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Sample records for livia kask lo

  1. Evaluation of environmental genotoxicity by comet assay in Columba livia.

    PubMed

    González-Acevedo, Anahi; García-Salas, Juan A; Gosálvez, Jaime; Fernández, José Luis; Dávila-Rodríguez, Martha I; Cerda-Flores, Ricardo M; Méndez-López, Luis F; Cortés-Gutiérrez, Elva I

    2016-01-01

    The concentrations of recognized or suspected genotoxic and carcinogenic agents found in the air of large cities and, in particular, developing countries, have raised concerns about the potential for chronic health effects in the populations exposed to them. The biomonitoring of environmental genotoxicity requires the selection of representative organisms as "sentinels," as well as the development of suitable and sensitive assays, such as those aimed at assessing DNA damage. The aim of this study was to evaluate DNA damage levels in erythrocytes from Columba livia living in the metropolitan area of Monterrey, Mexico, compared with control animals via comet assay, and to confirm the results via Micronuclei test (MN) and DNA breakage detection-fluorescence in situ hybridization (DBD-FISH). Our results showed a significant increase in DNA migration in animals from the area assayed compared with that observed in control animals sampled in non-contaminated areas. These results were confirmed by MN test and DBD-FISH. In conclusion, these observations confirm that the examination of erythrocytes from Columba livia via alkaline comet assay provides a sensitive and reliable end point for the detection of environmental genotoxicants. PMID:26608565

  2. Molecular cloning and sequencing analysis of the interferon receptor (IFNAR-1) from Columba livia

    PubMed Central

    Chang, Wei Shan

    2014-01-01

    Objective Partial sequence cloning of interferon receptor (IFNAR-1) of Columba livia. Material and methods In order to obtain a certain length (630 bp) of gene, a pair of primers was designed according to the conserved nucleotide sequence of Gallus (EU477527.1) and Taeniopygia guttata (XM_002189232.1) IFNAR-1 gene fragment that was published by GenBank. Special primers were designed by the Race method to amplify the 3'terminal cDNA. Results The Columba livia IFNAR-1 displayed 88.5%, 80.5% and 73.8% nucleotide identity to Falco peregrinus, Gallus and Taeniopygia guttata, respectively. Phylogenetic analysis of the IFNAR1 gene showed that the relationship of Columba livia, Falco peregrinus and chicken had high homology. Conclusions We successfully obtained a Columba livia IFNAR-1 gene partial sequence. Analysis of the genetic tree showed that the relationship of Columba livia and Falco peregrinus IFNAR-1 had high homology. This result can be used as reference for further research and practical application. PMID:26155117

  3. GFEChutes Lo-Fi

    NASA Technical Reports Server (NTRS)

    Gist, Emily; Turner, Gary; Shelton, Robert; Vautier, Mana; Shaikh, Ashraf

    2013-01-01

    NASA needed to provide a software model of a parachute system for a manned re-entry vehicle. NASA has parachute codes, e.g., the Descent Simulation System (DSS), that date back to the Apollo Program. Since the space shuttle did not rely on parachutes as its primary descent control mechanism, DSS has not been maintained or incorporated into modern simulation architectures such as Osiris and Antares, which are used for new mission simulations. GFEChutes Lo-Fi is an object-oriented implementation of conventional parachute codes designed for use in modern simulation environments. The GFE (Government Furnished Equipment), low-fidelity (Lo-Fi) parachute model (GFEChutes Lo-Fi) is a software package capable of modeling the effects of multiple parachutes, deployed concurrently and/or sequentially, on a vehicle during the subsonic phase of reentry into planetary atmosphere. The term "low-fidelity" distinguishes models that represent the parachutes as simple forces acting on the vehicle, as opposed to independent aerodynamic bodies. GFEChutes Lo-Fi was created from these existing models to be clean, modular, certified as NASA Class C software, and portable, or "plug and play." The GFE Lo-Fi Chutes Model provides basic modeling capability of a sequential series of parachute activities. Actions include deploying the parachute, changing the reefing on the parachute, and cutting away the parachute. Multiple chutes can be deployed at any given time, but all chutes in that case are assumed to behave as individually isolated chutes; there is no modeling of any interactions between deployed chutes. Drag characteristics of a deployed chute are based on a coefficient of drag, the face area of the chute, and the local dynamic pressure only. The orientation of the chute is approximately modeled for purposes of obtaining torques on the vehicle, but the dynamic state of the chute as a separate entity is not integrated - the treatment is simply an approximation. The innovation in GFEChutes

  4. Acute, fatal Sarcocystis calchasi-associated hepatitis in Roller pigeons (Columbia livia f. dom.) at Philadelphia Zoo

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four Roller pigeons (Columba livia f. dom.) at the Philadelphia Zoo died suddenly. Necropsy examination revealed macroscopic hepatitis. Microscopically, the predominant lesions were in liver, characterized with necrosis and mixed cell inflammatory response. Sarcocystis calchasi-like schizonts and fr...

  5. Stress-induced core temperature changes in pigeons (Columba livia).

    PubMed

    Bittencourt, Myla de Aguiar; Melleu, Fernando Falkenburger; Marino-Neto, José

    2015-02-01

    Changes in body temperature are significant physiological consequences of stressful stimuli in mammals and birds. Pigeons (Columba livia) prosper in (potentially) stressful urban environments and are common subjects in neurobehavioral studies; however, the thermal responses to stress stimuli by pigeons are poorly known. Here, we describe acute changes in the telemetrically recorded celomatic (core) temperature (Tc) in pigeons given a variety of potentially stressful stimuli, including transfer to a novel cage (ExC) leading to visual isolation from conspecifics, the presence of the experimenter (ExpR), gentle handling (H), sham intracelomatic injections (SI), and the induction of the tonic immobility (TI) response. Transfer to the ExC cage provoked short-lived hyperthermia (10-20 min) followed by a long-lasting and substantial decrease in Tc, which returned to baseline levels 2 h after the start of the test. After a 2-hour stay in the ExC, the other potentially stressful stimuli evoked only weak, marginally significant hyperthermic (ExpR, IT) or hypothermic (SI) responses. Stimuli delivered 26 h after transfer to the ExC induced definite and intense increases in Tc (ExpR, H) or hypothermic responses (SI). These Tc changes appear to be unrelated to modifications in general activity (as measured via telemetrically recorded actimetric data). Repeated testing failed to affect the hypothermic responses to the transference to the ExC, even after nine trials and at 1- or 8-day intervals, suggesting that the social (visual) isolation from conspecifics may be a strong and poorly controllable stimulus in this species. The present data indicated that stress-induced changes in Tc may be a consistent and reliable physiological parameter of stress but that they may also show stressor type-, direction- and species-specific attributes. PMID:25479572

  6. Mycoplasma columbinum Isolated From a Racing Pigeon ( Columba livia ) With Arthritis.

    PubMed

    Hellebuyck, Tom; Garmyn, An; De Cooman, Lien; Boyen, Filip; Pasmans, Frank; Martel, An

    2014-09-01

    A juvenile racing pigeon ( Columba livia ) was presented with drooping of the wing and inability to fly. On physical examination, the right shoulder joint was swollen. The pigeon was euthanatized and submitted for necropsy. An excessive amount of fibrin was present in the canalis triosseus with severe arthritis of the affected shoulder joint. A pure growth of Mycoplasma-like colonies was obtained on microbiological culture of the shoulder joint. A 16S ribosomal RNA gene-specific polymerase chain reaction assay was performed on the isolate and revealed 100% similarity with Mycoplasma columbinum . Although infectious arthritis in homing pigeons is primarily associated with paratyphoid and Streptococcus gallolyticus infection, clinical practitioners should consider the potential role of Mycoplasma columbinum in arthritis in pigeons. PMID:25843324

  7. Invasion of Flukes of the Echinostomatidae Family in Racing Pigeon ( Columba livia var. domestica) Lofts.

    PubMed

    Ledwoń, Aleksandra; Dolka, Beata; Piasecki, Tomasz; Dolka, Izabella; Szeleszczuk, Piotr

    2016-06-01

    Over 4 years, only two known cases of fluke invasions were diagnosed in racing pigeons ( Columba livia ) originating from different regions of Poland. In both cases, the invasion was characterized by a very high mortality (approximately 70%), and the source of the infestation was snails of the Lymnaeidae family eaten by pigeons. Fluke invasions in pigeons are extremely rare and to date have not been described in Poland. Therefore, the occurrence of the symptoms of hemorrhagic diarrhea and sudden deaths of either adult pigeons or nestlings were suspected to be associated with poisoning. Autopsy revealed an invasion of flukes causing hemorrhagic enteritis. Renal failure and spleen atrophy were also found in the birds. Using molecular biology techniques, infestation with the fluke Echinostoma revolutum was determined in the second case. PMID:27309299

  8. Helminth-bacteria interaction in the gut of domestic pigeon Columba livia domestica.

    PubMed

    Biswal, Debraj; Nandi, Anadi Prasad; Chatterjee, Soumendranath

    2016-03-01

    The present paper is an attempt to study the interaction between the helminth parasite and bacteria residing in the gut of domestic pigeon, Columba livia domestica. Biochemical and molecular characterization of the gut bacterial isolate were done and the isolate was identified as Staphylococcus sp. DB1 (JX442510). The interaction of Staphylococcus sp. with Cotugnia cuneata, an intestinal helminth parasite of domestic pigeon was studied on the basis of the difference between 'mean worm burden' of antibiotic treated infected pigeons and infected pigeons without any antibiotic treatment. The ANOVA and Tukey tests of the data obtained showed that antibiotic treatment reduced the mean worm burden significantly. The biochemical properties of Staphylococcus sp. DB1 (JX442510) also showed a mutualistic relationship with the physiology of C. cuneata. PMID:27065609

  9. Age-correlation of blood values in the rock pigeon (Columba livia).

    PubMed

    Prinzinger, Roland; Misovic, Andrea

    2010-07-01

    Hematological adaptations to age (1-17 years) and about variability per se for free-living rock pigeons Columba livia are presented. Increasing age is correlated with decreasing values of hematocrit and hemoglobin. A marked reduction of lactate dehydrogenase (EC 1.1.1.27) activity in the first 2-3 years may be caused by a training-based increase of the relative portion of the aerobically working red breast muscles (responsible for endurance) at the expense of the proportion of anaerobically working white breast muscles. The age-correlated increase in glucose could indicate a decreasing tolerance for carbohydrates. Optimal flight performance is achieved by the doves at an age of about 2-3 years; the high performance is retained until an age range of 7-9 years. PMID:20184962

  10. Astrometric Study of Lo 1339

    NASA Astrophysics Data System (ADS)

    Wiramihardja, S. D.; Arifyanto, M. I.; Sugianto, Y.; Kunjaya, C.

    2010-10-01

    We presented a preliminary result of astrometric study of galactic cluster Lo 1339 using proper motion data from UCAC2 catalog. We applied the maximum likelihood method to determine cluster membership by using the proper motion data. The Padova isochrones lines with solar metallicity were fitted upon the Color Magnitude Diagram in near-infrared to derive physical parameters of the cluster, where we obtained the age of cluster log t = 8.4+/-0.2, the distance of 1284+/-140 pc, and the absorption AJ = 0.26+/-0.13 mag with cluster diameter of 4.9+/-0.5 pc.

  11. Implicit learning in cotton-top tamarins (Saguinus oedipus) and pigeons (Columba livia).

    PubMed

    Locurto, Charles; Fox, Maura; Mazzella, Andrea

    2015-06-01

    There is considerable interest in the conditions under which human subjects learn patterned information without explicit instructions to learn that information. This form of learning, termed implicit or incidental learning, can be approximated in nonhumans by exposing subjects to patterned information but delivering reinforcement randomly, thereby not requiring the subjects to learn the information in order to be reinforced. Following acquisition, nonhuman subjects are queried as to what they have learned about the patterned information. In the present experiment, we extended the study of implicit learning in nonhumans by comparing two species, cotton-top tamarins (Saguinus oedipus) and pigeons (Columba livia), on an implicit learning task that used an artificial grammar to generate the patterned elements for training. We equated the conditions of training and testing as much as possible between the two species. The results indicated that both species demonstrated approximately the same magnitude of implicit learning, judged both by a random test and by choice tests between pairs of training elements. This finding suggests that the ability to extract patterned information from situations in which such learning is not demanded is of longstanding origin. PMID:25673101

  12. Endoscopic Vasectomy of Male Feral Pigeons (Columba livia) as a Possible Method of Population Control.

    PubMed

    Heiderich, Elisabeth; Schildger, Bernd; Lierz, Michael

    2015-03-01

    To evaluate whether single-entry endoscopic vasectomy of male feral pigeons (Columba livia) significantly reduced fertility and would potentially be valuable for control of feral pigeon populations, 252 male feral pigeons were caught in the city of Berne and endoscopically vasectomized. In this procedure, approximately 1 cm of the deferent duct was removed bilaterally. Rapid, uneventful recoveries occurred in 94% (237/252) of the pigeons, whereas 6% (15/252) died because of complications associated with the procedure, consisting of perforation of the ureter (9/15), major hemorrhage (5/15), and respiratory arrest (1/15). Mean anesthesia time was 23±6 minutes. The vasectomized males were habituated to 2 pigeon houses together with fertile females. Another pigeon house with fertile pairs acted as control. All eggs laid were candled weekly to assess fertility. In the 2 pigeon houses with vasectomized males, the mean fertilization rate was 0.9% (5/563), while in the control pigeon house, the rate was 100% (39/39). The results indicate that endoscopic vasectomy of male feral pigeons may be a promising tool for field control of feral pigeon populations, especially in combination with other methods such as pigeon houses. PMID:25867661

  13. Homing pigeons ( Columba livia f. domestica) can use magnetic cues for locating food

    NASA Astrophysics Data System (ADS)

    Thalau, Peter; Holtkamp-Rötzler, Elke; Fleissner, Gerta; Wiltschko, Wolfgang

    2007-10-01

    An experimental group of homing pigeons ( Columba livia f. domestica) learned to associate food with a magnetic anomaly produced by bar magnets that were fixed to the bowl in which they received their daily food ration in their home loft; the control group lacked this experience. Both groups were trained to search for two hidden food depots in a rectangular sand-filled arena without obvious visual cues; for the experimental birds, these depots were also marked with three 1.15 × 106 μT bar magnets. During the tests, there were two food depots, one marked with the magnets, the other unmarked; their position within the arena was changed from test to test. The experimental birds searched within 10 cm of the magnetically marked depot in 49% of the test sessions, whereas the control birds searched there in only 11% of the sessions. Both groups searched near the control depot in 11 and 13% of the sessions, respectively. The significant preference of the magnetically marked food depot by the experimental birds shows that homing pigeons cannot only detect a magnetic anomaly but can also use it as a cue for locating hidden food in an open arena.

  14. Acute, fatal Sarcocystis calchasi-associated hepatitis in Roller pigeons (Columba livia f. dom.) at Philadelphia Zoo.

    PubMed

    Trupkiewicz, J G; Calero-Bernal, R; Verma, S K; Mowery, J; Davison, S; Habecker, P; Georoff, T A; Ialeggio, D M; Dubey, J P

    2016-01-30

    Four Roller pigeons (Columba livia f. dom.) at the Philadelphia Zoo died suddenly. Necropsy examination revealed macroscopic hepatitis. Microscopically, the predominant lesions were in liver, characterized with necrosis and mixed cell inflammatory response. Sarcocystis calchasi-like schizonts and free merozoites were identified in liver. Transmission electron microscopy confirmed that schizonts were in hepatocytes. A few schizonts were in spleen. PCR using S. calchasi-specific primers confirmed the diagnosis. Neither lesions nor protozoa were found in brain and muscles. This is the first report of acute visceral S. calchasi-associated sarcocystosis in naturally infected avian hosts. PMID:26801595

  15. Monitoring air pollution at Mohammedia (Morocco): Pb, Cd and Zn in the blood of pigeons (Columba livia).

    PubMed

    Kouddane, N; Mouhir, L; Fekhaoui, M; Elabidi, A; Benaakame, R

    2016-05-01

    The concentrations of Pb, Cd and Zn were investigated in the blood of pigeons (Columba livia) in order to assess the degree of pollution by heavy metal. For this, wild city pigeons were caught at four different locations in Mohammedia classified according to their industrial activity and road traffic density. Significant difference in heavy metal concentrations were observed between sites studied, the highest lead and cadmium levels were found in industrial area and center town, while the highest zinc level was found in the less contaminated area. These results indicate that the industrial activities and the road traffic are the most important source of pollution. PMID:26903169

  16. Muscle function during takeoff and landing flight in the pigeon (Columba livia).

    PubMed

    Robertson, Angela M Berg; Biewener, Andrew A

    2012-12-01

    This study explored the muscle strain and activation patterns of several key flight muscles of the pigeon (Columba livia) during takeoff and landing flight. Using electromyography (EMG) to measure muscle activation, and sonomicrometry to quantify muscle strain, we evaluated the muscle function patterns of the pectoralis, biceps, humerotriceps and scapulotriceps as pigeons flew between two perches. These recordings were analyzed in the context of three-dimensional wing kinematics. To understand the different requirements of takeoff, midflight and landing, we compared the activity and strain of these muscles among the three flight modes. The pectoralis and biceps exhibited greater fascicle strain rates during takeoff than during midflight or landing. However, the triceps muscles did not exhibit notable differences in strain among flight modes. All observed strain, activation and kinematics were consistent with hypothesized muscle functions. The biceps contracted to stabilize and flex the elbow during the downstroke. The humerotriceps contracted to extend the elbow at the upstroke-downstroke transition, followed by scapulotriceps contraction to maintain elbow extension during the downstroke. The scapulotriceps also appeared to contribute to humeral elevation. Greater muscle activation intensity was observed during takeoff, compared with mid-flight and landing, in all muscles except the scapulotriceps. The timing patterns of muscle activation and length change differed among flight modes, yet demonstrated that pigeons do not change the basic mechanical actions of key flight muscles as they shift from flight activities that demand energy production, such as takeoff and midflight, to maneuvers that require absorption of energy, such as landing. Similarly, joint kinematics were consistent among flight modes. The stereotypy of these neuromuscular and joint kinematic patterns is consistent with previously observed stereotypy of wing kinematics relative to the pigeon's body

  17. Pigeons (Columba livia) as Trainable Observers of Pathology and Radiology Breast Cancer Images

    PubMed Central

    Levenson, Richard M.; Krupinski, Elizabeth A.; Navarro, Victor M.; Wasserman, Edward A.

    2015-01-01

    Pathologists and radiologists spend years acquiring and refining their medically essential visual skills, so it is of considerable interest to understand how this process actually unfolds and what image features and properties are critical for accurate diagnostic performance. Key insights into human behavioral tasks can often be obtained by using appropriate animal models. We report here that pigeons (Columba livia)—which share many visual system properties with humans—can serve as promising surrogate observers of medical images, a capability not previously documented. The birds proved to have a remarkable ability to distinguish benign from malignant human breast histopathology after training with differential food reinforcement; even more importantly, the pigeons were able to generalize what they had learned when confronted with novel image sets. The birds’ histological accuracy, like that of humans, was modestly affected by the presence or absence of color as well as by degrees of image compression, but these impacts could be ameliorated with further training. Turning to radiology, the birds proved to be similarly capable of detecting cancer-relevant microcalcifications on mammogram images. However, when given a different (and for humans quite difficult) task—namely, classification of suspicious mammographic densities (masses)—the pigeons proved to be capable only of image memorization and were unable to successfully generalize when shown novel examples. The birds’ successes and difficulties suggest that pigeons are well-suited to help us better understand human medical image perception, and may also prove useful in performance assessment and development of medical imaging hardware, image processing, and image analysis tools. PMID:26581091

  18. Pigeons (Columba livia) as Trainable Observers of Pathology and Radiology Breast Cancer Images.

    PubMed

    Levenson, Richard M; Krupinski, Elizabeth A; Navarro, Victor M; Wasserman, Edward A

    2015-01-01

    Pathologists and radiologists spend years acquiring and refining their medically essential visual skills, so it is of considerable interest to understand how this process actually unfolds and what image features and properties are critical for accurate diagnostic performance. Key insights into human behavioral tasks can often be obtained by using appropriate animal models. We report here that pigeons (Columba livia)-which share many visual system properties with humans-can serve as promising surrogate observers of medical images, a capability not previously documented. The birds proved to have a remarkable ability to distinguish benign from malignant human breast histopathology after training with differential food reinforcement; even more importantly, the pigeons were able to generalize what they had learned when confronted with novel image sets. The birds' histological accuracy, like that of humans, was modestly affected by the presence or absence of color as well as by degrees of image compression, but these impacts could be ameliorated with further training. Turning to radiology, the birds proved to be similarly capable of detecting cancer-relevant microcalcifications on mammogram images. However, when given a different (and for humans quite difficult) task-namely, classification of suspicious mammographic densities (masses)-the pigeons proved to be capable only of image memorization and were unable to successfully generalize when shown novel examples. The birds' successes and difficulties suggest that pigeons are well-suited to help us better understand human medical image perception, and may also prove useful in performance assessment and development of medical imaging hardware, image processing, and image analysis tools. PMID:26581091

  19. Discovery and characterization of the first genuine avian leptin gene in the rock dove (Columba livia).

    PubMed

    Friedman-Einat, Miriam; Cogburn, Larry A; Yosefi, Sara; Hen, Gideon; Shinder, Dmitry; Shirak, Andrey; Seroussi, Eyal

    2014-09-01

    Leptin, the key regulator of mammalian energy balance, has been at the center of a great controversy in avian biology for the last 15 years since initial reports of a putative leptin gene (LEP) in chickens. Here, we characterize a novel LEP in rock dove (Columba livia) with low similarity of the predicted protein sequence (30% identity, 47% similarity) to the human ortholog. Searching the Sequence-Read-Archive database revealed leptin transcripts, in the dove's liver, with 2 noncoding exons preceding 2 coding exons. This unusual 4-exon structure was validated by sequencing of a GC-rich product (76% GC, 721 bp) amplified from liver RNA by RT-PCR. Sequence alignment of the dove leptin with orthologous leptins indicated that it consists of a leader peptide (21 amino acids; aa) followed by the mature protein (160 aa), which has a putative structure typical of 4-helical-bundle cytokines except that it is 12 aa longer than human leptin. Extra residues (10 aa) were located within the loop between 2 5'-helices, interrupting the amino acid motif that is conserved in tetrapods and considered essential for activation of leptin receptor (LEPR) but not for receptor binding per se. Quantitative RT-PCR of 11 tissues showed highest (P < .05) expression of LEP in the dove's liver, whereas the dove LEPR peaked (P < .01) in the pituitary. Both genes were prominently expressed in the gonads and at lower levels in tissues involved in mammalian leptin signaling (adipose; hypothalamus). A bioassay based on activation of the chicken LEPR in vitro showed leptin activity in the dove's circulation, suggesting that dove LEP encodes an active protein, despite the interrupted loop motif. Providing tools to study energy-balance control at an evolutionary perspective, our original demonstration of leptin signaling in dove predicts a more ancient role of leptin in growth and reproduction in birds, rather than appetite control. PMID:24758303

  20. Defensive behaviors and prosencephalic neurogenesis in pigeons (Columba livia) are affected by environmental enrichment in adulthood.

    PubMed

    Melleu, F F; Pinheiro, M V; Lino-de-Oliveira, C; Marino-Neto, J

    2016-05-01

    Neurogenesis in the adult brain appears to be phylogenetically conserved across the animal kingdom. In pigeons and other adult non-oscine birds, immature neurons are observed in several prosencephalic areas, suggesting that neurogenesis may participate in the control of different behaviors. The mechanisms controlling neurogenesis and its relevance to defensive behaviors in non-oscine birds remain elusive. Herein, the contribution of the environment to behavior and neurogenesis of pigeons was investigated. Adult pigeons (Columba livia, n = 6/group), housed in standard (SE) or enriched environment (EE) for 42 days, were exposed to an unfamiliar environment (UE) followed by presentation to a novel object (NO). Video recordings of UE+NO tests were analyzed and scored for latency, duration and frequency of angular head movements, peeping, grooming, immobility and locomotion. Twenty-four hours later, pigeons were submitted to the tonic immobility test (TI) and number of trials for TI and TI duration were scored, followed by euthanasia 2 h later. Brains were immunohistochemically processed to reveal doublecortin (DCX), a marker for newborn neurons. Compared to those housed in SE, the pigeons housed in EE responded to a NO with more immobility. In addition, the pigeons housed in EE presented longer TI, more DCX-immunoreactive (DCX-ir) cells in the hippocampus and fewer DCX-ir cells in the lateral striatum than those housed in SE. There was no correlation between the number of DCX-ir cells and the scores of immobility in behavioral tests. Together, these data suggest that enrichment favored behavioral inhibition and neurogenesis in the adult pigeons through different, parallel mechanisms. PMID:25869276

  1. Photocurrents in retinal rods of pigeons (Columba livia): kinetics and spectral sensitivity.

    PubMed Central

    Palacios, A G; Goldsmith, T H

    1993-01-01

    1. Membrane photocurrents were recorded from outer segments of isolated retinal rods of pigeons (Columba livia), the first such measurements on the photoreceptors of a bird. The amplitude of the response to 20 ms flashes of narrow wavelength bands of light increases linearly with intensity at low photon fluxes and saturates at higher intensities. The maximum (saturating) photocurrent observed in forty-nine rod cells was 50 pA. Larger responses with less variability in the intensity for half-maximal responses were observed when the physiological saline contained 20 mM bicarbonate (in addition to Hepes buffer). 2. The dependence of peak amplitude on intensity is well fitted by an exponential function; it is usually less well fitted by the Michaelis-Menten (Naka-Rushton) equation. 3. In the presence of bicarbonate, the average sensitivity of pigeon rods to dim flashes was 0.56 pA photon-1 microns -2. The effective collecting area per photon was 1.8 microns 2. About 83 +/- 26 (mean +/- S.D.) photoisomerizations were required for a half-saturating response. 4. The response kinetics of rods to dim flashes can be reasonably well described by a series of four to five either Poisson or independent filters. The time to peak, measured from the mid-point of a 20 ms flash, was 319 +/- 83 ms (mean +/- S.D.). The integration time of the response was 851 +/- 86 ms (mean +/- S.D.) with bicarbonate present and 572 +/- 126 ms in the absence of bicarbonate. The responses of pigeon rods appear to be slower than those of mammals at the same temperature. The fraction of current suppressed by a single photoisomerization is smaller in pigeon than in mammalian rods by a factor of at least two. 5. The spectral sensitivity function was measured between 680 and 330 nm. The maximum at about 505 nm (range 497-508 nm) corresponds to the alpha-band of a vertebrate rhodopsin and agrees with previous behavioural measurements of scotopic sensitivity of pigeons as well as the absorption spectrum of

  2. LoWMob: Intra-PAN Mobility Support Schemes for 6LoWPAN.

    PubMed

    Bag, Gargi; Raza, Muhammad Taqi; Kim, Ki-Hyung; Yoo, Seung-Wha

    2009-01-01

    Mobility in 6LoWPAN (IPv6 over Low Power Personal Area Networks) is being utilized in realizing many applications where sensor nodes, while moving, sense and transmit the gathered data to a monitoring server. By employing IEEE802.15.4 as a baseline for the link layer technology, 6LoWPAN implies low data rate and low power consumption with periodic sleep and wakeups for sensor nodes, without requiring them to incorporate complex hardware. Also enabling sensor nodes with IPv6 ensures that the sensor data can be accessed anytime and anywhere from the world. Several existing mobility-related schemes like HMIPv6, MIPv6, HAWAII, and Cellular IP require active participation of mobile nodes in the mobility signaling, thus leading to the mobility-related changes in the protocol stack of mobile nodes. In this paper, we present LoWMob, which is a network-based mobility scheme for mobile 6LoWPAN nodes in which the mobility of 6LoWPAN nodes is handled at the network-side. LoWMob ensures multi-hop communication between gateways and mobile nodes with the help of the static nodes within a 6LoWPAN. In order to reduce the signaling overhead of static nodes for supporting mobile nodes, LoWMob proposes a mobility support packet format at the adaptation layer of 6LoWPAN. Also we present a distributed version of LoWMob, named as DLoWMob (or Distributed LoWMob), which employs Mobility Support Points (MSPs) to distribute the traffic concentration at the gateways and to optimize the multi-hop routing path between source and destination nodes in a 6LoWPAN. Moreover, we have also discussed the security considerations for our proposed mobility schemes. The performance of our proposed schemes is evaluated in terms of mobility signaling costs, end-to-end delay, and packet success ratio. PMID:22346730

  3. Specialized and independent processing of orientation and shape in visual field maps LO1 and LO2.

    PubMed

    Silson, Edward H; McKeefry, Declan J; Rodgers, Jessica; Gouws, Andre D; Hymers, Mark; Morland, Antony B

    2013-03-01

    We identified human visual field maps, LO1 and LO2, in object-selective lateral occipital cortex. Using transcranial magnetic stimulation (TMS), we assessed the functions of these maps in the perception of orientation and shape. TMS of LO1 disrupted orientation, but not shape, discrimination, whereas TMS of LO2 disrupted shape, but not orientation, discrimination. This double dissociation suggests that specialized and independent processing of different visual attributes occurs in LO1 and LO2. PMID:23377127

  4. Precision Pointing of IBEX-Lo Observations

    NASA Astrophysics Data System (ADS)

    Hłond, M.; Bzowski, M.; Möbius, E.; Kucharek, H.; Heirtzler, D.; Schwadron, N. A.; O'Neill, M. E.; Clark, G.; Crew, G. B.; Fuselier, S.; McComas, D. J.

    2012-02-01

    Post-launch boresight of the IBEX-Lo instrument on board the Interstellar Boundary Explorer (IBEX) is determined based on IBEX-Lo Star Sensor observations. Accurate information on the boresight of the neutral gas camera is essential for precise determination of interstellar gas flow parameters. Utilizing spin-phase information from the spacecraft attitude control system (ACS), positions of stars observed by the Star Sensor during two years of IBEX measurements were analyzed and compared with positions obtained from a star catalog. No statistically significant differences were observed beyond those expected from the pre-launch uncertainty in the Star Sensor mounting. Based on the star observations and their positions in the spacecraft reference system, pointing of the IBEX satellite spin axis was determined and compared with the pointing obtained from the ACS. Again, no statistically significant deviations were observed. We conclude that no systematic correction for boresight geometry is needed in the analysis of IBEX-Lo observations to determine neutral interstellar gas flow properties. A stack-up of uncertainties in attitude knowledge shows that the instantaneous IBEX-Lo pointing is determined to within ~0fdg1 in both spin angle and elevation using either the Star Sensor or the ACS. Further, the Star Sensor can be used to independently determine the spacecraft spin axis. Thus, Star Sensor data can be used reliably to correct the spin phase when the Star Tracker (used by the ACS) is disabled by bright objects in its field of view. The Star Sensor can also determine the spin axis during most orbits and thus provides redundancy for the Star Tracker.

  5. PRECISION POINTING OF IBEX-Lo OBSERVATIONS

    SciTech Connect

    Hlond, M.; Bzowski, M.; Moebius, E.; Kucharek, H.; Heirtzler, D.; Schwadron, N. A.; Neill, M. E. O'; Clark, G.; Crew, G. B.; Fuselier, S.; McComas, D. J. E-mail: eberhard.moebius@unh.edu E-mail: stephen.a.fuselier@linco.com E-mail: DMcComas@swri.edu

    2012-02-01

    Post-launch boresight of the IBEX-Lo instrument on board the Interstellar Boundary Explorer (IBEX) is determined based on IBEX-Lo Star Sensor observations. Accurate information on the boresight of the neutral gas camera is essential for precise determination of interstellar gas flow parameters. Utilizing spin-phase information from the spacecraft attitude control system (ACS), positions of stars observed by the Star Sensor during two years of IBEX measurements were analyzed and compared with positions obtained from a star catalog. No statistically significant differences were observed beyond those expected from the pre-launch uncertainty in the Star Sensor mounting. Based on the star observations and their positions in the spacecraft reference system, pointing of the IBEX satellite spin axis was determined and compared with the pointing obtained from the ACS. Again, no statistically significant deviations were observed. We conclude that no systematic correction for boresight geometry is needed in the analysis of IBEX-Lo observations to determine neutral interstellar gas flow properties. A stack-up of uncertainties in attitude knowledge shows that the instantaneous IBEX-Lo pointing is determined to within {approx}0.{sup 0}1 in both spin angle and elevation using either the Star Sensor or the ACS. Further, the Star Sensor can be used to independently determine the spacecraft spin axis. Thus, Star Sensor data can be used reliably to correct the spin phase when the Star Tracker (used by the ACS) is disabled by bright objects in its field of view. The Star Sensor can also determine the spin axis during most orbits and thus provides redundancy for the Star Tracker.

  6. Heterotopic implantation of autologous bone marrow in rock pigeons (Columba livia): possible applications in avian bone grafting.

    PubMed

    Sanaei, M Reza; Abu, Jalila; Nazari, Mojgan; Faiz, Nik Mohd; Bakar, Mohd Zuki Abu; Allaudin, Zeenathul N

    2011-12-01

    Autologous bone marrow, alone or as a composite marrow graft, has received much attention in various species. To assess the potential osteogenicity of autologous, extramedullary bone marrow implants in an avian model, 24 adult pigeons (Columba livia) were given intramuscular implantations of autologous marrow aspirated from the medial tibiotarsus. Birds were euthanatized at 1, 4, 6, 8, 10, and 12 weeks after surgery to evaluate whether ectopic bone had formed at the implant sites. Primary evaluations by in situ radiography and postmortem histologic examinations showed no evidence of bone formation. Further evaluation with histologic scores and histomorphometry revealed a significantly increased rate of angiogenesis at the implant sites by the sixth and tenth week postimplantation (P < .05). No significant differences between the treatment and control sites were present at any other endpoints. Results of this study show that, although autologous bone marrow lacks heterotopic osteogenic potentials in this avian model, it could still function as a useful adjunct to routine bone grafting techniques because of its unique capabilities to promote early angiogenesis. PMID:22458179

  7. Who are the real bird brains? Qualitative differences in behavioral flexibility between dogs (Canis familiaris) and pigeons (Columba livia).

    PubMed

    Laude, Jennifer R; Pattison, Kristina F; Rayburn-Reeves, Rebecca M; Michler, Daniel M; Zentall, Thomas R

    2016-01-01

    Pigeons given a simultaneous spatial discrimination reversal, in which a single reversal occurs at the midpoint of each session, consistently show anticipation prior to the reversal as well as perseveration after the reversal, suggesting that they use a less effective cue (time or trial number into the session) than what would be optimal to maximize reinforcement (local feedback from the most recent trials). In contrast, rats (Rattus norvegicus) and humans show near-optimal reversal learning on this task. To determine whether this is a general characteristic of mammals, in the present research, pigeons (Columba livia) and dogs (Canis familiaris) were tested with a simultaneous spatial discrimination mid-session reversal. Overall, dogs performed the task more poorly than pigeons. Interestingly, both pigeons and dogs employed what resembled a timing strategy. However, dogs showed greater perseverative errors, suggesting that they may have relatively poorer working memory and inhibitory control with this task. The greater efficiency shown by pigeons with this task suggests they are better able to time and use the feedback from their preceding choice as the basis of their future choice, highlighting what may be a qualitative difference between the species. PMID:26364290

  8. Chlamydia psittaci genotype B in a pigeon (Columba livia) inhabiting a public place in San José, Costa Rica

    PubMed Central

    Dolz, G.; Solórzano-Morales, Á.; Angelova, L.; Tien, C.; Fonseca, L.; Bonilla, M.C.

    2013-01-01

    Human chlamydiosis is a zoonotic disease of avian origin caused by Chlamydia psittaci. The highest infection rates have been detected in parrots (Psittacidae) and pigeons (Columbiformes), the latter most frequently carry the genotypes B and E. These genotypes have been shown to also infect humans. Because pigeons (Columba livia) cohabit with humans in urban areas, C. psittaci present in the dust from dry feces of infected pigeons may be transmitted by inhalation and represent a significant public health problem. Between 2012 and 2013 a total of 120 fecal samples were collected from pigeons at four public places (Plaza de la Cultura, Parque Morazán, Parque Central de Guadalupe, Plaza de las Garantías Sociales) in San José, Costa Rica. A nested polymerase chain reaction (PCR) was used to amplify a region of the outer membrane protein A gene of C. psittaci. Only one sample was positive in PCR and the positive sample was further subjected to sequencing and genotyping. Sequencing identified this sample as C. psittaci genotype B. This study is the first report to show the presence of this organism in pigeons of Costa Rica, and shows that the infected pigeons may represent a significant risk for humans who visit public places that are inhabited by pigeons. PMID:26623327

  9. Quantitative ultrasound, magnetic resonance imaging, and histologic image analysis of hepatic iron accumulation in pigeons (Columbia livia).

    PubMed

    Matheson, Jodi S; Paul-Murphy, Joanne; O'Brien, Robert T; Steinberg, Howard

    2007-06-01

    Iron overload was induced by iron dextran i.v. in clinically healthy adult pigeons, Columbia livia, (n = 8). Hemosiderosis was induced in all treated birds. Two control pigeons received no iron injections. Pigeons did not show clinical signs of iron overload during the 6-wk study. Ultrasound examination of the liver in the pigeons receiving iron dextran was performed on days 0, 13, 28, and 42. No ultrasound images were collected on the control pigeons. Magnetic resonance imaging was performed on days 0, 13, 28, and 42 on all study pigeons and imaging sequences were collected in three different imaging formats: T1, T2, and gradient-recalled echo (GRE). Surgical liver biopsies were performed on pigeons receiving iron dextran on days 2, 16, and 45 (at necropsy). A single liver sample was collected at necropsy from the control birds. Histologic examination, quantitative image analysis, and tissue iron analysis by thin-layer chromatography were performed on each liver sample and compared to the imaging studies. Although hemosiderosis was confirmed histologically in each experimental pigeon, no significant change in pixel intensity of the ultrasound images was seen at any point in the study. Signal intensity, in all magnetic resonance imaging formats, significantly decreased in a linear fashion as the accumulation of iron increased. PMID:17679505

  10. The effect of alpha2-adrenergic receptors on cutaneous water evaporation in the rock pigeon (Columba livia).

    PubMed

    Ophir, Eshel; Arieli, Yehuda; Marder, Jacob

    2004-12-01

    The role of beta-adrenergic receptors in regulating cutaneous water evaporation (CWE) in the rock pigeon (Columba livia) is well documented. Here, we studied the involvement of the alpha2-adrenergic receptors in this cooling mechanism of the heat-acclimated (HAc) pigeon. Systemic alpha2-adrenergic activation [clonidine, 50 microg kg(-1), intramuscular (i.m.)] was found to increase CWE in heat-acclimated pigeons at an ambient temperature (T(a)) of 25 degrees C. Subcutaneous administration of the drug had no significant effect. Preinjection of an alpha2-adrenergic antagonist (yohimbine, 10 mg kg(-1), i.m.) completely prevented clonidine-induced CWE and attenuated propranolol-induced CWE by 53%. Pretreatment with a beta-adrenergic agonist (isoproterenol, 4 mg kg(-1), i.m.) abolished the effect of clonidine. None of the above treatments was found to elicit significant CWE in nonacclimated (NAc) pigeons. These findings, in addition to previously reported data, indicate a complex regulatory pathway of CWE in the heat-acclimated pigeon consisting of alpha2- and beta2-adrenergic receptors. The possible hierarchical pattern of these receptors is discussed. PMID:15596385

  11. Chlamydia psittaci genotype B in a pigeon (Columba livia) inhabiting a public place in San José, Costa Rica.

    PubMed

    Dolz, G; Solórzano-Morales, Á; Angelova, L; Tien, C; Fonseca, L; Bonilla, M C

    2013-01-01

    Human chlamydiosis is a zoonotic disease of avian origin caused by Chlamydia psittaci. The highest infection rates have been detected in parrots (Psittacidae) and pigeons (Columbiformes), the latter most frequently carry the genotypes B and E. These genotypes have been shown to also infect humans. Because pigeons (Columba livia) cohabit with humans in urban areas, C. psittaci present in the dust from dry feces of infected pigeons may be transmitted by inhalation and represent a significant public health problem. Between 2012 and 2013 a total of 120 fecal samples were collected from pigeons at four public places (Plaza de la Cultura, Parque Morazán, Parque Central de Guadalupe, Plaza de las Garantías Sociales) in San José, Costa Rica. A nested polymerase chain reaction (PCR) was used to amplify a region of the outer membrane protein A gene of C. psittaci. Only one sample was positive in PCR and the positive sample was further subjected to sequencing and genotyping. Sequencing identified this sample as C. psittaci genotype B. This study is the first report to show the presence of this organism in pigeons of Costa Rica, and shows that the infected pigeons may represent a significant risk for humans who visit public places that are inhabited by pigeons. PMID:26623327

  12. Lo Gnomone Clementino Astronomia Meridiana in Basilica

    NASA Astrophysics Data System (ADS)

    Sigismondi, Costantino

    2014-05-01

    Costruito per chiara volontà del papa 70 anni dopo il caso Galileo, lo Gnomone Clementino è un grande telescopio solare che non fa uso di lenti a 92 anni dall’invenzione del cannocchiale. Queste due caratteristiche basterebbero da sole a giustificare l’interesse verso questo strumento. L’astronomia meridiana è alla base dell’astrometria e dell’astrofisica moderna. Lo Gnomone Clementino sta oggi all’astronomia, come il veliero “Amerigo Vespucci” sta alla Marina Italiana. E’ possibile svolgere ogni genere di osservazione e studio su questo strumento, e dal 2002 vi tengo lezioni teorico-pratiche del corso di Storia dell’Astronomia e La Terra nel Sistema Solare della Sapienza, Università di Roma, Facoltà di Lettere e Filosofia. Questo testo aggiunge alcuni tasselli alla ricerca storica sulla meridiana, appoggiandosi, com’è naturale, sulle spalle di giganti che mi hanno preceduto in questi studi. In particolare la misura dell’azimut della meridiana, ed il suo inquadramento tra gli strumenti simili ed alcuni studi di astrometria sui dati del 1701-1703 di Bianchini, che sono apparsi fin’ora soltanto su riviste specializzate ed in Inglese vengono qui proposti in Italiano e semplificati, per valorizzare sempre più questa straordinaria opera d’arte e di scienza.

