoma and occludable angles seem to have significantly shorter axial lengths, shallower anterior chambers and greater lens thickness compared to the normal group.

  15. Structural assessment of glycyl mutations in invariantly conserved motifs.

    PubMed

    Prakash, Tulika; Sandhu, Kuljeet Singh; Singh, Nitin Kumar; Bhasin, Yasha; Ramakrishnan, C; Brahmachari, Samir K

    2007-11-15

    Motifs that are evolutionarily conserved in proteins are crucial to their structure and function. In one of our earlier studies, we demonstrated that the conserved motifs occurring invariantly across several organisms could act as structural determinants of the proteins. We observed the abundance of glycyl residues in these invariantly conserved motifs. The role of glycyl residues in highly conserved motifs has not been studied extensively. Thus, it would be interesting to examine the structural perturbations induced by mutation in these conserved glycyl sites. In this work, we selected a representative set of invariant signature (IS) peptides for which both the PDB structure and mutation information was available. We thoroughly analyzed the conformational features of the glycyl sites and their local interactions with the surrounding residues. Using Ramachandran angles, we showed that the glycyl residues occurring in these IS peptides, which have undergone mutation, occurred more often in the L-disallowed as compared with the L-allowed region of the Ramachandran plot. Short range contacts around the mutation site were analyzed to study the steric effects. With the results obtained from our analysis, we hypothesize that any change of activity arising because of such mutations must be attributed to the long-range interaction(s) of the new residue if the glycyl residue in the IS peptide occurred in the L-allowed region of the Ramachandran plot. However, the mutation of those conserved glycyl residues that occurred in the L-disallowed region of the Ramachandran plot might lead to an altered activity of the protein as a result of an altered conformation of the backbone in the immediate vicinity of the glycyl residue, in addition to long range effects arising from the long side chains of the new residue. Thus, the loss of activity because of mutation in the conserved glycyl site might either relate to long range interactions or to local perturbations around the site

  16. MECP2 mutations in males

    PubMed Central

    Villard, Laurent

    2007-01-01

    Rett syndrome (RS; MIM 312750) is a severe neurological disorder affecting exclusively females. Its prevalence is about 1 in 10 000 female births, and it is a prominent cause of profound mental handicap in women. RS is caused by mutations in the X‐linked methyl CpG‐binding protein 2 (MECP2) gene. These mutations were initially thought to be lethal in males. However, MECP2 mutations are now frequently identified in mentally retarded male patients. The frequency of disease‐causing MECP2 mutations in this population is between 1.3% and 1.7%. Surprisingly, MECP2 mutations in males are responsible for a wide spectrum of neurological disorders, ranging from mild mental retardation to severe neonatal encephalopathy. The aim of this review is to describe the nature of the MECP2 mutations identified in male patients to date and their associated phenotypes. PMID:17351020

  17. Graphene spin valve: An angle sensor

    NASA Astrophysics Data System (ADS)

    Iqbal, Muhammad Zahir; Hussain, Ghulam; Siddique, Salma; Iqbal, Muhammad Waqas

    2017-06-01

    Graphene spin valves can be optimized for various spintronic applications by tuning the associated experimental parameters. In this work, we report the angle dependent magnetoresistance (MR) in graphene spin valve for different orientations of applied magnetic field (B). The switching points of spin valve signals show a clear shift towards higher B for each increasing angle of the applied field, thus sensing the response for respective orientation of the magnetic field. The angular variation of B shifts the switching points from ±95 G to ±925 G as the angle is varied from 0° to 90° at 300 K. The observed shifts in switching points become more pronounced (±165 G to ±1450 G) at 4.2 K for similar orientation. A monotonic increase in MR ratio is observed as the angle of magnetic field is varied in the vertical direction at 300 K and 4.2 K temperatures. This variation of B (from 0° to 90°) increases the magnitude of MR ratio from ∼0.08% to ∼0.14% at 300 K, while at 4.2 K it progresses to ∼0.39% from ∼0.14%. The sensitivity related to angular variation of such spin valve structure can be employed for angle sensing applications.

  18. LVAD Outflow Graft Angle and Thrombosis Risk.

    PubMed

    Aliseda, Alberto; Chivukula, Venkat Keshav; Mcgah, Patrick; Prisco, Anthony R; Beckman, Jennifer A; Garcia, Guilherme J M; Mokadam, Nahush A; Mahr, Claudius

    This study quantifies thrombogenic potential (TP) of a wide range of left ventricular assist device (LVAD) outflow graft anastomosis angles through state-of-the-art techniques: 3D imaged-based patient-specific models created via virtual surgery and unsteady computational fluid dynamics with Lagrangian particle tracking. This study aims at clarifying the influence of a single parameter (outflow graft angle) on the thrombogenesis associated with flow patterns in the aortic root after LVAD implantation. This is an important and poorly-understood aspect of LVAD therapy, because several studies have shown strong inter and intrapatient thrombogenic variability and current LVAD implantation strategies do not incorporate outflow graft angle optimization. Accurate platelet-level investigation, enabled by statistical treatment of outliers in Lagrangian particle tracking, demonstrates a strong influence of outflow graft anastomoses angle on thrombogenicity (platelet residence times and activation state characterized by shear stress accumulation) with significantly reduced TP for acutely-angled anastomosed outflow grafts. The methodology presented in this study provides a device-neutral platform for conducting comprehensive thrombogenicity evaluation of LVAD surgical configurations, empowering optimal patient-focused surgical strategies for long-term treatment and care for advanced heart failure patients.

  19. NORAD LOOK ANGLES AND PIO SATELLITE PACKAGE

    NASA Technical Reports Server (NTRS)

    ANONYMOUS

    1994-01-01

    This program package consists of two programs. First is the NORAD Look Angles Program, which computes satellite look angles (azimuth, elevation, and range) as well as the subsatellite points (latitude, longitude, and height). The second program in this package is the PIO Satellite Program, which computes sighting directions, visibility times, and the maximum elevation angle attained during each pass of an earth-orbiting satellite. Computations take into consideration the observing location and the effect of the earth's shadow on the satellite visibility. Input consists of a magnetic tape prepared by the NORAD Look Angles Program and punched cards containing reference Julian date, right ascension, declination, mean sidereal time at zero hours universal time of the reference date, and daily changes of these quantities. Output consists of a tabulated listing of the satellite's rise and set times, direction, and the maximum elevation angle visible from each observing location. This program has been implemented on the GE 635. The program Assembler code can easily be replaced by FORTRAN statements.

  20. Infrared Solar Spectroscopic Measurements of Free Tropospheric CO, C2H6, and HCN above Mauna Loa, Hawaii: Seasonal Variations and Evidence for Enhanced Emissions from the Southeast Asian Tropical Fires of 1997-1998

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Goldman, A.; Murcray, F. J.; Stephen, T. M.; Pougatchev, N. S.; Fishman, J.; David, S. J.; Blatherwick, R. D.; Novelli, P. C.; Jones, N. B.

    1999-01-01

    High spectral resolution (0.003 per cm) infrared solar absorption measurements of CO, C2H6, and HCN have been recorded at the Network for the Detection of Stratospheric Change station on Mauna Loa, Hawaii, (19.5N, 155.6W, altitude 3.4 km). The observations were obtained on over 250 days between August 1995 and February 1998. Column measurements are reported for the 3.4-16 km altitude region, which corresponds approximately to the free troposphere above the station. Average CO mixing ratios computed for this layer have been compared with flask sampling CO measurements obtained in situ at the station during the same time period. Both show asymmetrical seasonal cycles superimposed on significant variability. The first 2 years of observations exhibit a broad January-April maximum and a sharper CO minimum during late summer. The C2H6 and CO 3.4-16 km columns were highly correlated throughout the observing period with the C2H6/CO slope intermediate between higher and lower values derived from similar infrared spectroscopic measurements at 32'N and 45'S latitude, respectively. Variable enhancements in CO, C2H6, and particularly HCN were observed beginning in about September 1997. The maximum HCN free tropospheric monthly mean column observed in November 1997 corresponds to an average 3.4-16 km mixing ratio of 0.7 ppbv (1 ppbv = 10(exp -9) per unit volume), more than a factor of 3 above the background level. The HCN enhancements continued through the end of the observational series. Back-trajectory calculations suggest that the emissions originated at low northern latitudes in southeast Asia. Surface CO mixing ratios and the C2H6 tropospheric columns measured during the same time also showed anomalous autumn 1997 maxima. The intense and widespread tropical wild fires that burned during the strong El Nino warm phase of 1997- 1998 are the likely source of the elevated emission products.

  1. Metrology of the Solar Spectral Irradiance at the Top Of Atmosphere in the Near Infrared using Ground Based Instruments. Presentation of the PYR-ILIOS campaign (Mauna Loa Observatory, June-July 2016).

