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32822. Resonant period of free core nutation: its observed changes and excitations
- Creator:
- Jan Vondrák and Cyril Ron
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, Earth orientation, Free Core Nutation, space techniques, VLBI, 7, and 551
- Language:
- English
- Description:
- The motion of Earth’s spin axis in space is monitored by Very Long-Baseline Interferometry (VLBI), and since 1994 also its rate is measured by Global Positioning System (GPS). From the direct analysis of the combined VLBI/GPS solution in the interval 1994.3-2004.6 we recently found that the apparent period of the Retrograde Free Core Nutation (RFCN) grew from original 435 days to 460 days during the past ten years, but the resonance effects yielded a stable period of about 430 days. Now we repeat the same study with VLBI-only data, covering much longer interval (1982.4 - 2005.6). Direct analysis shows again a substantial increase of the apparent period during the last decade or so. The resonant period is given by internal structure of the Earth (mainly by the flattening of the core), so it is highly improbable that it is so much variable. From the same observations we derive corrections of certain nutation terms. A subsequent study of indirect determination of resonance RFCN period from the observed forced nutation terms through the resonance effects proves that the natural resonance period remains stable and is equal to 430.32±0.07 solar days. From this follows that an excitation by outer layers of the Earth (atmospheric, oceanic) should exist, with a terrestrial frequency close to that of RFCN (of about -1.0050 cycles per solar day, i.e. with period of -23h53m mean solar time), invoking the apparent changes of the directly observed RFCN period. Thanks to a close proximity of the resonance, any excitation with this period is extremely amplified so that the excitation necessary to explain the difference can be very small. The atmosphere alone contains enough power to excite the observed changes., Jan Vondrák and Cyril Ron., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
32823. Resource guarding by Ptomascopus morio: Simple parental care in the Nicrophorinae (Coleoptera: Silphidae)
- Creator:
- Suzuki, Seizi and Nagano, Masahiro
- Type:
- article, model:article, and TEXT
- Subject:
- Coleoptera, Silphidae, parental care, comparative method, resource guarding, predation, Nicrophorus, Ptomascopus, and Ontholestes
- Language:
- English
- Description:
- Nicrophorine beetles use small vertebrate carrion for breeding resource. While Nicrophorus spp. have highly developed biparental care, no form of parental care is recorded for Ptomascopus spp. We examined two effects of resource guarding by Ptomascopus morio. The presence of parents, especially the female, reduced the number of fly larvae on chicken carrion. Parents also enhanced the survival of brood faced with predation by the rove beetle, Ontholestes gracilis. In 6 out of 20 trials, the rove beetle predators were killed by Ptomascopus morio parents. We conclude that Ptomascopus morio has a simple, and possibly primitive form of parental care.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
32824. Resources for British butterflies (Lepidoptera: Hesperioidea, Papilionoidea). The alien consumer component and its significance for butterfly habitats
- Creator:
- Hardy, Peter B. and Dennis, Roger L.H.
- Type:
- article, model:article, and TEXT
- Subject:
- Lepidoptera, biotope, distributions, habitat, gardens, geographical range, introductions, and migration
- Language:
- English
- Description:
- With climatic warming there is an expectation that phytophagous insects will increasingly use alien (non native) plants as nectar sources and larval host plants. Alien plant use is investigated in British butterflies. Butterflies are considered to be larval host plant specialists relative to their use of nectar plants. Supporting this view, use of alien plants as nectar sources (50.1%, 27 novel plant families) is almost twice that of their use as larval host plants (21.6%; three novel plant families). Some 80% of the variation in percent alien nectar plant use is accounted against 30% of that for percent alien host plant use. The key variable accounting for alien plant use is butterfly mobility. Other prominent variables that facilitate access to alien nectar plants are southern distributions, longer adult life span, host plants in garden biotopes. A different set of variables additionally account for alien host plant exploitation (% alien host plant use: woody host plants; number of alien host plants: polyphagy; greater abundance of native host plants in gardens). Although threatened butterfly species do not depend on alien plants, this may well reflect on specialisation in resource use accompanying habitat fragmentation and an inability to use novel resources that are becoming increasingly available. Detailed study of alien resources is advocated to assess the importance of alien plant resources for phytophagous insects.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
32825. Respiratory control index of mitochondria isolated from regenerating rat liver
- Creator:
- Svátková, R., Červinková, Z., Kalous, M., Rauchová, H., and Drahota, Z.