  13. Starspots on LO Pegasi, 2006-2015

    NASA Astrophysics Data System (ADS)

    Harmon, Robert O.; Chalmers, Mark; Geda, Robel; Henry, Brandi; Sliupas, Viesulas

    2016-01-01

    LO Pegasi is a rapidly rotating (P = 10.154 hr) young solar analog (spectral class K5-7V) variable star of BY Dra type that exhibits dark starspots on its surface that modulate its brightness as they are carried into and out of view by the star's rotation. Surface maps of the spot distribution were produced based on BVRI photometry obtained at Perkins Observatory from 2006-2015. The maps were generated from the light curves via a non-linear inversion algorithm that uses the differences in the limb darkening through different filter passbands to improve the latitude resolution of the maps. We present an analysis of variations in the size of a polar spot suggested by changes in the average brightness and the amplitude of the rotational modulation from year to year.

  14. Starspots on LO Pegasi, 2006-2014

    NASA Astrophysics Data System (ADS)

    Harmon, Robert O.; Berry, Dominique; Chalmers, Mark; Denison, Josh; Stevens, Don; Yuhas, Kaylee

    2015-01-01

    BVRI light curves of LO Pegasi obtained at Perkins Observatory (Ohio Wesleyan University) from 2006-2014 were used to study the evolution of starspots on its surface over that interval. We present surface maps obtained via a constrained non-linear inversion algorithm that uses variations in limb darkening as seen through different filters to improve the latitude resolution of the reconstructions. In addition, a detailed period analysis of the entire data set using the ANOVA method was performed to search for variations associated with differential rotation. No evidence of period change was found, as the periods for each year were equal to within their uncertainties. For the data set as a whole, the period of rotation was determined to be 10.1538 ± 0.0009 hr, in agreement with previously published results.

  15. Stellar Surface Imaging of LO Pegasi

    NASA Astrophysics Data System (ADS)

    Decker, Rachel; Moore, Conrad; Harmon, Robert

    2008-10-01

    We present images of dark starspots on the surface of the K8 main-sequence star LO Pegasi. CCD camera images of the star and surrounding field were acquired through B, V, R and I filters at Perkins Observatory in Delaware, OH on clear nights in June and July, 2008. The images were dark-subtracted and flat-fielded and then aperture photometry was performed to yield light curves through each of the four filters. These light curves were then simultaneously inverted via an algorithm devised by one of us (Harmon) so as to yield images of the spots based on the rotational modulation they produced in the light curves. The use of multiple filters significantly improves the latitude resolution of the reconstructions. Comparison of our results with results from 2006 and 2007 shows that the spot structure was more complex in 2008 than in the prior years.

  16. Parasite distribution and early-stage encephalitis in Sarcocystis calchasi infections in domestic pigeons (Columba livia f. domestica).

    PubMed

    Maier, Kristina; Olias, Philipp; Enderlein, Dirk; Klopfleisch, Robert; Mayr, Sylvia L; Gruber, Achim D; Lierz, Michael

    2015-01-01

    Pigeon protozoal encephalitis is a biphasic, neurologic disease of domestic pigeons (Columba livia f. domestica) caused by the apicomplexan parasite Sarcocystis calchasi. Despite severe inflammatory lesions of the brain, associated parasitic stages have only rarely been identified and the cause of the lesions is still unclear. The aim of this study was therefore to characterize the tissue distribution of S. calchasi within pigeons between the two clinical phases and during the occurrence of neurological signs. For this purpose, a semi-quantitative real-time polymerase chain reaction (PCR) was developed. Forty-five domestic pigeons were infected orally (via a cannula into the crop) with 200 S. calchasi sporocysts and euthanized in groups of three pigeons at intervals of 2 to 10 days over a period of 61 days. Tissue samples including brain and skeletal muscle were examined by histology, immunohistochemistry, and PCR. Schizonts were detected in the liver of one pigeon at day 10 post infection. A mild encephalitis was detected at day 20 post infection, around 4 weeks before the onset of neurological signs. At the same time, immature sarcocysts were present in the skeletal muscle. In seven pigeons a few sarcocysts were identified in the brain, but not associated with any lesion. These results suggest that the encephalitis is induced at a very early stage of the S. calchasi lifecycle rather than in the chronic phase of pigeon protozoal encephalitis. Despite the increasing severity of lesions in the central nervous system, the amount of sarcocysts did not increase. This supports the hypothesis of a delayed-type hypersensitivity response as the cause of the encephalitis. The study also demonstrated that S. calchasi DNA is detectable in tissues negative by histological methods, indicating a higher sensitivity of the real-time PCR. PMID:25338141

  17. Histologic Evaluation of Critical Size Defect Healing With Natural and Synthetic Bone Grafts in the Pigeon ( Columba livia ) Ulna.

    PubMed

    Tunio, Ahmed; Jalila, Abu; Goh, Yong Meng; Shameha-Intan; Shanthi, Ganabadi

    2015-06-01

    Fracture and bone segment loss are major clinical problems in birds. Achieving bone formation and clinical union in a fracture case is important for the survival of the bird. To evaluate the efficacy of bone grafts for defect healing in birds, 2 different bone grafts were investigated in the healing of a bone defect in 24 healthy pigeons ( Columba livia ). In each bird, a 1-cm critical size defect (CSD) was created in the left ulna, and the fracture was stabilized with external skeletal fixation (ESF). A graft of hydroxyapatite (HA) alone (n = 12 birds) or demineralized bone matrix (DBM) combined with HA (n = 12 birds) was implanted in the CSD. The CSD healing was evaluated at 3 endpoints: 3, 6, and 12 weeks after surgery. Four birds were euthanatized at each endpoint from each treatment group, and bone graft healing in the ulna CSD was evaluated by histologic examination. The CSD and graft implants were evaluated for quality of union, cortex development, and bone graft incorporation. Results showed no graft rejection in any bird, and all birds had connective tissue formation in the defect because of the bone graft application. These results suggest that bone defect healing can be achieved by a combination of osteoinductive and osteoconductive bone graft materials for clinical union and new bone regeneration in birds. The combination of DBM and HA resulted in a better quality bone graft (P < .05) than did HA alone, but there was no significant differences in cortex development or bone graft incorporation at 3, 6, or 12 weeks. From the results of this study, we conclude that HA bone grafts, alone or in combination with DBM, with external skeletal fixation is suitable and safe for bone defect and fracture treatment in pigeons. PMID:26115209

  18. Trace metals, melanin-based pigmentation and their interaction influence immune parameters in feral pigeons (Columba livia).

    PubMed

    Chatelain, M; Gasparini, J; Frantz, A

    2016-04-01

    Understanding the effects of trace metals emitted by anthropogenic activities on wildlife is of great concern in urban ecology; yet, information on how they affect individuals, populations, communities and ecosystems remains scarce. In particular, trace metals may impact survival by altering the immune system response to parasites. Plumage melanin is assumed to influence the effects of trace metals on immunity owing to its ability to bind metal ions in feathers and its synthesis being coded by a pleiotropic gene. We thus hypothesized that trace metal exposure would interact with plumage colouration in shaping immune response. We experimentally investigated the interactive effect between exposure to an environmentally relevant range of zinc and/or lead and melanin-based plumage colouration on components of the immune system in feral pigeons (Columba livia). We found that zinc increased anti-keyhole limpet hemocyanin (KLH) IgY primary response maintenance, buffered the negative effect of lead on anti-KLH IgY secondary response maintenance and tended to increase T-cell mediated phytohaemagglutinin (PHA) skin response. Lead decreased the peak of the anti-KLH IgY secondary response. In addition, pheomelanic pigeons exhibited a higher secondary anti-KLH IgY response than did eumelanic ones. Finally, T-cell mediated PHA skin response decreased with increasing plumage eumelanin level of birds exposed to lead. Neither treatments nor plumage colouration correlated with endoparasite intensity. Overall, our study points out the effects of trace metals on some parameters of birds' immunity, independently from other confounding urbanization factors, and underlines the need to investigate their impacts on other life history traits and their consequences in the ecology and evolution of host-parasite interactions. PMID:26809976

  19. Starspots on LO Pegasi, 2006-2013

    NASA Astrophysics Data System (ADS)

    Harmon, Robert O.; Cole, B.; Denison, J.; Gray, K.

    2014-01-01

    LO Pegasi is a K8 main-sequence variable of BY Dra type, exhibiting dark starspots on its surface which modulate its brightness as they are carried into and out of view by the star's rotation. We present the results of BVRI photometry obtained at Perkins Observatory in Delaware, OH from 2006-2013. The light curve shape and by implication the spot configuration is stable on a time scale of several months, but shows substantial year-to-year variations. In particular, the V modulation was a maximum of approximately 0.15 mag in June-July 2011, and a minimum of approximately 0.04 mag in 2012 and 2013. In addition, the mean brightness was lowest in 2012, suggesting the growth of a large spot on the visible rotation pole, which would simultaneously account for the small modulation and lowered mean brightness. In 2013, the mean brightness increased by about 0.05 mag compared to 2012, suggesting that the polar spot is shrinking in size.

  20. Advances in LO2 Propellant Conditioning

    NASA Technical Reports Server (NTRS)

    Mehta, Gopal; Orth, Michael; Stone, William; Perry, Gretchen; Holt, Kimberly; Suter, John

    1994-01-01

    This paper describes the cryogenic testing and analysis that has recently been completed as part of a multi-year effort to develop a new, more robust and operable LO2 propellant conditioning system. Phase 1 of the program consisted of feasibility demonstrations ot four novel propellant conditioning concepts. A no-bleed, passive propellant conditioning option was shown for the first time to successfully provide desired propellant inlet conditions. The benefits of passive conditioning are reduced operations costs, decreased hardware costs, enhanced operability and increased reliability on future expendable launch vehicles In Phase 2 of the test program, effects of major design parameters were studied and design correlation for future vehicle design were developed. Simultaneously, analytical models were developed and validated. Over 100 tests were conducted with a full-scale feedline using LN2 as the test fluid. A circulation pump provided a range of pressure and flow conditions. The test results showed that the passive propellant conditioning system is insensitive to variations in many of the parameters. The test program provides the validation necessary to incorporate the passive conditioning system into the baseline of future vehicles. Modeling of these systems using computational fluid dynamics seems highly promising.

  1. Carbon deposition characteristics of LO2/HC propellants

    NASA Technical Reports Server (NTRS)

    Hernandez, Rosemary; Mercer, Steve D.

    1987-01-01

    The generation and deposition of carbon have been studied using subscale hardware with LO2/RP-1, LO2/propane, and LO2/methane at low mixture ratio conditions. The deposition of carbon on the turbine simulator tubes was evaluated at mixture ratios of 0.20 to 0.60, and at chamber pressures from 720 to 1650 psia. The carbon-deposition rate is a strong function of mixture ratio and a weak function of chamber pressure. There is a mixture ratio that will minimize deposition for LO2/RP-1; a threshold mixture ratio for LO2/propane; and no deposition for LO2/methane at any mixture ratio tested. The turbine drive operating limits were defined for each fuel tested.

  2. Growth of embryo and gene expression of nutrient transporters in the small intestine of the domestic pigeon (Columba livia).

    PubMed

    Chen, Ming-xia; Li, Xiang-guang; Yang, Jun-xian; Gao, Chun-qi; Wang, Bin; Wang, Xiu-qi; Yan, Hui-chao

    2015-06-01

    The objective of this study was to investigate the relationship between gene expression of nutrient (amino acid, peptide, sodium and proton) transporters in the small intestine and embryonic growth in domestic pigeons (Columba livia). One hundred and twenty-five fertilized eggs were randomly assigned into five groups and were incubated under optimal conditions (temperature of 38.1 °C and relative humidity of 55%). Twenty embryos/birds from each group were sacrificed by cervical dislocation on embryonic day (E) 9, 11, 13, 15 and day of hatch (DOH). The eggs, embryos (without yolk sac), and organs (head, brain, heart, liver, lungs, kidney, gizzard, small intestine, legs, and thorax) were dissected, cleaned, and weighed. Small intestine samples were collected for RNA isolation. The mRNA abundance of intestinal nutrient transporters was evaluated by real-time reverse transcription-polymerase chain reaction (RT-PCR). We classified these ten organs into four types according to the changes in relative weight during embryonic development. In addition, the gene expression of nutrient transporters was differentially regulated by embryonic day. The mRNA abundances of b(0,+)AT, EAAT3, y(+)LAT2, PepT1, LAT4, NHE2, and NHE3 increased linearly with age, whereas mRNA abundances of CAT1, CAT2, LAT1, EAAT2, SNAT1, and SNAT2 were increased to higher levels on E9 or E11 and then decreased to lower levels until DOH. The results of correlation analysis showed that the gene expressions of b(0,+)AT, EAAT3, PepT1, LAT4, NHE2, NHE3, and y(+)LAT2 had positive correlations with body weight (0.71

  3. Growth of embryo and gene expression of nutrient transporters in the small intestine of the domestic pigeon (Columba livia)*

    PubMed Central

    Chen, Ming-xia; Li, Xiang-guang; Yang, Jun-xian; Gao, Chun-qi; Wang, Bin; Wang, Xiu-qi; Yan, Hui-chao

    2015-01-01

    The objective of this study was to investigate the relationship between gene expression of nutrient (amino acid, peptide, sodium and proton) transporters in the small intestine and embryonic growth in domestic pigeons (Columba livia). One hundred and twenty-five fertilized eggs were randomly assigned into five groups and were incubated under optimal conditions (temperature of 38.1 °C and relative humidity of 55%). Twenty embryos/birds from each group were sacrificed by cervical dislocation on embryonic day (E) 9, 11, 13, 15 and day of hatch (DOH). The eggs, embryos (without yolk sac), and organs (head, brain, heart, liver, lungs, kidney, gizzard, small intestine, legs, and thorax) were dissected, cleaned, and weighed. Small intestine samples were collected for RNA isolation. The mRNA abundance of intestinal nutrient transporters was evaluated by real-time reverse transcription-polymerase chain reaction (RT-PCR). We classified these ten organs into four types according to the changes in relative weight during embryonic development. In addition, the gene expression of nutrient transporters was differentially regulated by embryonic day. The mRNA abundances of b0,+AT, EAAT3, y+LAT2, PepT1, LAT4, NHE2, and NHE3 increased linearly with age, whereas mRNA abundances of CAT1, CAT2, LAT1, EAAT2, SNAT1, and SNAT2 were increased to higher levels on E9 or E11 and then decreased to lower levels until DOH. The results of correlation analysis showed that the gene expressions of b0,+AT, EAAT3, PepT1, LAT4, NHE2, NHE3, and y+LAT2 had positive correlations with body weight (0.71

  4. Como Lo Hago Yo: Mielomeningocele En Bolivia

    PubMed Central

    Dabdoub, Carlos F.; Dabdoub, Carlos B.; Villavicencio, Ramiro; Quevedo, Germán

    2014-01-01

    Introducción: Las malformaciones del tubo neural (MTN) representan la segunda causa más frecuente de anomalías congénitas, luego de las cardiopatías. En este grupo se destaca el mielomeningocele (MMC) por su mayor incidencia, y por ser la más incapacitante y la más compleja entre todas las demás malformaciones del sistema nervioso c`entral (SNC). En Bolivia, como en muchos países de Sudamérica, los bajos niveles socio-culturales y la debilidad en el sistema sanitario, hacen que su incidencia y su morbilidad, sean mayores que en las naciones más desarrolladas. Material y Métodos: Se realizó un estudio retrospectivo y descriptivo de 70 casos de MMC, atendidos por un equipo multidisciplinario en el Hospital Universitario Japonés (HUJ) de Santa Cruz de la Sierra, entre 2008-2011. De ellos, 60 fueron intervenidos quirúrgicamente. Resultados: Se realizaron controles prenatales sólo en 27 mujeres (38.6%), diagnosticándose una disrafia espinal en apenas dos casos (7.4%). La edad de ingreso del MMC en su mayoría fue después de las 24 horas (65.6%), predominando su localización en la región lumbosacra (64.3%). De ellos, 67.2% eran abiertos, presentando un 32.9% un daño neurológico motor parcial mientras que 47.1% tenían paraplejia por debajo de la lesión. De los 70 casos, tres (4.3%) no fueron intervenidos, por presentar defectos congénitos severos o estado general grave. Las principales complicaciones posoperatorias inmediatas fueron: dehiscencia de sutura y/o infección de la herida (16.6%), fístula de líquido cefalorraquídeo (LCR) (10%) e infección del SNC (11.7%). La mortalidad general y postoperatoria fue de 7.1% y 3.3%, respectivamente. Al mes de vida presentaban hidrocefalia un 80% de los pacientes operados, colocándose una derivación ventriculoperitoneal (DVP) de presión media. De 9 pacientes que tuvieron un acompanamiento de dos o más años, seis presentaron una médula anclada, que fueron intervenidas quirúrgicamente. Conclusi

  5. Lo/Ld phase coexistence modulation induced by GM1.

    PubMed

    Puff, Nicolas; Watanabe, Chiho; Seigneuret, Michel; Angelova, Miglena I; Staneva, Galya

    2014-08-01

    Lipid rafts are assumed to undergo biologically important size-modulations from nanorafts to microrafts. Due to the complexity of cellular membranes, model systems become important tools, especially for the investigation of the factors affecting "raft-like" Lo domain size and the search for Lo nanodomains as precursors in Lo microdomain formation. Because lipid compositional change is the primary mechanism by which a cell can alter membrane phase behavior, we studied the effect of the ganglioside GM1 concentration on the Lo/Ld lateral phase separation in PC/SM/Chol/GM1 bilayers. GM1 above 1mol % abolishes the formation of the micrometer-scale Lo domains observed in GUVs. However, the apparently homogeneous phase observed in optical microscopy corresponds in fact, within a certain temperature range, to a Lo/Ld lateral phase separation taking place below the optical resolution. This nanoscale phase separation is revealed by fluorescence spectroscopy, including C12NBD-PC self-quenching and Laurdan GP measurements, and is supported by Gaussian spectral decomposition analysis. The temperature of formation of nanoscale Lo phase domains over an Ld phase is determined, and is shifted to higher values when the GM1 content increases. A "morphological" phase diagram could be made, and it displays three regions corresponding respectively to Lo/Ld micrometric phase separation, Lo/Ld nanometric phase separation, and a homogeneous Ld phase. We therefore show that a lipid only-based mechanism is able to control the existence and the sizes of phase-separated membrane domains. GM1 could act on the line tension, "arresting" domain growth and thereby stabilizing Lo nanodomains. PMID:24835016

  6. Investigations into the uricolytic properties of urate oxidase in a granivorous (Columba livia domestica) and in a carnivorous (Buteo jamaicensis) avian species.

    PubMed

    Poffers, J; Lumeij, J T; Redig, P T

    2002-12-01

    To study the uricolytic properties of urate oxidase in granivorous and carnivorous birds, experiments were conducted in pigeons (Columba livia domestica) and Red-tailed Hawks (Buteo jamaicensis). Plasma concentrations of allantoin and uric acid were determined at various times in experimental groups before and after receiving 100, 200, and 600 U/kg urate oxidase once daily and were compared with controls. All regimens caused a significant decrease in plasma uric acid concentrations within 2 days after the first administration, when compared with controls. Furthermore, both doses used in Red-tailed Hawks (200 and 100 U/kg) caused a significant postprandial suppression of plasma uric acid concentrations. Plasma allantoin concentrations were significantly higher when compared with controls. The ability of urate oxidase to prevent the physiological postprandial hyperuricaemia in Red-tailed Hawks and to reduce plasma uric acid concentrations to undetectable levels, shows the great potential of this drug for treating avian hyperuricaemia. PMID:12593740

  7. Experimental infection of rock pigeons (Columba livia) with three West Nile virus lineage 1 strains isolated in Italy between 2009 and 2012.

    PubMed

    Spedicato, M; Carmine, I; Bellacicco, A L; Marruchella, G; Marini, V; Pisciella, M; Di Francesco, G; Lorusso, A; Monaco, F; Savini, G

    2016-04-01

    West Nile virus (WNV) circulation dynamics in the context of the urban environment is not yet elucidated. In this perspective, three groups of eight rock pigeons (Columbia livia) were inoculated with three WNV lineage 1 strains isolated in Italy between 2009 and 2012. The pigeons did not develop any clinical signs consistent with WNV acute infection. All animals seroconverted and shed virus up to 15 days post-infection by the oral or cloacal routes. In all infected groups viraemia lasted for 4 days post-infection. No WNV-specific gross or histological lesions were found in infected birds compared to control birds and immunohistochemistry remained constantly negative from all tissues. The reservoir competence index was also assessed and it ranged between 0·11 and 0·14. This study demonstrates that pigeons are competent reservoir hosts for Italian WNV lineage 1 circulating strains thus potentially posing a risk to the public health system. PMID:26493864

  8. The Sublime Corpse in Gertrudis Gomez de Avellaneda's Women's Journal "Album Cubano de lo Bueno y lo Bello" (1860)

    ERIC Educational Resources Information Center

    LaGreca, Nancy

    2009-01-01

    This article examines Gertrudis Gomez de Avellaneda's choice to include articles depicting the advanced decay of cadavers, which are simultaneously horrible and awesome, in her women's periodical "Album Cubano de lo Bueno y lo Bello". Background on Avellaneda's biography, women's print culture, and theories of the sublime provide a frame for the…

  9. 77 FR 50185 - LoCorr Fund Management, LLC and LoCorr Investment Trust; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-20

    ... standard. 3. Applicants assert that the shareholders expect the Adviser and the Board to select the... shareholder approval. Applicants: LoCorr Fund Management, LLC (``LFM'' or the ``Adviser'') and LoCorr... materially amend Subadvisory Agreements without obtaining shareholder approval. The requested relief will...

  10. Evaluations of University of Wisconsin Silicon Carbide Temperature Monitors 300 LO and 400 LO B

    SciTech Connect

    K. L. Davis; J. L. Rempe; D. L. Knudson; B. M. Chase; T. C. Unruh

    2011-12-01

    Silicon carbide (SiC) temperature monitors 05R4-02-A KG1403 (300 LO) and 05R4-01-A KG1415 (400 LO B) were evaluated at the High Temperature Test Lab (HTTL) to determine their peak irradiation temperatures. HTTL measurements indicate that the peak irradiation temperature for the 300 LO monitor was 295 {+-} 20 C and the peak irradiation temperature for the 400 LO B monitor was 294 {+-} 25 C. Two silicon carbide (SiC) temperature monitors irradiated in the Advanced Test Reactor (ATR) were evaluated at the High Temperature Test Lab (HTTL) to determine their peak temperature during irradiation. These monitors were irradiated as part of the University of Wisconsin Pilot Project with a target dose of 3 dpa. Temperature monitors were fabricated from high density (3.203 g/cm3) SiC manufactured by Rohm Haas with a nominal size of 12.5 mm x 1.0 mm x 0.75 mm (see Attachment A). Table 1 provides identification for each monitor with an expected peak irradiation temperature range based on preliminary thermal analysis (see Attachment B). Post irradiation calculations are planned to reduce uncertainties in these calculated temperatures. Since the early 1960s, SiC has been used as a post-irradiation temperature monitor. As noted in Reference 2, several researchers have observed that neutron irradiation induced lattice expansion of SiC annealed out when the post-irradiation annealing temperature exceeds the peak irradiation temperature. As noted in Reference 3, INL uses resistivity measurements to infer peak irradiation temperature from SiC monitors. Figure 1 depicts the equipment at the HTTL used to evaluate the SiC monitors. The SiC monitors are heated in the annealing furnace using isochronal temperature steps that, depending on customer needs, can range from 50 to 800 C. This furnace is located under a ventilation hood within the stainless steel enclosure. The ventilation system is activated during heating so that any released vapors are vented through this system. Annealing

  11. 12. DETAIL VIEW OF WEST ABUTMENT AT Lo, SHOWING BRIDGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. DETAIL VIEW OF WEST ABUTMENT AT Lo, SHOWING BRIDGE SEAT, TIMBER PILES, STEEL SILL AND BACKWALL/WlNGWALL BOARDS, LOOKING NORTH - Cottonville Bridge, County Road D-61 at Farmer's Creek, Maquoketa, Jackson County, IA

  12. Low-z LoBAL QSOs: orientation or evolution?

    NASA Astrophysics Data System (ADS)

    Lazarova, M.

    2015-09-01

    Low-ionization Broad Absorption Line QSOs (LoBALs) are redder type-1 QSOs characterized by broad, blue-shifted absorptions of Mg II, indicating gas outflows at velocities up to 0.2c. There is still much debate regarding the nature of these objects. In the orientation paradigm, LoBALs are present in all QSOs, but can only be observed along limited lines of sight that skim the obscuring torus. Conversely, in the evolution paradigm LoBALS have been interpreted as being a short phase in the early stages of the QSO lifecycle, when QSO-driven winds are expelling gas and dust from the central regions. To explore the suggestion by previous work that LoBALS are more likely to be observed in mergers and recently fueled QSOs, we conducted a morphological analysis of a volume-limited sample of 22 SDSS-selected LoBALs at 0.5 < z < 0.6 using HST/WFC3. We find signs of recent or ongoing tidal interaction in 2/3 of the host galaxies, and detailed surface brightness analysis with GALFIT indicates that the vast majority have early-type morphologies. Our results confirm the high rate of mergers in LoBAL hosts and they further show that LoBALs can be observed at any stage of the merger when QSO activity is expected, according to numerical simulations. While the morphologies of these objects may support the evolution paradigm, their SEDs do not suggest they are a population of QSOs statistically different from optically-selected type-1 QSOs. We discuss the two possible explanations for LoBALs implied by our results.

  13. LoFASM's FPGA-based Digital Acquisition System

    NASA Astrophysics Data System (ADS)

    Dartez, Louis P.; Jenet, F.; Creighton, T. D.; Ford, A. J.; Hicks, B.; Hinojosa, J.; Kassim, N. E.; Price, R. H.; Stovall, K.; Ray, P. S.; Taylor, G. B.

    2014-01-01

    The Low Frequency All Sky Monitor (LoFASM) is a distributed array of dipole antennas that are sensitive to radio frequencies from 10 to 88 MHz. LoFASM consists of antennas and front end electronics that were originally developed for the Long Wavelength Array (LWA) by the U.S. Naval Research Lab, the University of New Mexico, Virginia Tech, and the Jet Propulsion Laboratory. LoFASM, funded by the U.S. Department of Defense, will initially consist of 4 stations, each consisting of 12 dual-polarization dipole antenna stands. The primary science goals of LoFASM will be the detection and study of low-frequency radio transients, a high priority science goal as deemed by the National Research Council's decadal survey. The data acquisition system for the LoFASM antenna array will be using Field Programmable Gate Array (FPGA) technology to implement a real time full Stokes spectrometer and data recorder. This poster presents an overview of the current design and digital architecture of a single station of the LoFASM array as well as the status of the entire project.

  14. Morphological and molecular characterization of Eimeria labbeana-like (Apicomplexa:Eimeriidae) in a domestic pigeon (Columba livia domestica, Gmelin, 1789) in Australia.

    PubMed

    Yang, Rongchang; Brice, Belinda; Elloit, Aileen; Ryan, Una

    2016-07-01

    An Eimeria species is described from a domestic pigeon (Columba livia domestica). Sporulated oocysts (n = 35) were subspherical, with a smooth bi-layered oocyst wall (1.0 μm thick). Oocysts measured 20.2 × 16.1 (22.0-18.9 × 15.7-18.9) μm, oocyst length/width (L/W) ratio, 1.38. Oocyst residuum and a polar granule were present. The micropyle was absent. Sporocysts are elongate-ovoid, 13.0 × 6.1 (14.5-12.5 × 5.5-7.0) μm, sporocyst L/W ratio, 2.13 (2.0-2.2), sporocyst residuum was present, composed of numerous granules in a spherical or ovoid mass. Each sporocyst contained 2 banana-shaped sporozoites, 12.3 × 3.5 (11.8-13.0 × 3.3-3.6) μm. A spherical-ellipsoid posterior refractile body was found in the sporozoites. A nucleus was located immediately anterior to the posterior refractile body. Molecular analysis was conducted at three loci; the 18S and 28S ribosomal RNA genes and the mitochondrial cytochrome oxidase gene (COI). At the 18S locus, the new isolate shared 98.0% genetic similarity with three Isospora isolates from Japan from the domestic pigeon (Columba livia domestica). At the 28S locus, it grouped separately and shared 92.4% and 92.5% genetic similarity with Isospora anthochaerae (KF766053) from a red wattlebird (Anthochaera carunculata) from Australia and an Isospora sp. (MS-2003 - AY283845) from a Himalayan grey-headed bullfinch (Pyrrhula erythaca) respectively. At COI locus, this new isolate was in a separate clade and shared 95.6% and 90.0% similarity respectively with Eimeria tiliquae n. sp. from a shingleback skink in Australia and an Eimeria sp. from a common pheasant (Phasianus colchicus) from America. Based on the morphological data, this isolate is most similar to Eimeria labbeana. As no molecular data for E. labbeana is available and previous morphological data is incomplete, we refer to the current isolate as E. labbeana-like. PMID:27080159

  15. Quadrature Mixer LO Leakage Suppression Through Quadrature DC Bias

    SciTech Connect

    BALDWIN, JESSE G; DUBBERT, DALE F.

    2002-05-01

    A new concept has been developed which allows direct-to-RF conversion of digitally synthesized waveforms. The concept named Quadrature Error Corrected Digital Waveform Synthesis (QECDWS) employs quadrature amplitude and phase predistortion to the complex waveform to reduce the undesirable quadrature image. Another undesirable product of QECDWS-based RF conversion is the Local Oscillator (LO) leakage through the quadrature upconverter (mixer). A common technique for reducing this LO leakage is to apply a quadrature bias to the mixer I and Q inputs. This report analyzes this technique through theory, lab measurement, and data analysis for a candidate quadrature mixer for Synthetic Aperture Radar (SAR) applications.

  16. Low energy neutron deuteron scattering to N3LO

    NASA Astrophysics Data System (ADS)

    Margaryan, Arman; Vanasse, Jared; Springer, Roxanne

    2015-10-01

    We calculate the next-to-next-to-next-to-leading order (N3LO) nd scattering amplitude in the framework of nonrelativistic pionless effective field theory (EFTπ/). This theory is only valid when the typical momentum exchange in the scattering is smaller then the mass of the pion. The power counting parameter for EFTπ/ is the ratio Q/Λπ /, where Q is the typical momentum exchange in the scattering and Λπ / is the EFTπ/ breakdown scale, Λπ / LO. At N3LO new 2-body forces appear, which introduce four new EFTπ/ coefficients. These coefficients are fixed by the 3PJ and 1P1 phase shifts of NN scattering. We find that these terms have an important impact. The results of this calculation at N3LO will be important for understanding spin polarization observables in nd scattering, in particular the longstanding Ay puzzle. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Nuclear Physics, under Award Number DE-FG02-05ER41368.

  17. BabeLO--An Extensible Converter of Programming Exercises Formats

    ERIC Educational Resources Information Center

    Queiros, R.; Leal, J. P.

    2013-01-01

    In the last two decades, there was a proliferation of programming exercise formats that hinders interoperability in automatic assessment. In the lack of a widely accepted standard, a pragmatic solution is to convert content among the existing formats. BabeLO is a programming exercise converter providing services to a network of heterogeneous…

  18. Prevalence and risk factors for Campylobacter spp., Salmonella spp., Coxiella burnetii, and Newcastle disease virus in feral pigeons (Columba livia) in public areas of Montreal, Canada.

    PubMed

    Gabriele-Rivet, Vanessa; Fairbrother, Julie-Hélène; Tremblay, Donald; Harel, Josée; Côté, Nathalie; Arsenault, Julie

    2016-01-01

    Feral pigeons (Columbia livia) can harbor a range of zoonotic pathogens. A transversal study was undertaken to estimate the prevalence of feral pigeons infected by various pathogens in public areas in Montreal, Quebec. Cloacal swabs from captured birds were cultured for Salmonella spp. and Campylobacter spp. and tested by real-time polymerase chain reaction (RT-PCR) for the detection of Coxiella burnetii. An oropharyngeal swab was also submitted to real-time reverse-transcription polymerase chain reaction (RRT-PCR) for the detection of Newcastle disease virus. Among the 187 pigeons tested from 10 public areas, 9.1% (95% CI: 3.0 to 15.2) were positive for Campylobacter spp. with all strains identified as Campylobacter jejuni. The Campylobacter status of birds was not associated with individual characteristics of birds, with the exception of body score. None of the pigeons tested positive for the other pathogens. Direct or indirect contacts with feral pigeons may constitute a potential risk for Campylobacter infection in humans. PMID:26733736

  19. Prevalence and risk factors for Campylobacter spp., Salmonella spp., Coxiella burnetii, and Newcastle disease virus in feral pigeons (Columba livia) in public areas of Montreal, Canada

    PubMed Central

    Gabriele-Rivet, Vanessa; Fairbrother, Julie-Hélène; Tremblay, Donald; Harel, Josée; Côté, Nathalie; Arsenault, Julie

    2016-01-01

    Feral pigeons (Columbia livia) can harbor a range of zoonotic pathogens. A transversal study was undertaken to estimate the prevalence of feral pigeons infected by various pathogens in public areas in Montreal, Quebec. Cloacal swabs from captured birds were cultured for Salmonella spp. and Campylobacter spp. and tested by real-time polymerase chain reaction (RT-PCR) for the detection of Coxiella burnetii. An oropharyngeal swab was also submitted to real-time reverse-transcription polymerase chain reaction (RRT-PCR) for the detection of Newcastle disease virus. Among the 187 pigeons tested from 10 public areas, 9.1% (95% CI: 3.0 to 15.2) were positive for Campylobacter spp. with all strains identified as Campylobacter jejuni. The Campylobacter status of birds was not associated with individual characteristics of birds, with the exception of body score. None of the pigeons tested positive for the other pathogens. Direct or indirect contacts with feral pigeons may constitute a potential risk for Campylobacter infection in humans. PMID:26733736

  20. Comparison of a Point-of-Care Glucometer and a Laboratory Autoanalyzer for Measurement of Blood Glucose Concentrations in Domestic Pigeons ( Columba livia domestica).

    PubMed

    Mohsenzadeh, Mahdieh Sadat; Zaeemi, Mahdieh; Razmyar, Jamshid; Azizzadeh, Mohammad

    2015-09-01

    Biochemical analysis is necessary for diagnosis and monitoring of diseases in birds; however, the small volume of blood that can be safely obtained from small avian species often limits laboratory diagnostic testing. Consequently, a suitable methodology requiring only a small volume of blood must be used. This study was designed to compare blood glucose concentrations in domestic pigeons ( Columba livia domestica) as measured by a commercial, handheld, human glucometer and a standard autoanalyzer. During the first phase of the study, whole blood samples obtained from 30 domestic pigeons were used to measure the blood glucose concentration with a glucometer, the packed cell volume (PCV), and the total erythrocyte count (nRBC). Plasma separated from the each sample was then used to obtain the plasma glucose concentration with the autoanalyzer. During the second phase of the study, 30 pigeons were assigned to 2 equal groups (n = 15). Hypoglycemia or hyperglycemia was induced in each group by intravenous injection of insulin or glucose, respectively. Blood was collected and processed, and glucose concentrations, PCV, and nRBC were measured as previously described. Linear-regression models demonstrated a significant relationship between results measured by the glucometer and autoanalyzer results from normoglycemic (correlation coefficient [R] = 0.43, P = .02), hypoglycemic (R = 0.95; P < .001), and hyperglycemic (R = 0.81; P < .001) birds. The results of this study suggest that we can predict the real blood-glucose concentration of pigeons by using results obtained by a glucometer. PMID:26378663

  1. Ultrasound therapy for the prevention and correction of contractures and bone mineral loss associated with wing bandaging in the domestic pigeon (Columba livia).

    PubMed

    Wimsatt, J; Dressen, P; Dennison, C; Turner, A S

    2000-06-01

    Figure-of-eight wing bandaging is widely used to treat wing injuries, to immobilize wings before and after fracture repair, and during transient wing paralysis. However, prolonged bandaging can lead to bone loss and to contractures and reduced range of joint motion. Studies evaluating the efficacy of therapeutic ultrasound to reverse and prevent bandaging-associated contractures in pigeons (Columba livia) showed a significant increase in elbow and carpal extension after 10 twice weekly ultrasound treatments when started either 4 or 11 days after bandage placement. In addition, after 42 days of wing bandaging, three ultrasound treatments stimulated a faster reversal of carpal wing rotation loss than removal of the bandage over the 10-day treatment period. Finally, bone loss in response to 28 days of bandaging was significant, progressed at 2.8% per week, and was not affected by ultrasound treatment twice weekly during this period. Therefore, therapeutic ultrasound prevented and reversed loss of wing extension associated with figure-of-eight bandaging but did not lessen the disuse osteoporosis created by bandaging in these birds. PMID:10982131

  2. Evaluation of hepatobiliary scintigraphy as an indicator of hepatic function in domestic pigeons (Columba livia) before and after exposure to ethylene glycol.

    PubMed

    Hadley, Tarah L; Daniel, Gregory B; Rotstein, David S; Avenell, James S; Zagaya, Nancy; Jones, Michael P

    2007-01-01

    This study investigated the use of quantitative hepatobiliary scintigraphy to assess liver function in 14 white Carneaux pigeons (Columba livia). Liver scintigraphy using 99mTc-mebrofenin was performed and liver function was quantified using deconvolutional analysis and the area under the normalized heart time-activity curve as previously described in the dog and horse. Liver biopsies were performed in all birds before and after toxin-induced liver damage with ethylene glycol. Before the induction of liver disease, all biopsy specimens showed varying degrees of granulomatous inflammation. After ethylene glycol administration, hepatic lesions were scored and compared with scintigraphic findings. Scintigraphic results showed a significant decrease (P = 0.04) in hepatic function using the area under the normalized time-activity curve. There was good correlation between the overall histologic score posttoxin exposure and scintigraphic measures of liver function (P < 0.03). Based upon these preliminary results, the area under the heart time-activity curve can determine hepatic extraction as a measure of hepatic parenchymal cell function. The results also showed that worsening hepatic cellular function correlated with increased histologic damage to the liver. The use of hepatobiliary scintigraphy using 99mTc-mebrofenin to determine liver function in pigeons has not been previously reported. Additional studies are warranted to evaluate the application of this technique in clinical patients and to establish the sensitivity of this technique. PMID:17385376

  3. 77 FR 2715 - D'Lo Gas Storage, LLC; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-19

    ... Energy Regulatory Commission D'Lo Gas Storage, LLC; Notice of Application Take notice that on December 29, 2011, D'Lo Gas Storage, LLC (D'Lo), 1002 East St. Mary Blvd., Lafayette, Louisiana 70503, filed in... D'Lo to construct, operate, and maintain a new natural gas storage project to be located in...