    NASA Astrophysics Data System (ADS)

    Cessateur, G.; Bolsée, D.; Pereira, N.; Sperfeld, P.; Pape, S.

    2016-12-01

    The availability of reference spectra for the Solar Spectral Irradiance (SSI) is of the most importance for the solar physics, the studies of planetary atmospheres and climatology. The near infrared (NIR) part of these spectra is of great interest for its main role for example, in the Earth's radiative budget. However, some large and unsolved discrepancies (up to 10 %) are observed in the 1.6 μm region between recent measurements from space instruments and modelling. We developed a ground-based instrumentation dedicated to SSI measurements of the Top Of Atmosphere (TOA), obtained through atmospheric NIR windows using the Bouguer-Langley technique. The instruments are a double spectroradiometer designed by Bentham (UK) and a 6-channels NIR filters radiometer. Both were radiometrically characterized at the Royal Belgian Institute for Space Aeronomy. In the following they were calibrated against a high-temperature blackbody as primary standard for spectral irradiance at the Physikalisch-Technische Bundesanstalt (Germany). The PYR-ILIOS campaign carried out in June to July 2016 at the Mauna Loa Observatory (Hawaii, USA, 3396 m a.s.l.) is a follower of the four-month IRESPERAD campaign which was carried out in 2011 at the Izaña Atmospheric Observatory (Canary Islands, 2367 m a.s.l.). We present here the results of the 3 weeks PYR-ILIOS campaign and compare them with the outcome from IRESPERAD as well as from other ground-based, airborne or space experiments will be presented. The standard uncertainty of the PYR-ILIOS results will be discussed.

  2. Infrared Solar Spectroscopic Measurements of Free Tropospheric CO, C2H6, and HCN above Mauna Loa, Hawaii: Seasonal Variations and Evidence for Enhanced Emissions from the Southeast Asian Tropical Fires of 1997-1998

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Goldman, A.; Murcray, F. J.; Stephen, T. M.; Pougatchev, N. S.; Fishman, J.; David, S. J.; Blatherwick, R. D.; Novelli, P. C.; Jones, N. B.

    1999-01-01

    High spectral resolution (0.003 per cm) infrared solar absorption measurements of CO, C2H6, and HCN have been recorded at the Network for the Detection of Stratospheric Change station on Mauna Loa, Hawaii, (19.5N, 155.6W, altitude 3.4 km). The observations were obtained on over 250 days between August 1995 and February 1998. Column measurements are reported for the 3.4-16 km altitude region, which corresponds approximately to the free troposphere above the station. Average CO mixing ratios computed for this layer have been compared with flask sampling CO measurements obtained in situ at the station during the same time period. Both show asymmetrical seasonal cycles superimposed on significant variability. The first 2 years of observations exhibit a broad January-April maximum and a sharper CO minimum during late summer. The C2H6 and CO 3.4-16 km columns were highly correlated throughout the observing period with the C2H6/CO slope intermediate between higher and lower values derived from similar infrared spectroscopic measurements at 32'N and 45'S latitude, respectively. Variable enhancements in CO, C2H6, and particularly HCN were observed beginning in about September 1997. The maximum HCN free tropospheric monthly mean column observed in November 1997 corresponds to an average 3.4-16 km mixing ratio of 0.7 ppbv (1 ppbv = 10(exp -9) per unit volume), more than a factor of 3 above the background level. The HCN enhancements continued through the end of the observational series. Back-trajectory calculations suggest that the emissions originated at low northern latitudes in southeast Asia. Surface CO mixing ratios and the C2H6 tropospheric columns measured during the same time also showed anomalous autumn 1997 maxima. The intense and widespread tropical wild fires that burned during the strong El Nino warm phase of 1997- 1998 are the likely source of the elevated emission products.

  3. Comparison of the atmospheric CO/sub 2/ measurement programs of GMCC/NOAA and SIO at Mauna Loa Observatory: results of the December 5-12, 1983 tests. Final draft

    SciTech Connect

    Gammon, R.; Thoning, K.; Keeling, C.D.; Moss, D.

    1984-05-03

    Field tests were conducted to assess possible instrumental sources of disagreement in a joint record of atmospheric CO/sub 2/ measurements at Mauna Loa Observatory. Results indicate that the CO/sub 2/ systems gave the same measured ambient atmospheric air value to within about 0.15 ppM. For tests through common plumbing the URAS-APC difference on average was 0.12 ppM. For tests through different plumbing a similar difference of 0.15 ppM was observed, disregarding the period of faulty pump performance during Test E. The sigma/sub m//sup -2/ weighted mean difference for all tests was 0.138 ppM with a weighted sigma/sub m/ = 0.016 ppM. A single cause was not discovered which accounted for these differences which did not appear to correlate with permutations in plumbing. On average no significant difference was observed when measuring CO/sub 2/-in-air from a pressurized cylinder with common plumbing. The observed differences are smaller but of the same sign as the mean difference provisionally computed between the NOAA and SIO systems. The overall level of agreement has been provisionally determined at the 0.3 to 0.6 ppM level for monthly means, with a relative drift of about 0.08 ppM y/sup -1/ from an initial difference of about -0.5 ppM in 1974 to + 0.6 ppM in 1982. 18 figures, 6 tables.

  4. Recurrent gene mutations in CLL.

    PubMed

    Martínez-Trillos, Alejandra; Quesada, Víctor; Villamor, Neus; Puente, Xose S; López-Otín, Carlos; Campo, Elías

    2013-01-01

    Next-generation sequencing of whole genomes and exomes in chronic lymphocytic leukemia (CLL) has provided the first comprehensive view of somatic mutations in this disease. Subsequent studies have characterized the oncogenic pathways and clinical implications of a number of these mutations. The global number of somatic mutations per case is lower than those described in solid tumors but is in agreement with previous estimates of less than one mutation per megabase in hematological neoplasms. The number and pattern of somatic mutations differ in tumors with unmutated and mutated IGHV, extending at the genomic level the clinical differences observed in these two CLL subtypes. One of the striking conclusions of these studies has been the marked genetic heterogeneity of the disease, with a relatively large number of genes recurrently mutated at low frequency and only a few genes mutated in up to 10-15 % of the patients. The mutated genes tend to cluster in different pathways that include NOTCH1 signaling, RNA splicing and processing machinery, innate inflammatory response, Wnt signaling, and DNA damage and cell cycle control, among others. These results highlight the molecular heterogeneity of CLL and may provide new biomarkers and potential therapeutic targets for the diagnosis and management of the disease.

  5. BRAF Mutations in Canine Cancers.

    PubMed

    Mochizuki, Hiroyuki; Kennedy, Katherine; Shapiro, Susan G; Breen, Matthew

    2015-01-01

    Activating mutations of the BRAF gene lead to constitutive activation of the MAPK pathway. Although many human cancers carry the mutated BRAF gene, this mutation has not yet been characterized in canine cancers. As human and canine cancers share molecular abnormalities, we hypothesized that BRAF gene mutations also exist in canine cancers. To test this hypothesis, we sequenced the exon 15 of BRAF, mutation hot spot of the gene, in 667 canine primary tumors and 38 control tissues. Sequencing analysis revealed that a single nucleotide T to A transversion at nucleotide 1349 occurred in 64 primary tumors (9.6%), with particularly high frequency in prostatic carcinoma (20/25, 80%) and urothelial carcinoma (30/45, 67%). This mutation results in the amino acid substitution of glutamic acid for valine at codon 450 (V450E) of canine BRAF, corresponding to the most common BRAF mutation in human cancer, V600E. The evolutional conservation of the BRAF V600E mutation highlights the importance of MAPK pathway activation in neoplasia and may offer opportunity for molecular diagnostics and targeted therapeutics for dogs bearing BRAF-mutated cancers.

  6. Residual angle closure one year after laser peripheral iridotomy in primary angle closure suspects.

    PubMed

    Baskaran, Mani; Yang, Elizabeth; Trikha, Sameer; Kumar, Rajesh S; Wong, Hon Tym; He, Mingguang; Chew, Paul Tk; Foster, Paul J; Friedman, David; Aung, Tin

    2017-09-05

    To determine the incidence and baseline clinical and anterior segment optical coherence tomography (AS-OCT) predictors associated with residual angle closure as assessed by gonioscopy 1 year after laser peripheral iridotomy (LPI) in primary angle closure suspects (PACS). Sub-analysis of randomized controlled trial data METHODS: AS-OCT images (Visante, Carl Zeiss Meditec, Dublin, CA) from 181 PACS subjects ≥ 50 years of age, were analyzed using customized software, prior to, and 1 year after LPI. Other parameters assessed were intraocular pressure (IOP) and axial length (Axl). Residual angle closure was defined as the inability to see the posterior trabecular meshwork for at least 2 quadrants on gonioscopy after LPI. Multivariate regression analysis determined the baseline predictors of residual angle closure 1 year after LPI. The mean age of participants was 62.4 (SD 9.9) years. The majority were female (137, 75.7%) and Chinese 174, 96.1%). At 1 year post LPI, 148 (81.8%) subjects had gonioscopic residual angle closure. Univariate analysis showed that baseline Axl, anterior chamber area, anterior chamber volume, angle opening distance at 750 microns from the scleral spur and angle recess area were smaller while baseline lens vault and iris curvature were larger in residual angle closure subjects (all p<0.05). Multivariate analysis revealed that baseline iris volume (B=-0.08, P=0.035) and baseline IOP (B=0.23, p=0.032) were predictors for residual angle closure. One year after LPI, >80% of PACS had gonioscopic residual angle closure. Greater baseline iris volume and higher IOP at baseline are independent risk factors for residual gonioscopic angle closure. Copyright © 2017. Published by Elsevier Inc.