- Type:
- article, model:article, and TEXT
- Subject:
- rat liver, regeneration, mitochondria, respiratory control index (RCI), and P/O quotient
- Language:
- English
- Description:
- Mitochondria were isolated from regenerating rat liver 12, 24 and 48 h after partial hepatectomy. The "State 3" and "State 4" respiration were measured in the presence of succinate. The P/O quotient and respiratory control index (RCI) were calculated. The experimental data showed that the partial uncoupling of oxidative phosphorylation in regenerating liver mitochondria occurring in the early period of regeneration is partly due to free fatty acids.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
32826. Respiratory function and dysfunction in Parkinson-type neurodegeneration
- Creator:
- Pokusa, Michal , Hajduchova, Dominika , Buday, Tomas , and Kralova Trancikova, Alzbeta
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- Parkinson’s disease, respiratory dysfunction, airway defence, animal models, and molecular mechanisms
- Language:
- English
- Description:
- Parkinson's disease (PD) is most commonly manifested by the presence of motor symptoms. However, non-motor symptoms occur several years before the onset of motor symptoms themselves. Hallmarks of dysfunction of the respiratory system are still outside the main focus of interest, whether by clinicians or scientists, despite their indisputable contribution to the morbidity and mortality of patients suffering from PD. In addition, many of the respiratory symptoms are already present in the early stages of the disease and efforts to utilize these parameters in the early diagnosis of PD are now intensifying. Mechanisms that lead to the development and progression of respiratory symptoms are only partially understood. This review focuses mainly on the comparison of respiratory problems observed in clinical studies with available findings obtained from experimental animal models. It also explains pathological changes observed in non-neuronal tissues in subjects with PD.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
32827. Respiratory metabolism of the pea aphid, Acyrthosiphon pisum (Hemiptera: Aphididae)
- Creator:
- Karel Sláma and Jedlička, Pavel
- Type:
- article, články, model:article, and TEXT
- Subject:
- Zoologie, zoologie, entomologie, Hemiptera, Aphididae, Acyrthosiphon pisum, O2 consumption, CO2 “bursts”, discontinuous respiration, respiratory acidaemia, virginoparae, oviparae, 2, and 59
- Language:
- English
- Description:
- 1_The respiratory metabolism of different polyphenic forms of the pea aphid, including wingless and winged asexual females (virginoparae), sexual females (oviparae) and winged or wingless adult males, was investigated using a micro-respirographic method. The records revealed sub-nanoliter amounts per min of O2 consumption or CO2 output. Respiratory metabolism of individuals was monitored for 3 to7 h after removal of the aphid from the food plant. Most of the recordings were for relatively large (3.5 mg), wingless asexual females (virginoparae). These aphids exhibited a continuous and very regular respiratory gas exchange (example: specimen of 3.5 mg body mass consumed 180 nl of O2 per min; released simultaneously 300 nl CO2 per min; = standard metabolic rate of 3085 µl O2 / g / h; R.Q. = 1.66). This continuous pattern of respiration occurred only when the aphids were kept at relatively high humidity. By contrast, aphids of various seasonal forms exhibited discontinuous respiratory gas exchange when kept in relatively dry air (atmospheric, room conditions). These patterns can be briefly described as follows: (a) Short and rather small micro-cycles of CO2 emission, manifested usually by the sudden expiration of 60–120 nl of CO2 once every 5 min; (b) Larger bursts of 240–480 nl of CO2 with a periodicity of one hour; (c) Enormously large, discontinuous bursts of 10–14 µl CO2, duration 10–30 min, repeated with a periodicity of several hours. There was no constant pattern of diffusive CO2 emission (DGC). The aphids exhibited a pattern of CO2 release that was appropriate for the external conditions, such as temperature and humidity, and internal physiological conditions such as metabolic activity, availability of reserve substances (carbohydrate, lipid) and water. Certain stages (wingless virginoparae) exhaled volumes of CO2 greatly in excess of their O2 consumption (R.Q. over 1.5)., 2_Sudden exhalations of CO2 from the body were a consequence of a bulk production and outflow of CO2 and not due to the diffusion of CO2 previously accumulated within the tracheal system. Due to their generally high metabolic activity (1142 to 6780 µl O2 / g / h), aphid tissue and organs produced relatively large amounts of metabolically formed carbonic acid. The resulting respiratory acidaemia was moderated by outbursts of gaseous CO2, liberated from liquid carbonate buffers by a regulatory mechanism based on enzymatic hydration and neutralization of carbonic acid by discontinuous formation of gaseous CO2., Karel Sláma, Pavel Jedlička., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
32828. Respiratory sinus arrhythmia as an index of cardiac vagal control in mitral valve prolapse
- Creator:
- Olexova, Lucia Bona, Sekaninova, Nikola , Jurko, Alexander , Visnovcova, Zuzana , Grendar, Marian , Jurko, Tomas , and Tonhajzerova, Ingrid
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- respiratory sinus arrhythmia, cardiac vagal control, mitral valve prolapse, and adolescents
- Language:
- English
- Description:
- Respiratory sinus arrhythmia (RSA), i.e. heart rate (HR) variations during inspiration and expiration, is considered as a noninvasive index of cardiac vagal control. Mitral valve prolapse (MVP) could be associated with increased cardiovascular risk; however, the studies are rare particularly at adolescent age. Therefore, we aimed to study cardiac vagal control indexed by RSA in adolescent patients suffering from MVP using short-term heart rate variability (HRV) analysis. We examined 12 adolescents (girls) with MVP (age 15.9±0.5 years) and 12 age and gender matched controls. Resting ECG was continuously recorded during 5 minutes. Evaluated HRV indices were RR interval (ms), rMSSD (ms), pNN50 (%), log HF (ms2 ), peak HF (Hz) and respiratory rate (breaths/min). RR interval was significantly shortened in MVP group compared to controls (p=0.004). HRV parameters-rMSSD, pNN50 and log HF were significantly lower in MVP compared to controls (p=0.017, p=0.014, p= 0.015 respectively). Our study revealed reduced RSA magnitude indicating impaired cardiac vagal control in MVP already at adolescent age that could be crucial for early diagnosis of cardiovascular risk in MVP.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
32829. Respiratory-induced hemodynamic changes measured by whole-body multichannel impedance plethysmography
- Creator:
- Langer, P., Pavel Jurák, Vladimír Vondra, Josef Halámek, Mešťaník, M., Ingrid Tonhajzerová, Viščor, I., Soukup, L., Matejkova, M., Eva Závodná, and Leinveber, P.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- dýchání, respiration, pulse wave velocity, bioimpedance, blood flow, blood volume, 14, and 612
- Language:
- English
- Description:
- The cardiovascular system is described by parameters including blood flow, blood distribution, blood pressure, heart rate and pulse wave velocity. Dynamic changes and mutual interactions of these parameters are important for understanding the physiological mechanisms in the cardiovascular system. The main objective of this study is to introduce a new technique based on parallel continuous bioimpedance measurements on different parts of the body along with continuous blood pressure, ECG and heart sound measurement during deep and spontaneous breathing to describe interactions of cardiovascular parameters. Our analysis of 30 healthy young adults shows surprisingly strong deep-breathing linkage of blood distribution in the legs, arms, neck and thorax. We also show that pulse wave velocity is affected by deep breathing differently in the abdominal aorta and extremities. Spontaneous breathing does not induce significant changes in cardiovascular parameters., P. Langer, P. Jurák, V. Vondra, J. Halámek, M. Mešťaník, I. Tonhajzerová, I. Viščor, L. Soukup, M. Matejkova, E. Závodná, P. Leinveber., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
32830. Response after repeated ketamine injections in a rat model of neuropathic pain
- Creator:
- Kim, Na Eun, Kim, Byung Gun, Lee, Junhyung, Chung, Hee Tae, Kwon, Hye Rim, Kim, Young Shin, Choi, Jong Bum, and Song, Jang Ho
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- ketamine, neuropathic pain, rat, and partial sciatic ligation
- Language:
- English
- Description:
- Ketamine, an N-methyl-D-aspartate antagonist, reduces pain by decreasing central sensitization and pain windup. However, chronic ketamine use can cause tolerance, dependency, impaired consciousness, urinary symptoms, and abdominal pain. This study aimed to investigate the effects of repeated ketamine injections and ketamine readministration after discontinuation in a rat model of neuropathic pain. To induce neuropathic pain, partial sciatic nerve ligation (PSNL) was performed in 15 male Wistar rats, and these animals were divided into three groups: PSNL (control), PSNL + ketamine 5 mg/kg (K5), and PSNL + ketamine 10 mg/kg (K10; n=5 each). Ketamine was injected intraperitoneally daily for 4 weeks, discontinued for 2 weeks, and then readministered for 1 week. Following PSNL, the mechanical withdrawal threshold was determined weekly using the Von Frey. The K10 group showed a significant increase in the mechanical withdrawal threshold, presented here as the target force (in g), at 21 and 28 days compared to the time point before ketamine injection (mean±SE, 276.0±24.0 vs. 21.6±2.7 and 300.0±0.0 vs. 21.6±2.7, respectively; P<0.01) and at 14, 21, and 28 days compared to the control group (108.2±51.2 vs. 2.7±1.3, 276.0±24.0 vs. 2.5±1.5, and 300.0±0.0 vs. 4.0±0.0, respectively; P<0.05). However, in the K10 group, the ketamine effects decreased significantly at 7 days after readministration compared to those after 28 days of repeated injections (P<0.05). In the K10 group, repeated ketamine injections showed a significant increase in antinociceptive effect for >2 weeks, but this ketamine effect decreased after drug readministration.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public