  4. Imaging Starspots on LO Pegasi via Light-curve Inversion

    NASA Astrophysics Data System (ADS)

    Harmon, Robert O.; Deskins, R.; Vutisalchavakul, N.

    2007-12-01

    We present maps of the star LO Pegasi obtained via Light-curve Inversion, a computational technique which produces an image of a star's surface features based on variations in the star's observed brightness as dark starspots rotate into and out of view from Earth. LO Pegasi is a rapidly rotating (P=10.17 hr) K8V young solar analog. We inverted BVRI light curves obtained from CCD images acquired on July 7-9 and July 22-23, 2007 at Perkins Observatory in Delaware, OH. Using multiple filters significantly improves the latitude resolution of our maps. Our inversions revealed the presence of a large mid-latitude spot or spotted region on the map from July 7-9, which appears to have evolved into a more complex two-spot configuration by July 22-23. The authors wish to acknowledge the support of the NSF REU Program and the Ohio Wesleyan University Summer Science Research Program.

  5. Liquid oxygen (LO2) propellant conditioning concept testing

    NASA Technical Reports Server (NTRS)

    Perry, Gretchen L. E.; Orth, Michael S.; Mehta, Gopal K.

    1993-01-01

    Testing of a simplified LO2 propellant conditioning concept for future expendable launch vehicles is discussed. Four different concepts are being investigated: no-bleed, low-bleed, use of a recirculation line, and He bubbling. A full-scale test article, which is a facsimile of a propellant feed duct with an attached section to simulate heat input from an LO2 turbopump, is to be tested at the Cold Flow Facility of the Marshall Space Flight Center West Test Area. Work to date includes: design and fabrication of the test article, design of the test facility and initial fabrication, development of a test matrix and test procedures, initial predictions of test output, and heat leak calibration and heat exchanger tests on the test articles.

  6. Liquid Oxygen (LO2) propellant conditioning concept testing

    NASA Technical Reports Server (NTRS)

    Perry, Gretchen L. E.; Orth, Michael S.; Mehta, Gopal K.

    1993-01-01

    Marshall Space Flight Center (MSFC) and industry contractors have undertaken activities to develop a simplified liquid oxygen (LO2) propellant conditioning concept for future expendable launch vehicles. The objective of these activities is to reduce operations costs and timelines and to improve safety of these vehicles. The approach followed has been to identify novel concepts through system level studies and demonstrate the feasibility of these concepts through small-scale and full-scale testing. Testing will also provide data for design guidelines and validation of analytical models. Four different concepts are being investigated: no-bleed, low-bleed, use of a recirculation line, and helium (He) bubbling. This investigation is being done under a Joint Institutional Research and Development (JIRAD) program currently in effect between MSFC and General Dynamics Space Systems (GDSS). A full-scale test article, which is a facsimile of a propellant feed duct with an attached section to simulate heat input from a LO2 turbopump, will be tested at the Cold Flow Facility at MSFC's West Test Area. Liquid nitrogen (LN2), which has similar properties to LO2, will be used in place of LO2 for safety and budget reasons. Work to date includes design and fabrication of the test article, design of the test facility and initial fabrication, development of a test matrix and test procedures, initial predictions of test output, and heat leak calibration and heat exchanger tests on the test article. The tests for all propellant conditioning concepts will be conducted in the summer of 1993, with the final report completed by October, 1993.

  7. LoCuSS: Testing hydrostatic equilibrium in galaxy clusters

    NASA Astrophysics Data System (ADS)

    Smith, G. P.; Mazzotta, P.; Okabe, N.; Ziparo, F.; Mulroy, S. L.; Babul, A.; Finoguenov, A.; McCarthy, I. G.; Lieu, M.; Bahé, Y. M.; Bourdin, H.; Evrard, A. E.; Futamase, T.; Haines, C. P.; Jauzac, M.; Marrone, D. P.; Martino, R.; May, P. E.; Taylor, J. E.; Umetsu, K.

    2016-02-01

    We test the assumption of hydrostatic equilibrium in an X-ray luminosity selected sample of 50 galaxy clusters at 0.15 < z < 0.3 from the Local Cluster Substructure Survey (LoCuSS). Our weak-lensing measurements of M500 control systematic biases to sub-4 per cent, and our hydrostatic measurements of the same achieve excellent agreement between XMM-Newton and Chandra. The mean ratio of X-ray to lensing mass for these 50 clusters is β_X= 0.95± 0.05, and for the 44 clusters also detected by Planck, the mean ratio of Planck mass estimate to LoCuSS lensing mass is β_P= 0.95± 0.04. Based on a careful like-for-like analysis, we find that LoCuSS, the Canadian Cluster Comparison Project, and Weighing the Giants agree on β_P ≃ 0.9-0.95 at 0.15 < z < 0.3. This small level of hydrostatic bias disagrees at ˜5σ with the level required to reconcile Planck cosmology results from the cosmic microwave background and galaxy cluster counts.

  8. Quadrature mixture LO suppression via DSW DAC noise dither

    DOEpatents

    Dubbert, Dale F.; Dudley, Peter A.

    2007-08-21

    A Quadrature Error Corrected Digital Waveform Synthesizer (QECDWS) employs frequency dependent phase error corrections to, in effect, pre-distort the phase characteristic of the chirp to compensate for the frequency dependent phase nonlinearity of the RF and microwave subsystem. In addition, the QECDWS can employ frequency dependent correction vectors to the quadrature amplitude and phase of the synthesized output. The quadrature corrections cancel the radars' quadrature upconverter (mixer) errors to null the unwanted spectral image. A result is the direct generation of an RF waveform, which has a theoretical chirp bandwidth equal to the QECDWS clock frequency (1 to 1.2 GHz) with the high Spurious Free Dynamic Range (SFDR) necessary for high dynamic range radar systems such as SAR. To correct for the problematic upconverter local oscillator (LO) leakage, precision DC offsets can be applied over the chirped pulse using a pseudo-random noise dither. The present dither technique can effectively produce a quadrature DC bias which has the precision required to adequately suppress the LO leakage. A calibration technique can be employed to calculate both the quadrature correction vectors and the LO-nulling DC offsets using the radar built-in test capability.

  9. Comparison between lead levels in blood and bone tissue of rock doves (Columba livia) treated with lead acetate or exposed to the environment of Alcala de Henares

    SciTech Connect

    Tejedor, M.C.; Gonzalez, M.

    1992-06-01

    The increase in the amount of lead released into the environment in developed countries during the last two to three decades has resulted in a significant increase in lead levels in organisms from completely different environments. Several surveys have been made in urban areas with high traffic densities in an attempt to identify plant and animal species that might reflect environmental metal concentrations so that those species could be used as sensitive biological indicators of heavy metal contamination. Studies of lead accumulation in U.K. rock doves imply that use of this species as a pollution indicator would facilitate periodic monitoring of chronic lead exposure conditions in the urban environment. Laboratory investigations cannot readily reflect environmental conditions since the validity of extrapolating laboratory results, where high doses are administered over short-time periods, to the natural environment has been seriously questioned. The present study was made on four rock dove (Columbia livia) populations: two groups (males and females) were dosed with lead acetate in the laboratory and two groups of males were housed in different parts of the city of Alcala de Henares. Data on lead bioaccumulation were collected in two situations: the first was in a laboratory with controlled amounts of lead, while in the second situation the amounts reflected the actual environmental levels in Alcala de Henares. Lead levels were determined in two tissues: blood, which is the target of first impact in possible acute situations; and bone, which is the main tissue where lead accumulates and, therefore, very important during chronic exposure. The study focused on the following three items: (1) lead tissue distribution; (2) variation with habitat; and (3) an evaluation of the levels of lead contamination in the city of Alcala de Henares. 19 refs., 3 figs., 1 tab.

  10. Flexible learning and use of multiple-landmark information by pigeons (Columba livia) in a touch screen-based goal searching task.

    PubMed

    Ushitani, Tomokazu; Jitsumori, Masako

    2011-08-01

    Three touch screen-based experiments were conducted to investigate whether pigeons would learn to use configural information about a goal's location in relation to a multiple-landmark array. In Experiment 1, 4 pigeons (Columba livia) were trained to peck a computer monitor at a location that constituted the third vertex of a hypothetical triangle defined by 2 different landmarks. The landmarks appeared in 3 orientations during the training, and the pigeons' goal-searching ability easily transferred to the landmarks presented in 3 novel orientations. Each landmark was asymmetric, so we next examined whether the pigeons used (a) the small-scale, local orientation information that could be inferred from each landmark individually, or (b) the large-scale, configural information that could be inferred from the spatial arrangement of multiple landmarks taken as a whole. Even when each single landmark appeared by itself, the pigeons were able to locate the goal accurately, suggesting that the large-scale, configural information was not essential. However, when 1 landmark locally pointed to a location that was consistent with the triangular configuration and the other landmark locally pointed to a different location, the pigeons predominantly pecked at the configurally array-consistent location. These results suggest that the pigeons redundantly learned both the large-scale, configural strategy and the local, single-landmark strategy, but they mainly used the latter information, and used the former information solely to disambiguate conflicts when the 2 landmarks pointed toward different targets. Such flexible learning and use of redundant information may reflect the pigeons' adaptation to unstable wild environments during their evolutionary history. PMID:21574692

  11. Prevalence of ectoparasites in free-range backyard chickens, domestic pigeons (Columba livia domestica) and turkeys of Kermanshah province, west of Iran.

    PubMed

    Rezaei, Farid; Hashemnia, Mohammad; Chalechale, Abdolali; Seidi, Shahin; Gholizadeh, Maryam

    2016-06-01

    This study was carried out on free-range backyard chickens, domestic pigeons (Columba livia domestica) and turkeys from May 2012 to April 2013 to determine the prevalence and identify the species of ectoparasites in Kermanshah province, west of Iran. Of the total of 600 free-range backyard chickens (185 ♂ and 415 ♀), 700 domestic pigeons (278 ♂ and 422 ♀) and 150 turkeys (53 ♂ and 97 ♀), 389 (64.83 %), 608 (86.85 %) and 54 (36 %) were infected with one or more parasites respectively. Eleven ectoparasites species including five of lice (50.16 % Menacanthus stramineus, 13.66 % Menopon gallinae, 4.83 % Cuclotogaster heterographus, 5.16 % Goniocotes gallinae, 2.33 % Goniodes gigas), three of mites (26.33 % Dermanyssus gallinae, 8.5 % Ornithonyssus bursa, 7 % Cnemidocoptes mutans), one of tick (78.66 % Argas persicus) and two of flea (12.33 % Echidnophaga gallinacea, 2 % Pulex irritans) were found in the backyard chickens. The domestic pigeons were infected with six species of parasites including: Columbicola columbae (61.7 %), M. gallinae (10.43 %), M. stramineus (9 %), D. gallinae (8.28 %), Argas reflexus (74.14 %) and Pseudolynchia canariensis (27.7 %). The ectoparasites species recorded in turkeys were M. gallinae (14 %), M. stramineus (8 %), D. gallinae (12.66 %), C. mutans (6 %), A. persicus (24.66 %) and E. gallinacean (6 %). This is the first survey to determine the prevalence and identify the species of ectoparasites among free-range backyard chicken, domestic pigeons and turkeys in Kermanshah province. The high prevalence rate of ectoparasites in free-range backyard chickens and domestic pigeons indicates that parasitic infection is a common problem in this area. PMID:27413319

  12. Evaluation of Two Miniplate Systems and Figure-of-eight Bandages for Stabilization of Experimentally Induced Ulnar and Radial Fractures in Pigeons ( Columba livia ).

    PubMed

    Bennert, Beatrice M; Kircher, Patrick R; Gutbrod, Andreas; Riechert, Juliane; Hatt, Jean-Michel

    2016-06-01

    Although plate fixation has advantages over other fixation methods for certain indications, it is rarely used in avian surgery, especially in birds that weigh less than 1000 g. Exceptionally small plating systems for these birds are required, which are relatively expensive and difficult to insert. To study avian fracture healing after repair using miniplates, we evaluated 2 steel miniplate systems in 27 pigeons ( Columba livia ) divided into 4 groups. In each pigeon, the left ulna and radius were transected and the ulna was repaired with a bone plate. In groups A and B, a 1.3-mm adaption plate was applied without and with a figure-of-eight bandage; in groups C and D, a 1.0-mm compression plate was applied without and with a bandage, respectively. Healing was evaluated with radiographs after 3, 14, and 28 days; flight tests were conducted after 14, 21, and 28 days; and the wing was macroscopically examined after euthanasia of birds on day 28. Fractures healed without bending or distortion of the plate in all 27 birds, and no significant differences in healing were found between treatment groups. At the end of the study, 23 pigeons (85.2%) showed good or very good flight ability. Results show the 1.3-mm adaption plate and the 1.0-mm compression plate meet the requirements for avian osteosynthesis and can be recommended for fracture repair of the ulna or other long bones in birds weighing less than 500 g. The application of a figure-of-eight bandage might be beneficial in fracture healing. PMID:27315377

  13. Prevalence of parasites and associated risk factors in domestic pigeons (Columba livia domestica) and free-range backyard chickens of Sistan region, east of Iran.

    PubMed

    Radfar, Mohammad Hossein; Khedri, Javad; Adinehbeigi, Keivan; Nabavi, Reza; Rahmani, Khatereh

    2012-10-01

    This study was carried out on free-range backyard chickens and domestic pigeons (Columba livia domestica) from December 2010 to November 2011 to determine the prevalence, intensity and species of internal and external parasites in Sistan region, east of Iran. Of the total of 59 (27 males and 32 females) free-range backyard chickens and 46 (26 males and 20 females) domestic pigeons inspected, 55 (93.22 %) and 39 (84.78 %) were infected respectively. Ten species of free-range backyard chickens parasites were collected from alimentary canals, body, head and neck, comprising of 3 species of nematodes, 4 species of cestodes and 3 species of ectoparasites as follows: Ascaridia galli (16.94 %), Heterakis gallinarum (23.72 %), Subulura brumpti (67.79 %), Raillietina tetragona (35.59 %), Raillietina echinobothrida (27.11 %), Raillietina cesticillus (15.25 %), Choanotaenia infundibulum (40.67 %), Argas persicus (16.94 %), Menopen gallinae (55.93 %) and Menacanthus stramineus (33.89 %). The domestic pigeons were infected with seven species of parasites including 2 species of nematodes, 2 species of cestodes and 3 species of ectoparasites as follows: Ascaridia colombae (15.21 %), Hadjelia truncata (17.39 %), Raillietina tetragona (26.08 %), Raillietina echinobothrida (28.26 %), Argas reflexus (13.04 %), Menopen gallinae (32.60 %), Columbicola Columba (41.30 %). This is the first survey to determine the prevalence and intensity of parasites among free-range backyard chicken and domestic pigeon species in Sistan region. PMID:24082532

  14. The change in heat shock protein expression in avermectin induced neurotoxicity of the pigeon (Columba livia) both in vivo and in vitro.

    PubMed

    Li, Ming; Wang, Xian-Song; Xu, Feng-Ping; Liu, Shuang; Xu, Shi-Wen; Li, Shu

    2014-12-01

    The expression of heat shock proteins (Hsps) commonly increases to provide neuroprotection when brain tissues are under stress conditions. Residues of avermectins (AVMs) have neurotoxic effects on a number of non-target organisms. The aim of this study was to investigate the effects of AVM exposure on the expression levels of Hsp 60, Hsp 70 and Hsp 90 for pigeon (Columba livia) neurons both in vivo and in vitro. The results showed that in general, the mRNA and protein levels of Hsps were increased in treated groups relative to control groups after AVM exposure for 30d, 60d and 90d in the cerebrum, cerebellum and optic lobe in vivo. However, AVM exposure had no significant effects on the transcription expression of Hsps for 90d in the optic lobe and decreased the translation expression of Hsps significantly for 90d in the optic lobe. In vitro, the LC50 of avermectin for King pigeon neurons is between 15μgL(-1) and 20μgL(-1). Following AVM (2.5-20μgL(-1)) exposure, the mRNA expression of the 3 Hsps was up-regulated to different degrees. Compared with the control groups, a significant decrease, a remarkable increase and a non-significant change was found in the protein expression of Hsp 60, Hsp 70 and Hsp 90 separately following AVM (2.5-20μgL(-1)) exposure. Based on these results, we conclude that AVM exposure can induce a protective stress response in pigeons by means of promoting the mRNA and protein expression of Hsps under in vivo and in vitro conditions, thus easing the neurotoxic effects of AVM to some extent. PMID:25202854

  15. The role of beta-adrenergic receptors in the cutaneous water evaporation mechanism in the heat-acclimated pigeon (Columba livia).

    PubMed

    Ophir, E; Arieli, Y; Raber, P; Marder, J

    2000-01-01

    The effects of selective and non-selective beta-adrenergic agents on cutaneous water evaporation (CWE) were studied in hand-reared rock pigeons (Columba livia). CWE was measured by the vapor diffusive resistance method, using a transient porometer. Intramuscular and subcutaneous injections of a non-selective beta-adrenergic antagonist (propranolol) or a selective beta(2)-adrenergic antagonist (ICI-118551) to heat-acclimated (HAc) pigeons at ambient temperature (T(a)) of 24 degrees C resulted in intensive CWE. The CWE values that were triggered by propranolol and ICI-118551 (18.59+/-0.73 and 16.48+/-0.70 mg cm(-2) h(-1), respectively) were close to those induced by heat exposure (17.62+/-1.40 mg cm(-2) h(-1)). Subcutaneous administration of propranolol produced local response. Intramuscular injection of salbutamol (selective beta(2)-adrenergic agonist) to HAc pigeons drastically diminished CWE induced by either propranolol, metoprolol or heat exposure. Such manipulations also enhanced panting at relatively low T(a)s (42 degrees C). The inhibition of beta(1)-adrenergic receptors by metoprolol increased CWE, while inhibition by atenolol produced no change from basal values. This difference may be attributed to their distinctive nature in penetrating the blood-brain barrier. Our findings indicate a regulatory pathway for CWE consisting of both beta(1)- and beta(2)-adrenergic receptors. We suggest that the beta(1)-adrenergic effect is restricted mainly to the CNS, while the beta(2)-adrenergic effect takes place at the effector level. We postulate this level to be either the cutaneous microvasculature or the epidermal layer. PMID:10779732

  16. Color differences among feral pigeons (Columba livia) are not attributable to sequence variation in the coding region of the melanocortin-1 receptor gene (MC1R)

    PubMed Central

    2013-01-01

    Background Genetic variation at the melanocortin-1 receptor (MC1R) gene is correlated with melanin color variation in many birds. Feral pigeons (Columba livia) show two major melanin-based colorations: a red coloration due to pheomelanic pigment and a black coloration due to eumelanic pigment. Furthermore, within each color type, feral pigeons display continuous variation in the amount of melanin pigment present in the feathers, with individuals varying from pure white to a full dark melanic color. Coloration is highly heritable and it has been suggested that it is under natural or sexual selection, or both. Our objective was to investigate whether MC1R allelic variants are associated with plumage color in feral pigeons. Findings We sequenced 888 bp of the coding sequence of MC1R among pigeons varying both in the type, eumelanin or pheomelanin, and the amount of melanin in their feathers. We detected 10 non-synonymous substitutions and 2 synonymous substitution but none of them were associated with a plumage type. It remains possible that non-synonymous substitutions that influence coloration are present in the short MC1R fragment that we did not sequence but this seems unlikely because we analyzed the entire functionally important region of the gene. Conclusions Our results show that color differences among feral pigeons are probably not attributable to amino acid variation at the MC1R locus. Therefore, variation in regulatory regions of MC1R or variation in other genes may be responsible for the color polymorphism of feral pigeons. PMID:23915680

  17. On the LO-polaron dispersion in D dimensions

    NASA Astrophysics Data System (ADS)

    Gerlach, B.; Kalina, F.; Smondyrev, M.

    2003-05-01

    We discuss the (LO)polaron dispersion for arbitrary spatial dimension D. Firstly, we review the existing literature; recent numerical work is critically analyzed. Secondly, we derive novel upper bounds for the dispersion, which incorporate the correct behaviour of the dispersion up to third order of the coupling constant . A totally analytical evaluation is performed in the case D = 1. We compare the upper bounds with previously published lower bounds. Apart from a surrounding of zero dispersion, the relative deviation is on a few-percent scale.

  18. Photometry of LO Pegasi in B, V, R colors

    NASA Astrophysics Data System (ADS)

    Csorvási, R.

    2006-09-01

    Variable magnetic activity manifested by starspot distribution is investigated on the single K5-K7 dwarf LO Peg, using one month long photometric observations. We supposed three circular spots for light curve solution. We find variable spot temperature, whose average is 3960 K. The sizes of spots were stable for two spots and one spot showed a significant decrease. Different migration periods on two spots indicate differential rotation, the magnitude of the migration is slow. During the measured 90 stellar rotations (38.5 days) the location of the activity remained on the same hemisphere of the star.

  19. Fast optically sectioned fluorescence HiLo endomicroscopy

    PubMed Central

    Lim, Daryl; Mertz, Jerome

    2012-01-01

    Abstract. We describe a nonscanning, fiber bundle endomicroscope that performs optically sectioned fluorescence imaging with fast frame rates and real-time processing. Our sectioning technique is based on HiLo imaging, wherein two widefield images are acquired under uniform and structured illumination and numerically processed to reject out-of-focus background. This work is an improvement upon an earlier demonstration of widefield optical sectioning through a flexible fiber bundle. The improved device features lateral and axial resolutions of 2.6 and 17 μm, respectively, a net frame rate of 9.5 Hz obtained by real-time image processing with a graphics processing unit (GPU) and significantly reduced motion artifacts obtained by the use of a double-shutter camera. We demonstrate the performance of our system with optically sectioned images and videos of a fluorescently labeled chorioallantoic membrane (CAM) in the developing G. gallus embryo. HiLo endomicroscopy is a candidate technique for low-cost, high-speed clinical optical biopsies. PMID:22463023

  20. Volumetric HiLo microscopy employing an electrically tunable lens.

    PubMed

    Philipp, Katrin; Smolarski, André; Koukourakis, Nektarios; Fischer, Andreas; Stürmer, Moritz; Wallrabe, Ulrike; Czarske, Jürgen W

    2016-06-27

    Electrically tunable lenses exhibit strong potential for fast motion-free axial scanning in a variety of microscopes. However, they also lead to a degradation of the achievable resolution because of aberrations and misalignment between illumination and detection optics that are induced by the scan itself. Additionally, the typically nonlinear relation between actuation voltage and axial displacement leads to over- or under-sampled frame acquisition in most microscopic techniques because of their static depth-of-field. To overcome these limitations, we present an Adaptive-Lens-High-and-Low-frequency (AL-HiLo) microscope that enables volumetric measurements employing an electrically tunable lens. By using speckle-patterned illumination, we ensure stability against aberrations of the electrically tunable lens. Its depth-of-field can be adjusted a-posteriori and hence enables to create flexible scans, which compensates for irregular axial measurement positions. The adaptive HiLo microscope provides an axial scanning range of 1 mm with an axial resolution of about 4 μm and sub-micron lateral resolution over the full scanning range. Proof of concept measurements at home-built specimens as well as zebrafish embryos with reporter gene-driven fluorescence in the thyroid gland are shown. PMID:27410654

  1. Advanced liquid oxygen (LO2) propellant conditioning concept testing

    NASA Technical Reports Server (NTRS)

    Perry, G. L. E.; Suter, J. D.; Turner, S. G.

    1995-01-01

    Advanced methods of liquid oxygen (LO2) propellant conditioning were studied as part of an effort for increasing reliability and operability while reducing cost of future heavy lift launch vehicles. The most promising conditioning concept evaluated was no-bleed (passive recirculation) followed by low-bleed, helium injection, and use of a recirculation line. Full-scale cryogenic testing was performed with a sloped feedline test article to validate models of behavior of LO2 in the feedline and to prove no-bleed feasibility. Test data are also intended to help generate design guidelines for the development of a main propulsion system feed duct. A design-of-experiments matrix of over 100 tests was developed to test all four propellant conditioning concepts and the impact of design parameters on the concepts. Liquid nitrogen was used as the test fluid. The work for this project was conducted from October 1992 through January 1994 at the hydrogen cold flow facility of the west test area of MSFC. Test data have shown that satisfactory temperatures are being obtained for the no-bleed conditioning concept.

  2. Human CD34(lo)CD133(lo) fetal liver cells support the expansion of human CD34(hi)CD133(hi) hematopoietic stem cells.

    PubMed

    Yong, Kylie Su Mei; Keng, Choong Tat; Tan, Shu Qi; Loh, Eva; Chang, Kenneth Te; Tan, Thiam Chye; Hong, Wanjin; Chen, Qingfeng

    2016-09-01

    We have recently discovered a unique CD34(lo)CD133(lo) cell population in the human fetal liver (FL) that gives rise to cells in the hepatic lineage. In this study, we further characterized the biological functions of FL CD34(lo)CD133(lo) cells. Our findings show that these CD34(lo)CD133(lo) cells express markers of both endodermal and mesodermal lineages and have the capability to differentiate into hepatocyte and mesenchymal lineage cells by ex vivo differentiation assays. Furthermore, we show that CD34(lo)CD133(lo) cells express growth factors that are important for human hematopoietic stem cell (HSC) expansion: stem cell factor (SCF), insulin-like growth factor 2 (IGF2), C-X-C motif chemokine 12 (CXCL12), and factors in the angiopoietin-like protein family. Co-culture of autologous FL HSCs and allogenic HSCs derived from cord blood with CD34(lo)CD133(lo) cells supports and expands both types of HSCs.These findings are not only essential for extending our understanding of the HSC niche during the development of embryonic and fetal hematopoiesis but will also potentially benefit adult stem cell transplantations in clinics because expanded HSCs demonstrate the same capacity as primary cells to reconstitute the human immune system and mediate long-term hematopoiesis in vivo. Together, CD34(lo)CD133(lo) cells not only serve as stem/progenitor cells for liver development but are also an essential component of the HSC niche in the human FL. PMID:27593483

  3. Risk assessment of Cumberland unit 2 L-O blades

    SciTech Connect

    Lam, T.C.T.; Puri, A.

    1996-12-31

    Concern about the reliability of the 1,300 mw Cumberland steam turbine units after an unexpected blade tip failure in the fall of 1995 caused TVA to conduct an investigation into the current reliability of the L-O blades. A probabilistic model based on the measured frequencies, damping and material fatigue data was generated. The influence of significant erosion damage on the blade natural frequencies and on the local stresses was estimated. A probabilistic model of the local fatigue limit was generated based on test data. Monte Carlo simulation was employed to estimate the probability of blade failure by comparing the dynamic stress with the fatigue limit. Risk assessment of the blade failure is presented.

  4. Karhunen-Loéve expansion for random earthquake excitations

    NASA Astrophysics Data System (ADS)

    He, Jun

    2015-03-01

    This paper develops a trigonometric-basis-function based Karhunen-Loéve (KL) expansion for simulating random earthquake excitations with known covariance functions. The methods for determining the number of the KL terms and defining the involved random variables are described in detail. The simplified form of the KL expansion is given, whereby the relationship between the KL expansion and the spectral representation method is investigated and revealed. The KL expansion is of high efficiency for simulating long-term earthquake excitations in the sense that it needs a minimum number of random variables, as compared with the spectral representation method. Numerical examples demonstrate the convergence and accuracy of the KL expansion for simulating two commonly-used random earthquake excitation models and estimating linear and nonlinear random responses to the random excitations.

  5. Building an LO source at 1036 GHz for a receiver

    NASA Technical Reports Server (NTRS)

    Erickson, Neal R.

    1995-01-01

    The goal of the UMass work on this grant was to build an LO source at 1036 GHz for a receiver which was to be built at JPL. The 1 THz source will consist of a high power Gunn oscillator at 86 GHz followed by a cascaded pair of planar diode doublers and finally a whisker contacted tripler. All multipliers will use single mode waveguide mounts. This use of single mode waveguide even for the final mount is a departure from the original plan, and reflects the progress that has been made in fabricating small structures. The advantages to the use of waveguide over a quasi-optical approach are that the complete system is much more compact, and much easier to use.

  6. The reduction of the LO number for heterodyne coherent detection.

    PubMed

    Li, Xinying; Yu, Jianjun; Chi, Nan; Dong, Ze; Zhang, Junwen; Yu, Jianguo

    2012-12-31

    Relative to homodyne coherent detection, heterodyne coherent detection has simple architecture because no 90° hybrid and only half number of photodiodes and analog-to-digital convertor (ADC) chips are required. We experimentally demonstrate that the architecture of heterodyne coherent receivers can be further simplified. When the frequency offset is one half of the channel frequency spacing, one local oscillator (LO) laser can be used for two neighboring wavelength-division-multiplexing (WDM) channels, and therefore the number of LO lasers can be reduced into half compared to homodyne detection. We experimentally demonstrate simplified heterodyne coherent detection of 4 × 196.8-Gb/s polarization-division-multiplexing carrier-suppressed return-to-zero quadrature-phase-shift-keying (PDM-CSRZ-QPSK) modulation after transmission over 1040-km single-mode fiber (SMF)-28 on a 50-GHz grid with bit-error ratio (BER) smaller than pre-forward-error-correction (pre-FEC) limit of 3.8 × 10(-3). To our best knowledge, 196.8 Gb/s is the highest bit rate per channel for heterodyne coherent WDM transmission system. An arrayed waveguide grating (AWG) instead of wavelength selective switch (WSS) is used at the transmitter to spectrally shape and multiplex the WDM signal. We also experimentally demonstrate that heterodyne detection causes 3-dB optical signal-to-noise ratio (OSNR) penalty at the BER of 3.8 × 10(-3) for a certain single channel compared to homodyne detection. PMID:23388788

  7. Effect of egg weight on composition, embryonic growth, and expression of amino acid transporter genes in yolk sac membranes and small intestines of the domestic pigeon (Columba livia).

    PubMed

    Chen, M X; Li, X G; Yan, H C; Wang, X Q; Gao, C Q

    2016-06-01

    The objective of this study was to investigate the effect of egg weight on the composition of the egg, the growth of the embryo, and the expression of amino acid transporter genes in the yolk sac membranes and small intestines of the domestic pigeon (Columba livia). A total of 240 fertilized eggs were collected and divided into two groups based on the weight of the eggs, light (LE) and heavy (HE). The composition of 20 eggs from each group was measured, and the remaining eggs were weighed and placed in an incubator. On embryonic days (E) 9, 11, 13, and 15 and day of hatch (DOH), 15 embryos/hatchlings from each group were measured for embryonic growth, and samples were collected. The HE had heavier yolk and albumen weights than the LE (P < 0.01). Compared with the LE, the HE had heavier yolk-free embryonic body and yolk sac weights from E13 to DOH (P < 0.05). Additionally, the HE had larger yolk sac membrane weights from E13 to E15 (P < 0.05) and had more residual yolk sac content on DOH than those of the LE (P < 0.01). The yolk absorption was greater for the HE than for the LE from E11 to E13 (P < 0.05). Furthermore, the abundance of CAT2 and PepT1 mRNA in the yolk sac membranes was greater in the HE than in the LE on E13 (P < 0.05). Compared with the LE, the gene expression of EAAT2 in the intestine on E13 was greater in the HE, whereas the expression of EAAT3 was lower in the HE (P < 0.05). Taken together, our results suggest that egg weight influenced the composition of the eggs, embryonic development, and expression of amino acid transporter genes in the yolk sac membranes and small intestines of pigeon embryos. PMID:26957627

  8. Sarcocystis calchasi has an expanded host range and induces neurological disease in cockatiels (Nymphicus hollandicus) and North American rock pigeons (Columbia livia f. dom.).

    PubMed

    Olias, Philipp; Maier, Kristina; Wuenschmann, Arno; Reed, Leslie; Armién, Aníbal G; Shaw, Daniel P; Gruber, Achim D; Lierz, Michael

    2014-02-24

    Pigeon protozoal encephalitis (PPE) is an emerging central nervous system disease of pigeons (Columba livia f. domestica) caused by the apicomplexan parasite Sarcocystis calchasi. The intermediate host specificity of S. calchasi had been considered high, as domestic chickens were resistant to experimental infection. Here, we have re-evaluated this concept and expanded the known host range of S. calchasi by experimental infection of cockatiels (Nymphicus hollandicus), a species distantly related to pigeons. In this work, a group of eight cockatiels were experimentally infected with S. calchasi, which resulted in a biphasic central nervous system disease that paralleled PPE in many aspects, albeit with a more diverse pathology. All cockatiels became lethargic and polyuric between days 7 and 13 pi and during that time schizonts of S. calchasi were found primarily in the liver and spleen accompanied by necrosis and inflammation. As with pigeons, neurological signs occurred during a chronic phase of the disease in three cockatiels between 57 and 63 dpi. However, all five cockatiels necropsied in that period, or at the end of the trial at 76 dpi, had a severe lymphohistiocytic and necrotizing encephalitis. No tissue cysts were found in the heart, and cockatiels infected with 10(5) sporocysts only had a negligible parasite load in skeletal muscles despite the presence of severe central nervous system lesions. Notably, intralesional schizonts were identified in the brain of one cockatiel. In contrast to previous results, intralesional schizonts were also identified in the brains of three of six naturally infected pigeons from Minnesota and Missouri examined as part of an epidemiological investigation. In both the cockatiel and the pigeons, tissue cysts were found concurrently with schizonts suggesting an uncommon phenomenon in the Sarcocystis life cycle. Based on the results of this study, transmission of S. calchasi to avian species other than the domestic pigeon is

  9. Growth curves and age-related changes in carcass characteristics, organs, serum parameters, and intestinal transporter gene expression in domestic pigeon (Columba livia).

    PubMed

    Gao, C Q; Yang, J X; Chen, M X; Yan, H C; Wang, X Q

    2016-04-01

    Two experiments were conducted to fit growth curves, and determine age-related changes in carcass characteristics, organs, serum biochemical parameters, and gene expression of intestinal nutrient transporters in domestic pigeon (Columba livia). In experiment 1, body weight (BW) of 30 pigeons was respectively determined at 1, 3, 7, 14, 21, 28, and 35 days old to fit growth curves and to describe the growth of pigeons. In experiment 2, eighty-four 1-day-old squabs were grouped by weight into 7 groups. On d 1, 3, 7, 14, 21, 28, and 35, twelve birds from each group were randomly selected for slaughter and post-slaughter analysis. The results showed that BW of pigeons increased rapidly from d 1 to d 28 (a 25.7-fold increase), and then had little change until d 35. The Logistic, Gompertz, and Von Bertalanffy functions can all be well fitted with the growth curve of domestic pigeons (R2>0.90) and the Gompertz model showed the highest R2value among the models (R2=0.9997). The equation of Gompertz model was Y=507.72×e-(3.76exp(-0.17t))(Y=BW of pigeon (g); t=time (day)). In addition, breast meat yield (%) increased with age throughout the experiment, whereas the leg meat yield (%) reached to the peak on d 14. Serum total protein, albumin, globulin, and glucose concentration were increased with age, whereas serum uric acid concentration was decreased (P<0.05). Furthermore, the gene expressions of nutrient transporters (y+LAT2, LAT1, B0AT1, PepT1, and NHE2) in jejunum of pigeon were increased with age. The results of correlation analysis showed the gene expressions of B0AT1, PepT1, and NHE2 had positive correlations with BW (0.73

  10. Multivariate Patterns in the Human Object-Processing Pathway Reveal a Shift from Retinotopic to Shape Curvature Representations in Lateral Occipital Areas, LO-1 and LO-2

    PubMed Central

    Vernon, Richard J. W.; Gouws, André D.; Lawrence, Samuel J. D.; Wade, Alex R.

    2016-01-01

    Representations in early visual areas are organized on the basis of retinotopy, but this organizational principle appears to lose prominence in the extrastriate cortex. Nevertheless, an extrastriate region, such as the shape-selective lateral occipital cortex (LO), must still base its activation on the responses from earlier retinotopic visual areas, implying that a transition from retinotopic to “functional” organizations should exist. We hypothesized that such a transition may lie in LO-1 or LO-2, two visual areas lying between retinotopically defined V3d and functionally defined LO. Using a rapid event-related fMRI paradigm, we measured neural similarity in 12 human participants between pairs of stimuli differing along dimensions of shape exemplar and shape complexity within both retinotopically and functionally defined visual areas. These neural similarity measures were then compared with low-level and more abstract (curvature-based) measures of stimulus similarity. We found that low-level, but not abstract, stimulus measures predicted V1–V3 responses, whereas the converse was true for LO, a double dissociation. Critically, abstract stimulus measures were most predictive of responses within LO-2, akin to LO, whereas both low-level and abstract measures were predictive for responses within LO-1, perhaps indicating a transitional point between those two organizational principles. Similar transitions to abstract representations were not observed in the more ventral stream passing through V4 and VO-1/2. The transition we observed in LO-1 and LO-2 demonstrates that a more “abstracted” representation, typically considered the preserve of “category-selective” extrastriate cortex, can nevertheless emerge in retinotopic regions. SIGNIFICANCE STATEMENT Visual areas are typically identified either through retinotopy (e.g., V1–V3) or from functional selectivity [e.g., shape-selective lateral occipital complex (LOC)]. We combined these approaches to explore

  11. Dexamethasone promotes tolerance in vivo by enriching CD11clo CD40lo tolerogenic macrophages.

    PubMed

    Zheng, Guoxing; Zhong, Shibo; Geng, Yajun; Munirathinam, Gnanasekar; Cha, Isaac; Reardon, Catherine; Getz, Godfrey S; van Rooijen, Nico; Kang, Youmin; Wang, Bin; Chen, Aoshuang

    2013-01-01

    We previously showed that antigen immunization in the presence of the immunosuppressant dexamethasone (a strategy we termed "suppressed immunization") could tolerize established recall responses of T cells. However, the mechanism by which dexamethasone acts as a tolerogenic adjuvant has remained unclear. In the present study, we show that dexamethasone enriches CD11c(lo) CD40(lo) macrophages in a dose-dependent manner in the spleen and peripheral lymph nodes of mice by depleting all other CD11c(+) CD40(+) cells including dendritic cells. The enriched macrophages display a distinct MHC class II (MHC II)(lo) CD86(hi) phenotype. Upon activation by antigen in vivo, CD11c(lo) CD40(lo) macrophages upregulate IL-10, a classic marker for tolerogenic antigen-presenting cells, and elicit a serum IL-10 response. When presenting antigen in vivo, these cells do not elicit recall responses from memory T cells, but rather stimulate the expansion of antigen-specific regulatory T cells. Moreover, the depletion of CD11c(lo) CD40(lo) macrophages during suppressed immunization diminishes the tolerogenic efficacy of the treatment. These results indicate that dexamethasone acts as a tolerogenic adjuvant partly by enriching the CD11c(lo) CD40(lo) tolerogenic macrophages. PMID:23001956

  12. Going LO (laparoscopic oviductal) for ET and AI in Felids – Challenges, Strategies and Successes

    PubMed Central

    Swanson, WF

    2012-01-01

    Contents Embryo transfer (ET) and artificial insemination (AI) are potentially invaluable techniques for the propagation and management of genetically valuable domestic cat and endangered nondomestic cat populations. Many of the challenges that impair the effective application of ET and AI in felids may be overcome by using laparoscopic oviductal (LO) approaches. LO-ET and LO-AI are minimally-invasive procedures, requiring only two small skin incisions for insertion of a laparoscope and grasping forceps into the abdominal cavity to permit visualization and catheterization of the oviduct for embryo or semen deposition. With concurrent improvements in embryo culture systems and ovarian synchronization protocols, LO-ET has proven effective over the past decade for propagation of laboratory cats, cat models of hereditary disease and nondomestic cats. To date, viable offspring have been produced following LO-ET of non-frozen and frozen-thawed IVF-derived embryos in eight cat hereditary disease models and two nondomestic cat species, the ocelot and sand cat. LO-AI with low sperm numbers (~2–8 million motile) has shown similar efficacy to LO-ET, resulting in high pregnancy percentages (50–70%) following insemination of gonadotropin-treated domestic cats. Multiple kittens also have been produced in two hereditary disease models following LO-AI with frozen semen, and both ocelot and Pallas’ cat kittens have been born after LO-AI with freshly-collected semen. The application of LO-ET and LO-AI to felids has resulted in substantial improvement in the efficiency of assisted reproduction for genetic management of these invaluable domestic cat and wild cat populations. PMID:23279483

  13. A SCUBA-2 survey of FeLoBAL QSOs. Are FeLoBALs in a `transition phase' between ULIRGs and QSOs?

    NASA Astrophysics Data System (ADS)

    Violino, Giulio; Coppin, Kristen E. K.; Stevens, Jason A.; Farrah, Duncan; Geach, James E.; Alexander, Dave M.; Hickox, Ryan; Smith, Daniel J. B.; Wardlow, Julie L.