  7. Angle sensing with ferromagnetic nanowire arrays

    NASA Astrophysics Data System (ADS)

    Tannous, C.; Gieraltowski, J.

    2014-01-01

    Hysteresis loops and Ferromagnetic Resonance (FMR) linewidths of Nickel ferromagnetic nanowire arrays are measured versus angle θH between the applied magnetic field angle and the common nanowire axis. Using Preisach analysis, we extract from the hysteresis loop an interaction parameter σi that strongly depends on θH. Extending the analysis to FMR lineshapes, we deduce a strong dependence of the FMR field linewidth ΔH on θH through the interaction parameter σi. Existence of a link between static (hysteresis) and dynamic (FMR) cases through θH might be exploited in contactless absolute angle sensing devices that could compete with inductive, Hall, and magnetoresistive devices.

  8. High brightness angled cavity quantum cascade lasers

    SciTech Connect

    Heydari, D.; Bai, Y.; Bandyopadhyay, N.; Slivken, S.; Razeghi, M.

    2015-03-02

    A quantum cascade laser (QCL) with an output power of 203 W is demonstrated in pulsed mode at 283 K with an angled cavity. The device has a ridge width of 300 μm, a cavity length of 5.8 mm, and a tilt angle of 12°. The back facet is high reflection coated, and the front facet is anti-reflection coated. The emitting wavelength is around 4.8 μm. In distinct contrast to a straight cavity broad area QCL, the lateral far field is single lobed with a divergence angle of only 3°. An ultrahigh brightness value of 156 MW cm{sup −2 }sr{sup −1} is obtained, which marks the brightest QCL to date.

  9. A heterodyne interferometer for angle metrology.

    PubMed

    Hahn, Inseob; Weilert, M; Wang, X; Goullioud, R

    2010-04-01

    We have developed a compact, high-resolution, angle measurement instrument based on a heterodyne interferometer. Common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer set up, an optical mask is used to sample the laser beam reflecting back from four areas on a target surface. From the relative displacement measurements of the target surface areas, we can simultaneously determine angular rotations around two orthogonal axes in a plane perpendicular to the measurement beam propagation direction. The device is used in a testbed for a tracking telescope system where pitch and yaw angle measurements of a flat mirror are performed. Angle noise measurement of the device shows 0.1 nrad/square root of Hz at 1 Hz, at a working distance of 1 m. The operation range and nonlinearity of the device when used with a flat mirror is approximately +/-0.15 mrad, and 3 microrad rms, respectively.

  10. A heterodyne interferometer for angle metrology

    SciTech Connect

    Hahn, Inseob; Weilert, M.; Wang, X.; Goullioud, R.

    2010-04-15

    We have developed a compact, high-resolution, angle measurement instrument based on a heterodyne interferometer. Common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer set up, an optical mask is used to sample the laser beam reflecting back from four areas on a target surface. From the relative displacement measurements of the target surface areas, we can simultaneously determine angular rotations around two orthogonal axes in a plane perpendicular to the measurement beam propagation direction. The device is used in a testbed for a tracking telescope system where pitch and yaw angle measurements of a flat mirror are performed. Angle noise measurement of the device shows 0.1 nrad/{radical}(Hz) at 1 Hz, at a working distance of 1 m. The operation range and nonlinearity of the device when used with a flat mirror is approximately {+-}0.15 mrad, and 3 {mu}rad rms, respectively.

  11. Bicycle helmet ventilation and comfort angle dependence.

    PubMed

    Brühwiler, Paul A; Ducas, Charline; Huber, Roman; Bishop, Phillip A

    2004-09-01

    Five modern bicycle helmets were studied to elucidate some of the variations in ventilation performance, using both a heated manikin headform and human subjects (n = 7). Wind speed and head angle were varied to test their influence on the measured steady-state heat exchange (cooling power) in the skull section of the headform. The cooling power transmitted by the helmets varied from about 60% to over 90% of that of the nude headform, illustrating the range of present manufacturer designs. Angling the head forward by 30 degrees was found to provide better cooling power to the skull (up to 25%) for three of the helmets and almost equal cooling power in the remaining two cases. Comparisons of skull ventilation at these angles with human subjects strongly supported the headform results.

  12. Data for phase angle shift with frequency

    PubMed Central

    Paul, T.; Banerjee, D.; Kargupta, K.

    2016-01-01

    Phase angle shift between the current and voltage with frequency has been reported for a single phosphoric acid fuel cell in the cell temperature from 100 °C to 160 °C and the humidifier temperature from 40 °C to 90 °C. An electrochemical workbench is employed to find the shift. The figure of phase angle shift shows a peak in high humidifier temperatures. The peak in phase angle shift directs to lower frequency side with decreasing humidifier temperature. The estimation of electrochemical reaction time is also evaluated in the humidifier temperature zone from 50 °C to 90 °C. PMID:27158655

  13. Michelson interferometer for precision angle measurement.

    PubMed

    Ikram, M; Hussain, G

    1999-01-01

    An angle-measuring technique based on an optical interferometer is reported. The technique exploits a Michelson interferometric configuration in which a right-angle prism and a glass strip are introduced into a probe beam. Simultaneous rotation of both components along an axis results in an optical path difference between the reference and the probe beams. In a second arrangement two right-angle prisms and glass strips are introduced into two beams of a Michelson interferometer. The prisms and the strips are rotated simultaneously to introduce an optical path difference between the two beams. In our arrangement, optimization of various parameters makes the net optical path difference between the two beams approximately linear for a rotation as great as +/-20 degrees . Results are simulated that show an improvement of 2-3 orders of magnitude in error and nonlinearity compared with a previously reported technique.

  14. High brightness angled cavity quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Heydari, D.; Bai, Y.; Bandyopadhyay, N.; Slivken, S.; Razeghi, M.

    2015-03-01

    A quantum cascade laser (QCL) with an output power of 203 W is demonstrated in pulsed mode at 283 K with an angled cavity. The device has a ridge width of 300 μm, a cavity length of 5.8 mm, and a tilt angle of 12°. The back facet is high reflection coated, and the front facet is anti-reflection coated. The emitting wavelength is around 4.8 μm. In distinct contrast to a straight cavity broad area QCL, the lateral far field is single lobed with a divergence angle of only 3°. An ultrahigh brightness value of 156 MW cm-2 sr-1 is obtained, which marks the brightest QCL to date.

  15. Three paths toward the quantum angle operator

    SciTech Connect

    Gazeau, Jean Pierre; Szafraniec, Franciszek Hugon

    2016-12-15

    We examine mathematical questions around angle (or phase) operator associated with a number operator through a short list of basic requirements. We implement three methods of construction of quantum angle. The first one is based on operator theory and parallels the definition of angle for the upper half-circle through its cosine and completed by a sign inversion. The two other methods are integral quantization generalizing in a certain sense the Berezin–Klauder approaches. One method pertains to Weyl–Heisenberg integral quantization of the plane viewed as the phase space of the motion on the line. It depends on a family of “weight” functions on the plane. The third method rests upon coherent state quantization of the cylinder viewed as the phase space of the motion on the circle. The construction of these coherent states depends on a family of probability distributions on the line.

  16. Three paths toward the quantum angle operator

    NASA Astrophysics Data System (ADS)

    Gazeau, Jean Pierre; Szafraniec, Franciszek Hugon

    2016-12-01

    We examine mathematical questions around angle (or phase) operator associated with a number operator through a short list of basic requirements. We implement three methods of construction of quantum angle. The first one is based on operator theory and parallels the definition of angle for the upper half-circle through its cosine and completed by a sign inversion. The two other methods are integral quantization generalizing in a certain sense the Berezin-Klauder approaches. One method pertains to Weyl-Heisenberg integral quantization of the plane viewed as the phase space of the motion on the line. It depends on a family of "weight" functions on the plane. The third method rests upon coherent state quantization of the cylinder viewed as the phase space of the motion on the circle. The construction of these coherent states depends on a family of probability distributions on the line.