    2016-04-01

    It is thought that a class of broad absorption line (BAL) QSOs, characterized by Fe absorption features in their UV spectra (called `FeLoBALs'), could mark a transition stage between the end of an obscured starburst event and a youthful QSO beginning to shed its dust cocoon, where Fe has been injected into the interstellar medium by the starburst. To test this hypothesis, we have undertaken deep Submillimetre Common-User Bolometer Array 2 (SCUBA-2) 850 μm observations of a sample of 17 FeLoBAL QSOs with 0.89 ≤ z ≤ 2.78 and -23.31 ≤ MB ≤ -28.50 to directly detect an excess in the thermal emission of the dust which would probe enhanced star formation activity. We find that FeLoBALs are not luminous sources in the sub-mm, none of them are individually detected at 850 μm, nor as a population through stacking (Fs = 1.14 ± 0.58 mJy). Statistical and survival analyses reveal that FeLoBALs have sub-mm properties consistent with BAL and non-BAL QSOs with matched redshifts and magnitudes. An Spectral Energy Distribution fitting analysis shows that the far-infrared emission is dominated by active galactic nuclei activity, and a starburst component is required only in 6/17 sources of our sample; moreover the integrated total luminosity of 16/17 sources is L ≥ 1012 L⊙, high enough to classify FeLoBALs as infrared luminous. In conclusion, we do not find any evidence in support of FeLoBAL QSOs being a transition population between an ultraluminous infrared galaxy (ULIRG) and an unobscured QSO; in particular, FeLoBALs are not characterized by a cold starburst which would support this hypothesis.

  14. Resonant tunnelling diode oscillator as an alternative LO for SIS receiver applications

    NASA Technical Reports Server (NTRS)

    Blundell, R.; Papa, D. C.; Brown, E. R.; Parker, C. D.

    1993-01-01

    The resonant tunnelling diode (RTD) oscillator has been demonstrated for the first time as a local oscillator (LO) in a heterodyne receiver. Noise measurements made on a sensitive 200 GHz superconductor-insulator-superconductor receiver using both a multiplied Gunn diode and an RTD oscillator as the LO revealed no difference in receiver noise as a function of oscillator type.

  15. A ROACH Based Data Acquisition System for the Low Frequency All Sky Monitor (LoFASM)

    NASA Astrophysics Data System (ADS)

    Dartez, Louis P.; Jenet, F.; Cohen, S.; Creighton, T. D.; Ford, A.; Garcia, A.; Hicks, B.; Hinojosa, J.; Kassim, N. E.; Longoria, C.; Lunsford, G.; Mata, A.; Miller, R. B.; Price, R. H.; Quintero, L.; Ray, P. S.; Reser, J.; Rivera, J.; Stovall, K.; Taylor, G. B.

    2013-01-01

    The Low Frequency All Sky Monitor (LoFASM) is a distributed array of dipole antennas that are sensitive to radio frequencies from 5 to 88 MHz. The primary science goals will be the detection and study of low-frequency radio transients. LoFASM consists of antennas and front end electronics that were originally developed for the Long Wavelength Array (LWA) by the U.S. Naval Research Lab, the University of New Mexico, Virginia Tech, and the Jet Propulsion Laboratory. LoFASM, funded by the U.S. Department of Defense, will initially consist of 4 stations, each consisting of 12 dual-polarization dipole antenna stands. The signals received by LoFASM are digitized and processed using Reconfigurable Open Architecture Computing Hardware (ROACH) boards. This poster will describe the LoFASM project with an emphasis on the ROACH data processing pipe-line.

  16. Contrast Invariant Interest Point Detection by Zero-Norm LoG Filter.

    PubMed

    Zhenwei Miao; Xudong Jiang; Kim-Hui Yap

    2016-01-01

    The Laplacian of Gaussian (LoG) filter is widely used in interest point detection. However, low-contrast image structures, though stable and significant, are often submerged by the high-contrast ones in the response image of the LoG filter, and hence are difficult to be detected. To solve this problem, we derive a generalized LoG filter, and propose a zero-norm LoG filter. The response of the zero-norm LoG filter is proportional to the weighted number of bright/dark pixels in a local region, which makes this filter be invariant to the image contrast. Based on the zero-norm LoG filter, we develop an interest point detector to extract local structures from images. Compared with the contrast dependent detectors, such as the popular scale invariant feature transform detector, the proposed detector is robust to illumination changes and abrupt variations of images. Experiments on benchmark databases demonstrate the superior performance of the proposed zero-norm LoG detector in terms of the repeatability and matching score of the detected points as well as the image recognition rate under different conditions. PMID:26302514

  17. TriLoNet: Piecing Together Small Networks to Reconstruct Reticulate Evolutionary Histories.

    PubMed

    Oldman, James; Wu, Taoyang; van Iersel, Leo; Moulton, Vincent

    2016-08-01

    Phylogenetic networks are a generalization of evolutionary trees that can be used to represent reticulate processes such as hybridization and recombination. Here, we introduce a new approach called TriLoNet (Trinet Level- one Network algorithm) to construct such networks directly from sequence alignments which works by piecing together smaller phylogenetic networks. More specifically, using a bottom up approach similar to Neighbor-Joining, TriLoNet constructs level-1 networks (networks that are somewhat more general than trees) from smaller level-1 networks on three taxa. In simulations, we show that TriLoNet compares well with Lev1athan, a method for reconstructing level-1 networks from three-leaved trees. In particular, in simulations we find that Lev1athan tends to generate networks that overestimate the number of reticulate events as compared with those generated by TriLoNet. We also illustrate TriLoNet's applicability using simulated and real sequence data involving recombination, demonstrating that it has the potential to reconstruct informative reticulate evolutionary histories. TriLoNet has been implemented in JAVA and is freely available at https://www.uea.ac.uk/computing/TriLoNet. PMID:27189565

  18. LoCoH: Non-parameteric kernel methods for constructing home ranges and utilization distributions

    USGS Publications Warehouse

    Getz, Wayne M.; Fortmann-Roe, Scott; Cross, Paul C.; Lyons, Andrew J.; Ryan, Sadie J.; Wilmers, Christopher C.

    2007-01-01

    Parametric kernel methods currently dominate the literature regarding the construction of animal home ranges (HRs) and utilization distributions (UDs). These methods frequently fail to capture the kinds of hard boundaries common to many natural systems. Recently a local convex hull (LoCoH) nonparametric kernel method, which generalizes the minimum convex polygon (MCP) method, was shown to be more appropriate than parametric kernel methods for constructing HRs and UDs, because of its ability to identify hard boundaries (e.g., rivers, cliff edges) and convergence to the true distribution as sample size increases. Here we extend the LoCoH in two ways: ‘‘fixed sphere-of-influence,’’ or r -LoCoH (kernels constructed from all points within a fixed radius r of each reference point), and an ‘‘adaptive sphere-of-influence,’’ or a -LoCoH (kernels constructed from all points within a radius a such that the distances of all points within the radius to the reference point sum to a value less than or equal to a ), and compare them to the original ‘‘fixed-number-of-points,’’ or k -LoCoH (all kernels constructed from k -1 nearest neighbors of root points). We also compare these nonparametric LoCoH to parametric kernel methods using manufactured data and data collected from GPS collars on African buffalo in the Kruger National Park, South Africa. Our results demonstrate that LoCoH methods are superior to parametric kernel methods in estimating areas used by animals, excluding unused areas (holes) and, generally, in constructing UDs and HRs arising from the movement of animals influenced by hard boundaries and irregular structures (e.g., rocky outcrops). We also demonstrate that a -LoCoH is generally superior to k - and r -LoCoH (with software for all three methods available at http://locoh.cnr.berkeley.edu).

  19. LoCoH: Nonparameteric Kernel Methods for Constructing Home Ranges and Utilization Distributions

    PubMed Central

    Getz, Wayne M.; Fortmann-Roe, Scott; Wilmers, Christopher C.

    2007-01-01

    Parametric kernel methods currently dominate the literature regarding the construction of animal home ranges (HRs) and utilization distributions (UDs). These methods frequently fail to capture the kinds of hard boundaries common to many natural systems. Recently a local convex hull (LoCoH) nonparametric kernel method, which generalizes the minimum convex polygon (MCP) method, was shown to be more appropriate than parametric kernel methods for constructing HRs and UDs, because of its ability to identify hard boundaries (e.g., rivers, cliff edges) and convergence to the true distribution as sample size increases. Here we extend the LoCoH in two ways: “fixed sphere-of-influence,” or r-LoCoH (kernels constructed from all points within a fixed radius r of each reference point), and an “adaptive sphere-of-influence,” or a-LoCoH (kernels constructed from all points within a radius a such that the distances of all points within the radius to the reference point sum to a value less than or equal to a), and compare them to the original “fixed-number-of-points,” or k-LoCoH (all kernels constructed from k-1 nearest neighbors of root points). We also compare these nonparametric LoCoH to parametric kernel methods using manufactured data and data collected from GPS collars on African buffalo in the Kruger National Park, South Africa. Our results demonstrate that LoCoH methods are superior to parametric kernel methods in estimating areas used by animals, excluding unused areas (holes) and, generally, in constructing UDs and HRs arising from the movement of animals influenced by hard boundaries and irregular structures (e.g., rocky outcrops). We also demonstrate that a-LoCoH is generally superior to k- and r-LoCoH (with software for all three methods available at http://locoh.cnr.berkeley.edu). PMID:17299587

  20. Higgs boson gluon-fusion production beyond threshold in N3LO QCD

    DOE PAGESBeta

    Anastasiou, Charalampos; Duhr, Claude; Dulat, Falko; Furlan, Elisabetta; Gehrmann, Thomas; Herzog, Franz; Mistlberger, Bernhard

    2015-03-18

    In this study, we compute the gluon fusion Higgs boson cross-section at N3LO through the second term in the threshold expansion. This calculation constitutes a major milestone towards the full N3LO cross section. Our result has the best formal accuracy in the threshold expansion currently available, and includes contributions from collinear regions besides subleading corrections from soft and hard regions, as well as certain logarithmically enhanced contributions for general kinematics. We use our results to perform a critical appraisal of the validity of the threshold approximation at N3LO in perturbative QCD.

  1. Development of HiLo Microscope and its use in In-Vivo Applications

    NASA Astrophysics Data System (ADS)

    Patel, Shreyas J.

    The functionality of achieving optical sectioning in biomedical research is invaluable as it allows for visualization of a biological sample at different depths while being free of background scattering. Most current microscopy techniques that offer optical sectioning, unfortunately, require complex instrumentation and thus are generally costly. HiLo microscopy, on the other hand, offers the same functionality and advantage at a relatively low cost. Hence, the work described in this thesis involves the design, build, and application of a HiLo microscope. More specifically, a standalone HiLo microscope was built in addition to implementing HiLo microscopy on a standard fluorescence microscope. In HiLo microscopy, optical sectioning is achieved by acquiring two different types of images per focal plane. One image is acquired under uniform illumination and the other is acquired under speckle illumination. These images are processed using an algorithm that extracts in-focus information and removes features and glare that occur as a result of background fluorescence. To show the benefits of the HiLo microscopy, several imaging experiments on various samples were performed under a HiLo microscope and compared against a traditional fluorescence microscope and a confocal microscope, which is considered the gold standard in optical imaging. In-vitro and ex-vivo imaging was performed on a set of pollen grains, and optically cleared mouse brain and heart slices. Each of these experiments showed great reduction in background scattering at different depths under HiLo microscopy. More importantly, HiLo imaging of optically cleared heart slice demonstrated emergence of different vasculature at different depths. Reduction of out-of-focus light increased the spatial resolution and allowed better visualization of capillary vessels. Furthermore, HiLo imaging was tested in an in-vivo model of a rodent dorsal window chamber model. When imaging the same sample under confocal microscope

  2. Effect of Propellant Flowrate and Purity on Carbon Deposition in LO2/Methane Gas Generators

    NASA Technical Reports Server (NTRS)

    Bossard, J. A.; Burkhardt, W. M.; Niiya, K. Y.; Braam, F.

    1989-01-01

    The generation and deposition of carbon was studied in the Carbon Deposition Program using subscale hardware with LO2/Liquid Natural Gas (LNG) and LO2/Methane propellants at low mixture ratios. The purpose of the testing was to evaluate the effect of methane purity and full scale injection density on carbon deposition. The LO2/LNG gas generator/preburner testing was performed at mixture ratios between 0.24 and 0.58 and chamber pressures from 5.8 to 9.4 MPa (840 to 1370 psia). A total of seven 200 second duration tests were performed. The LNG testing occurred at low injection densities, similar to the previous LO2/RP-1, LO2/propane, and LO2/methane testing performed on the carbon deposition program. The current LO2/methane test series occurred at an injection density factor of approximately 10 times higher than the previous testing. The high injection density LO2/methane testing was performed at mixture ratios between from 0.23 to 0.81 and chamber pressures from 6.4 to 15.2 MPa (925 to 2210 psia). A total of nine high injection density tests were performed. The testing performed demonstrated that low purity methane (LNG) did not produce any detectable change in carbon deposition when compared to pure methane. In addition, the C* performance and the combustion gas temperatures measured were similar to those obtained for pure methane. Similar results were obtained testing pure methane at higher propellant injection densities with coarse injector elements.

  3. Measurement Properties of the Low Back Activity Confidence Scale (LoBACS).

    PubMed

    Davenport, Todd E; Cleland, Joshua A; Yamada, Kimiko A; Kulig, Kornelia

    2016-06-01

    The purpose of this study was to determine the measurement properties of the Low Back Activity Confidence Scale (LoBACS) in individuals with post-acute low back pain (LBP) receiving nonsurgical intervention, including construct validity, factorial validity, and internal consistency reliability. Data were analyzed from an existing randomized clinical trial involving 112 patients with LBP. Evidence for convergent validity was observed through significant correlations between LoBACS subscale scores and other function, pain, and psychobehavioral measures. LoBACS subscales accounted for 36% of the unique variance in dependent variable measurements, suggesting a satisfactory level of statistical divergence between the LoBACS and other psychobehavioral measurements in this study. Cronbach's α ranged from .88 to .92 for LoBACS subscales, and item-total correlations exceeded .6, indicating high internal consistency reliability. Principal axis factoring confirmed the hypothesized three-subscale structure by correctly classifying 14 of the 15 items. These findings indicate the LoBACS is valid and internally consistent to measure domain-specific self-efficacy beliefs. PMID:24686745

  4. Deep analysis of Raman spectra of ZnO:Mo and ZnO:In sprayed thin films along with LO and TA+LO bands investigation

    NASA Astrophysics Data System (ADS)

    Souissi, A.; Amlouk, M.; Khemakhem, H.; Guermazi, S.

    2016-04-01

    ZnO and Mo, In doped ZnO thin films with the molar ratios (Mo/Zn) and (In/Zn) were dosed at 1%, 2% and 3%, respectively. These films were deposited on amorphous SiO2 substrate at 460 °C by the spray-pyrolysis process. A useful and concise reminder of the spatial resolutions of Raman spectroscopy was presented. The vibrational responses of these films at high doping exhibited strong fluctuations that were resolved by successive digital processing, choice of the optimal profile of the baseline, suppression of fluorescence and/or photoluminescence, and noise reduction. These treated spectra have allowed to identify possible multi-modes in highly doped studied samples and revealed the presence of LO and TA+LO broad bands, whose second was at cascade and could be explored in optoelectronic and sensitive systems.

  5. Selenoprotein X Gene Knockdown Aggravated H2O2-Induced Apoptosis in Liver LO2 Cells.

    PubMed

    Tang, Jiayong; Cao, Lei; Li, Qiang; Wang, Longqiong; Jia, Gang; Liu, Guangmang; Chen, Xiaoling; Cai, Jingyi; Shang, Haiying; Zhao, Hua

    2016-09-01

    To determine the roles of selenoprotein X gene (Selx) in protecting liver cells against oxidative damage, the influences of Selx knockdown on H2O2-induced apoptosis in human normal hepatocyte (LO2) cells were studied. pSilencer 3.1 was used to develop knockdown vector targeting the 3'-UTR of human Selx. The Selx knockdown and control cells were further exposed to H2O2, and cell viability, cell apoptosis rate, and the expression levels of mRNA and protein of apoptosis-related genes were detected. The results showed that vector targeting the 3'-UTR of Selx successfully silenced mRNA or protein expression of SelX in LO2 cells. Selx knockdown resulted in decreased cell viability, increased percentage of early apoptotic cells, decreased Bcl2A1 and Bcl-2 expression, and increased phosphorylation of P38 in LO2 cells. When Selx knockdown LO2 cells were exposed to H2O2, characteristics of H2O2-induced cell dysfunctions were further exacerbated. Taken together, our findings suggested that SelX played important roles in protecting LO2 cells against oxidative damage and reducing H2O2-induced apoptosis in liver cells. PMID:26899321

  6. Optically sectioned in vivo imaging with speckle illumination HiLo microscopy

    NASA Astrophysics Data System (ADS)

    Lim, Daryl; Ford, Tim N.; Chu, Kengyeh K.; Mertz, Jerome

    2011-01-01

    We present a simple wide-field imaging technique, called HiLo microscopy, that is capable of producing optically sectioned images in real time, comparable in quality to confocal laser scanning microscopy. The technique is based on the fusion of two raw images, one acquired with speckle illumination and another with standard uniform illumination. The fusion can be numerically adjusted, using a single parameter, to produce optically sectioned images of varying thicknesses with the same raw data. Direct comparison between our HiLo microscope and a commercial confocal laser scanning microscope is made on the basis of sectioning strength and imaging performance. Specifically, we show that HiLo and confocal 3-D imaging of a GFP-labeled mouse brain hippocampus are comparable in quality. Moreover, HiLo microscopy is capable of faster, near video rate imaging over larger fields of view than attainable with standard confocal microscopes. The goal of this paper is to advertise the simplicity, robustness, and versatility of HiLo microscopy, which we highlight with in vivo imaging of common model organisms including planaria, C. elegans, and zebrafish.

  7. Optically sectioned in vivo imaging with speckle illumination HiLo microscopy.

    PubMed

    Lim, Daryl; Ford, Tim N; Chu, Kengyeh K; Mertz, Jerome

    2011-01-01

    We present a simple wide-field imaging technique, called HiLo microscopy, that is capable of producing optically sectioned images in real time, comparable in quality to confocal laser scanning microscopy. The technique is based on the fusion of two raw images, one acquired with speckle illumination and another with standard uniform illumination. The fusion can be numerically adjusted, using a single parameter, to produce optically sectioned images of varying thicknesses with the same raw data. Direct comparison between our HiLo microscope and a commercial confocal laser scanning microscope is made on the basis of sectioning strength and imaging performance. Specifically, we show that HiLo and confocal 3-D imaging of a GFP-labeled mouse brain hippocampus are comparable in quality. Moreover, HiLo microscopy is capable of faster, near video rate imaging over larger fields of view than attainable with standard confocal microscopes. The goal of this paper is to advertise the simplicity, robustness, and versatility of HiLo microscopy, which we highlight with in vivo imaging of common model organisms including planaria, C. elegans, and zebrafish. PMID:21280920

  8. Laminarin-induced apoptosis in human colon cancer LoVo cells

    PubMed Central

    JI, CHEN-FENG; JI, YU-BIN

    2014-01-01

    A number of scientific studies have revealed that laminarin has antitumor effects. Therefore, the aim of the present study was to investigate the apoptosis of LoVo cells and the underlying mechanisms induced by laminarin. LoVo cells were treated with various concentrations of laminarin and fluorescence-inverted microscopy was used to observe the morphology of LoVo cells treated with laminarin. In addition, western blotting was performed to analyze the expression levels of death receptor (DR)4, DR5, TNF-related apoptosis-inducing ligand (TRAIL), Fas-associated protein with death domain (FADD), caspase-8, caspase-3, Bid and tBid. Flow cytometry was conducted to analyze the expressions of Bcl-2 and Bax, and spectrophotometry was performed to quantify the activity of caspases-8, -3, -6 and -7. Following the treatment of LoVo cells with laminarin for 24 h, the expression levels of DR4, DR5, TRAIL, FADD, Bid, tBid and Bax were observed to be upregulated, whereas the expression levels of pro-caspase-8, pro-caspase-3 and Bcl-2 were downregulated. In addition, the activities of casapse-8, -3, -6 and -7 were observed to increase, which was a significant difference when compared with those of the control group. Therefore, laminarin is considered to induce the apoptosis of LoVo cells, which may occur via a DR pathway, suggesting that laminarin may be a potent agent for cancer treatment. PMID:24765209

  9. Kinetic description of an electron--LO-phonon system with finite phonon lifetime

    SciTech Connect

    Nguyen, V.T.; Mahler, G. )

    1992-02-15

    We study the cooling of an electron plasma from a kinetic point of view. For this purpose, a quantum theory of fluctuations is applied to derive the kinetic equations for an electron--LO-phonon system from various model Hamiltonians. A polarization approximation is provided that goes beyond perturbation theory of the electron-phonon interaction. The description of electron-phonon energy exchange is shown to be impossible with the interacting Hamiltonian in Froehlich's one-phonon form unless dissipation of the bare LO phonon is included. For a Hamiltonian including effects of the scattering of LO phonons by acoustic phonons, kinetic equations are derived. The equation for LO phonons is shown to describe the collective excitations with finite lifetime, in the limiting case of weak damping of the plasmon-phonon coupled modes. A reduction of the cooling rate similar to the hot-phonon'' effect is shown to occur for the case of weak coupling without assuming a steady state of the LO phonons. Finally, an electron-phonon interaction Hamiltonian in two-phonon form is considered and it is shown that electron-phonon energy exchange may be described in the polarization approximation without introducing a finite phonon lifetime.

  10. Implementation and Evaluation of the Enhanced Header Compression (IPHC) for 6LoWPAN

    NASA Astrophysics Data System (ADS)

    Ludovici, Alessandro; Calveras, Anna; Catalan, Marisa; Gómez, Carles; Paradells, Josep

    6LoWPAN defines how to carry IPv6 packets over IEEE 802.15.4 low power wireless or sensor networks. Limited bandwidth, memory and energy resources require a careful application of IPv6 in a LoWPAN. The IEEE 802.15.4 standard defines a maximum frame size of 127 bytes that decreases to 102 bytes considering the header overhead. A further reduction is due to the security, network and transport protocols header overhead that, in case of IPv6 and UDP, leave only 33 bytes for application data. A compression algorithm is necessary in order to reduce the overhead and save space in data payload. This paper describes and compares the proposed IPv6 header compression mechanisms for 6LoWPAN environments.

  11. A Study of LoRa: Long Range & Low Power Networks for the Internet of Things.

    PubMed

    Augustin, Aloÿs; Yi, Jiazi; Clausen, Thomas; Townsley, William Mark

    2016-01-01

    LoRa is a long-range, low-power, low-bitrate, wireless telecommunications system, promoted as an infrastructure solution for the Internet of Things: end-devices use LoRa across a single wireless hop to communicate to gateway(s), connected to the Internet and which act as transparent bridges and relay messages between these end-devices and a central network server. This paper provides an overview of LoRa and an in-depth analysis of its functional components. The physical and data link layer performance is evaluated by field tests and simulations. Based on the analysis and evaluations, some possible solutions for performance enhancements are proposed. PMID:27618064

  12. Improving high resolution retinal image quality using speckle illumination HiLo imaging

    PubMed Central

    Zhou, Xiaolin; Bedggood, Phillip; Metha, Andrew

    2014-01-01

    Retinal image quality from flood illumination adaptive optics (AO) ophthalmoscopes is adversely affected by out-of-focus light scatter due to the lack of confocality. This effect is more pronounced in small eyes, such as that of rodents, because the requisite high optical power confers a large dioptric thickness to the retina. A recently-developed structured illumination microscopy (SIM) technique called HiLo imaging has been shown to reduce the effect of out-of-focus light scatter in flood illumination microscopes and produce pseudo-confocal images with significantly improved image quality. In this work, we adopted the HiLo technique to a flood AO ophthalmoscope and performed AO imaging in both (physical) model and live rat eyes. The improvement in image quality from HiLo imaging is shown both qualitatively and quantitatively by using spatial spectral analysis. PMID:25136486

  13. Efficacy of nicarbazin (Ovistop®) in the containment and reduction of the populations of feral pigeons (Columba livia var. domestica) in the city of Genoa, Italy: a retrospective evaluation.

    PubMed

    Albonetti, Paolo; Marletta, Antonio; Repetto, Ivano; Sasso, Emanuela Assunta

    2015-01-01

    This study describes the results of a retrospective evaluation (8 years: 2005-2012) of the efficacy of the anti-fertility drug, Ovistop® nicarbazin (800 ppm) added to corn kernels used to feed non-migratory feral pigeon colonies, Columba livia var. domestica, in the city of Genoa, Italy. The observation interested 4 non-migratory feral pigeon colonies located into well‑defined areas of the city of Genoa, Italy. Three of these colonies were treated for 12 months, with 10 g of drug (Ovistop®) provided per bird per day for 5 days each week; the other colony was treated in the same way but with a placebo (control station). Each colony and the relative area where the colony was located were both monitored with the same daily examination. Statistical analysis techniques were applied to the findings recorded - both descriptive (indices of central and dispersion trends) and comparative (one-way variance analysis). In the colonies treated with the drug, following an initial increase in the population ('magnet effect'), a reduction was observed over the following 4 years (-35% >x> -45%) and a further decrease (-65% >x> -70%) was observed over the subsequent 4 years (statistically significant one-way ANOVA p<0.01). This phenomenon was recorded across the board in the 3 treated stations, compared to the overall unstable trend observed for the control station. As no external or exceptional anthropic or natural factors were observed, it can be stated that, given the results observed, the drug seemed effective in reducing the treated bird populations. PMID:25842215

  14. A Simultaneous Discovery: The Case of Johannes Stark and Antonino Lo Surdo

    NASA Astrophysics Data System (ADS)

    Leone, Matteo; Paoletti, Alessandro; Robotti, Nadia

    2004-09-01

    In 1913 the German physicist Johannes Stark (1874 1957) and the Italian physicist Antonino Lo Surdo (1880 1949)discovered virtually simultaneously and independently that hydrogen spectral lines are split into components by an external electric field. Both of their discoveries ensued from studies on the same phenomenon, the Doppler effect in canal rays, but they arose in different theoretical contexts. Stark had been working within the context of the emerging quantum theory, following a research program aimed at studying the effect of an electric field on spectral lines. Lo Surdo had been working within the context of the classical theory, and his was an accidental discovery. Both discoveries, however, played important roles in the history of physics: Stark’s discovery contributed to the establishment of both the old and the new quantum theories; Lo Surdo’s discovery led Antonio Garbasso (1871 1933)to introduce research on the quantum theory into Italian physics. Ironically, soon after their discoveries, both Stark and Lo Surdo rejected developments in modern physics and allied themselves with the political and racial programs of Hitler and Mussolini.

  15. FLOYDS Classification of ASASSN-14lo as a Type Ia Supernova Near Peak

    NASA Astrophysics Data System (ADS)

    Arcavi, Iair; Sand, David; McCully, Curtis; Valenti, Stefano; Hosseinzadeh, Griffin; Howell, D. Andrew

    2014-12-01

    We obtained a spectrum of ASASSN-14lo (ATel #6794) on 2014 December 10 (UT) with the robotic FLOYDS instrument mounted on the Faulkes Telescope North. Using Superfit (Howell et al. 2005, ApJ 634, 1190) we find a good fit to the Type Ia SN 1996X around peak at the redshift of the proposed host galaxy (z=0.01993; NED).

  16. Structural Validity of the Professional Development Profile of the LoTi Digital-Age Survey

    ERIC Educational Resources Information Center

    Mehta, Vandhana; Hull, Darrell M.

    2013-01-01

    The present study was used to examine the structural construct validity of the Professional Development Profile of the LoTi Digital-Age Survey, a measure of teacher instructional practices with technology in the classroom. Teacher responses ("N" = 2,840) from across the United States were used to assess factor structure of the instrument using…

  17. Numerical Investigation of LO2 and LCH4 Storage Tanks on the Lunar Surface

    NASA Technical Reports Server (NTRS)

    Moder, Jeff; Barsi, Stephen; Kassemi, Mohammad

    2008-01-01

    Currently NASA is developing technologies to enable human exploration of the lunar surface for duration of up to 210 days. While trade studies are still underway, a cryogenic ascent stage using liquid oxygen (LO2) and liquid methane (LCH4) is being considered for the Altair lunar lander. For a representative Altair cryogenic ascent stage, we present a detailed storage analysis of the LO2 and LCH4 propellant tanks on the lunar surface for durations of up to 210 days. Both the LO2 and LCH4 propellant tanks are assumed to be pressurized with gaseous helium at launch. A two-phase lumped-vapor computational fluid dynamics model has been developed to account for the presence of a noncondensable gas in the ullage. The CFD model is used to simulate the initial pressure response of the propellant tanks while they are subjected to representative heat leak rates on the lunar surface. Once a near stationary state is achieved within the liquid phase, multizone model is used to extrapolate the solution farther in time. For fixed propellant mass and tank size, the long-term pressure response for different helium mass fractions in both the LO2 and LCH4 tanks is examined.

  18. Ka-im's Gift: A St:lo Legend (with Commentary by the Author).

    ERIC Educational Resources Information Center

    Gardner, Ethel B.

    1988-01-01

    Presents a modern retelling of a St:lo (Coast Salish) legend about the origin of a tribal treasure, the wondrous Sxwaixwe mask. Discusses the legend's origins, the process of transforming essentially oral sources into an accessible contemporary form, and the educational value of storytelling. Contains 13 references. (SV)

  19. Registration of WCL-LO4-Gail lesquerella with improved harvest index

    Technology Transfer Automated Retrieval System (TEKTRAN)

    WCL-LO4-Gail lesquerella (Physaria fendleri L.) germplasm line was publicly released jointly by the USDA, Agricultural Research Service and the University of Arizona, in 2012 as part of the new crops breeding program. The germplasm was developed by mass selection originating from lesquerella germpl...

  20. Forwarding techniques for IP fragmented packets in a real 6LoWPAN network.

    PubMed

    Ludovici, Alessandro; Calveras, Anna; Casademont, Jordi

    2011-01-01

    Wireless Sensor Networks (WSNs) are attracting more and more interest since they offer a low-cost solution to the problem of providing a means to deploy large sensor networks in a number of application domains. We believe that a crucial aspect to facilitate WSN diffusion is to make them interoperable with external IP networks. This can be achieved by using the 6LoWPAN protocol stack. 6LoWPAN enables the transmission of IPv6 packets over WSNs based on the IEEE 802.15.4 standard. IPv6 packet size is considerably larger than that of IEEE 802.15.4 data frame. To overcome this problem, 6LoWPAN introduces an adaptation layer between the network and data link layers, allowing IPv6 packets to be adapted to the lower layer constraints. This adaptation layer provides fragmentation and header compression of IP packets. Furthermore, it also can be involved in routing decisions. Depending on which layer is responsible for routing decisions, 6LoWPAN divides routing in two categories: mesh under if the layer concerned is the adaptation layer and route over if it is the network layer. In this paper we analyze different routing solutions (route over, mesh under and enhanced route over) focusing on how they forward fragments. We evaluate their performance in terms of latency and energy consumption when transmitting IP fragmented packets. All the tests have been performed in a real 6LoWPAN implementation. After consideration of the main problems in forwarding of mesh frames in WSN, we propose and analyze a new alternative scheme based on mesh under, which we call controlled mesh under. PMID:22346615

  1. The LO-BaFL method and ALS microarray expression analysis

    PubMed Central

    2012-01-01

    Background Sporadic Amyotrophic Lateral Sclerosis (sALS) is a devastating, complex disease of unknown etiology. We studied this disease with microarray technology to capture as much biological complexity as possible. The Affymetrix-focused BaFL pipeline takes into account problems with probes that arise from physical and biological properties, so we adapted it to handle the long-oligonucleotide probes on our arrays (hence LO-BaFL). The revised method was tested against a validated array experiment and then used in a meta-analysis of peripheral white blood cells from healthy control samples in two experiments. We predicted differentially expressed (DE) genes in our sALS data, combining the results obtained using the TM4 suite of tools with those from the LO-BaFL method. Those predictions were tested using qRT-PCR assays. Results LO-BaFL filtering and DE testing accurately predicted previously validated DE genes in a published experiment on coronary artery disease (CAD). Filtering healthy control data from the sALS and CAD studies with LO-BaFL resulted in highly correlated expression levels across many genes. After bioinformatics analysis, twelve genes from the sALS DE gene list were selected for independent testing using qRT-PCR assays. High-quality RNA from six healthy Control and six sALS samples yielded the predicted differential expression for 7 genes: TARDBP, SKIV2L2, C12orf35, DYNLT1, ACTG1, B2M, and ILKAP. Four of the seven have been previously described in sALS studies, while ACTG1, B2M and ILKAP appear in the context of this disease for the first time. Supplementary material can be accessed at: http://webpages.uncc.edu/~cbaciu/LO-BaFL/supplementary_data.html. Conclusion LO-BaFL predicts DE results that are broadly similar to those of other methods. The small healthy control cohort in the sALS study is a reasonable foundation for predicting DE genes. Modifying the BaFL pipeline allowed us to remove noise and systematic errors, improving the power of this

  2. Pseudo-scalar Higgs boson production at threshold N^3LO and N^3LL QCD

    NASA Astrophysics Data System (ADS)

    Ahmed, Taushif; Kumar, M. C.; Mathews, Prakash; Rana, Narayan; Ravindran, V.

    2016-06-01

    We present the first results on the production of pseudo-scalar Higgs boson through gluon fusion at the LHC to N^3LO in QCD taking into account only soft-gluon effects. We have used the effective Lagrangian that describes the coupling of the pseudo-scalar Higgs boson with the gluons in the large top quark mass limit. We have used quantities that have recently become available, namely the three-loop pseudo-scalar Higgs boson form factor and the third order universal soft function in QCD to achieve this. Along with the fixed order results, we also present the process dependent resummation coefficient for a threshold resummation to N^3LL in QCD. Phenomenological impact of these threshold N^3LO corrections to pseudo-scalar Higgs boson production at the LHC is presented and their role in the reduction of the renormalization scale dependence is demonstrated.

  3. Soft expansion of double-real-virtual corrections to Higgs production at N3LO

    NASA Astrophysics Data System (ADS)

    Anastasiou, Charalampos; Duhr, Claude; Dulat, Falko; Furlan, Elisabetta; Herzog, Franz; Mistlberger, Bernhard

    2015-08-01

    We present methods to compute higher orders in the threshold expansion for the one-loop production of a Higgs boson in association with two partons at hadron colliders. This process contributes to the N3LO Higgs production cross section beyond the soft-virtual approximation. We use reverse unitarity to expand the phase-space integrals in the small kinematic parameters and to reduce the coefficients of the expansion to a small set of master integrals. We describe two methods for the calculation of the master integrals. The first was introduced for the calculation of the soft triple-real radiation relevant to N3LO Higgs production. The second uses a particular factorization of the three body phase-space measure and the knowledge of the scaling properties of the integral itself. Our result is presented as a Laurent expansion in the dimensional regulator, although some of the master integrals are computed to all orders in this parameter.

  4. 100-LBF LO2/LCH4 - Reaction Control Engine Technology Development for Future Space Vehicles

    NASA Technical Reports Server (NTRS)

    Robinson, Philip J.; Veith, Eric M.; Hurlbert, Eric A.; Jimenez, Rafael; Smith, Timothy D.

    2008-01-01

    The National Aeronautics and Space Administration (NASA) has identified liquid oxygen (LO2)/liquid methane (LCH4) propulsion systems as promising options for some future space vehicles. NASA issued a contract to Aerojet to develop a 100-lbf (445 N) LO2/LCH4 Reaction Control Engine (RCE) aimed at reducing the risk of utilizing a cryogenic reaction control system (RCS) on a space vehicle. Aerojet utilized innovative design solutions to develop an RCE that can ignite reliably over a broad range of inlet temperatures, perform short minimum impulse bits (MIB) at small electrical pulse widths (EPW), and produce excellent specific impulse (Isp) across a range of engine mixture ratios (MR). These design innovations also provide a start transient with a benign MR, ensuring good thrust chamber compatibility and long life. In addition, this RCE can successfully operate at MRs associated with main engines, enabling the RCE to provide emergency backup propulsion to minimize vehicle propellant load and overall system mass.

  5. Karhunen-Loève transform for compressive sampling hyperspectral images

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Yan, Jingwen; Zheng, Xianwei; Peng, Hong; Guo, Di; Qu, Xiaobo

    2015-01-01

    Compressed sensing (CS) is a new jointly sampling and compression technology for remote sensing. In hyperspectral imaging, a typical CS method encodes the two-dimensional (2-D) spatial information of each spectral band or encodes the third spectral information simultaneously. However, encoding the spatial information is much easier than encoding the spectral information. Therefore, it is crucial to make use of the spectral information to improve the compression rate on 2-D CS data. We propose to encode the third spectral information with an adaptive Karhunen-Loève transform. With a mathematical proof, we show that interspectral correlations are preserved among 2-D randomly encoded spatial information. This property means that one can compress 2-D CS data effectively with a Karhunen-Loève transform. Experiments demonstrate that the proposed method can better reconstruct both spectral curves and spatial images than traditional compression methods at the bit rates 0 to 1.

  6. Combination of Vandetanib, Radiotherapy, and Irinotecan in the LoVo Human Colorectal Cancer Xenograft Model

    SciTech Connect

    Wachsberger, Phyllis; Burd, Randy; Ryan, Anderson; Daskalakis, Constantine; Dicker, Adam P.

    2009-11-01

    Purpose: The tumor growth kinetics of the human LoVo colorectal xenograft model was assessed in response to vandetanib, an orally available receptor tyrosine kinase inhibitor, radiotherapy (RT), or irinotecan (CPT-11), as single therapies and in combination. Methods and Materials: LoVo cells were injected subcutaneously into the right hind limb (5x10{sup 6} cells in 100muL phosphate-buffered saline) of athymic NCR NUM mice and tumors were grown to a volume of 200-300 mm{sup 3} before treatment. Vandetanib was administered at 50 mg/kg daily orally for 14 days starting on Day 1. RT was given as three fractions (3x3 Gy) on Days 1, 2, and 3. CPT-11 was given at 15 mg/kg intraperitoneally on Days 1 and 3. Tumor volumes were measured on a daily basis and calculated by measuring tumor diameters with digital calipers in two orthogonal dimensions. Results: All three single treatments (vandetanib, CPT-11, and radiation) significantly slowed LoVo colorectal tumor growth. Vandetanib significantly increased the antitumor effects of CPT-11 and radiation when given in combination with either of these treatments. These treatment combinations resulted in a slow tumor growth rate during the 2 weeks of vandetanib administration. The triple combination of vandetanib, CPT-11, and radiation produced the most marked improvement in response as observed by measurable shrinkage of tumors during the first week of treatment. Conclusions: The tumor growth delay kinetics observed in this study of the LoVo colorectal model suggest concurrent and sustained post-sequencing of vandetanib with cytotoxic therapy may be beneficial in tumors of this type.

  7. Two different periods present in the binary nucleus of the planetary nebula LoTr5

    NASA Astrophysics Data System (ADS)

    Kuczawska, Ewa; Mikolajewski, M.

    1993-10-01

    We present new photoelectric UBV observations of IN Com -- the binary nucleus of the planetary nebula LoTr5, carried out in April 1993 with the double beam photometer at Mt. Suhora Observatory. Low-amplitude variations were detected with a period of about 5.d92, in agreement with the results of Noskova (1989) and Bond and Livio (1990), but also higher frequency variability was discovered. A preliminary ephemeris is given. We speculate on the origin of the observed variabilities.

  8. Fast Calcium Imaging with Optical Sectioning via HiLo Microscopy.

    PubMed

    Lauterbach, Marcel A; Ronzitti, Emiliano; Sternberg, Jenna R; Wyart, Claire; Emiliani, Valentina

    2015-01-01

    Imaging intracellular calcium concentration via reporters that change their fluorescence properties upon binding of calcium, referred to as calcium imaging, has revolutionized our way to probe neuronal activity non-invasively. To reach neurons densely located deep in the tissue, optical sectioning at high rate of acquisition is necessary but difficult to achieve in a cost effective manner. Here we implement an accessible solution relying on HiLo microscopy to provide robust optical sectioning with a high frame rate in vivo. We show that large calcium signals can be recorded from dense neuronal populations at high acquisition rates. We quantify the optical sectioning capabilities and demonstrate the benefits of HiLo microscopy compared to wide-field microscopy for calcium imaging and 3D reconstruction. We apply HiLo microscopy to functional calcium imaging at 100 frames per second deep in biological tissues. This approach enables us to discriminate neuronal activity of motor neurons from different depths in the spinal cord of zebrafish embryos. We observe distinct time courses of calcium signals in somata and axons. We show that our method enables to remove large fluctuations of the background fluorescence. All together our setup can be implemented to provide efficient optical sectioning in vivo at low cost on a wide range of existing microscopes. PMID:26625116

  9. Fast Calcium Imaging with Optical Sectioning via HiLo Microscopy

    PubMed Central

    Sternberg, Jenna R.; Wyart, Claire; Emiliani, Valentina

    2015-01-01

    Imaging intracellular calcium concentration via reporters that change their fluorescence properties upon binding of calcium, referred to as calcium imaging, has revolutionized our way to probe neuronal activity non-invasively. To reach neurons densely located deep in the tissue, optical sectioning at high rate of acquisition is necessary but difficult to achieve in a cost effective manner. Here we implement an accessible solution relying on HiLo microscopy to provide robust optical sectioning with a high frame rate in vivo. We show that large calcium signals can be recorded from dense neuronal populations at high acquisition rates. We quantify the optical sectioning capabilities and demonstrate the benefits of HiLo microscopy compared to wide-field microscopy for calcium imaging and 3D reconstruction. We apply HiLo microscopy to functional calcium imaging at 100 frames per second deep in biological tissues. This approach enables us to discriminate neuronal activity of motor neurons from different depths in the spinal cord of zebrafish embryos. We observe distinct time courses of calcium signals in somata and axons. We show that our method enables to remove large fluctuations of the background fluorescence. All together our setup can be implemented to provide efficient optical sectioning in vivo at low cost on a wide range of existing microscopes. PMID:26625116

  10. Characterization of secreted proteins in HepG2 and LO2 cells by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Lin, Juqiang; Ruan, Qiuyong; Liao, Fadian; Lin, Jinyong; Huang, Zufang; Liu, Nenrong; Chen, Rong

    2014-11-01

    Secreted proteins, the promising source of biomarkers for early detection and diagnosis of cancer, have received considerable attention. Raman spectroscopy and principal component analysis (PCA) were used to characterize the secreted proteins collected from the cell cultures of human hepatoma cell line HepG2 and normal human liver cell line LO2 in this paper. We found the major difference of secreted proteins Raman spectra between HepG2 and LO2 cells were in the range of 1200cm-1-1800cm-1. Compared with LO2 cells, some significant changes based on secondary structure of secreted proteins in HepG2 cells were observed, including the increase in the relative intensity of the band at 1004cm-1, 1445cm-1, 1674cm-1 and the decrease at 1074cm-1. These variations of Raman bands indicated that the species and conformation of secreted proteins in HepG2 cells changed. The measured Raman spectra of the two groups were separated into two distinct clusters with no overlap and high specificity and sensitivity by PCA. These results show that the combination of Raman spectroscopy and PCA analysis may be a powerful tool for distinguishing the secreted proteins between human hepatoma cells and normal human liver cells, provide a new thought to analyze the secreted proteins from cancer cells and find a novel cancer biomarker.

  11. Nature of the X(5568) — A critical Laplace sum rule analysis at N2LO

    NASA Astrophysics Data System (ADS)

    Albuquerque, R.; Narison, S.; Rabemananjara, A.; Rabetiarivony, D.

    2016-06-01

    We scrutinize recent QCD spectral sum rules (QSSR) results to lowest order (LO) predicting the masses of the BK molecule and (su)(bd¯) four-quark states. We improve these results by adding NLO and N2LO corrections to the PT contributions giving a more precise meaning on the b-quark mass definition used in the analysis. We extract our optimal predictions using Laplace sum rule (LSR) within the standard stability criteria versus the changes of the external free parameters (τ-sum rule variable, tc continuum threshold and subtraction constant μ). The smallness of the higher order PT corrections justifies (a posteriori) the LO order results ⊕ the uses of the ambiguous heavy quark mass to that order. However, our predicted spectra in the range (5173 ˜ 5226) MeV, summarized in Table 7, for exotic hadrons built with four different flavors (buds), do not support some previous interpretations of the D0 candidate,1 X(5568), as a pure molecule or a four-quark state. If experimentally confirmed, it could result from their mixing with an angle: sin 2𝜃 ≈ 0.15. One can also scan the region (2327 ˜ 2444) MeV (where the Ds0∗(2317) might be a good candidate) and the one (5173 ˜ 5226) MeV for detecting these (cuds) and (buds) unmixed exotic hadrons (if any) via, eventually, their radiative or π+hadrons decays.

  12. A Network Access Control Framework for 6LoWPAN Networks

    PubMed Central

    Oliveira, Luís M. L.; Rodrigues, Joel J. P. C.; de Sousa, Amaro F.; Lloret, Jaime

    2013-01-01

    Low power over wireless personal area networks (LoWPAN), in particular wireless sensor networks, represent an emerging technology with high potential to be employed in critical situations like security surveillance, battlefields, smart-grids, and in e-health applications. The support of security services in LoWPAN is considered a challenge. First, this type of networks is usually deployed in unattended environments, making them vulnerable to security attacks. Second, the constraints inherent to LoWPAN, such as scarce resources and limited battery capacity, impose a careful planning on how and where the security services should be deployed. Besides protecting the network from some well-known threats, it is important that security mechanisms be able to withstand attacks that have not been identified before. One way of reaching this goal is to control, at the network access level, which nodes can be attached to the network and to enforce their security compliance. This paper presents a network access security framework that can be used to control the nodes that have access to the network, based on administrative approval, and to enforce security compliance to the authorized nodes. PMID:23334610

  13. A network access control framework for 6LoWPAN networks.

    PubMed

    Oliveira, Luís M L; Rodrigues, Joel J P C; de Sousa, Amaro F; Lloret, Jaime

    2013-01-01

    Low power over wireless personal area networks (LoWPAN), in particular wireless sensor networks, represent an emerging technology with high potential to be employed in critical situations like security surveillance, battlefields, smart-grids, and in e-health applications. The support of security services in LoWPAN is considered a challenge. First, this type of networks is usually deployed in unattended environments, making them vulnerable to security attacks. Second, the constraints inherent to LoWPAN, such as scarce resources and limited battery capacity, impose a careful planning on how and where the security services should be deployed. Besides protecting the network from some well-known threats, it is important that security mechanisms be able to withstand attacks that have not been identified before. One way of reaching this goal is to control, at the network access level, which nodes can be attached to the network and to enforce their security compliance. This paper presents a network access security framework that can be used to control the nodes that have access to the network, based on administrative approval, and to enforce security compliance to the authorized nodes. PMID:23334610

  14. Ultra-low-voltage CMOS-based current bleeding mixer with high LO-RF isolation.

    PubMed

    Tan, Gim Heng; Sidek, Roslina Mohd; Ramiah, Harikrishnan; Chong, Wei Keat; Lioe, De Xing

    2014-01-01

    This journal presents an ultra-low-voltage current bleeding mixer with high LO-RF port-to-port isolation, implemented on 0.13 μm standard CMOS technology for ZigBee application. The architecture compliments a modified current bleeding topology, consisting of NMOS-based current bleeding transistor, PMOS-based switching stage, and integrated inductors achieving low-voltage operation and high LO-RF isolation. The mixer exhibits a conversion gain of 7.5 dB at the radio frequency (RF) of 2.4 GHz, an input third-order intercept point (IIP3) of 1 dBm, and a LO-RF isolation measured to 60 dB. The DC power consumption is 572 µW at supply voltage of 0.45 V, while consuming a chip area of 0.97 × 0.88 mm(2). PMID:25197694

  15. Stella Surface Imaging of LO Pegasi via Light-Curve Inversion

    NASA Astrophysics Data System (ADS)

    Miller, Jessie; Richard, Andrea; Harmon, Robert

    2009-10-01

    The purpose of this research was to map the starspots on LO Pegasi (HIP 106231), a K8 main-sequence star, in order to create an image of the star's photosphere. CCD images of LO Pegasi were taken during May, June, and July 2009 through B, V, R, and I photometric filters using a 0.2-m Meade Instruments LX200 Schmidt-Cassegrain telescope and Santa Barbara Instruments Group ST-8XE CCD camera at Perkins Observatory. Differential aperture photometry was performed on the images so as to create light curves in the form of plots of intensity vs. rotational phase. The lightcurves were processed via the Light-Curve Inversion (LI) algorithm. This algorithm creates a reconstructed image of the star's surface showing the locations of starspots. The locations of the spots visible on the 2009 are at lower latitudes than those deduced from the 2008 light curves. In addition, overall dimming observed of LO Pegasi since 2008 implies that there is a spot on the visible pole. Since a polar spot does not modulate the rotational light curve, it is not reproduced in our images.

  16. Effects of ADMA on gene expression and metabolism in serum-starved LoVo cells.

    PubMed

    Zheng, Ningning; Wang, Ke; He, Jiaojiao; Qiu, Yunping; Xie, Guoxiang; Su, Mingming; Jia, Wei; Li, Houkai

    2016-01-01

    Serum starvation is a typical way for inducing tumor cell apoptosis and stress. Asymmetric dimethylarginine (ADMA) is an endogenous metabolite. Our previous study reveals the plasma ADMA level is elevated in colon cancer patients, which can attenuate serum starvation-induced apoptosis in LoVo cells. In current study, we evaluated the effects of ADMA on gene expression and metabolism in serum-starved LoVo cells with gene microarray and metabolomic approaches. Our results indicated that 96 h serum starvation induced comprehensive alterations at transcriptional level, and most of them were restored by ADMA. The main signaling pathways induced by serum starvation included cancers-related pathways, pathways in cell death, apoptosis, and cell cycle etc. Meanwhile, the metabolomic data showed serum-starved cells were clearly separated with control cells, but not with ADMA-treated cells in PCA model. The identified differential metabolites indicated serum starvation significantly suppressed TCA cycle, altered glucose and fatty acids metabolism, as well as nucleic acids metabolism. However, very few differential metabolites were identified between ADMA and serum-starved cells. In summary, our current results indicated serum starvation profoundly altered the gene expression and metabolism of LoVo cells, whereas ADMA could restore most of the changes at transcriptional level, but not at metabolic level. PMID:27180883

  17. Effects of ADMA on gene expression and metabolism in serum-starved LoVo cells

    PubMed Central

    Zheng, Ningning; Wang, Ke; He, Jiaojiao; Qiu, Yunping; Xie, Guoxiang; Su, Mingming; Jia, Wei; Li, Houkai

    2016-01-01

    Serum starvation is a typical way for inducing tumor cell apoptosis and stress. Asymmetric dimethylarginine (ADMA) is an endogenous metabolite. Our previous study reveals the plasma ADMA level is elevated in colon cancer patients, which can attenuate serum starvation-induced apoptosis in LoVo cells. In current study, we evaluated the effects of ADMA on gene expression and metabolism in serum-starved LoVo cells with gene microarray and metabolomic approaches. Our results indicated that 96 h serum starvation induced comprehensive alterations at transcriptional level, and most of them were restored by ADMA. The main signaling pathways induced by serum starvation included cancers-related pathways, pathways in cell death, apoptosis, and cell cycle etc. Meanwhile, the metabolomic data showed serum-starved cells were clearly separated with control cells, but not with ADMA-treated cells in PCA model. The identified differential metabolites indicated serum starvation significantly suppressed TCA cycle, altered glucose and fatty acids metabolism, as well as nucleic acids metabolism. However, very few differential metabolites were identified between ADMA and serum-starved cells. In summary, our current results indicated serum starvation profoundly altered the gene expression and metabolism of LoVo cells, whereas ADMA could restore most of the changes at transcriptional level, but not at metabolic level. PMID:27180883

  18. G-LoSA: An efficient computational tool for local structure-centric biological studies and drug design.

    PubMed

    Lee, Hui Sun; Im, Wonpil

    2016-04-01

    Molecular recognition by protein mostly occurs in a local region on the protein surface. Thus, an efficient computational method for accurate characterization of protein local structural conservation is necessary to better understand biology and drug design. We present a novel local structure alignment tool, G-LoSA. G-LoSA aligns protein local structures in a sequence order independent way and provides a GA-score, a chemical feature-based and size-independent structure similarity score. Our benchmark validation shows the robust performance of G-LoSA to the local structures of diverse sizes and characteristics, demonstrating its universal applicability to local structure-centric comparative biology studies. In particular, G-LoSA is highly effective in detecting conserved local regions on the entire surface of a given protein. In addition, the applications of G-LoSA to identifying template ligands and predicting ligand and protein binding sites illustrate its strong potential for computer-aided drug design. We hope that G-LoSA can be a useful computational method for exploring interesting biological problems through large-scale comparison of protein local structures and facilitating drug discovery research and development. G-LoSA is freely available to academic users at http://im.compbio.ku.edu/GLoSA/. PMID:26813336

  19. Ultra-broadband IF/LO system of NTU W-band interferometer array

    NASA Astrophysics Data System (ADS)

    Teng, Hsiao-Feng; Wu, Jing-Cheng; Li, Huan-Hsin; Chiueh, Tzi-Hong; Niu, Dou-Chih; Hu, Robert

    2010-07-01

    NTU-Array is designed for W-band (78-113Ghz) interferometric observations of Sunyaev-Zeldovich effects. The first phase operation of the telescope with 6 receivers had its first light in 2008 with single-polarization and half the full bandwidth. The second-phase operation of NTU-Array in Nevada will begin the dual-polarization, full-band observation in 2010. One-bit sampling at 18Ghz and digital correlation are in use in this telescope. Due to the ultra broadband coverage, the IF system divides the 35GHz full-band into four 8.7GHz sub-bands. The first stage of IF module containing a 35GHz broadband amplifier with fairly flat-gain performance over 25db gain divides the first-stage IF into two outputs. The 2nd-stage IF module further divides the two input IF signals and down-converts them to four basebands of DC-8.7Ghz. An LO module with 8.7Ghz input is to generate outputs with x2, x3 and x9 harmonics for the down-conversion. The Walsh function is injected into the x9 LO via an IQ mixer. Each IF baseband is transmitted through an optical link to the 18Ghz, 1-bit sampling ADC located in the control room. The analog optical link contains a driver and equalizer to compensate for the path loss. Considering the limited size of the telescope mount, the entire IF/LO system of each receiver has a compact size about 20cm cubed. This physical size can be further reduced to fit the future 19-pixel-receiver upgrade of NTU-Array

  20. Higgs boson gluon-fusion production beyond threshold in N3LO QCD

    SciTech Connect

    Anastasiou, Charalampos; Duhr, Claude; Dulat, Falko; Furlan, Elisabetta; Gehrmann, Thomas; Herzog, Franz; Mistlberger, Bernhard

    2015-03-18

    In this study, we compute the gluon fusion Higgs boson cross-section at N3LO through the second term in the threshold expansion. This calculation constitutes a major milestone towards the full N3LO cross section. Our result has the best formal accuracy in the threshold expansion currently available, and includes contributions from collinear regions besides subleading corrections from soft and hard regions, as well as certain logarithmically enhanced contributions for general kinematics. We use our results to perform a critical appraisal of the validity of the threshold approximation at N3LO in perturbative QCD.

  1. Hilbert-space Karhunen-Loève transform with application to image analysis.

    PubMed

    Levy, A; Rubinstein, J

    1999-01-01

    A generalization of the Karhunen-Loève (KL) transform to Hilbert spaces is developed. It allows one to find the best low-dimensional approximation of an ensemble of images with respect to a variety of distance functions other than the traditional mean square error (L2 norm). A simple and intuitive characterization of the family of Hilbert norms in finite-dimensional spaces leads to an algorithm for calculating the Hilbert-KL expansion. KL approximations of ensembles of objects and faces optimized with respect to a norm based on the modulation transfer function of the human visual system are compared with the standard L2 approximations. PMID:9919692

  2. Potential NRQCD for unequal masses and the B c spectrum at N3LO

    NASA Astrophysics Data System (ADS)

    Peset, Clara; Pineda, Antonio; Stahlhofen, Maximilian

    2016-05-01

    We determine the 1 /m and 1 /m 2 spin-independent heavy quarkonium potentials in the unequal mass case with {O} ( α 3) and {O} ( α 2) accuracy, respectively. We discuss in detail different methods to calculate the potentials, and show the equivalence among them. In particular we obtain, for the first time, the manifestly gauge invariant 1 /m and 1 /m 2 potentials in terms of Wilson loops with next-to-leading order (NLO) precision. As an application of our results we derive the theoretical expression for the B c spectrum in the weak-coupling limit through next-to-next-to-next-to-leading order (N3LO).

  3. Surface Maps of LO Pegasi May-July 2011 Generated via BVRI Light Curve Inversion

    NASA Astrophysics Data System (ADS)

    Harmon, Robert O.; Johns Vidaurri, P.; Krug, S.

    2012-01-01

    The young solar analog LO Pegasi is a rapidly rotating (P ≈ 10.2 hr) K8 main sequence star known to exhibit large cool spots on its surface. We present surface maps based on BVRI photometry obtained at Perkins Observatory from May-July 2011 and inverted with an algorithm which makes no a priori assumptions regarding the number of spots or their shapes, and compare the results to images generated from 2006-2010. This work was supported by the NSF REU Program.

  4. Cryptanalysis of the Hwang-Lo-Lin Scheme Based on an ID-Based Cryptosystem and Its Improvement

    NASA Astrophysics Data System (ADS)

    Park, Haeryong; Chun, Kilsoo; Ahn, Seungho

    Hwang-Lo-Lin proposed a user identification scheme [3] based on the Maurer-Yacobi scheme [6] that is suitable for application to the mobile environment. Hwang-Lo-Lin argued that their scheme is secure against any attack. Against the Hwang-Lo-Lin argument, Liu-Horng-Liu showed that the Hwang-Lo-Lin scheme is insecure against a Liu-Horng-Liu attack mounted by an eavesdrop attacker. However, Liu-Horng-Liu did not propose any improved version of the original identification scheme which is still secure against the Liu-Horng-Liu attack. In this paper, we propose an identification scheme that can solve this problem and a non-interactive public key distribution scheme also.

  5. Karhunen-Loève basis of Kolmogorov phase screens covering a rectangular stripe

    NASA Astrophysics Data System (ADS)

    Mathar, Richard J.

    2010-01-01

    Karhunen-Loève functions are statistically independent base functions to be multiplied with randomized coefficients to generate instances of the underlying statistics with specific covariances. In the context of numerical simulation of atmospheric turbulence, they are tools to generate phase distributions in the input pupil of telescope optics. Within the Taylor frozen screen approximation, the favorable geometry of phase screens is a stripe as wide as the telescope diameter, but much longer. A phase screen movie is generated by dragging the stripe across the telescope pupil. The aim is to avoid the wasteful alternative of cutting through a virtual circular phase screen with a diameter equal to the stripe's length. We calculate Karhunen-Loève functions over rectangular stripes by solving the well-known integral equation for isotropic variance of the phase distribution. They are expanded in products of Legendre functions along the two Cartesian coordinates, represented by spherical Bessel functions in Fourier space. The rectangular shape of the integral's domain breaks the symmetry of the structure function. Yet, the matrix elements of the eigenvalue equation can be calculated by separating the primitive Cartesian basis via a Neumann series of radial and azimuthal terms.

  6. Non-linear analysis of PESA-Lo electrostatic analyzer data and solar wind temperature anisotropies

    NASA Astrophysics Data System (ADS)

    Djordjevic, B. Z.; Maruca, B.; Bale, S. D.; Wilson, L. B., III; Larson, D. E.

    2015-12-01

    In this study, non-linear fitting techniques are applied to ion measurements from the Wind spacecraft's PESA-Lo electrostatic analyzer. Previous studies have relied primarily on moments-analyses, which, although satisfactory for simple distributions and density calculations, often return unreasonable values for higher order moments (e.g., temperature) and fail to account for non-thermal effects (e.g., temperature anisotropy and beams) and multiple ion-species. A Levenberg-Marquadt non-linear algorithm is applied to the PESA-Lo data in order to calculate the characteristic parameters of the proton, alpha-particle, and beam distributions. This analysis is augmented with calibration data from the WIND Faraday cups and magnetic-field data from WIND/MFI. Preliminary results from this non-linear analysis indicate that it indeed provides higher-quality ion parameters than the existing moments-analysis. When this analysis is complete, the set of bulk-parameter values will be suitable for studies of microinstabilities in the solar wind and of possible correlation between magnetic field fluctuations and non-thermal properties of the ion distributions. Applications of thermodynamic principles, such as the Boltzmann H-theorem, will allow for further characterization of the non-thermal properties of the solar wind.

  7. Soft Expansion of Double-Real-Virtual Corrections to Higgs Production at N$^3$LO

    DOE PAGESBeta

    Anastasiou, Charalampos; Duhr, Claude; Dulat, Falko; Furlan, Elisabetta; Herzog, Franz; Mistlberger, Bernhard

    2015-05-15

    We present methods to compute higher orders in the threshold expansion for the one-loop production of a Higgs boson in association with two partons at hadron colliders. This process contributes to the N3LO Higgs production cross section beyond the soft-virtual approximation. We use reverse unitarity to expand the phase-space integrals in the small kinematic parameters and to reduce the coefficients of the expansion to a small set of master integrals. We describe two methods for the calculation of the master integrals. The first was introduced for the calculation of the soft triple-real radiation relevant to N3LO Higgs production. The secondmore » uses a particular factorization of the three body phase-space measure and the knowledge of the scaling properties of the integral itself. Our result is presented as a Laurent expansion in the dimensional regulator, although some of the master integrals are computed to all orders in this parameter.« less

  8. Soft Expansion of Double-Real-Virtual Corrections to Higgs Production at N$^3$LO

    SciTech Connect

    Anastasiou, Charalampos; Duhr, Claude; Dulat, Falko; Furlan, Elisabetta; Herzog, Franz; Mistlberger, Bernhard

    2015-05-15

    We present methods to compute higher orders in the threshold expansion for the one-loop production of a Higgs boson in association with two partons at hadron colliders. This process contributes to the N3LO Higgs production cross section beyond the soft-virtual approximation. We use reverse unitarity to expand the phase-space integrals in the small kinematic parameters and to reduce the coefficients of the expansion to a small set of master integrals. We describe two methods for the calculation of the master integrals. The first was introduced for the calculation of the soft triple-real radiation relevant to N3LO Higgs production. The second uses a particular factorization of the three body phase-space measure and the knowledge of the scaling properties of the integral itself. Our result is presented as a Laurent expansion in the dimensional regulator, although some of the master integrals are computed to all orders in this parameter.

  9. THE EXTRAORDINARY MID-INFRARED SPECTRAL PROPERTIES OF FeLoBAL QUASARS

    SciTech Connect

    Farrah, D.; Urrutia, T.; Lacy, M.; Lebouteiller, V.; Spoon, H. W. W.; Bernard-Salas, J.; Houck, J.; Connolly, N.; Afonso, J.; Connolly, B.

    2010-07-10

    We present mid-infrared (mid-IR) spectra of six FeLoBAL quasi-stellar objects (QSOs) at 1 < z < 1.8, taken with the Spitzer Space Telescope. The spectra span a range of shapes, from hot dust-dominated active galactic nuclei (AGNs) with silicate emission at 9.7 {mu}m to moderately obscured starbursts with strong polycyclic aromatic hydrocarbon (PAH) emission. The spectrum of one object, SDSS 1214-0001, shows the most prominent PAHs yet seen in any QSO at any redshift, implying that the starburst dominates the mid-IR emission with an associated star formation rate on the order of 2700 M{sub sun} yr{sup -1}. With the caveats that our sample is small and not robustly selected, we combine our mid-IR spectral diagnostics with previous observations to propose that FeLoBAL QSOs are at least largely comprised of systems in which (1) a merger-driven starburst is ending, (2) a luminous AGN is in the last stages of burning through its surrounding dust, and (3) we may be viewing over a restricted line-of-sight range.

  10. Pavement crack detection combining non-negative feature with fast LoG in complex scene

    NASA Astrophysics Data System (ADS)

    Wang, Wanli; Zhang, Xiuhua; Hong, Hanyu

    2015-12-01

    Pavement crack detection is affected by much interference in the realistic situation, such as the shadow, road sign, oil stain, salt and pepper noise etc. Due to these unfavorable factors, the exist crack detection methods are difficult to distinguish the crack from background correctly. How to extract crack information effectively is the key problem to the road crack detection system. To solve this problem, a novel method for pavement crack detection based on combining non-negative feature with fast LoG is proposed. The two key novelties and benefits of this new approach are that 1) using image pixel gray value compensation to acquisit uniform image, and 2) combining non-negative feature with fast LoG to extract crack information. The image preprocessing results demonstrate that the method is indeed able to homogenize the crack image with more accurately compared to existing methods. A large number of experimental results demonstrate the proposed approach can detect the crack regions more correctly compared with traditional methods.

  11. LO Peg: surface differential rotation, flares, and spot-topographic evolution

    NASA Astrophysics Data System (ADS)

    Karmakar, Subhajeet; Pandey, J. C.; Savanov, I. S.; Taş, G.; Pandey, S. B.; Misra, K.; Joshi, S.; Dmitrienko, E. S.; Sakamoto, T.; Gehrels, N.; Okajima, T.

    2016-07-01

    Using the wealth of ˜24 yr multiband data, we present an in-depth study of the star-spot cycles, surface differential rotations (SDR), optical flares, evolution of star-spot distributions, and coronal activities on the surface of young, single, main-sequence, ultrafast rotator LO Peg. From the long-term V-band photometry, we derive rotational period of LO Peg to be 0.4231 ± 0.0001 d. Using the seasonal variations on the rotational period, the SDR pattern is investigated, and shows a solar-like pattern of SDR. A cyclic pattern with period of ˜2.7 yr appears to be present in rotational period variation. During the observations, 20 optical flares are detected with a flare frequency of ˜1 flare per two days and with flare energy of ˜1031-34 erg. The surface coverage of cool spots is found to be in the range of ˜9-26 per cent. It appears that the high- and low-latitude spots are interchanging their positions. Quasi-simultaneous observations in X-ray, UV, and optical photometric bands show a signature of an excess of X-ray and UV activities in spotted regions.

  12. Cocaine withdrawal in rats selectively bred for low (LoS) versus high (HiS) saccharin intake.

    PubMed

    Radke, Anna K; Zlebnik, Natalie E; Carroll, Marilyn E

    2015-02-01

    Cocaine use results in anhedonia during withdrawal, but it is not clear how this emotional state interacts with an individual's vulnerability for addiction. Rats selectively bred for high (HiS) or low (LoS) saccharin intake are a well-established model of drug abuse vulnerability, with HiS rats being more likely to consume sweets and drugs of abuse such as cocaine and heroin (Carroll et al., 2002) than LoS rats. This study examined whether the motivational consequences of cocaine withdrawal are differentially expressed in HiS and LoS rats. HiS and LoS rats were trained to respond for a sucrose reward on a progressive ratio (PR) schedule of reinforcement and breakpoints were measured during and after chronic, continuous exposure to cocaine (30 mg/kg/day). Cocaine, but not saline, treatment resulted in lower breakpoints for sucrose during withdrawal in LoS rats only. These results suggest anhedonia during withdrawal is more pronounced in the less vulnerable LoS rats. Fewer motivational deficits during withdrawal may contribute to greater drug vulnerability in the HiS line. PMID:25482327

  13. Cocaine withdrawal in rats selectively bred for low (LoS) versus high (HiS) saccharin intake

    PubMed Central

    Radke, Anna K.; Zlebnik, Natalie E.; Carroll, Marilyn E.

    2014-01-01

    Cocaine use results in anhedonia during withdrawal, but it is not clear how this emotional state interacts with an individual's vulnerability for addiction. Rats selectively bred for high (HiS) or low (LoS) saccharin intake are a well-established model of drug abuse vulnerability, with HiS rats being more likely to consume sweets and drugs of abuse such as cocaine and heroin (Carroll et al. 2002) than LoS rats. This study examined whether the motivational consequences of cocaine withdrawal are differentially expressed in HiS and LoS rats. HiS and LoS rats were trained to respond for a sucrose reward on a progressive ratio (PR) schedule of reinforcement and breakpoints were measured during and after chronic, continuous exposure to cocaine (30 mg/kg/day). Cocaine, but not saline, treatment resulted in lower breakpoints for sucrose during withdrawal in LoS rats only. These results suggest anhedonia during withdrawal is more pronounced in the less vulnerable LoS rats. Fewer motivational deficits during withdrawal may contribute to drug vulnerability in the HiS line. PMID:25482327

  14. Real-virtual contributions to the inclusive Higgs cross-section at N3LO

    NASA Astrophysics Data System (ADS)

    Anastasiou, Charalampos; Duhr, Claude; Dulat, Falko; Herzog, Franz; Mistlberger, Bernhard

    2013-12-01

    We compute the contributions to the N3LO inclusive Higgs boson cross-section from the square of one-loop amplitudes with a Higgs boson and three QCD partons as external states. Our result is a Taylor expansion in the dimensional regulator ɛ, where the coefficients of the expansion are analytic functions of the ratio of the Higgs boson mass and the partonic center of mass energy and they are valid for arbitrary values of this ratio. We also perform a threshold expansion around the limit of soft-parton radiation in the final state. The expressions for the coefficients of the threshold expansion are valid for arbitrary values of the dimension. As a by-product of the threshold expansion calculation, we have developed a soft expansion method at the integrand level by identifying the relevant soft and collinear regions for the loop-momentum.

  15. HIEN-LO: An experiment for charge determination of cosmic rays of interplanetary and solar origin

    NASA Technical Reports Server (NTRS)

    Klecker, B.; Hovestadt, D.; Mason, G. M.; Blake, J. B.; Nicholas, J.

    1988-01-01

    The experiment is designed to measure the heavy ion environment at low altitude (HIEN-LO) in the energy range 0.3 to 100 MeV/nucleon. In order to cover this wide energy range a complement of three sensors is used. A large area ion drift chamber and a time-of-flight telescope are used to determine the mass and energy of the incoming cosmic rays. A third omnidirectional counter serves as a proton monitor. The analysis of mass, energy and incoming direction in combination with the directional geomagnetic cut-off allows the determination of the ionic charge of the cosmic rays. The ionic charge in this energy range is of particular interest because it provides clues to the origin of these particles and to the plasma conditions at the acceleration site. The experiment is expected to be flown in 1988/1989.

  16. Screening materials with the XIA UltraLo alpha particle counter at Southern Methodist University

    NASA Astrophysics Data System (ADS)

    Nakib, M. Z.; Cooley, J.; Guiseppe, V. E.; Kara, B.; Qiu, H.; Rielage, K.; Schnee, R. W.; Scorza, S.

    2013-08-01

    Southern Methodist University houses one of five existing commercially available UltraLo 1800 production model alpha counters made by XIA LLC. The instrument has an electron drift chamber with a 707 cm2 or 1800 cm2 counting region which is determined by selecting the inner electrode size. The SMU team operating this device is part of the SuperCDMS screening working group, and uses the alpha counter to study the background rates from the decay of radon in materials used to construct the SuperCDMS experiment. We have studied four acrylic samples obtained from the MiniCLEAN direct dark matter search with the XIA instrument demonstrating its utility in low background experiments by investigating the plate-out of 210Pb and comparing the effectiveness of cleaning procedures in removing 222Rn progenies from the samples.

  17. Screening materials with the XIA UltraLo alpha particle counter at Southern Methodist University

    SciTech Connect

    Nakib, M. Z.; Cooley, J.; Kara, B.; Qiu, H.; Scorza, S.; Guiseppe, V. E.; Rielage, K.; Schnee, R. W.

    2013-08-08

    Southern Methodist University houses one of five existing commercially available UltraLo 1800 production model alpha counters made by XIA LLC. The instrument has an electron drift chamber with a 707 cm{sup 2} or 1800 cm{sup 2} counting region which is determined by selecting the inner electrode size. The SMU team operating this device is part of the SuperCDMS screening working group, and uses the alpha counter to study the background rates from the decay of radon in materials used to construct the SuperCDMS experiment. We have studied four acrylic samples obtained from the MiniCLEAN direct dark matter search with the XIA instrument demonstrating its utility in low background experiments by investigating the plate-out of {sup 210}Pb and comparing the effectiveness of cleaning procedures in removing {sup 222}Rn progenies from the samples.

  18. Starspot Modulation of BVRI Light Curves of LO Pegasi from 2012 June-October

    NASA Astrophysics Data System (ADS)

    Harmon, Robert O.; Avril, R.; Rossi De La Fuente, E.; Brechtel, C. E.

    2013-01-01

    We present BVRI light curves acquired at Perkins Observatory in 2012 June-October of the K8V star LO Pegasi, a young solar analog known to exhibit magnetic activity on its surface in the form of large starspots. We find that the amplitudes of the brightness variations have diminished significantly in comparison to data acquired from 2006-2011, and that the overall brightness is comparable to the brightness minima in the prior years. We speculate that these changes are due to the growth of a polar spot, coupled with a reduction in the relative sizes of projections of the polar spot into lower-latitude regions and/or a reduction in the area covered by independent spots at lower latitudes. This work was funded by the National Science Foundation Research Experiences for Undergraduates Program Award #1003992 and Ohio Wesleyan University.

  19. Stellar Surface Image of LO Pegasi via Light-curve Inversion

    NASA Astrophysics Data System (ADS)

    Harmon, Robert O.; Moore, C.; Decker, R.

    2009-01-01

    We present images of dark starspots on the surface of the K8 main-sequence star LO Pegasi. CCD images of the star and surrounding field were acquired through B, V, R and I filters at Perkins Observatory in June and July, 2008. The images were dark-subtracted and flat-fielded and then aperture photometry was performed to yield light curves through each of the four filters. These light curves were then simultaneously inverted via an algorithm devised by one of us (Harmon) so as to yield images of the spots based on the rotational modulation they produced in the light curves. The use of multiple filters significantly improves the latitude resolution of the reconstructions. Comparison of our results with results from 2006 and 2007 shows that the spot structure was more complex in 2008 than in the prior years. This research was funded by the NSF REU Program and the Ohio Wesleyan University Summer Science Research Program.

  20. Photometric Imaging of Starspots on LO Pegasi in May, June and July of 2009

    NASA Astrophysics Data System (ADS)

    Harmon, Robert O.; Miller, J.; Richard, A.

    2010-01-01

    CCD images of the K8 young solar analog LO Pegasi were obtained during May, June and July of 2009 through B, V, R, and I photometric filters at Perkins Observatory. Differential aperture photometry was performed on the images to generate light curves through each filter. The lightcurves were processed via the Light-Curve Inversion algorithm so as to invert the light curves to produce images of the star's photosphere. The locations of the starspots visible in the 2009 images are at lower latitudes than those deduced from the summer 2008 light curves. In addition, secular dimming since 2008 implies that there is a spot on the visible pole, which does not appear in our images because it does not significantly modulate the rotational light curve.

  1. Non-collinear magnetism calculated using the APW+lo method

    NASA Astrophysics Data System (ADS)

    Laskowski, Robert; Blaha, Peter; Schwarz, Karlheinz; Madsen, Georg K. H.

    2003-03-01

    Our implementation of non-collinear magnetism (NCM) into the APW+lo - WIEN2k code allows calculations of both, the atomic moment approximation (AMA) as well as a full NCM mode, and includes spin-orbit coupling and LDA+U corrections. In AMA only the diagonal part of spin-potential and density matrices inside the atomic spheres (AS) are taken into account, but the complete potential and density matrices are used in the interstitial region. In full NCM also off-diagonal terms inside the AS are considered. In both cases, the implementation utilizes a basis set of rotated spinors inside the AS and pure-spinors in the interstitial. We present ab-initio calculation of UO_2, where three NCM structures are considered, namely, 1k - antiferromagnetic type-I, 2k with momenta pointing in (110) and equivalent directions, and 3k with momenta along (111) directions.

  2. Vanishing absorption and blueshifted emission in FeLoBAL quasars

    NASA Astrophysics Data System (ADS)

    Rafiee, Alireza; Pirkola, Patrik; Hall, Patrick B.; Galati, Natalee; Rogerson, Jesse; Ameri, Abtin

    2016-07-01

    We study the dramatic decrease in iron absorption strength in the iron low-ionization broad absorption line quasar SDSS J084133.15+200525.8. We report on the continued weakening of absorption in the prototype of this class of variable broad absorption line quasar, FBQS J140806.2+305448. We also report a third example of this class, SDSS J123103.70+392903.6; unlike the other two examples, it has undergone an increase in observed continuum brightness (at 3000 Å rest frame) as well as a decrease in iron absorption strength. These changes could be caused by absorber transverse motion or by ionization variability. We note that the Mg II and UV Fe II lines in several FeLoBAL quasars are blueshifted by thousands of km s-1 relative to the H β emission line peak. We suggest that such emission arises in the outflowing winds normally seen only in absorption.

  3. Bayesian estimation of Karhunen-Loève expansions; A random subspace approach

    NASA Astrophysics Data System (ADS)

    Chowdhary, Kenny; Najm, Habib N.

    2016-08-01

    One of the most widely-used procedures for dimensionality reduction of high dimensional data is Principal Component Analysis (PCA). More broadly, low-dimensional stochastic representation of random fields with finite variance is provided via the well known Karhunen-Loève expansion (KLE). The KLE is analogous to a Fourier series expansion for a random process, where the goal is to find an orthogonal transformation for the data such that the projection of the data onto this orthogonal subspace is optimal in the L2 sense, i.e., which minimizes the mean square error. In practice, this orthogonal transformation is determined by performing an SVD (Singular Value Decomposition) on the sample covariance matrix or on the data matrix itself. Sampling error is typically ignored when quantifying the principal components, or, equivalently, basis functions of the KLE. Furthermore, it is exacerbated when the sample size is much smaller than the dimension of the random field. In this paper, we introduce a Bayesian KLE procedure, allowing one to obtain a probabilistic model on the principal components, which can account for inaccuracies due to limited sample size. The probabilistic model is built via Bayesian inference, from which the posterior becomes the matrix Bingham density over the space of orthonormal matrices. We use a modified Gibbs sampling procedure to sample on this space and then build probabilistic Karhunen-Loève expansions over random subspaces to obtain a set of low-dimensional surrogates of the stochastic process. We illustrate this probabilistic procedure with a finite dimensional stochastic process inspired by Brownian motion.

  4. Downregulation of MDM2 expression by RNAi inhibits LoVo human colorectal adenocarcinoma cells growth and the treatment of LoVo cells with mdm2siRNA3 enhances the sensitivity to cisplatin

    SciTech Connect

    Yu Yan . E-mail: gyfyuyan@hotmail.com; Sun Ping . E-mail: sunny19750502@hotmail.com; Sun Lichun; Liu Guoyi; Chen Guohua . E-mail: olivebranch_82@hotmail.com; Shang Lihua . E-mail: leval1000@sina.com; Wu Hongbo . E-mail: whpwl@sina.com; Hu Jing; Li Yue; Mao Yinling; Sui Guangjie; Sun Xiwen

    2006-01-06

    To investigate the biological effect of mdm2 in human colorectal adenocarcinoma LoVo cells, three mdm2siRNA constructions were recombinated and transient transfected into human colorectal adenocarcinoma LoVo cells with low differentiation character in vitro. The results showed that mdm2siRNA3 reduced mRNA level of mdm2 and protein level of mdm2, leading to proliferation inhibition on LoVo cells, and reduced tumor growth in nude mice. It was found that depletion of MDM2 in this pattern promoted apoptosis of LoVo cells and Cisplatin (DDP) treated in the mdm2siRNA3 transfected cell population would result in a substantial decrease by MTT colorimetry. Decreasing the MDM2 protein level in LoVo cells by RNAi could significantly inhibit tumor growth both in vitro and in vivo, which indicated that mdm2 gene played a definite role in the development and aggressiveness of human colon carcinoma. It also could be a therapeutic target in colorectal carcinoma. The synergistic activation of RNAi and cell toxicity agents indicated that the combination of chemotherapy and gene therapy will be a promising approach in the future.