  17. Small Angle X-Ray Scattering Detector

    SciTech Connect

    Hessler, Jan P.

    2004-06-15

    A detector for time-resolved small-angle x-ray scattering includes a nearly constant diameter, evacuated linear tube having an end plate detector with a first fluorescent screen and concentric rings of first fiber optic bundles for low angle scattering detection and an annular detector having a second fluorescent screen and second fiber optic bundles concentrically disposed about the tube for higher angle scattering detection. With the scattering source, i.e., the specimen under investigation, located outside of the evacuated tube on the tube's longitudinal axis, scattered x-rays are detected by the fiber optic bundles, to each of which is coupled a respective photodetector, to provide a measurement resolution, i.e., dq/q, where q is the momentum transferred from an incident x-ray to an x-ray scattering specimen, of 2% over two (2) orders of magnitude in reciprocal space, i.e., qmax/qmin approx=lO0.

  18. Angle-averaged Compton cross sections

    SciTech Connect

    Nickel, G.H.

    1983-01-01

    The scattering of a photon by an individual free electron is characterized by six quantities: ..cap alpha.. = initial photon energy in units of m/sub 0/c/sup 2/; ..cap alpha../sub s/ = scattered photon energy in units of m/sub 0/c/sup 2/; ..beta.. = initial electron velocity in units of c; phi = angle between photon direction and electron direction in the laboratory frame (LF); theta = polar angle change due to Compton scattering, measured in the electron rest frame (ERF); and tau = azimuthal angle change in the ERF. We present an analytic expression for the average of the Compton cross section over phi, theta, and tau. The lowest order approximation to this equation is reasonably accurate for photons and electrons with energies of many keV.

  19. Positron Emission Mammography with Multiple Angle Acquisition

    SciTech Connect

    Mark F. Smith; Stan Majewski; Raymond R. Raylman

    2002-11-01

    Positron emission mammography (PEM) of F-18 fluorodeoxyglucose (FDG) uptake in breast tumors with dedicated detectors typically has been accomplished with two planar detectors in a fixed position with the breast under compression. The potential use of PEM imaging at two detector positions to guide stereotactic breast biopsy has motivated us to use PEM coincidence data acquired at two or more detector positions together in a single image reconstruction. Multiple angle PEM acquisition and iterative image reconstruction were investigated using point source and compressed breast phantom acquisitions with 5, 9, 12 and 15 mm diameter spheres and a simulated tumor:background activity concentration ratio of 6:1. Image reconstruction was performed with an iterative MLEM algorithm that used coincidence events between any two detector pixels on opposed detector heads at each detector position. This present study compared two acquisition protocols: 2 angle acquisition with detector angular positions of -15 and +15 degrees and 11 angle acquisition with detector positions spaced at 3 degree increments over the range -15 to +15 degrees. Three- dimensional image resolution was assessed for the point source acquisitions, and contrast and signal-to-noise metrics were evaluated for the compressed breast phantom with different simulated tumor sizes. Radial and tangential resolutions were similar for the two protocols, while normal resolution was better for the 2 angle acquisition. Analysis is complicated by the asymmetric point spread functions. Signal- to-noise vs. contrast tradeoffs were better for 11 angle acquisition for the smallest visible 9 mm sphere, while tradeoff results were mixed for the larger and more easily visible 12 mm and 15 mm diameter spheres. Additional study is needed to better understand the performance of limited angle tomography for PEM. PEM tomography experiments with complete angular sampling are planned.

  20. Positron Emission Mammography with Multiple Angle Acquisition

    SciTech Connect

    Mark F. Smith; Stan Majewski; Raymond R. Raylman

    2002-11-01

    Positron emission mammography (PEM) of F-18 fluorodeoxyglucose (FbG) uptake in breast tumors with dedicated detectors typically has been accomplished with two planar detectors in a fixed position with the breast under compression. The potential use of PEM imaging at two detector positions to guide stereotactic breast biopsy has motivated us to use PEM coincidence data acquired at two or more detector positions together in a single image reconstruction. Multiple angle PEM acquisition and iterative image reconstruction were investigated using point source and compressed breast phantom acquisitions with 5, 9, 12 and 15 mm diameter spheres and a simulated tumor:background activity concentration ratio of 6:1. Image reconstruction was performed with an iterative MLEM algorithm that used coincidence events between any two detector pixels on opposed detector heads at each detector position. This present study compared two acquisition protocols: 2 angle acquisition with detector angular positions of -15 and +15 degrees and 11 angle acquisition with detector positions spaced at 3 degree increments over the range -15 to +15 degrees. Three-dimensional image resolution was assessed for the point source acquisitions, and contrast and signal-to-noise metrics were evaluated for the compressed breast phantom with different simulated tumor sizes. Radial and tangential resolutions were similar for the two protocols, while normal resolution was better for the 2 angle acquisition. Analysis is complicated by the asymmetric point spread functions. Signal- to-noise vs. contrast tradeoffs were better for 11 angle acquisition for the smallest visible 9 mm sphere, while tradeoff results were mixed for the larger and more easily visible 12 mm and 15 mm diameter spheres. Additional study is needed to better understand the performance of limited angle tomography for PEM. PEM tomography experiments with complete angular sampling are planned.

  1. Methodology for high accuracy contact angle measurement.

    PubMed

    Kalantarian, A; David, R; Neumann, A W

    2009-12-15

    A new version of axisymmetric drop shape analysis (ADSA) called ADSA-NA (ADSA-no apex) was developed for measuring interfacial properties for drop configurations without an apex. ADSA-NA facilitates contact angle measurements on drops with a capillary protruding into the drop. Thus a much simpler experimental setup, not involving formation of a complete drop from below through a hole in the test surface, may be used. The contact angles of long-chained alkanes on a commercial fluoropolymer, Teflon AF 1600, were measured using the new method. A new numerical scheme was incorporated into the image processing to improve the location of the contact points of the liquid meniscus with the solid substrate to subpixel resolution. The images acquired in the experiments were also analyzed by a different drop shape technique called theoretical image fitting analysis-axisymmetric interfaces (TIFA-AI). The results were compared with literature values obtained by means of the standard ADSA for sessile drops with the apex. Comparison of the results from ADSA-NA with those from TIFA-AI and ADSA reveals that, with different numerical strategies and experimental setups, contact angles can be measured with an accuracy of less than 0.2 degrees. Contact angles and surface tensions measured from drops with no apex, i.e., by means of ADSA-NA and TIFA-AI, were considerably less scattered than those from complete drops with apex. ADSA-NA was also used to explore sources of improvement in contact angle resolution. It was found that using an accurate value of surface tension as an input enhances the accuracy of contact angle measurements.

  2. Magic-angle turning with double acquisition.

    PubMed

    Matsunaga, Tatsuya; Takegoshi, K

    2017-01-01

    The double-acquisition scheme for efficient data collection of hypercomplex data (the States method) of a two-dimensional experiment is adopted to magic-angle hopping (MAH) and magic-angle turning (MAT) experiments, which are powerful methods to measure the principal values of the chemical shift anisotropy (CSA) in a powder sample. It is shown that the double acquisition MAT (DAMAT) sequence realizes the S/N ratio comparable to or better than those of other variants of the MAH/MAT sequences. In addition, we show that DAMAT has preferable features that there are no spinning sidebands in the indirect dimension, and no spectral shearing is necessary.

  3. Magic-angle turning with double acquisition

    NASA Astrophysics Data System (ADS)

    Matsunaga, Tatsuya; Takegoshi, K.

    2017-01-01

    The double-acquisition scheme for efficient data collection of hypercomplex data (the States method) of a two-dimensional experiment is adopted to magic-angle hopping (MAH) and magic-angle turning (MAT) experiments, which are powerful methods to measure the principal values of the chemical shift anisotropy (CSA) in a powder sample. It is shown that the double acquisition MAT (DAMAT) sequence realizes the S/N ratio comparable to or better than those of other variants of the MAH/MAT sequences. In addition, we show that DAMAT has preferable features that there are no spinning sidebands in the indirect dimension, and no spectral shearing is necessary.

  4. Taper Angle Evolution in Taiwan Accretionary Wedge

    NASA Astrophysics Data System (ADS)

    Chen, L.; Chi, W.; Liu, C.