  5. Selenoprotein Genes Exhibit Differential Expression Patterns Between Hepatoma HepG2 and Normal Hepatocytes LO2 Cell Lines.

    PubMed

    Zhao, Hua; Tang, Jiayong; Xu, Jingyang; Cao, Lei; Jia, Gang; Long, Dingbiao; Liu, Guangmang; Chen, Xiaoling; Wang, Kangning

    2015-10-01

    The purpose of this study was to compare messenger RNA (mRNA) expression of selenoprotein genes between hepatoma HepG2 and normal hepatocytes LO2 cell lines. Liver HepG2 and LO2 cells were cultured in 12-well plates under the same condition until cells grew to complete confluence, and then cells were harvested for total RNA and protein extraction. The qPCRs were performed to compare gene expression of 14 selenoprotein genes and 5 cancer signaling-related genes. Enzyme activities were also assayed. The results showed that human hepatoma HepG2 cells grew faster than normal hepatocytes LO2 cells. Among the genes investigated, 10 selenoprotein genes (Gpx1, Gpx3, Gpx4, Selx, Sepp, Sepw1, Sepn1, Selt, Seli, Selh) and 3 cancer signaling-related genes (Bcl-2A, caspase-3, and P38) were upregulated (P < 0.05), while Selo and Bcl-2B were downregulated (P < 0.05) in hepatoma HepG2 cells compared to LO2 cells. Significant correlations were found between selenoprotein genes and the cancer signaling-related genes Caspase3, P53, Bc1-2A, and Bc1-2B. Our results revealed that selenoprotein genes were aberrantly expressed in hepatoma HepG2 cells compared to normal liver LO2 cells, which indicated that those selenoprotein genes may play important roles in the occurrence and development of liver carcinogenesis. PMID:25846212

  6. Effect of a 5-lipoxygenase (5-LO)/cyclooxygenase (CO) inhibitor, WY-47, 288, on cutaneous models of inflammation.

    PubMed

    Carlson, R P; O'Neill-Davis, L; Calhoun, W; Datko, L; Musser, J H; Kreft, A F; Chang, J Y

    1989-03-01

    WY-47,288 (2-[(1-naphthalenyloxy)methyl]quinoline) demonstrated topical antiinflammatory activity in several animal models of skin inflammation. Application of WY-47,288 to mouse ear surfaces inhibited arachidonic acid (ED50 = 0.3 mg/ear) and tetradecanoylphorbol acetate (TPA)-induced inflammation (40% at 1 mg/ear). Administration of WY-47,288 (1 mg/ear) at 30 min and 5 h after TPA reduced ear edema and epidermal proliferation by 50%. WY-47,288 also inhibited oxazolone-induced contact hypersensitivity in mouse ears (ED50 = 0.4 mg/ear) and UVB-induced guinea pig skin erythema (ED50 approximately 0.25 mg/spot). These antiinflammatory effects may be due to inhibition of 5-lipoxygenase (5-LO) and cyclooxygenase (CO) since the synthesis of 5-LO and CO products by rat neutrophils and mouse macrophages was dose-dependently reduced by WY-47,288. By contrast, WY-47,288 demonstrated no appreciable inhibition of 12-LO (rabbit platelet), 15-LO (soybean) or phospholipase A2 (human platelet). Furthermore, no systemic adverse effects were observed after topical, parenteral or oral administration of WY-47,288, suggesting that WY-47,288 is a safe topical 5-LO/CO inhibitor for treating skin inflammation. PMID:2500009

  7. Regulatory drinking in the pigeon Columba livia.

    PubMed

    Kaufman, S; Peters, G

    1980-09-01

    Pigeons were subjected to stimuli known to induce regulatory drinking in mammals. Water-satiated birds drank in response to intravenous (iv) hypertonic NaCl, intraperitoneal (ip) hyperoncotic polyethylene glycol (PEG) (20 M), iv infusions of angiotensinamide, subcutaneous (sc) isoprenaline, and iv chicken kidney extract. Intravenous porcine renin failed to elicit a major drinking response. Drinking after water deprivation was reduced by an iv preload of isotonic saline. Water intake after iv hypertonic NaCl equaled the volume required for dilution to isotonicity. Water intake in response to ip PEG was larger than in rats and resulted in a parallel increase in body weight. Sensitivity to isoprenaline and angiotensinamide was less than or equal to that of rats although pigeons drank much more. Drinking responses to iv hypertonic NaCl plus ip hyperoncotic PEG were additive. Small (5 ml/kg body wt) blood losses induced delayed (after 4 h) drinking; larger blood losses were ineffective. There was no simple additive relationship between the responses to hemorrhage and hypertonic saline. In summary, the dipsogenic response of pigeons was much greater than that of mammals although sensitivity was sometimes higher and sometimes lower. PMID:7435592

  8. Spatial context learning in pigeons (Columba livia).

    PubMed

    Gibson, Brett M; Leber, Andrew B; Mehlman, Max L

    2015-10-01

    In a seminal paper in the cognitive sciences, Chun and Jiang (1998) described the contextual cueing paradigm in which they used artificial stimuli and showed that people became faster to locate a target when the background predicted the location of a target compared to when it did not. Here we examined contextual cueing in pigeons for the first time using artificial stimuli and procedures similar to those of Chun and Jiang. In the first test, we had pigeons search for a target among a display of seven distractors; during one condition, the position of the distractors predicted the location of the target, and in the second condition, there was no relationship between the two. In a second test, we presented the pigeons with the predictive displays from Test 1 and a second set of displays that also predicted the location of a target to see if learning about one set of predictive backgrounds disrupted learning about a second set. The pigeons were quick to acquire context-based knowledge and retain that information when faced with additional contexts. The results suggest that contextual cueing can occur for a variety of stimuli in nonhuman animals and that it may be a common mechanism for processing visual information across a wide variety of species. PMID:26167773

  9. LoFEx — A local framework for calculating excitation energies: Illustrations using RI-CC2 linear response theory

    NASA Astrophysics Data System (ADS)

    Baudin, Pablo; Kristensen, Kasper

    2016-06-01

    We present a local framework for the calculation of coupled cluster excitation energies of large molecules (LoFEx). The method utilizes time-dependent Hartree-Fock information about the transitions of interest through the concept of natural transition orbitals (NTOs). The NTOs are used in combination with localized occupied and virtual Hartree-Fock orbitals to generate a reduced excitation orbital space (XOS) specific to each transition where a standard coupled cluster calculation is carried out. Each XOS is optimized to ensure that the excitation energies are determined to a predefined precision. We apply LoFEx in combination with the RI-CC2 model to calculate the lowest excitation energies of a set of medium-sized organic molecules. The results demonstrate the black-box nature of the LoFEx approach and show that significant computational savings can be gained without affecting the accuracy of CC2 excitation energies.

  10. Summary of LO2/Ethanol OMS/RCS Technology and Advanced Development 99-2744

    NASA Technical Reports Server (NTRS)

    Curtis, Leslie A.; Hurlbert, Eric A.

    1999-01-01

    NASA is pursuing non-toxic propellant technologies applicable to RLV and Space Shuttle orbital maneuvering system (OMS) and reaction control system (RCS). The primary objectives of making advancements in an OMS/RCS system are improved safety, reliability, and reduced operations and maintenance cost, while meeting basic operational and performance requirements. An OMS/RCS has a high degree of direct interaction with the vehicle and crew and requires subsystem and components that are compatible with integration into the vehicle with regard to external mold-line, power, and thermal control. In July 1997, a Phase I effort for the technology and advanced development of an upgrade of the space shuttle was conducted to define the system architecture, propellant tank, feed system, RCS thrusters, and OMS engine. Phase I of the project ran from July 1997 to October 1998. Phase II is currently being planned for the development and test of full-scale prototype of the system in 1999 and 2000. The choice of pressure-fed liquid oxygen (LO2) and ethanol is the result of numerous trade studies conducted from 1980 to 1996. Liquid oxygen and ethanol are clean burning, high-density propellants that provide a high degree of commonality with other spacecraft subsystems including life support, power, and thermal control, and with future human exploration and development of space missions. The key to this pressure-fed system is the use of subcooled liquid oxygen at 350 psia. In this approach, there is 80 degrees R of subcooling, which means that boil-off will not occur until the temperature has risen 80 R. The sub-cooling results naturally from loading propellants at 163 R, which is the saturation temperature at 14.7 psia, and then pressurizing to 350 psia on the launch pad. Thermal insulation and conditioning techniques are then used to limit the LO2 temperature to 185 R maximum, and maintain the sub-cooling. The other key is the wide temperature range of ethanol, -173 F to +300 F, which

  11. Karhunen-Loève expansion revisited for vector-valued random fields: Scaling, errors and optimal basis.

    NASA Astrophysics Data System (ADS)

    Perrin, G.; Soize, C.; Duhamel, D.; Funfschilling, C.

    2013-06-01

    Due to scaling effects, when dealing with vector-valued random fields, the classical Karhunen-Loève expansion, which is optimal with respect to the total mean square error, tends to favorize the components of the random field that have the highest signal energy. When these random fields are to be used in mechanical systems, this phenomenon can introduce undesired biases for the results. This paper presents therefore an adaptation of the Karhunen-Loève expansion that allows us to control these biases and to minimize them. This original decomposition is first analyzed from a theoretical point of view, and is then illustrated on a numerical example.

  12. On the application of Karhunen-Loève transform to transient dynamic systems

    NASA Astrophysics Data System (ADS)

    Glüsmann, Philipp; Kreuzer, Edwin

    2009-12-01

    The Karhunen-Loève transform (KLT) has become a popular method in various fields of engineering science. Due to its ability to identify the most prominent features in the underlying system dynamics the KLT is a favorable method for such tasks as process monitoring, model order reduction or optimum control. However, it is a well-known fact that the KLT is 'case sensitive'. That is that changes in the dynamic system behavior can decisively affect the KLT results. As much as this property is desired for monitoring problems, it limits the performance of KLT in model order reduction or optimum control problems, if systems are subject to structural changes. Recent research interest focuses on extending applications of KLT to systems with transient dynamic behavior or changing boundary conditions. Approaches have been published that circumvent the limitations of KLT by either assuming reasonable comparability of system dynamics or by measuring the representative performance of KLT-bases a posteriori. However, such methods require additional simulations of the full size system and thus jeopardize the idea of model order reduction. In this paper, we introduce a novel a priori measure to evaluate the performance of the current KLT-basis. This procedure can be of great help in either monitoring or adaptive control of systems that show intermittent transient and (quasi-)stationary dynamic behavior. This a priori measure prepares the path for adaptive model order reduction schemes. Moreover, it can be used to measure the stationarity of multidimensional dynamic processes.

  13. Aggregation of LoD 1 building models as an optimization problem

    NASA Astrophysics Data System (ADS)

    Guercke, R.; Götzelmann, T.; Brenner, C.; Sester, M.

    3D city models offered by digital map providers typically consist of several thousands or even millions of individual buildings. Those buildings are usually generated in an automated fashion from high resolution cadastral and remote sensing data and can be very detailed. However, not in every application such a high degree of detail is desirable. One way to remove complexity is to aggregate individual buildings, simplify the ground plan and assign an appropriate average building height. This task is computationally complex because it includes the combinatorial optimization problem of determining which subset of the original set of buildings should best be aggregated to meet the demands of an application. In this article, we introduce approaches to express different aspects of the aggregation of LoD 1 building models in the form of Mixed Integer Programming (MIP) problems. The advantage of this approach is that for linear (and some quadratic) MIP problems, sophisticated software exists to find exact solutions (global optima) with reasonable effort. We also propose two different heuristic approaches based on the region growing strategy and evaluate their potential for optimization by comparing their performance to a MIP-based approach.

  14. Optimized suppression of coherent noise from seismic data using the Karhunen-Loève transform.

    PubMed

    Montagne, Raúl; Vasconcelos, Giovani L

    2006-07-01

    Signals obtained in land seismic surveys are usually contaminated with coherent noise, among which the ground roll (Rayleigh surface waves) is of major concern for it can severely degrade the quality of the information obtained from the seismic record. This paper presents an optimized filter based on the Karhunen-Loève transform for processing seismic images contaminated with ground roll. In this method, the contaminated region of the seismic record, to be processed by the filter, is selected in such way as to correspond to the maximum of a properly defined coherence index. The main advantages of the method are that the ground roll is suppressed with negligible distortion of the remnant reflection signals and that the filtering procedure can be automated. The image processing technique described in this study should also be relevant for other applications where coherent structures embedded in a complex spatiotemporal pattern need to be identified in a more refined way. In particular, it is argued that the method is appropriate for processing optical coherence tomography images whose quality is often degraded by coherent noise (speckle). PMID:16907183

  15. Tolerance of the frequency deviation of LO sources at a MIMO system

    NASA Astrophysics Data System (ADS)

    Xiao, Jiangnan; Li, Xingying; Zhang, Zirang; Xu, Yuming; Chen, Long; Yu, Jianjun

    2015-11-01

    We analyze and simulate the tolerance of frequency offset at a W-band optical-wireless transmission system. The transmission system adopts optical polarization division multiplexing (PDM), and multiple-input multiple-output (MIMO) reception. The transmission signal adopts optical quadrature phase shift keying (QPSK) modulation, and the generation of millimeter-wave is based on the optical heterodyning technique. After 20-km single-mode fiber-28 (SMF-28) transmission, tens of Gb/s millimeter-wave signal is delivered. At the receiver, two millimeter-wave signals are down-converted into electrical intermediate-frequency (IF) signals in the analog domain by mixing with two electrical local oscillators (LOs) with different frequencies. We investigate the different frequency LO effect on the 2×2 MIMO system performance for the first time, finding that the process during DSP of implementing frequency offset estimation (FOE) before cascaded multi-modulus-algorithm (CMMA) equalization can get rid of the inter-channel interference (ICI) and improve system bit-error-ratio (BER) performance in this type of transmission system.

  16. Study of LO-phonon decay in semiconductors for hot carrier solar cell

    NASA Astrophysics Data System (ADS)

    Levard, Hugo; Vidal, Julien; Laribi, Sana; Guillemoles, Jean-François

    2014-03-01

    Knowledge of phonon decay is of crucial importance when studying basic properties of semiconductors, since they are closely related to Raman linewidth and non-equilibrium-hot-carriers cooling. The latter indeed cools down to the bottom of the conduction band within a picosecond range because of electron-phonon interaction. The eventual emitted hot phonons then decay in few picoseconds. The hot carriers cooling can be slowed down by considering the decay rate dependence of phonon on conservation rules, whose tuning may reduce the allowed two-phonon final states density. This is of direct interest for the third generation photovoltaic devices that are Hot Carrier Solar Cells (HCSC), in which the photoexcited carriers are extracted at an energy higher than thermal equilibrium. One of the HCSC main challenges then is to find an absorber material in which the hot phonons has a relaxation time longer than the carriers cooling time, so that we can expect the electron to ``reabsorb'' a phonon, slowing down the electronic cooling. HCSC yield is ultimately limited by LO phonon decay, though. In this work, we present theoretical results obtained from ab initio calculations of phonon lifetime in III-V and IV-IV semiconductors through a three-phonon process. Common approximations in the literature are questioned. In particular, we show that the usual ``zone-center approximation'' is not valid in some specific semiconductors. The analysis allows to correctly investigate phonon decay mechanisms in bulk and nanostructured materials.

  17. Breeding for reduced post-harvest seed dormancy in switchgrass: registration of TEM-LoDorm switchgrass germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The switchgrass (Panicum virgatum L.) germplasm line TEM-LoDorm (Reg. No. GP-98, PI 636468) was developed by the USDA-ARS in cooperation with the Texas Agricultural Experiment Station (currently Texas AgriLife Research) and was released in May 2007. Establishment of desirable stands of switchgrass ...

  18. Nonlinear Analysis of the Space Shuttle Superlightweight LO2 Tank. Part 1; Bahavior Under Booster Ascent Loads

    NASA Technical Reports Server (NTRS)

    Young, Richard D.; Nemeth, Michael P.; Collins, Timothy J.; Starnes, James H., Jr.

    1998-01-01

    Results of linear bifurcation and nonlinear analyses of the Space Shuttle superlightweight (SLWT) external liquid-oxygen (LO2) tank for an important early booster ascent loading condition are presented. These results for thin-walled linear elastic shells that are subjected to combined mechanical and thermal loads illustrate an important type of response mode that may be encountered in the design of other liquid-fuel launch vehicles. Linear bifurcation analyses are presented that predict several nearly equal eigenvalues that correspond to local buckling modes in the forward ogive section of the LO2 tank. In contrast, the nonlinear response phenomenon is shown to consist of short-wavelength bending deformations in the forward ogive and barrel sections of the LO2 tank that growing amplitude in a stable manner increasing load. Imperfection sensitivity analyses are presented that show that the presence of several nearly equal eigenvalues does not lead to a premature general instability mode for the forward ogive section. For the linear bifurcation and nonlinear analyses, the results show that accurate predictions of the response of the shield generally require a large-scale, high-fidelity finite-element model. Results are also presented that show that the SLWT LO2 tank can support loads in excess of approximately 2.6 times the values of the operational loads considered.

  19. CXCR6 marks a novel subset of T-bet(lo)Eomes(hi) natural killer cells residing in human liver.

    PubMed

    Stegmann, Kerstin A; Robertson, Francis; Hansi, Navjyot; Gill, Upkar; Pallant, Celeste; Christophides, Theodoros; Pallett, Laura J; Peppa, Dimitra; Dunn, Claire; Fusai, Giuseppe; Male, Victoria; Davidson, Brian R; Kennedy, Patrick; Maini, Mala K

    2016-01-01

    Natural killer cells (NK) are highly enriched in the human liver, where they can regulate immunity and immunopathology. We probed them for a liver-resident subset, distinct from conventional bone-marrow-derived NK. CXCR6+ NK were strikingly enriched in healthy and diseased liver compared to blood (p < 0.0001). Human hepatic CXCR6+ NK had an immature phenotype (predominantly CD56(bright)CD16-CD57-), and expressed the tissue-residency marker CD69. CXCR6+ NK produced fewer cytotoxic mediators and pro-inflammatory cytokines than the non-liver-specific CXCR6- fraction. Instead CXCR6+ NK could upregulate TRAIL, a key death ligand in hepatitis pathogenesis. CXCR6 demarcated liver NK into two transcriptionally distinct populations: T-bet(hi)Eomes(lo)(CXCR6-) and T-bet(lo)Eomes(hi)(CXCR6+); the latter was virtually absent in the periphery. The small circulating CXCR6+ subset was predominantly T-bet(hi)Eomes(lo), suggesting its lineage was closer to CXCR6- peripheral than CXCR6+ liver NK. These data reveal a large subset of human liver-resident T-bet(lo)Eomes(hi) NK, distinguished by their surface expression of CXCR6, adapted for hepatic tolerance and inducible anti-viral immunity. PMID:27210614

  20. The LO Model and the Traditional French Organisational Culture: A Paradigmatic Contradiction Leading to a Limited Implementation

    ERIC Educational Resources Information Center

    Belet, Daniel

    2010-01-01

    This article deals with the issue of the very weak implementation of the LO model in France, although it appears as an appealing new management paradigm that can allow companies to better face a fast changing environment. The author argues that there is a strong philosophical contradiction between this innovative management model and the still…

  1. High-contrast 3D image acquisition using HiLo microscopy with an electrically tunable lens

    NASA Astrophysics Data System (ADS)

    Philipp, Katrin; Smolarski, André; Fischer, Andreas; Koukourakis, Nektarios; Stürmer, Moritz; Wallrabe, Ulricke; Czarske, Jürgen

    2016-04-01

    We present a HiLo microscope with an electrically tunable lens for high-contrast three-dimensional image acquisition. HiLo microscopy combines wide field and speckled illumination images to create optically sectioned images. Additionally, the depth-of-field is not fixed, but can be adjusted between wide field and confocal-like axial resolution. We incorporate an electrically tunable lens in the HiLo microscope for axial scanning, to obtain three-dimensional data without the need of moving neither the sample nor the objective. The used adaptive lens consists of a transparent polydimethylsiloxane (PDMS) membrane into which an annular piezo bending actuator is embedded. A transparent fluid is filled between the membrane and the glass substrate. When actuated, the piezo generates a pressure in the lens which deflects the membrane and thus changes the refractive power. This technique enables a large tuning range of the refractive power between 1/f = (-24 . . . 25) 1/m. As the NA of the adaptive lens is only about 0.05, a fixed high-NA lens is included in the setup to provide high resolution. In this contribution, the scan properties and capabilities of the tunable lens in the HiLo microscope are analyzed. Eventually, exemplary measurements are presented and discussed.

  2. Mode sequence, frequency change of nonsoft phonons, and LO-TO splitting in strained tetragonal BaTiO3

    NASA Astrophysics Data System (ADS)

    Raeliarijaona, Aldo; Fu, Huaxiang

    2015-09-01

    Ultraviolet Raman spectroscopy revealed the existence of an unusual large-frequency shift occurring to a nonsoft mode of E (TO4 ) when BaTiO3 is strained to a SrTiO3 substrate [D. Tenne et al., Science 313, 1614 (2006), 10.1126/science.1130306]. It raised two interesting questions: (i) whether there are other nonsoft modes that possess similar or even larger strain-induced frequency shifts and (ii) how the mode sequence is altered by these shifts in frequency. Note that mode sequence is also pivotal in correctly indexing and assigning the spectroscopy peaks observed in all Raman experiments. By mapping out the evolutions of individual phonon modes as a function of strain using first-principles density functional perturbation calculations, we determine the mode sequence and strain-induced phonon frequency shifts in prototypical BaTiO3. Our study reveals that the mode sequence is drastically different when BaTiO3 is strained to SrTiO3 compared to that in the unstrained structure, caused by multiple mode crossings. Furthermore, we predict that three other nonsoft modes, A1(TO2), E (LO4 ), and A1(TO3), display even larger strain-induced frequency shifts than E (TO4 ). The strain responses of individual modes are found to be highly mode specific, and a mechanism that regulates the magnitude of the frequency shift is provided. As another key outcome of this study, we tackle a long-standing problem of LO-TO splitting in ferroelectrics. A rigorous definition for the LO-TO splitting is formulated, which allows this critical quantity to be calculated quantitatively. The definition immediately reveals a new finding; that is, a large LO-TO splitting not only exists for E (LO4 ), which is previously known and originates from a soft mode, it also occurs for a nonsoft A1(LO3) mode. The LO-TO splitting is shown to decrease drastically with compressive strain, and this decrease cannot be explained by the Born effective charges and high-frequency dielectric constants.

  3. Nectary Structure and Nectar Secretion in Maxillaria coccinea (Jacq.) L.O. Williams ex Hodge (Orchidaceae)

    PubMed Central

    STPICZYŃSKA, M.; DAVIES, K. L.; GREGG, A.

    2004-01-01

    • Background and Aims It had previously been assumed that Maxillaria spp. produce no nectar. However, nectar has recently been observed in Maxillaria coccinea (Jacq.) L.O. Williams ex Hodge amongst other species. Furthermore, it is speculated that M. coccinea may be pollinated by hummingbirds. The aim of this paper is to investigate these claims further. • Methods Light microscopy, histochemistry, scanning and transmission electron microscopy. • Key Results This is the first detailed account of nectar secretion in Maxillaria Ruiz & Pav. A ‘faucet and sink’ arrangement occurs in M. coccinea. Here, the nectary is represented by a small protuberance upon the ventral surface of the column and nectar collects in a semi‐saccate reservoir formed by the fusion of the labellum and the base of the column‐foot. The nectary comprises a single‐layered epidermis and three or four layers of small subepidermal cells. Beneath these occur several layers of larger parenchyma cells. Epidermal cells lack ectodesmata and have a thin, permeable, reticulate cuticle with associated swellings that coincide with the middle lamella between adjoining epidermal cells. Nectar is thought to pass both along the apoplast and symplast and eventually through the stretched and distended cuticle. The secretory cells are collenchymatous, nucleated and have numerous pits with plasmodesmata, mitochondria, rough ER and plastids with many plastoglobuli but few lamellae. Subsecretory cells have fewer plastids than secretory cells. Nectary cells also contain large intravacuolar protein bodies. The floral morphology of M. coccinea is considered in relation to ornithophily and its nectary compared with a similar protuberance found in the entomophilous species M. parviflora (Poepp. & Endl.) Garay. • Conclusions Flowers of M. coccinea produce copious amounts of nectar and, despite the absence of field data, their morphology and the exact configuration of their parts argue strongly in favour of

  4. More food, low pollution (mo fo lo Po): a grand challenge for the 21st century.

    PubMed

    Davidson, Eric A; Suddick, Emma C; Rice, Charles W; Prokopy, Linda S

    2015-03-01

    Synthetic nitrogen fertilizer has been a double-edged sword, greatly improving human nutrition during the 20th century but also posing major human health and environmental challenges for the 21st century. In August 2013, about 160 agronomists, scientists, extension agents, crop advisors, economists, social scientists, farmers, representatives of regulatory agencies and nongovernmental organizations (NGOs), and other agricultural experts gathered to discuss the vexing challenge of how to produce more food to nourish a growing population while minimizing pollution to the environment. This collection of 14 papers authored by conference participants provides a much needed analysis of the many technical, economic, and social impediments to improving nitrogen use efficiency (NUE) in crop and animal production systems. These papers demonstrate that the goals of producing more food with low pollution (Mo Fo Lo Po) will not be achieved by technological developments alone but will also require policies that recognize the economic and social factors affecting farmer decision-making. Take-home lessons from this extraordinary interdisciplinary effort include the need (i) to develop partnerships among private and public sectors to demonstrate the most current, economically feasible, best management NUE practices at local and regional scales; (ii) to improve continuing education to private sector retailers and crop advisers; (iii) to tie nutrient management to performance-based indicators on the farm and in the downwind and downstream environment; and (iv) to restore investments in research, education, extension, and human resources that are essential for developing the interdisciplinary knowledge and innovative skills needed to achieve agricultural sustainability goals. PMID:26023950

  5. LoComatioN: a software tool for the analysis of low copy number DNA profiles.

    PubMed

    Gill, Peter; Kirkham, Amanda; Curran, James

    2007-03-01

    Previously, the interpretation of low copy number (LCN) STR profiles has been carried out using the biological or 'consensus' method-essentially, alleles are not reported, unless duplicated in separate PCR analyses [P. Gill, J. Whitaker, C. Flaxman, N. Brown, J. Buckleton, An investigation of the rigor of interpretation rules for STRs derived from less than 100 pg of DNA, Forens. Sci. Int. 112 (2000) 17-40]. The method is now widely used throughout Europe. Although a probabilistic theory was simultaneously introduced, its time-consuming complexity meant that it could not be easily applied in practice. The 'consensus' method is not as efficient as the probabilistic approach, as the former wastes information in DNA profiles. However, the theory was subsequently extended to allow for DNA mixtures and population substructure in a programmed solution by Curran et al. [J.M. Curran, P. Gill, M.R. Bill, Interpretation of repeat measurement DNA evidence allowing for multiple contributors and population substructure, Forens. Sci. Int. 148 (2005) 47-53]. In this paper, we describe an expert interpretation system (LoComatioN) which removes this computational burden, and enables application of the full probabilistic method. This is the first expert system that can be used to rapidly evaluate numerous alternative explanations in a likelihood ratio approach, greatly facilitating court evaluation of the evidence. This would not be possible with manual calculation. Finally, the Gill et al. and Curran et al. papers both rely on the ability of the user to specify two quantities: the probability of allelic drop-out, and the probability of allelic contamination ("drop-in"). In this paper, we offer some guidelines on how these quantities may be specified. PMID:16759831

  6. Balm mint extract (Lo-701) for topical treatment of recurring herpes labialis.

    PubMed

    Koytchev, R; Alken, R G; Dundarov, S

    1999-10-01

    A double-blind, placebo-controlled, randomized trial was carried out with the aim of proving efficacy of standardized balm mint cream [active ingredient: 1% Lo-701--dried extract from Melissa officinalis L. leaves (70:1)] for the therapy of herpes simplex labialis. Sixty six patients with a history of recurrent herpes labialis (at least four episodes per year) in one center were treated topically; 34 of them with verum and 32 with placebo. The cream had to be smeared on the affected area four times daily over five days. A combined symptom score of the values for complaints, size of affected area and blisters at day 2 of therapy was formed as the primary target parameter. There was a significant difference in the values of the primary target parameter between both treatment groups: verum 4.03 +/- 0.33 (3.0); placebo 4.94 +/- 0.40 (5.0); values given are mean +/- SEM (median) of the symptoms score on day 2 of therapy. The tested formulation is effective for the treatment of herpes simplex labialis. The significant difference in the combined symptom score on the second day of treatment is of particular importance having in mind that the complaints in patients suffering from herpes labialis are usually most intensive at that time. In addition to the shortening of the healing period, the prevention of a spreading of the infection and the rapid effect on typical symptoms of herpes like itching, tingling, burning, stabbing, swelling, tautness and erythema, the balm mint cream has a further advantage. The different mechanism of action of the balm mint extract rules out the development of resistance of the herpes virus. Some indication exists that the intervals between the periods with herpes might be prolonged with balm mint cream treatment. PMID:10589440

  7. Spark Ignition Characteristics of a LO2/LCH4 Engine at Altitude Conditions

    NASA Technical Reports Server (NTRS)

    Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

    2012-01-01

    The use of non-toxic propellants in future exploration vehicles would enable safer, more cost effective mission scenarios. One promising "green" alternative to existing hypergols is liquid methane/liquid oxygen. To demonstrate performance and prove feasibility of this propellant combination, a 100lbf LO2/LCH4 engine was developed and tested under the NASA Propulsion and Cryogenic Advanced Development (PCAD) project. Since high ignition energy is a perceived drawback of this propellant combination, a test program was performed to explore ignition performance and reliability versus delivered spark energy. The sensitivity of ignition to spark timing and repetition rate was also examined. Three different exciter units were used with the engine's augmented (torch) igniter. Propellant temperature was also varied within the liquid range. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks (in quiescent, room air). The escalating pressure and flow environment increases spark impedance and may at some point compromise an exciter.s ability to deliver a spark. Reduced spark energies of these sparks result in more erratic ignitions and adversely affect ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1-6mJ, though multiple, similarly timed sparks of 55-75mJ were required for reliable ignition. An optimum time interval for spark application and ignition coincided with propellant introduction to the igniter and engine. Shifts of ignition timing were manifested by changes in the characteristics of the resulting ignition.

  8. Estradiol agonists inhibit human LoVo colorectal-cancer cell proliferation and migration through p53

    PubMed Central

    Hsu, Hsi-Hsien; Kuo, Wei-Wen; Ju, Da-Tong; Yeh, Yu-Lan; Tu, Chuan-Chou; Tsai, Ying-Lan; Shen, Chia-Yao; Chang, Sheng-Huang; Chung, Li-Chin; Huang, Chih-Yang

    2014-01-01

    AIM: To investigate the effects of 17β-estradiol via estrogen receptors (ER) or direct administration of ER agonists on human colorectal cancer. METHODS: LoVo cells were established from the Bioresource Collection and Research Center and cultured in phenol red-free DMEM (Sigma, United States). To investigate the effects of E2 and/or ER selective agonists on cellular proliferation, LoVo colorectal cells were treated with E2 or ER-selective agonists for 24 h and 48 h and subjected to the MTT (Sigma) assay to find the concentration. And investigate the effects of E2 and/or ER selective agonists on cell used western immunoblotting to find out the diversification of signaling pathways. In order to observe motility and migration the wound healing assay and a transwell chamber (Neuro Probe) plate were tased. For a quantitative measure, we counted the number of migrating cells to the wound area post-wounding for 24 h. We further examined the cellular migration-regulating factors urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA) and matrix metalloproteinase (MMP)-9 in human LoVo cells so gelatin zymography that we used and gelatinolytic activity was visualized by Coomassie blue staining. And these results are presented as means ± SE, and statistical comparisons were made using Student’s t-test. RESULTS: The structure was first compared with E2 and ER agonists. We then treated the LoVo cells with E2 and ER agonists (10-8 mol/L) for 24 h and 48 h and subsequently measured the cell viability using MTT assay. Our results showed that treatment with 17β-estradiol and/or ER agonists in human LoVo colorectal cancer cells activated p53 and then up-regulated p21 and p27 protein levels, subsequently inhibiting the downstream target gene, cyclin D1, which regulates cell proliferation. Taken together, our findings demonstrate the anti-tumorigenesis effects of 17β-estradiol and/or ER agonists and suggest that these compounds may prove to be a

  9. Volatile organic compound fluxes and concentrations in London (ClearfLo)

    NASA Astrophysics Data System (ADS)

    Valach, Amy; Langford, Ben; Nemitz, Eiko; MacKenzie, Rob; Hewitt, Nick

    2014-05-01

    Volatile organic compounds (VOCs) from anthropogenic sources such as fuel combustion or evaporative emissions can directly and indirectly affect human health. Some VOCs, such as benzene and 1,3- butadiene are carcinogens. These and other VOCs contribute to the formation of ozone (O3) and aerosol particles, which have effects on human health and the radiative balance of the atmosphere. Although in the UK VOC emissions are subject to control under European Commission Directive 2008/50/EC and emission reducing technologies have been implemented, urban air pollution remains a concern. Urban air quality is likely to remain a priority since currently >50% of the global population live in urban areas with trends in urbanization and population migration predicted to increase. The ClearfLo project is a large multi-institutional consortium funded by the UK Natural Environment Research Council (NERC) and provides integrated measurements of meteorology, gas phase and particulate composition of the atmosphere over London. Both long term and IOP measurements were made at street and elevated locations at a range of sites across London and its surroundings during 2011 and 2012. Mixing ratios of a selection of nine VOCs were measured using a high sensitivity proton transfer reaction-mass spectrometer (PTR-MS) at a ground level urban background (North Kensington) and kerbside (Marylebone Road) site during the winter IOP. VOC fluxes were measured by virtually disjunct eddy covariance (vDEC) at an elevated urban site (King's College Strand) in Aug-Dec 2012. Our results for the first IOP showed that most of the selected compound concentrations depended on traffic emissions, although there was a marked difference between the urban background and kerbside sites. We identified some temperature effects on VOC concentrations. We also present the first analyses of VOC flux measurements over London. Preliminary analyses indicate most compounds associated with vehicle emissions closely

  10. 100-Lb(f) LO2/LCH4 Reaction Control Engine Technology Development for Future Space Vehicles

    NASA Technical Reports Server (NTRS)

    Robinson, Philip J.; Veith, Eric M.; Hurlbert, Eric A.; Jimenez, Rafael; Smith, Timothy D.

    2008-01-01

    The National Aeronautics and Space Administration (NASA) has identified liquid oxygen (LO2)/liquid methane (LCH4) propulsion systems as promising options for some future space vehicles. NASA issued a contract to Aerojet to develop a 100-lbf (445 N) LO2/LCH4 Reaction Control Engine (RCE) aimed at reducing the risk of utilizing a cryogenic reaction control system (RCS) on a space vehicle. Aerojet utilized innovative design solutions to develop an RCE that can ignite reliably over a broad range of inlet temperatures, perform short minimum impulse bits (MIB) at small electrical pulse widths (EPW), and produce excellent specific impulse (Isp) across a range of engine mixture ratios (MR). These design innovations also provide a start transient with a benign MR, ensuring good thrust chamber compatibility and long life. In addition, this RCE can successfully operate at MRs associated with main engines, enabling the RCE to provide emergency backup propulsion to minimize vehicle propellant load and overall system mass.

  11. Rosiglitazone-induced CD36 up-regulation resolves inflammation by PPARγ and 5-LO-dependent pathways.

    PubMed

    Ballesteros, Iván; Cuartero, María I; Pradillo, Jesús M; de la Parra, Juan; Pérez-Ruiz, Alberto; Corbí, Angel; Ricote, Mercedes; Hamilton, John A; Sobrado, Mónica; Vivancos, José; Nombela, Florentino; Lizasoain, Ignacio; Moro, María A

    2014-04-01

    PPARγ-achieved neuroprotection in experimental stroke has been explained by the inhibition of inflammatory genes, an action in which 5-LO, Alox5, is involved. In addition, PPARγ is known to promote the expression of CD36, a scavenger receptor that binds lipoproteins and mediates bacterial recognition and also phagocytosis. As phagocytic clearance of neutrophils is a requisite for resolution of the inflammatory response, PPARγ-induced CD36 expression might help to limit inflammatory tissue injury in stroke, an effect in which 5-LO might also be involved. Homogenates, sections, and cellular suspensions were prepared from brains of WT and Alox5(-/-) mice exposed to distal pMCAO. BMMs were obtained from Lys-M Cre(+) PPARγ(f/f) and Lys-M Cre(-) PPARγ(f/f) mice. Stereological counting of double-immunofluorescence-labeled brain sections and FACS analysis of cell suspensions was performed. In vivo and in vitro phagocytosis of neutrophils by microglia/macrophages was analyzed. PPARγ activation with RSG induced CD36 expression in resident microglia. This process was mediated by the 5-LO gene, which is induced in neurons by PPARγ activation and at least by one of its products--LXA4--which induced CD36 independently of PPARγ. Moreover, CD36 expression helped resolution of inflammation through phagocytosis, concomitantly to neuroprotection. Based on these findings, in addition to a direct modulation by PPARγ, we propose in brain a paracrine model by which products generated by neuronal 5-LO, such as LXA4, increase the microglial expression of CD36 and promote tissue repair in pathologies with an inflammatory component, such as stroke. PMID:24338629

  12. Immune Reconstitution after Autologous Hematopoietic Transplantation with Lin−, CD34+, Thy-1LO Selected or Intact Stem Cell Products*

    PubMed Central

    Singh, Rakesh K.; Varney, Michelle L.; Leutzinger, Cheryl; Vose, Julie M.; Bierman, Philip J.; Buyukberber, Suleyman; Ino, Kazuhiko; Loh, Kevin; Nichols, Craig; Inwards, David; Rifkin, Robert; Talmadge, James E.