    2011-12-01

    Liwen Chena,b, Wu-Cheng Chia, Char-Shine Liuc aInstitute of Earth Sciences, Academia Sinica, Taipei, Taiwan bInstitute of Geosciences, National Taiwan University, Taipei, Taiwan cInstitute of Oceanography, National Taiwan University, Taipei, Taiwan The critical taper model, originally developed using onland Taiwan as an example, is governed by force balance of a horizontal compressional wedge. This model has been successfully applied to many mountainous regions around the world. Among them, Taiwan is located in an oblique collision between the Luzon Arc and the Chinese Passive margin. Previous critical taper angle studies of Taiwan are mainly focusing on utilizing land data. In this study we want to extend these studies to offshore region from the subduction zone to collision zone. Here we study the varying taper angles of the double-vergent wedge derived from 1,000 km of reflection seismic profiles in both the pro-wedge and retro-wedge locations. These profiles were collected in the last two decades. For the retro-wedge, the topography slope angle changes from 2 to 8.8 degrees; some of the steep slope suggests that some part of the retrowedge is currently in a super-critical angle state. Such dramatic changes in taper angle probably strongly affect regional sedimentary processes, including slumping, in addition to structural deformation. These complex processes might even help develop a mélange or re-open a closed basin. We are currently working on studying the taper angle evolution of the pro-wedge from subduction to arc-continent collision zone in the offshore region. Though further works are needed, our preliminary results show that the evolution of wedge angles and the geometry of the wedge are closely linked and inseparable. The structures of the subducting plate might have strong influence on the deformation style of the over-riding plate. It would be interesting to combine the angle variation with the structure interpretation of the accretionary wedge

  5. Spherical Parameterization Balancing Angle and Area Distortions.

    PubMed

    Nadeem, Saad; Su, Zhengyu; Zeng, Wei; Kaufman, Arie; Gu, Xianfeng

    2017-06-01

    This work presents a novel framework for spherical mesh parameterization. An efficient angle-preserving spherical parameterization algorithm is introduced, which is based on dynamic Yamabe flow and the conformal welding method with solid theoretic foundation. An area-preserving spherical parameterization is also discussed, which is based on discrete optimal mass transport theory. Furthermore, a spherical parameterization algorithm, which is based on the polar decomposition method, balancing angle distortion and area distortion is presented. The algorithms are tested on 3D geometric data and the experiments demonstrate the efficiency and efficacy of the proposed methods.

  6. Brewster's angle silicon wafer terahertz linear polarizer.

    PubMed

    Wojdyla, Antoine; Gallot, Guilhem

    2011-07-18

    We present a new cost-effective terahertz linear polarizer made from a stack of silicon wafers at Brewster's angle, andevaluate its performances. We show that this polarizer is wide-band, has a high extinction ratio (> 6 × 10(3)) and very small insertion losses (< 1%). We provide measurements of the temporal waveforms after linearly polarizing the THz beam and show that there is no distortion of the pulse. We compare its performances with a commercial wire-grid polarizer, and show that the Brewster's angle polarizer can conveniently be used to control the power of a terahertz beam.

  7. Angle-resolved RABBITT: theory and numerics

    NASA Astrophysics Data System (ADS)

    Hockett, Paul

    2017-08-01

    Angle-resolved (AR) RABBITT measurements offer a high information content measurement scheme, due to the presence of multiple, interfering, ionization channels combined with a phase-sensitive observable in the form of angle and time-resolved photoelectron interferograms. In order to explore the characteristics and potentials of AR-RABBITT, a perturbative 2-photon model is developed; based on this model, example AR-RABBITT results are computed for model and real systems, for a range of RABBITT schemes. These results indicate some of the phenomena to be expected in AR-RABBITT measurements, and suggest various applications of the technique in photoionization metrology.

  8. Tank-Binding Kinase 1 (TBK1) Gene and Open-Angle Glaucomas (An American Ophthalmological Society Thesis).

    PubMed

    Fingert, John H; Robin, Alan L; Scheetz, Todd E; Kwon, Young H; Liebmann, Jeffrey M; Ritch, Robert; Alward, Wallace L M

    2016-08-01

    To investigate the role of TANK-binding kinase 1 (TBK1) gene copy-number variations (ie, gene duplications and triplications) in the pathophysiology of various open-angle glaucomas. In previous studies, we discovered that copy-number variations in the TBK1 gene are associated with normal-tension glaucoma. Here, we investigated the prevalence of copy-number variations in cohorts of patients with other open-angle glaucomas-juvenile-onset open-angle glaucoma (n=30), pigmentary glaucoma (n=209), exfoliation glaucoma (n=225), and steroid-induced glaucoma (n=79)-using a quantitative polymerase chain reaction assay. No TBK1 gene copy-number variations were detected in patients with juvenile-onset open-angle glaucoma, pigmentary glaucoma, or steroid-induced glaucoma. A TBK1 gene duplication was detected in one (0.44%) of the 225 exfoliation glaucoma patients. TBK1 gene copy-number variations (gene duplications and triplications) have been previously associated with normal-tension glaucoma. An exploration of other open-angle glaucomas detected a TBK1 copy-number variation in a patient with exfoliation glaucoma, which is the first example of a TBK1 mutation in a glaucoma patient with a diagnosis other than normal-tension glaucoma. A broader phenotypic range may be associated with TBK1 copy-number variations, although mutations in this gene are most often detected in patients with normal-tension glaucoma.

  9. Tank-Binding Kinase 1 (TBK1) Gene and Open-Angle Glaucomas (An American Ophthalmological Society Thesis)

    PubMed Central

    Fingert, John H.; Robin, Alan L.; Scheetz, Todd E.; Kwon, Young H.; Liebmann, Jeffrey M.; Ritch, Robert; Alward, Wallace L.M.

    2016-01-01

    Purpose To investigate the role of TANK-binding kinase 1 (TBK1) gene copy-number variations (ie, gene duplications and triplications) in the pathophysiology of various open-angle glaucomas. Methods In previous studies, we discovered that copy-number variations in the TBK1 gene are associated with normal-tension glaucoma. Here, we investigated the prevalence of copy-number variations in cohorts of patients with other open-angle glaucomas—juvenile-onset open-angle glaucoma (n=30), pigmentary glaucoma (n=209), exfoliation glaucoma (n=225), and steroid-induced glaucoma (n=79)—using a quantitative polymerase chain reaction assay. Results No TBK1 gene copy-number variations were detected in patients with juvenile-onset open-angle glaucoma, pigmentary glaucoma, or steroid-induced glaucoma. A TBK1 gene duplication was detected in one (0.44%) of the 225 exfoliation glaucoma patients. Conclusions TBK1 gene copy-number variations (gene duplications and triplications) have been previously associated with normal-tension glaucoma. An exploration of other open-angle glaucomas detected a TBK1 copy-number variation in a patient with exfoliation glaucoma, which is the first example of a TBK1 mutation in a glaucoma patient with a diagnosis other than normal-tension glaucoma. A broader phenotypic range may be associated with TBK1 copy-number variations, although mutations in this gene are most often detected in patients with normal-tension glaucoma. PMID:27881886

  10. Understanding Angle and Angle Measure: A Design-Based Research Study Using Context Aware Ubiquitous Learning

    ERIC Educational Resources Information Center

    Crompton, Helen

    2015-01-01

    Mobile technologies are quickly becoming tools found in the educational environment. The researchers in this study use a form of mobile learning to support students in learning about angle concepts. Design-based research is used in this study to develop an empirically-substantiated local instruction theory about students' develop of angle and…

  11. Using Digital Technology to See Angles from Different Angles. Part 2: Openings and Turns

    ERIC Educational Resources Information Center

    Host, Erin; Baynham, Emily; McMaster, Heather

    2015-01-01

    Ever wondered how to use technology to teach angles? This article follows on from an earlier article published last year, providing a range of ideas for integrating technology and concrete materials with the teaching of angle concepts. The authors also provide a comprehensive list of free online games and learning objects that can be used to teach…

  12. Understanding Angle and Angle Measure: A Design-Based Research Study Using Context Aware Ubiquitous Learning

    ERIC Educational Resources Information Center

    Crompton, Helen

    2015-01-01

    Mobile technologies are quickly becoming tools found in the educational environment. The researchers in this study use a form of mobile learning to support students in learning about angle concepts. Design-based research is used in this study to develop an empirically-substantiated local instruction theory about students' develop of angle and…

  13. Using Digital Technology to See Angles from Different Angles. Part 2: Openings and Turns

    ERIC Educational Resources Information Center

    Host, Erin; Baynham, Emily; McMaster, Heather

    2015-01-01

    Ever wondered how to use technology to teach angles? This article follows on from an earlier article published last year, providing a range of ideas for integrating technology and concrete materials with the teaching of angle concepts. The authors also provide a comprehensive list of free online games and learning objects that can be used to teach…

  14. A fringe shadow method for measuring flapping angle and torsional angle of a dragonfly wing

    NASA Astrophysics Data System (ADS)

    Zeng, Lijiang; Matsumoto, Hirokazu; Kawachi, Keiji

    1996-05-01

    A fringe shadow (FS) method was developed for measuring the flapping angle and torsional angle of a dragonfly wing during beating motion. This new method involves two sets of fringe patterns projected onto the wing from orthogonal directions. The torsional angle is determined using the length of the shadow of the wing chord that is cast by the two sets of fringe patterns. The flapping angle is determined using the shadowgraph of the wing projected by a laser. The advantages of the FS method are its capability (i) to measure the flapping angle and torsional angle of a dragonfly wing simultaneously using only one high-speed camera and (ii) to recognize the spanwise position of a section from the number of fringes, without having to use diffuse marks that are common in current methods. The resolution of the FS method can be changed easily by adjusting the fringe spacing. The measurement results for the torsional angle and flapping angle of a dragonfly wing prove the effectiveness of the FS method in studying the flight performance of dragonflies.

  15. Exposing synonymous mutations.

    PubMed

    Hunt, Ryan C; Simhadri, Vijaya L; Iandoli, Matthew; Sauna, Zuben E; Kimchi-Sarfaty, Chava

    2014-07-01

    Synonymous codon changes, which do not alter protein sequence, were previously thought to have no functional consequence. Although this concept has been overturned in recent years, there is no unique mechanism by which these changes exert biological effects. A large repertoire of both experimental and bioinformatic methods has been developed to understand the effects of synonymous variants. Results from this body of work have provided global insights into how biological systems exploit the degeneracy of the genetic code to control gene expression, protein folding efficiency, and the coordinated expression of functionally related gene families. Although it is now clear that synonymous variants are important in a variety of contexts, from human disease to the safety and efficacy of therapeutic proteins, there is no clear consensus on the approaches to identify and validate these changes. Here, we review the diverse methods to understand the effects of synonymous mutations.

  16. Identification of BnaYUCCA6 as a candidate gene for branch angle in Brassica napus by QTL-seq

    PubMed Central

    Wang, Hui; Cheng, Hongtao; Wang, Wenxiang; Liu, Jia; Hao, Mengyu; Mei, Desheng; Zhou, Rijin; Fu, Li; Hu, Qiong

    2016-01-01

    Oilseed rape (Brassica napus L.) is one of the most important oil crops in China as well as worldwide. Branch angle as a plant architecture component trait plays an important role for high density planting and yield performance. In this study, bulked segregant analysis (BSA) combined with next generation sequencing technology was used to fine map QTL for branch angle. A major QTL, designated as branch angle 1 (ba1) was identified on A06 and further validated by Indel marker-based classical QTL mapping in an F2 population. Eighty-two genes were identified in the ba1 region. Among these genes, BnaA0639380D is a homolog of AtYUCCA6. Sequence comparison of BnaA0639380D from small- and big-branch angle oilseed rape lines identified six SNPs and four amino acid variation in the promoter and coding region, respectively. The expression level of BnaA0639380D is significantly higher in the small branch angle line Purler than in the big branch angle line Huyou19, suggesting that the genomic mutations may result in reduced activity of BnaA0639380D in Huyou19. Phytohormone determination showed that the IAA content in Purler was also obviously increased. Taken together, our results suggested BnaA0639380D is a possible candidate gene for branch angle in oilseed rape. PMID:27922076

  17. PTCH mutations: distribution and analyses.

    PubMed

    Lindström, Erika; Shimokawa, Takashi; Toftgård, Rune; Zaphiropoulos, Peter G

    2006-03-01

    Mutations in the PTCH (PTCH1) gene are the underlying cause of nevoid basal cell carcinoma syndrome (NBCCS), and are also found in many different sporadic tumors in which PTCH is thought to act as a tumor suppressor gene. To investigate the distribution pattern of these mutations in tumors and NBCCS, we analyzed 284 mutations and 48 SNPs located in the PTCH gene that were compiled from our PTCH mutation database. We found that the PTCH mutations were mainly clustered into the predicted two large extracellular loops and the large intracellular loop. The SNPs appeared to be clustered around the sterol sensing domain and the second half of the protein. The NBCCS cases and each class of tumor analyzed revealed a different distribution of the mutations in the various PTCH domains. Moreover, the types of mutations were also unique for the different groups. Finally, the PTCH gene harbors mutational hot spot residues and regions, including a slippage-sensitive sequence in the N-terminus.

  18. ENAM Mutations with Incomplete Penetrance

    PubMed Central

    Seymen, F.; Lee, K.-E.; Koruyucu, M.; Gencay, K.; Bayram, M.; Tuna, E.B.; Lee, Z.H.; Kim, J.-W.

    2014-01-01

    Amelogenesis imperfecta (AI) is a genetic disease affecting tooth enamel formation. AI can be an isolated entity or a phenotype of syndromes. To date, more than 10 genes have been associated with various forms of AI. We have identified 2 unrelated Turkish families with hypoplastic AI and performed mutational analysis. Whole-exome sequencing identified 2 novel heterozygous nonsense mutations in the ENAM gene (c.454G>T p.Glu152* in family 1, c.358C>T p.Gln120* in family 2) in the probands. Affected individuals were heterozygous for the mutation in each family. Segregation analysis within each family revealed individuals with incomplete penetrance or extremely mild enamel phenotype, in spite of having the same mutation with the other affected individuals. We believe that these findings will broaden our understanding of the clinical phenotype of AI caused by ENAM mutations. PMID:25143514

  19. Spirality: Spiral arm pitch angle measurement

    NASA Astrophysics Data System (ADS)

    Shields, Douglas W.; Boe, Benjamin; Pfountz, Casey; Davis, Benjamin L.; Hartley, Matthew; Pour Imani, Hamed; Slade, Zac; Kennefick, Daniel; Kennefick, Julia

    2015-12-01

    Spirality measures spiral arm pitch angles by fitting galaxy images to spiral templates of known pitch. Written in MATLAB, the code package also includes GenSpiral, which produces FITS images of synthetic spirals, and SpiralArmCount, which uses a one-dimensional Fast Fourier Transform to count the spiral arms of a galaxy after its pitch is determined.

  20. Association between Bolton discrepancy and Angle malocclusions.

    PubMed

    Cançado, Rodrigo Hermont; Gonçalves Júnior, Waldir; Valarelli, Fabrício Pinelli; Freitas, Karina Maria Salvatore de; Crêspo, Janaina Aparecida Lima

    2015-01-01

    This study aimed to assess and compare the overall and anterior ratios of tooth size discrepancies in all Angle malocclusion groups. The following null hypothesis (H0) was tested: no difference between tooth size discrepancies (overall and anterior) would be observed among Angle malocclusion groups. The sample comprised of 711 pre-orthodontic treatment study casts of Brazilian patients with a mean age of 17.42 years selected from private practices in Brazil. The casts were divided into 3 groups according to the type of malocclusion: Class I (n = 321), Class II (n = 324), and Class III patients (n = 66). The measurement of the greatest mesiodistal width of the teeth was performed using a centesimal precision digital caliper directly on the study casts, from the distal surface of the left first molar to the distal surface of the right first molar. The overall and anterior ratios between the maxillary and mandibular teeth were evaluated using Bolton's method. The following statistical tests were applied: chi-square, independent t-test, and one-way ANOVA. Results showed that all Angle malocclusions groups exhibited a ratio compatible with those recommended by Bolton. With respect to the overall and anterior ratios among the malocclusion groups, no statistically significant differences were found. The null hypothesis was accepted because the results showed no differences in the overall and anterior ratios of tooth size discrepancies among different Angle malocclusion groups.

  1. Recent Results on the CKM Angle Alpha

    SciTech Connect

    Mihalyi, A.; /Wisconsin U., Madison

    2005-10-18

    The method to measure the CKM angle {alpha} and the modes sensitive to it are discussed. It is shown that the B {yields} {rho}{rho} decays provide the most stringent constraint on {alpha}, which is found to be {alpha} = 96{sup o} {+-} 10{sup o}(stat) {+-} 4{sup o}(syst){+-} 13{sup o}(penguin).

  2. Camber Angle Inspection for Vehicle Wheel Alignments

    PubMed Central

    Young, Jieh-Shian; Hsu, Hong-Yi; Chuang, Chih-Yuan

    2017-01-01

    This paper introduces an alternative approach to the camber angle measurement for vehicle wheel alignment. Instead of current commercial approaches that apply computation vision techniques, this study aims at realizing a micro-control-unit (MCU)-based camber inspection system with a 3-axis accelerometer. We analyze the precision of the inspection system for the axis misalignments of the accelerometer. The results show that the axes of the accelerometer can be aligned to the axes of the camber inspection system imperfectly. The calibrations that can amend these axis misalignments between the camber inspection system and the accelerometer are also originally proposed since misalignments will usually happen in fabrications of the inspection systems. During camber angle measurements, the x-axis or z-axis of the camber inspection system and the wheel need not be perfectly aligned in the proposed approach. We accomplished two typical authentic camber angle measurements. The results show that the proposed approach is applicable with a precision of ±0.015∘ and therefore facilitates the camber measurement process without downgrading the precision by employing an appropriate 3-axis accelerometer. In addition, the measured results of camber angles can be transmitted via the medium such as RS232, Bluetooth, and Wi-Fi. PMID:28165365

  3. Flare angles measured with ball gage

    NASA Technical Reports Server (NTRS)

    Cleghorn, D.; Wall, W. A.