    2007-01-01

    In sequential studies, we compared immune reconstitution following high dose chemotherapy (HDT) and stem cell transplantation (SCT) using intact mobilized peripheral blood stem cell (PSC) in intermediate grade non-Hodgkin's lymphoma (NHL) patients and CD34+, lineage negative (Lin−), Thy-1lo (CD34+Lin−Thy-1lo) stem cells in low-grade NHL patients. Cytokine expression and cellular phenotype and function were used as the basis for comparison. Despite differences in cellular composition of the stem cell grafts, immune reconstitution in both groups was similar. Significantly higher levels of type 1 and 2-associated cytokine messenger ribonucleic acid (mRNA) were observed both prior to and following transplant in the peripheral blood (PB) of both cohorts as compared to normal individuals. Similar levels of interleukin (IL)-4, IL-10, interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α) mRNA were seen in PB mononuclear cells following transplant with either product. In contrast, patients receiving isolated CD34+Lin−Thy-1lo cells expressed significantly higher IL-2 levels at all times examined post-transplant. Despite the high levels of cytokine gene expression and rapid restoration to pretransplant levels of CD3 cell number by day 30, T cell function and CD4:CD8 and CD4+CD45RA:CD4+CD45RO+ ratios were significantly depressed in both cohorts compared to normal donors, and significantly lower in patients transplanted with CD34+Lin−Thy-1lo compared to patients receiving an intact PSC product. These data suggest that the peripheral tolerance in patients receiving HDT and an autologous SCT occurs independent of graft composition, although immune function and CD4 recovery is better facilitated by transplantation of an intact product. PMID:17570320

  13. Enhancement of the HIF-1α/15-LO/15-HETE Axis Promotes Hypoxia-Induced Endothelial Proliferation in Preeclamptic Pregnancy

    PubMed Central

    Liu, Qian; Zhang, Yanhua; Li, Huiying; Li, Peiling; Zhu, Daling

    2014-01-01

    Preeclampsia (PE) is an extremely serious condition in pregnant women and the leading cause of maternal and fetal morbidity and mortality. Despite active research, the etiological factors of this disorder remain elusive. The increased release of 15-hydroxyeicosatetraenoic acid (15-HETE) in the placenta of preeclamptic patients has been studied, but its exact role in PE pathogenesis remains unknown. Mounting evidence shows that PE is associated with placental hypoxia, impaired placental angiogenesis, and endothelial dysfunction. In this study, we confirmed the upregulated expression of hypoxia-inducible factor 1α (HIF-1α) and 15-lipoxygenase-1/2 (15-LO-1/2) in patients with PE. Production of the arachidonic acid metabolite, 15-HETE, also increased in the preeclamptic placenta, which suggests enhanced activation of the HIF-1α–15-LO–15-HETE axis. Furthermore, this study is the first to show that the umbilical cord of preeclamptic women contains significantly higher serum concentrations of 15-HETE than that of healthy pregnant women. The results also show that expression of 15-LO-1/2 is upregulated in both human umbilical vein endothelial cells (HUVECs) collected from preeclamptic women and in those cultured under hypoxic conditions. Exogenous 15-HETE promotes the migration of HUVECs and in vitro tube formation and promotes cell cycle progression from the G0/G1 phase to the G2/M + S phase, whereas the 15-LO inhibitor, NDGA, suppresses these effects. The HIF-1α/15-LO/15-HETE pathway is therefore significantly associated within the pathology of PE. PMID:24796548

  14. 77 FR 6793 - D'Lo Gas Storage, LLC; Notice of Intent To Prepare an Environmental Assessment for the PROPOSED D...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-09

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF ENERGY Federal Energy Regulatory Commission D'Lo Gas Storage, LLC; Notice of Intent To Prepare an Environmental Assessment for the PROPOSED D'LO Gas Storage Project, Request for Comments on Environmental Issues, and Notice of Onsite Environmental Review...

  15. A Study of the Relationship between Levels of Technology Implementation (LoTi) and Student Performance on Texas Assessment of Knowledge and Skills (TAKS) Scores

    ERIC Educational Resources Information Center

    Berkeley-Jones, Catherine Spotswood

    2012-01-01

    The purpose of this study was to examine teacher Levels of Technology Implementation (LoTi) self-ratings and student Texas Assessment of Knowledge and Skills (TAKS) scores. The study assessed the relationship between LoTi ratings and TAKS scores of 6th, 7th, and 8th grade students as reported in student records at Alamo Heights Independent School…

  16. Three dimensional HiLo-based structured illumination for a digital scanned laser sheet microscopy (DSLM) in thick tissue imaging

    PubMed Central

    Bhattacharya, Dipanjan; Singh, Vijay Raj; Zhi, Chen; So, Peter T. C.; Matsudaira, Paul; Barbastathis, George

    2012-01-01

    Laser sheet based microscopy has become widely accepted as an effective active illumination method for real time three-dimensional (3D) imaging of biological tissue samples. The light sheet geometry, where the camera is oriented perpendicular to the sheet itself, provides an effective method of eliminating some of the scattered light and minimizing the sample exposure to radiation. However, residual background noise still remains, limiting the contrast and visibility of potentially interesting features in the samples. In this article, we investigate additional structuring of the illumination for improved background rejection, and propose a new technique, “3D HiLo” where we combine two HiLo images processed from orthogonal directions to improve the condition of the 3D reconstruction. We present a comparative study of conventional structured illumination based demodulation methods, namely 3Phase and HiLo with a newly implemented 3D HiLo approach and demonstrate that the latter yields superior signal-to-background ratio in both lateral and axial dimensions, while simultaneously suppressing image processing artifacts. PMID:23262684

  17. The Host Galaxies of LoBAL QSOs at Low z: A Perspective from HST UVIS Images

    NASA Astrophysics Data System (ADS)

    Behn, Wyatt Alan; Lazarova, Mariana; Canalizo, Gabriela

    2016-06-01

    We present GALFIT models of a complete optically-selected volume-limited sample of Low-Ionization Broad Absorption Line QSOs (LoBALs) in the redshift range 0.5-0.6 observed with HST WFC3 UVIS F475W. We investigate the morphologies in the rest frame u which map the younger stellar populations. In addition, we present statistics on the number of neighborhood galaxies within 150 kpc and possible trends between clustering and host galaxy properties. This sample of LoBALs is selected from QSOs characterized by their extreme blue-shifted absorption in the Mg II line—which is a signature of high velocity winds towards the observer. Only ~1-3% of optically selected QSOs are LoBALs. Their low fraction could be explained by their orientation or by a short period of outflow manifest in all QSOs during their lifetime. We aim to better understand the possibility of the evolutionary model by studying their morphologies in detail. Previous work on this sample, from images with F125W filter (rest frame i), shows that at least 60% of these objects exhibit signs of recent merger activity. We complement those results with our results from the UVIS observations and neighborhood clustering statistics.

  18. Lava bubble-wall fragments formed by submarine hydrovolcanic explosions on Lo'ihi Seamount and Kilauea Volcano

    USGS Publications Warehouse

    Clague, D.A.; Davis, A.S.; Bischoff, J.L.; Dixon, J.E.; Geyer, R.

    2000-01-01

    Glassy bubble-wall fragments, morphologically similar to littoral limu o Pele, have been found in volcanic sands erupted on Lo'ihi Seamount and along the submarine east rift zone of Kilauea Volcano. The limu o Pele fragments are undegassed with respect to H2O and S and formed by mild steam explosions. Angular glass sand fragments apparently form at similar, and greater, depths by cooling-contraction granulation. The limu o Pele fragments from Lo'ihi Seamount are dominantly tholeiitic basalt containing 6.25-7.25% MgO. None of the limu o Pele samples from Lo'ihi Seamount contains less than 5.57% MgO, suggesting that higher viscosity magmas do not form lava bubbles. The dissolved CO2 and H2O contents of 7 of the limu o Pele fragments indicate eruption at 1200??300 m depth (120??30 bar). These pressures exceed that generally thought to limit steam explosions. We conclude that hydrovolcanic eruptions are possible, with appropriate pre-mixing conditions, at pressures as great as 120 bar.

  19. Intracranial self-stimulation reward thresholds during morphine withdrawal in rats bred for high (HiS) and low (LoS) saccharin intake

    PubMed Central

    Holtz, Nathan A.; Radke, Anna K.; Zlebnik, Natalie E.; Harris, Andrew C.; Carroll, Marilyn E.

    2015-01-01

    Rational Sweet preference is a marker of vulnerability to substance use disorders, and rats selectively bred for high (HiS) vs. low saccharin (LoS) intake display potentiated drug-seeking behaviors. Recent work indicated that LoS rats were more responsive to the negative effects of drugs in several assays. Objective The current study used the intracranial self-stimulation (ICSS) procedure to investigate the anhedonic component of morphine withdrawal in male HiS and LoS rats. Methods Rats were administered morphine (10 mg/kg) or saline for 8 days. To evaluate withdrawal effects, reward thresholds were measured 24 and 28 h following the 8th morphine injection (spontaneous withdrawal) and again for 4 days following daily acute morphine and naloxone (1 mg/kg) administration (precipitated withdrawal). Results Twenty-four hr following the final morphine injection, reward thresholds in LoS rats were significantly elevated compared to reward thresholds in LoS controls, indicating spontaneous withdrawal. This effect was not observed in HiS rats. LoS rats also showed greater elevations of reward thresholds on several days during naloxone-precipitated withdrawal compared to their HiS counterparts. Conclusions LoS rats were more sensitive to morphine withdrawal-mediated elevations in ICSS thresholds than HiS rats. While these differences were generally modest, our data suggest that severity of the negative affective component of opiate withdrawal may be influenced by genotypes related to addiction vulnerability. PMID:25582876

  20. Reduced emotional signs of opiate withdrawal in rats selectively bred for low (LoS) versus high (HiS) saccharin intake

    PubMed Central

    Radke, Anna K.; Holtz, Nathan A.; Gewirtz, Jonathan C.; Carroll, Marilyn E.

    2013-01-01

    Rationale Rats bred for high (HiS) and low (LoS) saccharin intake exhibit divergent behavioral responses to multiple drugs of abuse, with HiS rats displaying greater vulnerability to drug taking. Previous research indicates that this effect may be due to increased sensitivity to reward in HiS rats and to the aversive effects of acute drug administration in LoS rats. Objective The current study investigated whether HiS and LoS rats also exhibit different behavioral signs of withdrawal following one or repeated opiate exposures. Methods Emotional signs of opiate withdrawal were assessed with potentiation of the acoustic startle reflex and conditioned place aversion (CPA) in male and female HiS and LoS rats. Startle was measured before and 4 h after a 10 mg/kg injection of morphine on days 1, 2, and 7 of opiate exposure. CPA was induced with a two-day, naloxone-precipitated conditioning paradigm. Somatic signs of withdrawal and weight loss were used also measured. Results Male and female LoS rats exhibited lower startle potentiation than HiS rats on the seventh day of morphine exposure. LoS male rats also failed to develop a CPA to morphine withdrawal. No differences in physical withdrawal signs were observed between HiS and LoS rats, but males of both lines had more physical signs of withdrawal than females. Conclusions These results suggest that LoS rats are less vulnerable to the negative emotional effects of morphine withdrawal than HiS rats. A less severe withdrawal syndrome may contribute to decreased levels of drug taking in the LoS line. PMID:23254375

  1. Interstellar Hydrogen Fluxes Measured by IBEX-Lo in 2009: Numerical Modeling and Comparison with the Data

    NASA Astrophysics Data System (ADS)

    Katushkina, O. A.; Izmodenov, V. V.; Alexashov, D. B.; Schwadron, N. A.; McComas, D. J.

    2015-10-01

    In this paper, we perform numerical modeling of the interstellar hydrogen fluxes measured by IBEX-Lo during orbit 23 (spring 2009) using a state-of-the-art kinetic model of the interstellar neutral hydrogen distribution in the heliosphere. This model takes into account the temporal and heliolatitudinal variations of the solar parameters as well as the non-Maxwellian kinetic properties of the hydrogen distribution due to charge exchange in the heliospheric interface. We found that there is a qualitative difference between the IBEX-Lo data and the modeling results obtained with the three-dimensional, time-dependent model. Namely, the model predicts a larger count rate in energy bin 2 (20-41 eV) than in energy bin 1 (11-21 eV), while the data shows the opposite case. We perform study of the model parameter effects on the IBEX-Lo fluxes and the ratio of fluxes in two energy channels. We show that the most important parameter, which has a major influence on the ratio of the fluxes in the two energy bins, is the solar radiation pressure. The parameter fitting procedure shows that the best agreement between the model result and the data occurs when the ratio of the solar radiation pressure to the solar gravitation, μ0, is {1.26}-0.076+0.06, and the total ionization rate of hydrogen at 1 AU is {β }E,0={3.7}-0.35+0.39× {10}-7 s-1. We have found that the value of μ0 is much larger than μ0 = 0.89, which is the value derived from the integrated solar Lyα flux data for the period of time studied. We discuss possible reasons for the differences.

  2. The origins of metamodality in visual object area LO: Bodily topographical biases and increased functional connectivity to S1.

    PubMed

    Tal, Zohar; Geva, Ran; Amedi, Amir

    2016-02-15

    Recent evidence from blind participants suggests that visual areas are task-oriented and sensory modality input independent rather than sensory-specific to vision. Specifically, visual areas are thought to retain their functional selectivity when using non-visual inputs (touch or sound) even without having any visual experience. However, this theory is still controversial since it is not clear whether this also characterizes the sighted brain, and whether the reported results in the sighted reflect basic fundamental a-modal processes or are an epiphenomenon to a large extent. In the current study, we addressed these questions using a series of fMRI experiments aimed to explore visual cortex responses to passive touch on various body parts and the coupling between the parietal and visual cortices as manifested by functional connectivity. We show that passive touch robustly activated the object selective parts of the lateral-occipital (LO) cortex while deactivating almost all other occipital-retinotopic-areas. Furthermore, passive touch responses in the visual cortex were specific to hand and upper trunk stimulations. Psychophysiological interaction (PPI) analysis suggests that LO is functionally connected to the hand area in the primary somatosensory homunculus (S1), during hand and shoulder stimulations but not to any of the other body parts. We suggest that LO is a fundamental hub that serves as a node between visual-object selective areas and S1 hand representation, probably due to the critical evolutionary role of touch in object recognition and manipulation. These results might also point to a more general principle suggesting that recruitment or deactivation of the visual cortex by other sensory input depends on the ecological relevance of the information conveyed by this input to the task/computations carried out by each area or network. This is likely to rely on the unique and differential pattern of connectivity for each visual area with the rest of the

  3. The origins of metamodality in visual object area LO: Bodily topographical biases and increased functional connectivity to S1

    PubMed Central

    Tal, Zohar; Geva, Ran; Amedi, Amir

    2016-01-01

    Recent evidence from blind participants suggests that visual areas are task-oriented and sensory modality input independent rather than sensory-specific to vision. Specifically, visual areas are thought to retain their functional selectivity when using non-visual inputs (touch or sound) even without having any visual experience. However, this theory is still controversial since it is not clear whether this also characterizes the sighted brain, and whether the reported results in the sighted reflect basic fundamental a-modal processes or are an epiphenomenon to a large extent. In the current study, we addressed these questions using a series of fMRI experiments aimed to explore visual cortex responses to passive touch on various body parts and the coupling between the parietal and visual cortices as manifested by functional connectivity. We show that passive touch robustly activated the object selective parts of the lateral–occipital (LO) cortex while deactivating almost all other occipital–retinotopic-areas. Furthermore, passive touch responses in the visual cortex were specific to hand and upper trunk stimulations. Psychophysiological interaction (PPI) analysis suggests that LO is functionally connected to the hand area in the primary somatosensory homunculus (S1), during hand and shoulder stimulations but not to any of the other body parts. We suggest that LO is a fundamental hub that serves as a node between visual-object selective areas and S1 hand representation, probably due to the critical evolutionary role of touch in object recognition and manipulation. These results might also point to a more general principle suggesting that recruitment or deactivation of the visual cortex by other sensory input depends on the ecological relevance of the information conveyed by this input to the task/computations carried out by each area or network. This is likely to rely on the unique and differential pattern of connectivity for each visual area with the rest of the

  4. Investigation of lightweight designs and materials for LO2 and LH2 propellant tanks for space vehicles, phase 1

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Design, analysis, and fabrication studies were performed on nonintegral (suspended) tanks using a representative space tug design. The LH2 and LO2 tank concept selection was developed. Tank geometries and support relationships were investigated using tug design propellant inertias and ullage pressures, then compared based on total tug systems effects. The tank combinations which resulted in the maximum payload were selected. Tests were conducted on samples of membrane material which was processed in a manner simulating production tank fabrication operations to determine fabrication effects on the fracture toughness of the tank material. Fracture mechanics analyses were also performed to establish a preliminary set of allowables for initial defects.

  5. Seasonality and paleoecology of the late Cretaceous multi-taxa vertebrate assemblage of "Lo Hueco" (central eastern Spain).

    PubMed

    Domingo, Laura; Barroso-Barcenilla, Fernando; Cambra-Moo, Oscar

    2015-01-01

    Isotopic studies of multi-taxa terrestrial vertebrate assemblages allow determination of paleoclimatic and paleoecological aspects on account of the different information supplied by each taxon. The late Campanian-early Maastrichtian "Lo Hueco" Fossil-Lagerstätte (central eastern Spain), located at a subtropical paleolatitude of ~31°N, constitutes an ideal setting to carry out this task due to its abundant and diverse vertebrate assemblage. Local δ18OPO4 values estimated from δ18OPO4 values of theropods, sauropods, crocodyliforms, and turtles are close to δ18OH2O values observed at modern subtropical latitudes. Theropod δ18OH2O values are lower than those shown by crocodyliforms and turtles, indicating that terrestrial endothermic taxa record δ18OH2O values throughout the year, whereas semiaquatic ectothermic taxa δ18OH2O values represent local meteoric waters over a shorter time period when conditions are favorable for bioapatite synthesis (warm season). Temperatures calculated by combining theropod, crocodyliform, and turtle δ18OH2O values and gar δ18OPO4 have enabled us to estimate seasonal variability as the difference between mean annual temperature (MAT, yielded by theropods) and temperature of the warmest months (TWMs, provided by crocodyliforms and turtles). ΔTWMs-MAT value does not point to a significantly different seasonal thermal variability when compared to modern coastal subtropical meteorological stations and Late Cretaceous rudists from eastern Tethys. Bioapatite and bulk organic matter δ13C values point to a C3 environment in the "Lo Hueco" area. The estimated fractionation between sauropod enamel and diet is ~15‰. While waiting for paleoecological information yielded by the ongoing morphological study of the "Lo Hueco" crocodyliforms, δ13C and δ18OCO3 results point to incorporation of food items with brackish influence, but preferential ingestion of freshwater. "Lo Hueco" turtles showed the lowest δ13C and δ18OCO3 values of the

  6. Seasonality and Paleoecology of the Late Cretaceous Multi-Taxa Vertebrate Assemblage of “Lo Hueco” (Central Eastern Spain)

    PubMed Central

    Domingo, Laura; Barroso-Barcenilla, Fernando; Cambra-Moo, Oscar

    2015-01-01

    Isotopic studies of multi-taxa terrestrial vertebrate assemblages allow determination of paleoclimatic and paleoecological aspects on account of the different information supplied by each taxon. The late Campanian-early Maastrichtian “Lo Hueco” Fossil-Lagerstätte (central eastern Spain), located at a subtropical paleolatitude of ~31°N, constitutes an ideal setting to carry out this task due to its abundant and diverse vertebrate assemblage. Local δ18OPO4 values estimated from δ18OPO4 values of theropods, sauropods, crocodyliforms, and turtles are close to δ18OH2O values observed at modern subtropical latitudes. Theropod δ18OH2O values are lower than those shown by crocodyliforms and turtles, indicating that terrestrial endothermic taxa record δ18OH2O values throughout the year, whereas semiaquatic ectothermic taxa δ18OH2O values represent local meteoric waters over a shorter time period when conditions are favorable for bioapatite synthesis (warm season). Temperatures calculated by combining theropod, crocodyliform, and turtle δ18OH2O values and gar δ18OPO4 have enabled us to estimate seasonal variability as the difference between mean annual temperature (MAT, yielded by theropods) and temperature of the warmest months (TWMs, provided by crocodyliforms and turtles). ΔTWMs-MAT value does not point to a significantly different seasonal thermal variability when compared to modern coastal subtropical meteorological stations and Late Cretaceous rudists from eastern Tethys. Bioapatite and bulk organic matter δ13C values point to a C3 environment in the “Lo Hueco” area. The estimated fractionation between sauropod enamel and diet is ~15‰. While waiting for paleoecological information yielded by the ongoing morphological study of the “Lo Hueco” crocodyliforms, δ13C and δ18OCO3 results point to incorporation of food items with brackish influence, but preferential ingestion of freshwater. “Lo Hueco” turtles showed the lowest δ13C and δ18OCO3

  7. Optical and X-ray studies of chromospherically active stars: FR Cancri, HD 95559 and LO Pegasi

    NASA Technical Reports Server (NTRS)

    Pandey, J. C.; Singh, K. P.; Drake, S. A.; Sagar, R.

    2005-01-01

    We present a multiwavelength study of three chromospherically active stars, namely FR Cnc (= BD +16 degrees 1753), HD 95559 and LO Peg (=BD +22 degrees 4409), including newly obtained optical photometry, (for FR Cnc) low-resolution optical spectroscopy, as well as archival IR and X-ray observations. The BVR photometry carried out during the years 2001 - 2004 has found significant photometric variability to be present in all three stars. For FR Cnc, a photometric period 0.826685 +/- 0.000034 d has been established. The strong variation in the phase and amplitude of the FR Cnc light curves when folded on this period implies the presence of evolving and migrating spots or spot groups on its surface. Two independent spots with migration periods of 0.97 and 0.93 years respectively are inferred. The photometry of HD 95559 suggests the formation of a spot (group) during the interval of our observations. We infer the existence of two independent spots or groups in the photosphere of LO Peg, one of which has a migration period of 1.12 years. The optical spectroscopy of FR Cnc carried out during 2002-2003, reveals the presence of strong and variable Ca I1 H and K, H(sub beta) and H(sub alpha) emission features indicative of high level of chromospheric activity. The value of 5.3 for the ratio of the excess emission in H(sub alpha) to H(sub beta), EH(sub alpha)/EH(sub beta), suggests that the chromospheric emission may arise from an extended off-limb region. We have searched for the presence of color excesses in the near-IR JHK bands of these stars using 2MASS data, but none of them appear to have any significant color excess. We have also analyzed archival X-ray observations of HD 95559 and LO Peg carried out by with the ROSAT observatory. The best fit models to their X-ray spectra imply the presence of two coronal plasma components of differing temperatures and with sub-solar metal abundances. The inferred emission measures and temperatures of these systems are similar to

  8. Advantages of Karhunen Loève transform over fast Fourier transform for planetary radar and space debris detection

    NASA Astrophysics Data System (ADS)

    Maccone, Claudio

    2007-04-01

    The present article describes that the range of any radiotelescope (and radar in general) may be increased by virtue of software, if one replaces the fast Fourier transform by the Karhunen Loève transform. The range increases with the inverse of the fourth root of the signal-to-noise ratio when this ratio decreases. Thus, the range on any radiotelescope (and radar) may be increased without changing the hardware at all, but by changing the software only. This improvement in the range of the radiotelescope is currently implemented at the 32-m antenna located at Medicina, near Bologna, in Italy, for both SETI and general radioastronomy.

  9. Optical and X-Ray Studies of Chromospherically Active Stars: FR Cancri, HD 95559, and LO Pegasi

    NASA Astrophysics Data System (ADS)

    Pandey, J. C.; Singh, K. P.; Drake, S. A.; Sagar, R.

    2005-09-01

    We present a multiwavelength study of three chromospherically active stars, namely, FR Cnc (BD +16°1753), HD 95559, and LO Peg (BD +22°4409), including newly obtained optical photometry and low-resolution optical spectroscopy for FR Cnc, as well as archival IR and X-ray observations. The BVR photometry carried out from 2001 to 2004 has found significant photometric variability to be present in all three stars. For FR Cnc, a photometric period of 0.8267+/-0.0004 days has been established. The strong variation in the phase and amplitude of the FR Cnc light curves when folded on this period implies the presence of evolving and migrating spots or spot groups on its surface. Two independent spots with migration periods of 0.97 and 0.93 yr, respectively, are inferred. The photometry of HD 95559 suggests the formation of a spot (group) during the interval of our observations. We infer the existence of two independent spots or groups in the photosphere of LO Peg, one of which has a migration period of 1.12 yr. The optical spectroscopy of FR Cnc carried out during 2002-2003 reveals the presence of strong and variable Ca II H and K, Hβ, and Hα emission features indicative of a high level of chromospheric activity. The value of 5.3 for the ratio of the excess emission in Hα to Hβ, EHα/EHβ, suggests that the chromospheric emission may arise from an extended off-limb region. We have searched for the presence of color excesses in the near-IR JHK bands of these stars using Two Micron All Sky Survey data, but none of them appear to have any significant color excess. We have also analyzed archival X-ray observations of HD 95559 and LO Peg carried out with the ROSAT observatory. The best-fit models to their X-ray spectra imply the presence of two coronal plasma components of differing temperatures and with subsolar metal abundances. The inferred emission measures and temperatures of these systems are similar to those found for other active dwarf stars. The kinematics of FR

  10. Inhibition of migration and induction of apoptosis in LoVo human colon cancer cells by polysaccharides from Ganoderma lucidum.

    PubMed

    Liang, Zeng-Enni; Yi, You-Jin; Guo, Yu-Tong; Wang, Ren-Cai; Hu, Qiu-Long; Xiong, Xing-Yao

    2015-11-01

    Ganoderma lucidum polysaccharides (GLPs), which were purified from the medicinal herb G. lucidum followed by ethanol precipitation, protein depletion using the Sevage assay, purification using DEAE‑cellulose (DE-52), dialysis and the use of ultrafiltration membranes, are used as an ingredient in traditional anticancer treatments in China. The aim of the current study was to evaluate the anticancer effects and investigate the underlying molecular mechanisms of GLPs on LoVo human colon cancer cells. The results demonstrated that the GLP‑mediated anticancer effect in LoVo cells was characterized by cytotoxicity, migration inhibition, enhanced DNA fragmentation, morphological alterations and increased lactate dehydrogenase release. Furthermore, the activation of caspases‑3, ‑8 and ‑9 was involved in GLP‑stimulated apoptosis. Additionally, treatment with GLPs promoted the expression of Fas and caspase‑3 proteins, whilst reducing the expression of cleaved poly(ADP‑ribose) polymerase. These data indicate that GLPs demonstrate potential antitumor activity in human colon cancer cells, predominantly through the inhibition of migration and induction of apoptosis. Furthermore, activation of the Fas/caspase-dependent apoptosis pathway is involved in the cytotoxicity of GLPs. PMID:26397202

  11. Titanosaur Osteoderms from the Upper Cretaceous of Lo Hueco (Spain) and Their Implications on the Armor of Laurasian Titanosaurs

    PubMed Central

    Vidal, Daniel; Ortega, Francisco; Sanz, José Luis

    2014-01-01

    Titanosaurs are the only sauropod dinosaurs known to bear a dermal armor. Their osteoderms are relatively rare finds, with few more than a hundred specimens recovered worldwide. Also, little is known about their intra-individual, intra-specific or inter-specific variability. The macrovertebrate site of Lo Hueco (Upper Cretaceous; Cuenca, Spain) has yielded several complete specimens of osteoderms, some associated with fairly articulated specimens. They are all variations of the morphotype known as bulb and root. The presence of only this morphotype in Europe, which is considered as the primitive condition among titanosaurs, seems to indicate that the known Upper Cretaceous Laurasian titanosaurs only bore these referred bulb and root osteoderms. An eliptic Fourier analysis on the outline of complete specimens from this morphotype reveals: i) that they truly are part of a morphological cline; and ii) the existence of a consistent correlation between the outline and the morphology of the bulb. Such variation along a cline is more consistent with intra-individual rather than inter-specific variation. The osteoderms associated with a single titanosaur individual from Lo Hueco reinforce this hypothesis. PMID:25118985

  12. Jet-vetoed Higgs cross section in gluon fusion at N3LO+NNLL with small-R resummation

    NASA Astrophysics Data System (ADS)

    Banfi, Andrea; Caola, Fabrizio; Dreyer, Frédéric A.; Monni, Pier Francesco; Salam, Gavin P.; Zanderighi, Giulia; Dulat, Falko

    2016-04-01

    We present new results for the jet-veto efficiency and zero-jet cross section in Higgs production through gluon fusion. We incorporate the N3LO corrections to the total cross section, the NNLO corrections to the 1-jet rate, NNLL resummation for the jet p t and LL resummation for the jet radius dependence. Our results include known finite-mass corrections and are obtained using the jet-veto efficiency method, updated relative to earlier work to take into account what has been learnt from the new precision calculations that we include. For 13 TeV collisions and using our default choice for the renormalisation and factorisation scales, μ 0 = m H /2, the matched prediction for the jet-veto efficiency increases the pure N3LO prediction by about 2% and the two have comparable uncertainties. Relative to NNLO+NNLL results, the new prediction is 2% smaller and the uncertainty reduces from about 10% to a few percent. Results are also presented for the central scale μ 0 = m H .

  13. Metformin suppressed the proliferation of LoVo cells and induced a time-dependent metabolic and transcriptional alteration.

    PubMed

    He, Jiaojiao; Wang, Ke; Zheng, Ningning; Qiu, Yunping; Xie, Guoxiang; Su, Mingming; Jia, Wei; Li, Houkai

    2015-01-01

    Metformin is a widely used anti-diabetic drug with potential anti-tumor activity. However, little is known about its global metabolic and transcriptional impacts on tumor cells. In current study, we performed a metabolic profiling on human-derived colon cancer LoVo cells treated by 10 mM metformin for 8, 24 and 48 h. An obvious time-dependent metabolic alteration was observed from 8 to 48 h, prior to the reduction of cell viability. A total of 47, 45 and 66 differential metabolites were identified between control and metformin-treated cells at three time points. Most of the metabolites were up-regulated at 8 h, but down-regulated at 24 and 48 h by metformin. These metabolites were mainly involved in carbohydrates, lipids, amino acids, vitamins and nucleotides metabolism pathways. Meanwhile, the transcirptomic profile revealed 134 and 3061 differentially expressed genes at 8 and 24 h by metformin. In addition to the cancer signaling pathways, expression of genes involved in cell energy metabolism pathways was significantly altered, which were further validated with genes in glucose metabolism pathway. Altogether, our current data indicate that metformin suppressed the proliferation of LoVo cells, which may be due to the modulation on cell energy metabolism at both metabolic and transcriptional levels in a time-dependent way. PMID:26616174

  14. Metformin suppressed the proliferation of LoVo cells and induced a time-dependent metabolic and transcriptional alteration

    PubMed Central

    He, Jiaojiao; Wang, Ke; Zheng, Ningning; Qiu, Yunping; Xie, Guoxiang; Su, Mingming; Jia, Wei; Li, Houkai

    2015-01-01

    Metformin is a widely used anti-diabetic drug with potential anti-tumor activity. However, little is known about its global metabolic and transcriptional impacts on tumor cells. In current study, we performed a metabolic profiling on human-derived colon cancer LoVo cells treated by 10 mM metformin for 8, 24 and 48 h. An obvious time-dependent metabolic alteration was observed from 8 to 48 h, prior to the reduction of cell viability. A total of 47, 45 and 66 differential metabolites were identified between control and metformin-treated cells at three time points. Most of the metabolites were up-regulated at 8 h, but down-regulated at 24 and 48 h by metformin. These metabolites were mainly involved in carbohydrates, lipids, amino acids, vitamins and nucleotides metabolism pathways. Meanwhile, the transcirptomic profile revealed 134 and 3061 differentially expressed genes at 8 and 24 h by metformin. In addition to the cancer signaling pathways, expression of genes involved in cell energy metabolism pathways was significantly altered, which were further validated with genes in glucose metabolism pathway. Altogether, our current data indicate that metformin suppressed the proliferation of LoVo cells, which may be due to the modulation on cell energy metabolism at both metabolic and transcriptional levels in a time-dependent way. PMID:26616174

  15. Navier-Stokes computations with finite-rate chemistry for LO2/LH2 rocket engine plume flow studies

    NASA Technical Reports Server (NTRS)

    Dougherty, N. Sam; Liu, Baw-Lin

    1991-01-01

    Computational fluid dynamics methods have been developed and applied to Space Shuttle Main Engine LO2/LH2 plume flow simulation/analysis of airloading and convective base heating effects on the vehicle at high flight velocities and altitudes. New methods are described which were applied to the simulation of a Return-to-Launch-Site abort where the vehicle would fly briefly at negative angles of attack into its own plume. A simplified two-perfect-gases-mixing approach is used where one gas is the plume and the other is air at 180-deg and 135-deg flight angle of attack. Related research has resulted in real gas multiple-plume interaction methods with finite-rate chemistry described herein which are applied to the same high-altitude-flight conditions of 0 deg angle of attack. Continuing research plans are to study Orbiter wake/plume flows at several Mach numbers and altitudes during ascent and then to merge this model with the Shuttle 'nose-to-tail' aerodynamic and SRB plume models for an overall 'nose-to-plume' capability. These new methods are also applicable to future launch vehicles using clustered-engine LO2/LH2 propulsion.

  16. English vowel production by native Mandarin speakers: Influences of AoA, LoR, education, perception, and orthography

    NASA Astrophysics Data System (ADS)

    Bell-Berti, Fredericka; Yu, Yan Helen

    2005-09-01

    This study investigates relations among several factors that are expected to influence vowel production in second language learning, including AoA, LoR, L2 and general education, L2 perception, and orthography. Vowel production will be examined through duration and formant frequency measurements and listener identification. The results will be analyzed in relation to educational background and language use. Among the educational factors examined are general education level, English education (in their native land and/or New York City), and sound-annotating system experiences in Mandarin (Pinyin or Zhuyin). The language-use factors include AoA, LoR, language spoken at work and at home, and perception of English vowels. The hypotheses addressed include: (1) educational background, language use, and sound-annotating system experiences in Mandarin all influence L2 English speakers perception and production of English vowels; (2) the more accurately an L2 listener discriminates a vowel contrast, the more distinctly he/she produces that contrast.

  17. Listeria monocytogenes LO28: Surface Physicochemical Properties and Ability To Form Biofilms at Different Temperatures and Growth Phases

    PubMed Central

    Chavant, Patrick; Martinie, Brigitte; Meylheuc, Thierry; Bellon-Fontaine, Marie-Noëlle; Hebraud, Michel

    2002-01-01

    The surface physicochemical properties of Listeria monocytogenes LO28 under different conditions (temperature and growth phase) were determined by use of microelectrophoresis and microbial adhesion to solvents. The effect of these parameters on adhesion and biofilm formation by L. monocytogenes LO28 on hydrophilic (stainless steel) and hydrophobic (polytetrafluoroethylene [PTFE]) surfaces was assessed. The bacterial cells were always negatively charged and possessed hydrophilic surface properties, which were negatively correlated with growth temperature. The colonization of the two surfaces, monitored by scanning electron microscopy, epifluorescence microscopy, and cell enumeration, showed that the strain had a great capacity to colonize both surfaces whatever the incubation temperature. However, biofilm formation was faster on the hydrophilic substratum. After 5 days at 37 or 20°C, the biofilm structure was composed of aggregates with a three-dimensional shape, but significant detachment took place on PTFE at 37°C. At 8°C, only a bacterial monolayer was visible on stainless steel, while no growth was observed on PTFE. The growth phase of bacteria used to inoculate surfaces had a significant effect only in some cases during the first steps of biofilm formation. The surface physicochemical properties of the strain are correlated with adhesion and surface colonization. PMID:11823213

  18. A Passive Thermal Carrier (LoTEC(c )) for Temperature Sensitive Materials Being Moved to and From ISS and for Shuttle (STS) Flights

    NASA Astrophysics Data System (ADS)

    Wessling, F. C.; Blackwood, J. M.; Holt, H. R.

    2002-01-01

    the use of power for transporting temperature sensitive materials to and from the International Space Station. LoTEC uses a combination of high thermal resistance insulation, careful thermal design and phase change materials to maintain temperature. It has been tested with phase change materials for three different interior temperatures (-16C, 0C, +4C). These temperatures are usable for preservation of many biological materials during transport. The exterior dimensions of LoTEC are approximately 250.7 x 436.9 x 514.1 mm. Thus, LoTEC fits into a standard mid-deck locker, an Express Rack, a SpaceHab rack or a rack in the Multi-Purpose Logistics Module (MPLM). LoTEC has an empty mass of approximately 9.6 kg and an internal volume of 22 Liters. This volume is reduced by the amount and type of phase change material (PCM) used. For example, eight kg of water ice and its containers would take up approximately half of the internal volume, leaving 11 Liters of space for the payload. Several different configurations have been considered to accommodate different payload dimensions.The interior dimensions of LoTEC are approximately 406 x 343 x 158 mm. Measured energy gain by LoTEC is approximately 0.14 watts per degrees Celsius. Performance data in the form of temperature versus time curves are included. Eight kg of PCM gives approximately eight days of constant temperature at typical STS interior temperatures. The temperature distribution in LoTEC is dependent on the PCM containers, the PCM used, and the location of the containers in LoTEC. Small, stand-alone data loggers record the temperatures. Refreezing of phase change materials depends on the facilities on board the ISS or the STS. Various methods of refreezing of phase change materials on the ISS are discussed.

  19. Investigation of lightweight designs and materials for LO2 and LH2 propellant tanks for space vehicles, phase 2 and phase 3

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Full size Tug LO2 and LH2 tank configurations were defined, based on selected tank geometries. These configurations were then locally modeled for computer stress analysis. A large subscale test tank, representing the selected Tug LO2 tank, was designed and analyzed. This tank was fabricated using procedures which represented production operations. An evaluation test program was outlined and a test procedure defined. The necessary test hardware was also fabricated.

  20. Overexpression of molecular chaperons GRP78 and GRP94 in CD44hi/CD24lo breast cancer stem cells

    PubMed Central

    Nami, Babak; Ghasemi-Dizgah, Armin; Vaseghi, Akbar

    2016-01-01

    Introduction: Breast cancer stem cell with CD44hi/CD24lo phonotype is described having stem cell properties and represented as the main driving factor in breast cancer initiation, growth, metastasis and low response to anti-cancer agents. Glucoseregulated proteins (GRPs) are heat shock protein family chaperons that are charged with regulation of protein machinery and modulation of endoplasmic reticulum homeostasis whose important roles in stem cell development and invasion of various cancers have been demonstrated. Here, we investigated the expression levels of GRP78 and GRP94 in CD44hi/CD24lo phenotype breast cancer stem cells (BCSCs). Methods: MCF7, T-47D and MDA-MB-231 breast cancer cell lines were used. CD44hi/CD24lo phenotype cell population were analyzed and sorted by fluorescence-activated cell sorting (FACS). Transcriptional and translational expression of GRP78 and GRP94 were investigated by western blotting and quantitative real time PCR. Results: Results showed different proportion of CD44hi/CD24lo phenotype cell population in their original bulk cells. The ranking of the cell lines in terms of CD44hi/CD24lo phenotype cell population was as MCF7lo phenotype cells exhibited higher mRNA and protein expression level of GRP78 and GRP94 compared to their original bulk cells. Conclusion: Our results show a relationship between overexpression of GRP78 and GRP94 and exhibiting CD44hi/CD24lo phenotype in breast cancer cells. We conclude that upregulation of GRPs may be an important factor in the emergence of CD44hi/CD24lo phenotype BCSCs features. PMID:27525228

  1. [Rousseau on the couch. "La nouvelle Héloïse as a key to his childhood trauma].

    PubMed

    Niemeyer, C

    1993-05-01

    Whereas many interpreters and biographers of Rousseau tend to present their subject as a pathological figure, Niemeyer will have no truck with such ascriptions. His reading of Rousseau's epistolary novel Julie ou la Nouvelle Héloïse (1761) draws upon the autobiographical Confessions and reveals that Rousseau uses this novel as a species of self-therapy. In the novel the constellations in which certain scenes recur invite their interpretation as complementary scenes to Rousseau's traumatic "Urszene"--the death of his mother when giving birth to him. In Niemeyer's view, the way in which Rousseau turns his re-working of his childhood trauma to literary account qualifies him as a predecessor of psychoanalysis. PMID:8511325

  2. ‘Introducing Michael Gove to Loïc Wacquant’: Why Social Work Needs Critical Sociology

    PubMed Central

    Michael Garrett, Paul

    2016-01-01

    In 2013, Michael Gove, then Secretary of State for Education and Health in the UK coalition government, criticised social workers for laying insufficient emphasis on the ‘agency’ of individuals and for being too preoccupied with social and economic inequalities. Such a perspective, which is not unique to Gove, needs to be countered by reaffirming the significance of an expansively critical sociology for social work. In this context, the thematic concerns of the French theorist, Loïc Wacquant, illuminates key aspects of social work engagement with clients which Gove and his ideological associates appear intent on ignoring. The issues raised have significant political resonances given the pending UK General Election taking place in May 2015. PMID:27559203

  3. Modelling and simulation of passive Lab-on-a-Chip (LoC) based micromixer for clinical application

    NASA Astrophysics Data System (ADS)

    Saikat, Chakraborty; Sharath, M.; Srujana, M.; Narayan, K.; Pattnaik, Prasant Kumar

    2016-03-01

    In biomedical application, micromixer is an important component because of many processes requires rapid and efficient mixing. At micro scale, the flow is Laminar due to small channel size which enables controlled rapid mixing. The reduction in analysis time along with high throughput can be achieved with the help of rapid mixing. In LoC application, micromixer is used for mixing of fluids especially for the devices which requires efficient mixing. Micromixer of this type of microfluidic devices with a rapid mixing is useful in application such as DNA/RNA synthesis, drug delivery system & biological agent detection. In this work, we design and simulate a microfluidic based passive rapid micromixer for lab-on-a-chip application.

  4. A green laser at 517 nm based on intracavity frequency doubling of the diode-pumped Yb:LO laser

    NASA Astrophysics Data System (ADS)

    Li, Yong-liang; Li, Xiu-fei; Hu, Hong-wei; Hai, Xiao-quan; Liu, Yang; Wang, Jin-nan

    2014-09-01

    We report for the first time, to our knowledge, the diode-pumped continuous-wave (CW) thin-disk Yb3+-doped Lu2O3 (Yb:LO) laser at 1 034 nm and the second-harmonic generation at 517 nm. With a 6.3% output coupler, the maximum output power is 1.17 W under a pump power of 18.5 W. Moreover, the intracavity second-harmonic generation (SHG) is also achieved with power of 193 mW at 517 nm by using an LiB3O5 (LBO) nonlinear crystal. The beam quality factor M 2 is about 1.28. The fluctuation of the output power is about 3% in 1 h.

  5. Preliminary base heating environments for a generalized ALS LO2/LH2 launch vehicle, appendix 1 and 2

    NASA Technical Reports Server (NTRS)

    Bender, Robert L.; Reardon, John E.

    1989-01-01

    A secondary objective of contract NAS8-39141 is to provide base heating assessments, as required, to support Advanced Launch System (ALS) preliminary launch vehicle and propulsion system design studies. The ALS propulsion systems integration working group meeting (No. 3) recently completed in San Diego, California, focused attention on the need for base heating environment determination to provide preliminary requirements for LO2/LH2 propulsion systems currently being considered for ALS. We were requested to provide these environments for a range of possible propellant mixture and nozzle area ratios. Base heating environments can only be determined as a function of altitude when the engine operating conditions and vehicle base region geometry (engine arrangement) are known. If time dependent environments are needed to assess thermal loads, a trajectory must also be provided. These parameters are not fixed at this time since the ALS configurations and propulsion operating conditions are varied and continue to be studied by Phase B contractors. Therefore, for this study, a generalized LO2/LH2 system was selected along with a vehicle configuration consisting of a seven-engine booster and a three-engine core. MSFC provided guidance for the selection. We also selected a limited number of body points on the booster and core vehicles and engines for the environment estimates. Environments at these locations are representative of maximum heating conditions in the base region and are provided as a function of altitude only. Guidelines and assumptions for this assessment, methodology for determining the environments, and preliminary results are provided in this technical note. Refinements in the environments will be provided as the ALS design matures.

  6. Doppler imaging of the young late-type star LO Pegasi (BD+22°4409) in 2003 September

    NASA Astrophysics Data System (ADS)

    Piluso, N.; Lanza, A. F.; Pagano, I.; Lanzafame, A. C.; Donati, J.-F.

    2008-06-01

    A Doppler image of the zero-age main-sequence (ZAMS) late-type rapidly rotating star LO Pegasi, based on spectra acquired between 2003 September 12 and 15 is presented. The least-squares deconvolution technique is applied to enhance the signal-to-noise ratio of the mean rotational broadened line profiles extracted from the observed spectra. In the present application, an unbroadened spectrum is used as a reference, instead of a simple line list, to improve the deconvolution technique applied to extract the mean profiles. The reconstructed image is similar to those previously obtained from observations taken in 1993 and 1998, and shows that LO Peg photospheric activity is dominated by high-latitude spots with a non-uniform polar cap. The latter seems to be a persistent feature as it has been observed since 1993 with little modifications. Small spots, observed between ~10° and ~60° of latitude, appears to be different with respect to those present in the 1993 and 1998 maps. Based on observations made with the Italian Telescopio Nazionale Galileo operated on the island of La Palma by the Centro Galileo Galilei of INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque del los Muchachos of the Instituto de Astrofísica de Canarias. E-mail: nicolo.piluso@oact.inaf.it (NP); nuccio.lanza@oact.inaf.it (AFL); isabella.pagano@oact.inaf.it (IP); alessandro.lanzafame@oact.inaf.it (ACL); donati@ast.obs-mip.fr (J-FD)

  7. Evaluation of imaging performance of a taper optics CCD; FReLoN' camera designed for medical imaging.

    PubMed

    Coan, Paola; Peterzol, Angela; Fiedler, Stefan; Ponchut, Cyril; Labiche, Jean Claude; Bravin, Alberto

    2006-05-01

    The purpose of this work was to assess the imaging performance of an indirect conversion detector (taper optics CCD; FReLoN' camera) in terms of the modulation transfer function (MTF), normalized noise power spectrum (NNPS) and detective quantum efficiency (DQE). Measurements were made with a synchrotron radiation laminar beam at various monochromatic energies in the 20-51.5 keV range for a gadolinium-based fluorescent screen varying in thickness; data acquisition and analysis were made by adapting to this beam geometry protocols used for conventional cone beams. The pre-sampled MTFs of the systems were measured using an edge method. The NNPS of the systems were determined for a range of exposure levels by two-dimensional Fourier analysis of uniformly exposed radiographs. The DQEs were assessed from the measured MTF, NNPS, exposure and incoming number of photons. The MTF, for a given screen, was found to be almost energy independent and, for a given energy, higher for the thinnest screen. At 33 keV and for the 40 (100) microm screen, at 10% the MTF is 9.2 (8.6) line-pairs mm(-1). The NNPS was found to be different in the two analyzed directions in relation to frequency. Highest DQE values were found for the combination 100 microm and 25 keV (0.5); it was still equal to 0.4 at 51.5 keV (above the gadolinium K-edge). The DQE is limited by the phosphor screen conversion yield and by the CCD efficiency. At the end of the manuscript the results of the FReLoN characterization and those from a selected number of detectors presented in the literature are compared. PMID:16645252

  8. Simulating the Compton-Getting effect for hydrogen flux measurements: Implications for IBEX-Hi and -Lo observations

    SciTech Connect

    Zirnstein, E. J.; Heerikhuisen, J.; McComas, D. J.; Schwadron, N. A.

    2013-12-01

    The Interstellar Boundary EXplorer (IBEX), launched in 2008 October, has improved our understanding of the solar wind-local interstellar medium interaction through its detection of neutral atoms, particularly that of hydrogen (H). IBEX is able to create full maps of the sky in six-month intervals as the Earth orbits the Sun, detecting H with energies between ∼0.01 and 6 keV. Due to the relative motion of IBEX to the solar inertial frame, measurements made in the spacecraft frame introduce a Compton-Getting (CG) effect, complicating measurements at the lowest energies. In this paper we provide results from a numerical simulation that calculates fluxes of H atoms at 1 AU in the inertial and spacecraft frames (both ram and anti-ram), at energies relevant to IBEX-Hi and -Lo. We show theory behind the numerical simulations, applying a simple frame transformation to derived flux equations that provides a straightforward way to simulate fluxes in the spacecraft frame. We then show results of H energetic neutral atom fluxes simulated at IBEX-Hi energy passbands 2-6 in all frames, comparing with IBEX-Hi data along selected directions, and also show results simulated at energies relevant to IBEX-Lo. Although simulations at IBEX-Hi energies agree reasonably well with the CG correction method used for IBEX-Hi data, we demonstrate the importance of properly modeling low energy H fluxes due to inherent complexities involved with measurements made in moving frames, as well as dynamic radiation pressure effects close to the Sun.

  9. Observation of the distribution of heavy neutral atoms in the IBEX-Lo all-sky maps

    NASA Astrophysics Data System (ADS)

    Park, J.; Kucharek, H.; Moebius, E.

    2014-12-01

    We investigate the spatial distribution of heavy energetic neutral atoms, mostly oxygen and neon, in the sky maps taken with the Interstellar Boundary Explorer (IBEX) in 2009 - 2011. The IBEX-Lo sensor, one of two highly sensitive single-pixel cameras on the IBEX spacecraft, measures neutral particles within an energy range from 0.01 to 2 keV. In the time-of-flight detector of IBEX-Lo these neutral atoms can be identified as hydrogen or heavier atoms, such as oxygen. These measurements have provided all-sky maps of neutral hydrogen and oxygen. The dominant feature in these maps is the interstellar oxygen and neon gas flow. Its peak location is approximately consistent with the interstellar helium gas flow (Möbius et al., 2009, Science, 326, 969). The flow distribution is distributed over 210° - 240° ecliptic longitude and -6° - 12° ecliptic latitude. Another prominent feature in the oxygen sky maps at 0.2 to 0.8 keV is an extended tail of the oxygen signal toward lower longitude and higher positive latitude (180° - 210° ecliptic longitude and 0° - 24° ecliptic latitude). The measured peak rates in the extended tail is 3 - 5% of the maximum count rate in the primary oxygen and neon gas flow, but is four times higher than any other surrounding oxygen signals. The extended tail may indicate the secondary component of the interstellar oxygen, which is likely generated by charge exchange between local O+ ions and interstellar neutral H in the outer heliosheath. In this poster, we will discuss these two most prominent features in the oxygen sky maps and their implications for the source and the mechanism generating an extended tail in the oxygen signal.

  10. Experimental Investigation of Augmented Spark Ignition of a LO2/LCH4 Reaction Control Engine at Altitude Conditions

    NASA Technical Reports Server (NTRS)

    Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

    2012-01-01

    The use of nontoxic propellants in future exploration vehicles would enable safer, more cost-effective mission scenarios. One promising green alternative to existing hypergols is liquid methane (LCH4) with liquid oxygen (LO2). A 100 lbf LO2/LCH4 engine was developed under the NASA Propulsion and Cryogenic Advanced Development project and tested at the NASA Glenn Research Center Altitude Combustion Stand in a low pressure environment. High ignition energy is a perceived drawback of this propellant combination; so this ignition margin test program examined ignition performance versus delivered spark energy. Sensitivity of ignition to spark timing and repetition rate was also explored. Three different exciter units were used with the engine s augmented (torch) igniter. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks. This suggests that rising pressure and flow rate increase spark impedance and may at some point compromise an exciter s ability to complete each spark. The reduced spark energies of such quenched deliveries resulted in more erratic ignitions, decreasing ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1 to 6 mJ, though multiple, similarly timed sparks of 55 to 75 mJ were required for reliable ignition. Delayed spark application and reduced spark repetition rate both correlated with late and occasional failed ignitions. An optimum time interval for spark application and ignition therefore coincides with propellant introduction to the igniter.

  11. MicroRNA-674-5p/5-LO axis involved in autoimmune reaction of Concanavalin A-induced acute mouse liver injury.

    PubMed

    Su, Kunkai; Wang, Qi; Qi, Luoyang; Hua, Dasong; Tao, Jingjing; Mangan, Connor J; Lou, Yijia; Li, Lanjuan

    2016-09-01

    Autoimmune hepatitis is characterized, in part, by the pathways involving cysteinyl-leukotriene metabolites of arachidonic acid, the dynamics of which remain unclear. Here, we explored post-transcriptional regulation in the 5-lipoxygenase (5-LO) pathway of arachidonic acid in a Concanavalin A (Con A) induced mouse model. We found that Con A administration lead to 5-LO overexpression and cysteinyl-leukotriene release in early hepatic injury, which was attenuated by cyclosporin A pretreatment. Subsequent microarray and qRT-PCR analysis further showed that microRNA-674-5p (miR-674-5p) displayed a significant decrease in expression in Con A-damaged liver. Noting that miR-674-5p harbors a potential binding region for 5-LO, we further transfected hepatic cell lines with overexpressing miR-674-5p mimic and discovered a negative regulating effect of miR-674-5p on 5-LO expression in the presence of IL-6 or TNF-α. These findings suggest that miR-674-5p might be a negative regulator in 5-LO mediated autoimmune liver injury, representing a compelling avenue towards future therapeutic interventions. PMID:27313091

  12. Segregative clustering of Lo and Ld membrane microdomains induced by local pH gradients in GM1-containing giant vesicles: a lipid model for cellular polarization.

    PubMed

    Staneva, Galya; Puff, Nicolas; Seigneuret, Michel; Conjeaud, Hélène; Angelova, Miglena I

    2012-11-27

    Several cell polarization processes are coupled to local pH gradients at the membrane surface. We have investigated the involvement of a lipid-mediated effect in such coupling. The influence of lateral pH gradients along the membrane surface on lipid microdomain dynamics in giant unilamellar vesicles containing phosphatidylcholine, sphingomyelin, cholesterol, and the ganglioside GM1 was studied. Lo/Ld phase separation was generated by photosensitization. A lateral pH gradient was established along the external membrane surface by acid local microinjection. The gradient promotes the segregation of microdomains: Lo domains within an Ld phase move toward the higher pH side, whereas Ld domains within an Lo phase move toward the lower pH side. This results in a polarization of the vesicle membrane into Lo and Ld phases poles in the axis of the proton source. A secondary effect is inward tubulation in the Ld phase. None of these processes occurs without GM1 or with the analog asialo-GM1. These are therefore related to the acidic character of the GM1 headgroup. LAURDAN fluorescence experiments on large unilamellar vesicles indicated that, with GM1, an increase in lipid packing occurs with decreasing pH, attributed to the lowering of repulsion between GM1 molecules. Packing increase is much higher for Ld phase vesicles than for Lo phase vesicles. It is proposed that the driving forces for domain vectorial segregative clustering and vesicle polarization are related to such differences in packing variations with pH decrease between the Lo and Ld phases. Such pH-driven domain clustering might play a role in cellular membrane polarization processes in which local lateral pH gradients are known to be important, such as migrating cells and epithelial cells. PMID:23121205

  13. Karhunen-Loève treatment to remove noise and facilitate data analysis in sensing, spectroscopy and other applications.

    PubMed

    Zaharov, V V; Farahi, R H; Snyder, P J; Davison, B H; Passian, A

    2014-11-21

    Resolving weak spectral variations in the dynamic response of materials that are either dominated or excited by stochastic processes remains a challenge. Responses that are thermal in origin are particularly relevant examples due to the delocalized nature of heat. Despite its inherent properties in dealing with stochastic processes, the Karhunen-Loève expansion has not been fully exploited in measurement of systems that are driven solely by random forces or can exhibit large thermally driven random fluctuations. Here, we present experimental results and analysis of the archetypes (a) the resonant excitation and transient response of an atomic force microscope probe by the ambient random fluctuations and nanoscale photothermal sample response, and (b) the photothermally scattered photons in pump-probe spectroscopy. In each case, the dynamic process is represented as an infinite series with random coefficients to obtain pertinent frequency shifts and spectral peaks and demonstrate spectral enhancement for a set of compounds including the spectrally complex biomass. The considered cases find important applications in nanoscale material characterization, biosensing, and spectral identification of biological and chemical agents. PMID:25252650

  14. Local coupling (LoCo) vs. large-scale coupled (LsCo) land-atmosphere interactions in idealized experiments

    NASA Astrophysics Data System (ADS)

    Gentine, P.; Lintner, B. R.; Findell, K. L.; Rochetin, N.; Sobel, A. H.; Anber, U. M.

    2014-12-01

    We will present two idealized epxeriments/methodologies to investigate local (LoCo) and large-scale (LsCo) coupling between the surface and the atmsophere: the contiental Radiative-Convective Equilibrium (RCE) and the continental Weak Temperature Gradient (WTG). The RCE defines an equilibrium state of coupling between the surafce and the atmosphere isolated from any large-scale dependence, which were investigated within the single column model of the Laboratoire de Meteorologie Dynamique (LMD) coupled to a simple bucket land model. This studies emphasizes the role of low-level cloud and the diurnal cylce of the boundary layer on the final state of the system. In the WTG we investigate the coupling between the surface and the atmosphere during the dry and wet season of the Amazon with the WRF model coupled to the NOAH land-surface model. Large-scale coupling is obtained with the WTG. The dry and wet season demonstrate very fundamental behavior: in the dry season deep convection is generated by radiative cooling in the higher troposhere and is disconnected from the surface. In the wet season the coupling between the surface and the atmosphere is much tighter. We suggest that the WTG is a powerful tool to investigate the coupling between the surface and the atmosphere, which solves two major issues: the limited resolution of convection in GCMs and the lack of large-scale coupling in CRM. Later investigation will look at the effect of deforestation, water table and distance from the ocean.

  15. Analysis of 100-lb(sub f) (445-N) LO2-LCH4 Reaction Control Engine Impulse Bit Performance

    NASA Technical Reports Server (NTRS)

    Marshall, William M.; Klenhenz, Julie E.

    2012-01-01

    Recently, liquid oxygen-liquid methane (LO2-LCH4) has been considered as a potential green propellant alternative for future exploration missions. The Propulsion and Cryogenic Advanced Development (PCAD) project was tasked by NASA to develop this propulsion combination to enable safe and cost-effective exploration missions. To date, limited experience with such combinations exist, and as a result a comprehensive test program is critical to demonstrating with the viability of implementing such a system. The NASA Glenn Research Center conducted a test program of a 100-lbf (445-N) reaction control engine (RCE) at the Center s Altitude Combustion Stand (ACS), focusing on altitude testing over a wide variety of operational conditions. The ACS facility includes unique propellant conditioning feed systems (PCFS), which allow precise control of propellant inlet conditions to the engine. Engine performance as a result of these inlet conditions was examined extensively during the test program. This paper is a companion to the previous specific impulse testing paper, and discusses the pulsed-mode operation portion of testing, with a focus on minimum impulse bit (MIB) and repeatable pulse performance. The engine successfully demonstrated target MIB performance at all conditions, as well as successful demonstration of repeatable pulse widths. Some anomalous conditions experienced during testing are also discussed, including a double pulse phenomenon, which was not noted in previous test programs for this engine.

  16. Spectral Line Measurements in Exceptionally Low SNR Achieved by Virtue of the KLT (Karhunen-Loève Transform)

    NASA Astrophysics Data System (ADS)

    Maccone, C.; Pluchino, S.; Schillirò, F.

    2009-12-01

    A little-known tool for spectral line measurements is the KLT (Karhunen-Loève Transform). This mathematical algorithm is superior to the classical FFT in that: 1) The KLT can filter signals out of the background noise over both wide and narrow bands. On the contrary, the FFT rigorously applies to narrow-band signals only. 2) The KLT can be applied to random functions that are non-stationary in time, i.e. whose autocorrelation is a function of the two independent variables t1 and t2 separately. Again, this is a sheer advantage of the KLT over the FFT, since the FFT rigorously applies to stationary processes only, i.e. when the autocorrelation is a function of the absolute value of the difference of t1 and t2. 3) The KLT can detect signals embedded in noise to unbelievably small values of the Signal-to-Noise Ratio (SNR), like 10-3 or so. This particular feature of the KLT is described in detail in this paper.

  17. Nonlinear Analysis of the Space Shuttle Superlightweight LO2 Tank. Part 2; Behavior Under 3g End-of-Flight Loads

    NASA Technical Reports Server (NTRS)

    Nemeth, Michael P.; Young, Richard D.; Collins, Timothy J.; Starnes, James H.,Jr.

    1998-01-01

    Results of linear bifurcation and nonlinear analyses of the Space Shuttle super lightweight (SLWT) external liquid-oxygen (LO2) tank are presented for an important end-of-flight loading condition. These results illustrate an important type of response mode for thin-walled shells, that are subjected to combined mechanical and thermal loads, that may be encountered in the design of other liquid-fuel launch vehicles. Linear bifurcation analyses are presented that predict several nearly equal eigenvalues that correspond to local buckling modes in the aft dome of the LO2 tank. In contrast, the nonlinear response phenomenon is shown to consist of a short-wavelength bending deformation in the aft elliptical dome of the LO2 tank that grows in amplitude in a stable manner with increasing load. Imperfection sensitivity analyses are presented that show that the presence of several nearly equal eigenvalues does not lead to a premature general instability mode for the aft dome. For the linear bifurcation and nonlinear analyses, the results show that accurate predictions of the response of the shell generally require a large-scale, high fidelity finite-element model. Results are also presented that show that the SLWT LO2 tank can support loads in excess of approximately 1.9 times the values of the operational loads considered.

  18. The Design of the Low Frequency All Sky Monitor (LoFASM) for the Study of Radio Transients and Student Training

    NASA Astrophysics Data System (ADS)

    Jenet, Fredrick; Cohen, S.; Dartez, L. P.; Ford, A.; Garcia, A.; Hinojosa, J.; Longoria, C.; Lunsford, G.; Mata, A.; Miller, R. B.; Reser, J.; Rivera, J.; Stovall, K.; Creighton, T. D.; Hicks, B.; Price, R. H.; Taylor, G. B.

    2013-01-01

    The Astronomy and Astrophysics Decadal Survey (Astro2010) identified transient science and time-domain studies as one of the most promising discovery areas of the coming decade. The Low Frequency All Sky Monitor (LoFASM) is a new distributed radio array designed specifically to search for and to study transient radio phenomena in the 5-88 MHz frequency range. LoFASM consists of four stations, each made up of 12 cross dipole-antennas. The stations were constructed by undergraduates at the University of Texas at Brownsville's Center for Advanced Radio Astronomy. LoFASM utilizes the same antennas and front-end electronics developed for the Long Wavelength Array (LWA) project by the Naval Research Laboratory. The stations are located at Port Mansfield, Texas, the LWA North Arm site of the LWA1 Radio Observatory in New Mexico, the Green Bank Radio Observatory, West Virginia, and NASA's Goldstone tracking center in California. Having the stations in these geographically distinct regions allows for the immediate discrimination between bonafide astronomical transient events and radio frequency interference. In this presentation, we will give an overview of LoFASM's design and capabilities as well as the project's primary scientific objectives

  19. 76 FR 50152 - Airworthiness Directives; Lycoming Engines (L)O-360, (L)IO-360, AEIO-360, O-540, IO-540, AEIO-540...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-12

    ...-14778 (71 FR 57407, September 29, 2006), for Lycoming Engines (L)O-360, (L)IO-360, AEIO-360, O-540, IO... 12866, (2) Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034...-09, Amendment 39-14778 (71 FR 57407, September 29, 2006), and adding the following new AD:...

  20. Representations of Mexican American Migrant Childhood in Rivera's "...y no se lo trago la tierra" and Viramontes's "Under the Feet of Jesus"

    ERIC Educational Resources Information Center

    Beck, Scott A.; Rangel, Dolores E.

    2009-01-01

    This article gives an analysis of two books: Thomas Rivera's "...y no se lo trago la tierra" and Helena Maria Viramontes's "Under the Feet of Jesus". The two books are strong and important literary texts that stand in close relation to each other. Both texts treat the subject of migrant childhood by affirming central themes of Chicano literature.…

  1. Sea-Level Flight Demonstration and Altitude Characterization of a LO2/LCH4 Based Accent Propulsion Lander

    NASA Technical Reports Server (NTRS)

    Collins, Jacob; Hurlbert, Eric; Romig, Kris; Melcher, John; Hobson, Aaron; Eaton, Phil

    2009-01-01

    A 1,500 lbf thrust-class liquid oxygen (LO2)/Liquid Methane (LCH4) rocket engine was developed and tested at both sea-level and simulated altitude conditions. The engine was fabricated by Armadillo Aerospace (AA) in collaboration with NASA Johnson Space Center. Sea level testing was conducted at Armadillo Aerospace facilities at Caddo Mills, TX. Sea-level tests were conducted using both a static horizontal test bed and a vertical take-off and landing (VTOL) test bed capable of lift-off and hover-flight in low atmosphere conditions. The vertical test bed configuration is capable of throttling the engine valves to enable liftoff and hover-flight. Simulated altitude vacuum testing was conducted at NASA Johnson Space Center White Sands Test Facility (WSTF), which is capable of providing altitude simulation greater than 120,000 ft equivalent. The engine tests demonstrated ignition using two different methods, a gas-torch and a pyrotechnic igniter. Both gas torch and pyrotechnic ignition were demonstrated at both sea-level and vacuum conditions. The rocket engine was designed to be configured with three different nozzle configurations, including a dual-bell nozzle geometry. Dual-bell nozzle tests were conducted at WSTF and engine performance data was achieved at both ambient pressure and simulated altitude conditions. Dual-bell nozzle performance data was achieved over a range of altitude conditions from 90,000 ft to 50,000 ft altitude. Thrust and propellant mass flow rates were measured in the tests for specific impulse (Isp) and C* calculations.

  2. Establishing an Appropriate Level of Detail (LoD) for a Building Information Model (BIM) - West Block, Parliament Hill, Ottawa, Canada

    NASA Astrophysics Data System (ADS)

    Fai, S.; Rafeiro, J.

    2014-05-01

    In 2011, Public Works and Government Services Canada (PWGSC) embarked on a comprehensive rehabilitation of the historically significant West Block of Canada's Parliament Hill. With over 17 thousand square meters of floor space, the West Block is one of the largest projects of its kind in the world. As part of the rehabilitation, PWGSC is working with the Carleton Immersive Media Studio (CIMS) to develop a building information model (BIM) that can serve as maintenance and life-cycle management tool once construction is completed. The scale and complexity of the model have presented many challenges. One of these challenges is determining appropriate levels of detail (LoD). While still a matter of debate in the development of international BIM standards, LoD is further complicated in the context of heritage buildings because we must reconcile the LoD of the BIM with that used in the documentation process (terrestrial laser scan and photogrammetric survey data). In this paper, we will discuss our work to date on establishing appropriate LoD within the West Block BIM that will best serve the end use. To facilitate this, we have developed a single parametric model for gothic pointed arches that can be used for over seventy-five unique window types present in the West Block. Using the AEC (CAN) BIM as a reference, we have developed a workflow to test each of these window types at three distinct levels of detail. We have found that the parametric Gothic arch significantly reduces the amount of time necessary to develop scenarios to test appropriate LoD.

  3. The KLT (Karhunen-Loève Transform) to extend SETI searches to broad-band and extremely feeble signals

    NASA Astrophysics Data System (ADS)

    Maccone, Claudio

    2010-12-01

    The KLT (acronym for Karhunen-Loève Transform) is a mathematical algorithm superior to the classical FFT in many regards: The KLT can filter signals out of the background noise over both wide and narrow bands. This is in sharp contrast to the FFT that rigorously applies to narrow-band signals only. The KLT can be applied to random functions that are non-stationary in time, i.e. whose autocorrelation is a function of the two independent variables t1 and t2 separately. Again, this is a sheer advantage of the KLT over the FFT, inasmuch as the FFT rigorously applies to stationary processes only, i.e. processes whose autocorrelation is a function of the absolute value of the difference of t1 and t2 only. The KLT can detect signals embedded in noise to unbelievably small values of the Signal-to-Noise Ratio (SNR), like 10 -3 or so. This particular feature of the KLT is studied in detail in this paper. An excellent filtering algorithm like the KLT, however, comes with a cost that one must be ready to pay for especially in SETI: its computational burden is much higher than for the FFT. In fact, it can be shown that no fast KLT transform can possibly exist and, for an autocorrelation matrix of size N, the calculations must be of the order of N2, rather than N log( N). Nevertheless, for moderate values of N (in the hundreds), the KLT dominates over the FFT, as shown by the numerical simulations. Finally, an important and recent (2007-2008) development in the KLT theory, called the "Bordered Autocorrelation Method" (BAM), is presented. This BAM-KLT method gets around the difficulty of the N2 brunt calculations and ends up in the following unexpected theorem: the KLT of a feeble sinusoidal carrier embedded into a lot of white stationary noise is given by the Fourier transform of the derivative of the largest KLT eigenvalue with respect to the bordering index. This basic result is fully proved analytically in the final sections of this paper by virtue of a new theorem

  4. A New Titanosaurian Braincase from the Cretaceous "Lo Hueco" Locality in Spain Sheds Light on Neuroanatomical Evolution within Titanosauria.

    PubMed

    Knoll, Fabien; Witmer, Lawrence M; Ridgely, Ryan C; Ortega, Francisco; Sanz, Jose Luis

    2015-01-01

    Despite continuous improvements, our knowledge of the neurocranial anatomy of sauropod dinosaurs as a whole is still poor, which is especially true for titanosaurians even though their postcranial remains are common in many Upper Cretaceous sites worldwide. Here we describe a braincase from the uppermost Cretaceous locality of ''Lo Hueco" in Spain that is one of the most complete titanosaurian braincases found so far in Europe. Although the titanosaurian Ampelosaurus sp. is known from the same locality, this specimen is clearly a distinct taxon and presents a number of occipital characters found in Antarctosaurus and Jainosaurus, which are approximately coeval taxa from southern Gondwana. The specimen was subjected to X-ray computed tomographic (CT) scanning, allowing the generation of 3D renderings of the endocranial cavity enclosing the brain, cranial nerves, and blood vessels, as well as the labyrinth of the inner ear. These findings add considerable knowledge to the field of sauropod paleoneuroanatomy in general and titanosaurian endocast diversity in particular. Compared with that of many sauropodomorphs, the endocast appears only slightly flexed in lateral view and bears similarities (e.g., reduction of the rostral dural expansion) with Gondwanan titanosaurians such as Jainosaurus, Bonatitan, and Antarctosaurus. The vestibular system of the inner ear is somewhat contracted (i.e., the radius of the semicircular canals is small), but less so than expected in derived titanosaurians. However, as far as the new specimen and Jainosaurus can be contrasted, and with the necessary caution due to the small sample of comparative data currently available, the two taxa appear more similar to one another in endocast morphology than to other titanosaurians. Recent phylogenetic analyses of titanosaurians have not included virtually any of the taxa under consideration here, and thus the phylogenetic position of the new Spanish titanosaurian--even its generic, let alone

  5. Bile Stress Response in Listeria monocytogenes LO28: Adaptation, Cross-Protection, and Identification of Genetic Loci Involved in Bile Resistance

    PubMed Central

    Begley, Máire; Gahan, Cormac G. M.; Hill, Colin

    2002-01-01

    Bile is one of many barriers that Listeria monocytogenes must overcome in the human gastrointestinal tract in order to infect and cause disease. We demonstrated that stationary-phase cultures of L. monocytogenes LO28 were able to tolerate concentrations of bovine, porcine, and human bile and bile acids well in excess of those encountered in vivo. Strain LO28 was relatively bile resistant compared with other clinical isolates of L. monocytogenes, as well as with Listeria innocua, Salmonella enterica serovar Typhimurium LT2, and Lactobacillus sakei. While exponential-phase L. monocytogenes LO28 cells were exquisitely sensitive to unconjugated bile acids, prior adaptation to sublethal levels of bile acids or heterologous stresses, such as acid, heat, salt, or sodium dodecyl sulfate (SDS), significantly enhanced bile resistance. This adaptive response was independent of protein synthesis, and in the cases of bile and SDS adaptation, occurred in seconds. In order to identify genetic loci involved in the bile tolerance phenotype of L. monocytogenes LO28, transposon (Tn917) and plasmid (pORI19) integration banks were screened for bile-sensitive mutants. The disrupted genes included a homologue of the capA locus required for capsule formation in Bacillus anthracis; a gene encoding the transcriptional regulator ZurR; a homologue of an Escherichia coli gene, lytB, involved in isoprenoid biosynthesis; a gene encoding a homologue of the Bacillus subtilis membrane protein YxiO; and a gene encoding an amino acid transporter with a putative role in pH homeostasis, gadE. Interestingly, all of the identified loci play putative roles in maintenance of the cell envelope or in stress responses. PMID:12450822

  6. Bile stress response in Listeria monocytogenes LO28: adaptation, cross-protection, and identification of genetic loci involved in bile resistance.

    PubMed

    Begley, Máire; Gahan, Cormac G M; Hill, Colin

    2002-12-01

    Bile is one of many barriers that Listeria monocytogenes must overcome in the human gastrointestinal tract in order to infect and cause disease. We demonstrated that stationary-phase cultures of L. monocytogenes LO28 were able to tolerate concentrations of bovine, porcine, and human bile and bile acids well in excess of those encountered in vivo. Strain LO28 was relatively bile resistant compared with other clinical isolates of L. monocytogenes, as well as with Listeria innocua, Salmonella enterica serovar Typhimurium LT2, and Lactobacillus sakei. While exponential-phase L. monocytogenes LO28 cells were exquisitely sensitive to unconjugated bile acids, prior adaptation to sublethal levels of bile acids or heterologous stresses, such as acid, heat, salt, or sodium dodecyl sulfate (SDS), significantly enhanced bile resistance. This adaptive response was independent of protein synthesis, and in the cases of bile and SDS adaptation, occurred in seconds. In order to identify genetic loci involved in the bile tolerance phenotype of L. monocytogenes LO28, transposon (Tn917) and plasmid (pORI19) integration banks were screened for bile-sensitive mutants. The disrupted genes included a homologue of the capA locus required for capsule formation in Bacillus anthracis; a gene encoding the transcriptional regulator ZurR; a homologue of an Escherichia coli gene, lytB, involved in isoprenoid biosynthesis; a gene encoding a homologue of the Bacillus subtilis membrane protein YxiO; and a gene encoding an amino acid transporter with a putative role in pH homeostasis, gadE. Interestingly, all of the identified loci play putative roles in maintenance of the cell envelope or in stress responses. PMID:12450822

  7. Bio-guided isolation of the cytotoxic terpenoids from the roots of Euphorbia kansui against human normal cell lines L-O2 and GES-1.

    PubMed

    Zhang, Li; Gao, Lan; Li, Zhengjun; Yan, Xiaojing; Yang, Yanjing; Tang, Yuping; Cao, Yudan; Ding, Anwei

    2012-01-01

    The dried roots of Euphorbia kansui (kansui) have been used for centuries in China as a herbal medicine for edema, ascites, and asthma. The 95% ethanol extract showed a significant inhibition of cell proliferation against human normal cell lines L-O2 and GES-1. Bioassay-guided separation of the 95% ethanol extract from the roots of E. kansui led to the isolation of 12 diverse terpenoids whose structures were identified by (1)H, (13)C NMR spectroscopy and ESI-MS as kansuinine A (1), kansuinine B (2), kansuinine C (3), kansuiphorin C (4), 3-O-(2'E,4'Z-decadienoyl)-20-O-acetylingenol (5), 3-O-(2'E,4'Edecadienoyl)-20-O-acetylingenol (6), 3-O-(2'E,4'Z-decadienoyl)-20-deoxyingenol (7), 3-O-benzoyl-20-deoxyingenol (8), 5-O-benzoyl-20-deoxyingenol (9), kansenone (10), epi-kansenone (11), euphol (12). All these 12 terpernoids were evaluated in vitro for cytotoxicity on L-O2 and GES-1 cell lines. Most ingenane-type diterpenoids and 8-ene-7-one triterpenoids (5-11) exhibited a relatively lower IC(50) value; therefore, these compounds had stronger cytotoxicity against human normal cell lines L-O2 and GES-1 with dose-dependent relationships. These results will be significantly helpful to reveal the mechanism of toxicity of kansui and to effectively guide safer clinical application of this herb. PMID:23109850

  8. Bio-Guided Isolation of the Cytotoxic Terpenoids from the Roots of Euphorbia kansui against Human Normal Cell Lines L-O2 and GES-1

    PubMed Central

    Zhang, Li; Gao, Lan; Li, Zhengjun; Yan, Xiaojing; Yang, Yanjing; Tang, Yuping; Cao, Yudan; Ding, Anwei

    2012-01-01

    The dried roots of Euphorbia kansui (kansui) have been used for centuries in China as a herbal medicine for edema, ascites, and asthma. The 95% ethanol extract showed a significant inhibition of cell proliferation against human normal cell lines L-O2 and GES-1. Bioassay-guided separation of the 95% ethanol extract from the roots of E. kansui led to the isolation of 12 diverse terpenoids whose structures were identified by 1H, 13C NMR spectroscopy and ESI-MS as kansuinine A (1), kansuinine B (2), kansuinine C (3), kansuiphorin C (4), 3-O-(2′E,4′Z-decadienoyl)-20-O-acetylingenol (5), 3-O-(2′E,4′Edecadienoyl)-20-O-acetylingenol (6), 3-O-(2′E,4′Z-decadienoyl)-20-deoxyingenol (7), 3-O-benzoyl-20-deoxyingenol (8), 5-O-benzoyl-20-deoxyingenol (9), kansenone (10), epi-kansenone (11), euphol (12). All these 12 terpernoids were evaluated in vitro for cytotoxicity on L-O2 and GES-1 cell lines. Most ingenane-type diterpenoids and 8-ene-7-one triterpenoids (5–11) exhibited a relatively lower IC50 value; therefore, these compounds had stronger cytotoxicity against human normal cell lines L-O2 and GES-1 with dose-dependent relationships. These results will be significantly helpful to reveal the mechanism of toxicity of kansui and to effectively guide safer clinical application of this herb. PMID:23109850

  9. Flow of neutral interstellar helium into the heliosphere as inferred from IBEX-Lo observations and simulations

    NASA Astrophysics Data System (ADS)

    Bzowski, M.; Kubiak, M. A.; Hlond, M.; Moebius, E.; Leonard, T.; Heirtzler, D.; Kucharek, H.; Bochsler, P. A.; Schwadron, N. A.; Crew, G. B.; McComas, D. J.; Fuselier, S. A.

    2010-12-01

    Previously, a team coordinated through the International Space Science Institute (ISSI) examined direct neutral gas, pickup ion, and UV backscatter observations to produce consensus values for the inflow direction (λ, β), speed v, and temperature T of neutral interstellar helium from the Local Interstellar Cloud (LIC) with relatively small uncertainties. Since then, NASA’s Interstellar Boundary Explorer (IBEX) has started to provide new observations of the interstellar He flow in Earth orbit, with data currently available from the spring seasons of 2009 and 2010. Using a test-particle simulation to compute the spin-phase distributions that IBEX observes during each orbit, we optimize input LIC parameters to best fit the observations. The simulations take into account actual ionization rates as derived from solar EUV observations by SOHO CELIAS SEM, the OMNI solar wind data set, the positions and velocity vectors of the Earth during the actual integration intervals for each orbit, and the IBEX-Lo field-of-view. The simulations were performed on a grid of bulk flow vectors and temperatures, starting with the ISSI team consensus values based most heavily on Ulysses GAS observations (v = 26.4 km/s, T = 6318 K, and λ = 255.4o, β = -5.31o in J2000 coordinates). The Mach number of the flow derived from the IBEX observations is generally lower than derived from Ulysses measurements, which would be consistent with a higher temperature (up to 10 000 K) and/or a lower flow speed (down to ≈22.5 km/s) of the LIC. Based on these findings, the possible LIC parameter sets most probably lie within a narrow range between (λ = 255.4°, β = 5.3°, v = 26.4 km/s, M = 4.5 or T = 10,000 K) and (λ = 261.2°, β = 4.9, v = 23.05 km/s, M = 4.9, or T = 6300 K). At one end of the acceptable range, the parameters agree with the previous values except for the temperature, and at the other end, the temperatures agree, but the direction is different by almost 6° and the velocity is

  10. Measurement of NOx fluxes by eddy covariance from the BT tower, London during the ClearfLo project

    NASA Astrophysics Data System (ADS)

    Lee, James; Helfter, Carole; Nemitz, Eiko; Tremper, Anja; Stocker, Jenny; Carruthers, David

    2014-05-01

    The vast majority of air pollutants are emitted directly into the atmosphere from activities occurring at the Earth's surface. One of the key anthropogenic pollutants is NOx (defined as the sum of NO and NO2), which is emitted as a result of most anthropogenic combustion processes. Whilst the chemical reactions and atmospheric processing of NOx are reasonably well understood, and can be modelled with some skill, large uncertainties arise in models due to uncertainty associated with the rate of emissions. In recent years it has become clear that measured trends in certain pollutants, for example NO2, have not followed trends predicted by inventories. Continued exceedances of certain air pollution targets are of significant concern to governments, who have identified reducing this uncertainty associated with emissions as key evidence need. As part of the UK Natural Environment Research Council (NERC) Clean Air for London (ClearfLo) project, concentrations and fluxes of NOx were measured from the top of the BT tower, which is a 188m high telecommunications tower, situated in central London (51o31'17.4'N; 0o8'20.04W). The tower is surrounded by a mixture of commercial and residential buildings with an average height of 15 m. The typical daytime flux footprint of the tower is dominated by commercial/residential buildings and roads (82%) but also includes urban parkland (13%) and impervious ground (5%). High time resolution (10 Hz) chemiluminescence measurements of NO and NO2 (photolytic conversion to NO followed by chemiluminescence) were combined with fast turbulence measurements from a sonic anemometer to calculate fluxes using the eddy covariance technique. In brief, NOx fluxes per notional half-hourly averaging period were obtained by maximising the covariance between instantaneous (i.e. mean for the averaging period subtracted from each 10 Hz data point) fluctuations of NOx mixing ratio and vertical wind velocity. 24 hour NOx flux measurements were made on 36 days