    1968-01-01

    Precision tungsten carbide balls measure the internal angle of flared joints. Measurements from small and large balls in the flare throat to an external reference point are made. The difference in distances and diameters determine the average slope of the flare between the points of ball contact.

  4. Anterior chamber angle in the exfoliation syndrome.

    PubMed Central

    Wishart, P K; Spaeth, G L; Poryzees, E M

    1985-01-01

    The gonioscopic findings of 76 patients with the exfoliation syndrome were reviewed. A high frequency of narrowness of the anterior chamber (AC) angle was found (32%). 18% had angles considered occludable, and 14% had obvious angle-closure glaucoma as shown by the presence of peripheral anterior synechias (PAS). Increased pigmentation of the posterior trabecular meshwork (PTM) was noted in all cases. When this pigmentation was markedly asymmetrical, unilateral exfoliation with glaucoma was common in the more pigmented eye. In addition heavy angle pigmentation in the absence of exfoliation was noted in the fellow eye of patients with characteristic exfoliated material in the other eye. Increased pigmentation of the PTM may be the earliest detectable sign of the exfoliation syndrome (ES). The clinical significance of our estimating PTM pigmentation at the 12 o'clock position is discussed. In view of the accelerated optic nerve damage associated with the development of glaucoma secondary to ES, routine estimation of the pigmentation of the PTM at 12 o'clock is recommended in the hope of early detection of cases of otherwise inapparent ES. Images PMID:3966996

  5. Sensor Tracks the Sun From Any Angle

    NASA Technical Reports Server (NTRS)

    Birnbaum, M., M.; Bunker, R. L.

    1986-01-01

    Sensor system locates Sun from any angle and generates error signals to point object toward Sun and follow its motion. Sun-sensor system includes three photodetectors, each with separate field of view defined by set of apertures. As equipment rotates about axis, detectors put out time-varying signals processed by external electronics to determine rotation rate and direction to Sun.

  6. Instrument accurately measures weld angle and offset

    NASA Technical Reports Server (NTRS)

    Boyd, W. G.

    1967-01-01

    Weld angle is measured to the nearest arc minute and offset to one thousandth of an inch by an instrument designed to use a reference plane at two locations on a test coupon. A special table for computation has been prepared for use with the instrument.

  7. Camber Angle Inspection for Vehicle Wheel Alignments.

    PubMed

    Young, Jieh-Shian; Hsu, Hong-Yi; Chuang, Chih-Yuan

    2017-02-03

    This paper introduces an alternative approach to the camber angle measurement for vehicle wheel alignment. Instead of current commercial approaches that apply computation vision techniques, this study aims at realizing a micro-control-unit (MCU)-based camber inspection system with a 3-axis accelerometer. We analyze the precision of the inspection system for the axis misalignments of the accelerometer. The results show that the axes of the accelerometer can be aligned to the axes of the camber inspection system imperfectly. The calibrations that can amend these axis misalignments between the camber inspection system and the accelerometer are also originally proposed since misalignments will usually happen in fabrications of the inspection systems. During camber angle measurements, the x-axis or z-axis of the camber inspection system and the wheel need not be perfectly aligned in the proposed approach. We accomplished two typical authentic camber angle measurements. The results show that the proposed approach is applicable with a precision of ± 0.015 ∘ and therefore facilitates the camber measurement process without downgrading the precision by employing an appropriate 3-axis accelerometer. In addition, the measured results of camber angles can be transmitted via the medium such as RS232, Bluetooth, and Wi-Fi.

  8. Statistical analysis of Contact Angle Hysteresis

    NASA Astrophysics Data System (ADS)

    Janardan, Nachiketa; Panchagnula, Mahesh

    2015-11-01

    We present the results of a new statistical approach to determining Contact Angle Hysteresis (CAH) by studying the nature of the triple line. A statistical distribution of local contact angles on a random three-dimensional drop is used as the basis for this approach. Drops with randomly shaped triple lines but of fixed volumes were deposited on a substrate and their triple line shapes were extracted by imaging. Using a solution developed by Prabhala et al. (Langmuir, 2010), the complete three dimensional shape of the sessile drop was generated. A distribution of the local contact angles for several such drops but of the same liquid-substrate pairs is generated. This distribution is a result of several microscopic advancing and receding processes along the triple line. This distribution is used to yield an approximation of the CAH associated with the substrate. This is then compared with measurements of CAH by means of a liquid infusion-withdrawal experiment. Static measurements are shown to be sufficient to measure quasistatic contact angle hysteresis of a substrate. The approach also points towards the relationship between microscopic triple line contortions and CAH.

  9. Wideband Phase-Locked Angle Modulator

    NASA Technical Reports Server (NTRS)

    Nguyen, Lim

    1991-01-01

    Modified configuration for phase-locked angle modulator circuit makes possible to design filters in modulating portion of circuit independently of filter in phase-locked-loop portion. Bandwidth of phase- or frequency-modulated output not limited by low-pass nature of loop filter.

  10. Prediction of ultrasonic properties from grain angle

    Treesearch

    M.F. Kabir

    2001-01-01

    The ultrasonic properties of rubber wood were evaluated in three main symmetry axes – longitudinal (L), radial (R) and tangential direction and also at an angle rotating from the symmetry axes at different moisture content. The ultrasonic velocity were determined with a commercial ultrasonic tester of 45 kHz pulsed longitudinal waves. The experimental results were...

  11. Incidence angle normalization of radar backscatter data

    USDA-ARS?s Scientific Manuscript database

    NASA’s Soil Moisture Passive Active (SMAP) satellite (~2014) will include a radar system that will provide L-band multi-polarization backscatter at a constant incidence angle of 40º. During the pre-launch phase of the project there is a need for observations that will support the radar-based soil mo...

  12. Contact Angle Changes Induced by Immunocomplex Formation†

    PubMed Central

    Kim, Jong-Hoon; Shen, Amy Q.; Lee, Kyong-Hoon; Cangelosi, Gerard A.; Chung, Jae-Hyun

    2014-01-01

    Immunoassays analyzing interactions between antigens and antibodies can be affected by capillary action together with binding affinity. This paper studies contact-angle changes of bacterial suspensions on antibody immobilized surfaces. The capillary action and the dried pattern of the cell suspensions are analyzed and correlated with specific- and nonspecific bindings between bacteria and antibodies. PMID:24482797

  13. Partitioning Pythagorean Triangles Using Pythagorean Angles

    ERIC Educational Resources Information Center

    Swenson, Carl E.; Yandl, Andre L.

    2012-01-01

    Inside any Pythagorean right triangle, it is possible to find a point M so that drawing segments from M to each vertex of the triangle yields angles whose sines and cosines are all rational. This article describes an algorithm that generates an infinite number of such points.

  14. Partitioning Pythagorean Triangles Using Pythagorean Angles

    ERIC Educational Resources Information Center

    Swenson, Carl E.; Yandl, Andre L.

    2012-01-01

    Inside any Pythagorean right triangle, it is possible to find a point M so that drawing segments from M to each vertex of the triangle yields angles whose sines and cosines are all rational. This article describes an algorithm that generates an infinite number of such points.

  15. Raised-angle discrimination under passive finger movement.

    PubMed

    Wu, Jinglong; Yang, Jiajia; Ogasa, Takashi

    2010-01-01

    The characteristics of raised-line drawing discrimination can be defined as the sum of the discriminability of the length, curvature, and angles of the edges. The size of the angle between two edges constitutes an important feature of these tactile stimuli. In the first experiment, five standard angles (30 degrees, 60 degrees, 90 degrees, 120 degrees, and 150 degrees) and twenty comparison angles for each standard angle were used to investigate the human capacity for tactile discrimination of raised angles by passive finger movement. The subjects in this study were asked to identify the larger angle of each pair by passive finger movement. We found that the threshold doubled when the standard angle was increased from 30 degrees to 90 degrees; however, the threshold remained unchanged when the standard angle was greater than 90 degrees. In the second experiment, to investigate the influence of the endpoints on angle discriminability, we used one standard angle (60 degrees) and seven comparison angles that changed in four bisector orientations. The results indicate that cutaneous feedback from the local apex and endpoints of the angle contributed to the discrimination of acute angles. Taken together, these results suggest that, when an acute angle is presented, both local apex and endpoint informations are used, while cutaneous mechanoreceptors rely more on apex information to discriminate the angle size when an obtuse angle is presented.

  16. Compression failure of angle-ply laminates

    NASA Technical Reports Server (NTRS)

    Peel, Larry D.; Hyer, Michael W.; Shuart, Mark J.

    1991-01-01

    The present work deals with modes and mechanisms of failure in compression of angle-ply laminates. Experimental results were obtained from 42 angle-ply IM7/8551-7a specimens with a lay-up of ((plus or minus theta)/(plus or minus theta)) sub 6s where theta, the off-axis angle, ranged from 0 degrees to 90 degrees. The results showed four failure modes, these modes being a function of off-axis angle. Failure modes include fiber compression, inplane transverse tension, inplane shear, and inplane transverse compression. Excessive interlaminar shear strain was also considered as an important mode of failure. At low off-axis angles, experimentally observed values were considerably lower than published strengths. It was determined that laminate imperfections in the form of layer waviness could be a major factor in reducing compression strength. Previously developed linear buckling and geometrically nonlinear theories were used, with modifications and enhancements, to examine the influence of layer waviness on compression response. The wavy layer is described by a wave amplitude and a wave length. Linear elastic stress-strain response is assumed. The geometrically nonlinear theory, in conjunction with the maximum stress failure criterion, was used to predict compression failure and failure modes for the angle-ply laminates. A range of wave length and amplitudes were used. It was found that for 0 less than or equal to theta less than or equal to 15 degrees failure was most likely due to fiber compression. For 15 degrees less than theta less than or equal to 35 degrees, failure was most likely due to inplane transverse tension. For 35 degrees less than theta less than or equal to 70 degrees, failure was most likely due to inplane shear. For theta less than 70 degrees, failure was most likely due to inplane transverse compression. The fiber compression and transverse tension failure modes depended more heavily on wave length than on wave amplitude. Thus using a single

  17. Probe Without Moving Parts Measures Flow Angle

    NASA Technical Reports Server (NTRS)

    Corda, Stephen; Vachon, M. Jake

    2003-01-01

    The measurement of local flow angle is critical in many fluid-dynamic applications, including the aerodynamic flight testing of new aircraft and flight systems. Flight researchers at NASA Dryden Flight Research Center have recently developed, flight-tested, and patented the force-based flow-angle probe (FLAP), a novel, force-based instrument for the measurement of local flow direction. Containing no moving parts, the FLAP may provide greater simplicity, improved accuracy, and increased measurement access, relative to conventional moving vane-type flow-angle probes. Forces in the FLAP can be measured by various techniques, including those that involve conventional strain gauges (based on electrical resistance) and those that involve more advanced strain gauges (based on optical fibers). A correlation is used to convert force-measurement data to the local flow angle. The use of fiber optics will enable the construction of a miniature FLAP, leading to the possibility of flow measurement in very small or confined regions. This may also enable the tufting of a surface with miniature FLAPs, capable of quantitative flow-angle measurements, similar to attaching yarn tufts for qualitative measurements. The prototype FLAP was a small, aerodynamically shaped, low-aspect-ratio fin about 2 in. (approximately equal to 5 cm) long, 1 in. (approximately equal to 2.5 cm) wide, and 0.125 in. (approximately equal to 0.3 cm) thick (see Figure 1). The prototype FLAP included simple electrical-resistance strain gauges for measuring forces. Four strain gauges were mounted on the FLAP; two on the upper surface and two on the lower surface. The gauges were connected to form a full Wheatstone bridge, configured as a bending bridge. In preparation for a flight test, the prototype FLAP was mounted on the airdata boom of a flight-test fixture (FTF) on the NASA Dryden F-15B flight research airplane.

  18. A genotypic mutation system measuring mutations in restriction recognition sequences.

    PubMed Central

    Felley-Bosco, E; Pourzand, C; Zijlstra, J; Amstad, P; Cerutti, P

    1991-01-01

    The RFLP/PCR approach (restriction fragment length polymorphism/polymerase chain reaction) to genotypic mutation analysis described here measures mutations in restriction recognition sequences. Wild-type DNA is restricted before the resistant, mutated sequences are amplified by PCR and cloned. We tested the capacity of this experimental design to isolate a few copies of a mutated sequence of the human c-Ha-ras1 gene from a large excess of wild-type DNA. For this purpose we constructed a 272 bp fragment with 2 mutations in the PvuII recognition sequence 1727-1732 and studied the rescue by RFLP/PCR of a few copies of this 'PvuII mutant standard'. Following amplification with Taq-polymerase and cloning into lambda gt10, plaques containing wild-type sequence, PvuII mutant standard or Taq-polymerase induced bp changes were quantitated by hybridization with specific oligonucleotide probes. Our results indicate that 10 PvuII mutant standard copies can be rescued from 10(8) to 10(9) wild-type sequences. Taq polymerase errors originating from unrestricted, residual wild-type DNA were sequence dependent and consisted mostly of transversions originating at G.C bp. In contrast to a doubly mutated 'standard' the capacity to rescue single bp mutations by RFLP/PCR is limited by Taq-polymerase errors. Therefore, we assessed the capacity of our protocol to isolate a G to T transversion mutation at base pair 1698 of the MspI-site 1695-1698 of the c-Ha-ras1 gene from excess wild-type ras1 DNA. We found that 100 copies of the mutated ras1 fragment could be readily rescued from 10(8) copies of wild-type DNA. Images PMID:1676153

  19. Optimal Number of Angle Images for Calculating Anterior Angle Volume and Iris Volume Measurements

    PubMed Central

    Blieden, Lauren S.; Chuang, Alice Z.; Baker, Laura A.; Bell, Nicholas P.; Fuller, Timothy S.; Mankiewicz, Kimberly A.; Feldman, Robert M.

    2015-01-01

    Purpose. We determined the optimal number of angle images required to obtain reliable measurements of trabecular-iris circumferential volume (TICV) and iris volume (IV) using swept-source Fourier domain anterior segment optical coherence tomography (SSFD-ASOCT) scans in narrow angle eyes. Methods. Scleral spur landmarks (SSL) were manually identified on ASOCT angle images from 128 meridians from each of 24 eyes with chronic primary angle closure (PAC) spectrum of disease. The anterior and posterior corneal curves, and the anterior and posterior iris surfaces were identified automatically by the anterior chamber analysis and interpretation (ACAI) software, then manually examined and edited by the reader if required. Trabecular-iris circumferential volume at 750 μm from SSL (TICV750) and IV were subsequently calculated using varying numbers of angle images. Threshold error was determined to be less than the lower 95% confidence limit of mean absolute percent error (MAPE) of the change in TICV or IV resulting from laser peripheral iridotomy, which would be 17% for TICV and 5% for IV, based on previous studies. The optimal number of angle images was the smallest number of images where MAPE was less than this threshold for TICV and IV. Results. A total of 32 equally-spaced angle images (16 meridians) was required to estimate TICV750 and 16 angle images (8 meridians) to estimate IV. Both were within 4.6% and 1.6% of MAPE, respectively. Conclusions. It is possible to determine TICV and IV parameters reliably in narrow angles without evaluating all 128 meridians obtained with SSFD-ASOCT. PMID:25829412

  20. The Pluto System At Small Phase Angles

    NASA Astrophysics Data System (ADS)

    Verbiscer, Anne J.; Buie, Marc W.; Binzel, Richard; Ennico, Kimberly; Grundy, William M.; Olkin, Catherine B.; Showalter, Mark Robert; Spencer, John R.; Stern, S. Alan; Weaver, Harold A.; Young, Leslie; New Horizons Science Team

    2016-10-01

    Hubble Space Telescope observations of the Pluto system acquired during the New Horizons encounter epoch (HST Program 13667, M. Buie, PI) span the phase angle range from 0.06 to 1.7 degrees, enabling the measurement and characterization of the opposition effect for Pluto and its satellites at 0.58 microns using HST WFC3/UVIS with the F350LP filter, which has a broadband response and a pivot wavelength of 0.58 microns. At these small phase angles, differences in the opposition effect width and amplitude appear. The small satellites Nix and Hydra both exhibit a very narrow opposition surge, while the considerably larger moon Charon has a broader opposition surge. Microtextural surface properties derived from the shape and magnitude of the opposition surge of each surface contain a record of the collisional history of the system. We combine these small phase angle observations with those made at larger phase angles by the New Horizons Long Range Reconnaissance Imager (LORRI), which also has a broadband response with a pivot wavelength of 0.61 microns, to produce the most complete disk-integrated solar phase curves that we will have for decades to come. Modeling these disk-integrated phase curves generates sets of photometric parameters that will inform spectral modeling of the satellite surfaces as well as terrains on Pluto from spatially resolved New Horizons Ralph Linear Etalon Imaging Spectral Array (LEISA) data from 1.2 to 2.5 microns. Rotationally resolved phase curves of Pluto reveal opposition effects that only appear at phase angles less than 0.1 degree and have widths and amplitudes that are highly dependent on longitude and therefore on Pluto's diverse terrains. The high albedo region informally known as Sputnik Planum dominates the disk-integrated reflectance of Pluto on the New Horizons encounter hemisphere. These results lay the groundwork for observations at true opposition in 2018, when the Pluto system will be observable at phase angles so small that