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Sample records for dependent hatching rates

  1. Metabolic rates are elevated and influenced by maternal identity during the early, yolk-dependent, post-hatching period in an estuarine turtle, the diamondback terrapin (Malaclemys terrapin).

    PubMed

    Rowe, Christopher L; Woodland, Ryan J; Funck, Sarah A

    2017-02-01

    Non-genetic maternal effects, operating through a female's physiology or behavior, can influence offspring traits and performance. Here we examined potential maternal influences on metabolic rates (MR) of offspring in an estuarine turtle, the diamondback terrapin (Malaclemys terrapin). Females and their eggs were collected from the field and the eggs incubated in the laboratory for subsequent measurement of MR of females, late-stage embryos, newly-hatched individuals that were nutritionally dependent on yolk, and older hatchlings that had depleted their yolk reserves and thus were independent of energetic contributions from the female. Female identity significantly affected MR of yolk-dependent hatchlings but, after yolk was depleted, MR of offspring converged and no longer reflected the maternal influence. Offspring from different females also differed in size, which influenced offspring MR and growth, but there was no correlation between female MR or size and offspring traits. MR of the older, yolk-independent hatchlings was lower overall than yolk-dependent hatchlings but correlated positively with growth rates and prior developmental rate (e.g. negatively correlated with time to hatching). Unlike another turtle species (snapping turtles), in which maternally-related differences in offspring MR were retained after yolk depletion, the maternal influence on offspring MR in diamondback terrapins is limited to early hatchling development and growth. The transient nature of the maternal effect, which was present only during the period that hatchlings were metabolizing yolk, suggests that variation among females in the composition of yolk deposited in eggs could be responsible for the differences observed in this study.

  2. Transfer of spontaneously hatching or hatched blastocyst yields better pregnancy rates than expanded blastocyst transfer.

    PubMed

    Chimote, Natachandra M; Chimote, Nishad N; Nath, Nirmalendu M; Mehta, Bindu N

    2013-07-01

    Blastocyst stage embryo transfer (ET) has become routine practice in recent years. However, probably due to limitations of assisted hatching techniques, expanded blastocyst transfer (EBT) is still the preferred mode. Inexplicably, not much consideration has been given to spontaneously hatching/hatched blastocyst transfer (SHBT). This study aimed to investigate developmental potential of spontaneously hatching/hatched blastocyst against EBT in in vitro fertilization (IVF) cycles. Prospective study of 146 women undergoing their first IVF- ET cycle. On the basis of blastocyst status, women were classified into SHBT and EBT groups. Intracytoplasmic sperm injection cycles were excluded to remove male factor bias. Implantation rate (IR), clinical pregnancy rate, and live birth rate were the main outcome measures. Graph-pad Prism 5 statistical package. SHBT group showed significantly higher blastocyst formation rate (53.3 ± 17.5 vs. 43.1 ± 14.5%, P = 0.0098), top-quality blastocysts (71.8 vs. 53.7%, P = 0.0436), IR (43.6 vs. 27.9%, P = 0.0408), pregnancy rate (59.4 vs. 45.1%, P = 0.0173), and live birth rate (36.8 vs. 22.8%, P = 0.003) compared to EBT group. Multiple pregnancy rates remained comparable between the two groups. Implantation correlated strongly with top-quality blastocysts (Pearson, r = 0.4441) in SHBT group, while the correlation was nonsignificant in EBT group. Extending culture of expanded blastocysts by a few hours to allow transfer of spontaneously hatching/hatched blastocysts gives higher implantation and pregnancy rates with no added risk of multiple gestations. Spontaneously hatching/hatched blastocysts have a better potential to implant and develop into a positive pregnancy.

  3. The effects of laser assisted hatching on pregnancy rates

    PubMed Central

    Ghannadi, Alireza; Kazerooni, Marjaneh; Jamalzadeh, Fatemeh; Amiri, Sahar; Rostami, Parifar; Absalan, Forouzan

    2011-01-01

    Background: For infertile women aged over 35 years, failure of the ZP (zona pellucida) to rupture is believed to be associated with a decreased implantation rate in in vitro fertilization (IVF) or intra cytoplasmic sperm injection (ICSI). Objective: In this research, laser assisted hatching (LAH) was offered to patients with advanced maternal age to evaluate a possible benefit. Materials and Methods: Nine hundred thirty two cycles of IVF/ICSI in females were analyzed. Women included in this study were allocated in 4 groups. In group I and II, embryos were cultured and transferred with and without LAH in women aged ≤35, whereas embryos of group III and IV were examined with and without LAH in women aged ≥ 35. Laser manipulations were performed using a suturn-Tm3 system using 2-3 pulses of 0.8 millisecond with 400 voltage duration. The size of the hole made in the zona was measured to be 5-10 µm, depending on the zona thickness of each individual embryo. Results: The performance of LAH significantly increased clinical pregnancy rates in all patients. In group I and II, the chemical (50.99% and 31.61% respectively), clinical (50% and 30.69% respectively) and multiple pregnancies (22.27% and 5.94% respectively) significantly differ between these groups. In the patients with advanced female age ≥35 the performance of LAH significantly increased chemical (30.12%) and clinical pregnancy (27.71%) rates compared to whom without LAH (18.96% and 16.37% respectively). Conclusion: Our data demonstrate in the patients who were less than 35 years old, multiple pregnancy rates were significantly increased compared to other groups who aged over 35 years old. In addition benefit of LAH in improving pregnancy rates after IVF or ICSI in women of advanced age (≥35) was shown. PMID:25587254

  4. Hatching rates of resting eggs of 'Cladocera' (Crustacea; Branchiopoda) at a tropical bay, Brazil.

    PubMed

    Mugrabe, G; Barros, S; Marazzo, A; Valentin, J L

    2007-08-01

    The aim of this study was to determine the development time of embryos and to estimate the hatching rates of resting eggs of cladocerans found in the sediment of Guanabara Bay, Rio de Janeiro, Brazil, under experimental conditions. Eggs were sorted by species (Penilia avirostris--Sididae; Pleopis polyphemoides and Pseudevadne tergestina--Podonidae) and incubated at a temperature of 25 degrees C, salinity 35 and photoperiod 12 hours light/ 12 hours dark. Hatching rates were about 38% for Pseudevadne tergestina and 28% for Pleopis polyphemoides. Embryos of resting eggs of Penilia avirostris developed comparatively slowly (hatching after 86 days of incubation), with a hatching rate of only 5%. It was observed that development and hatching of resting eggs of marine cladocerans suggest that pulses of recruitment may exist, thus contributing to the rapid appearance and maintenance of planktonic populations of these crustaceans in Guanabara Bay.

  5. The relationship between hatching rate and number of embryos of the brood pouch in Littorina saxatilis

    NASA Astrophysics Data System (ADS)

    Conde-Padín, P.; Carballo, M.; Caballero, A.; Rolán-Alvarez, E.

    2008-10-01

    Littorina saxatilis is an ovoviviparous organism in which shelled embryos can be directly observed in nearly all mature females captured in the wild. This characteristic has been used a number of times as an indirect estimate for fecundity of natural populations. However, there is no experimental corroboration that the number of embryos within a female brood pouch is actually related to the rate of hatching per unit of time, a more realistic estimate of female fecundity. In order to make this corroboration we estimated the correlation between the number of embryos in the brood pouch and the hatching rate of isolated females grown in the laboratory. We also compared the hatching rates of females from two sympatric ecotypes (RB and SU) of this species, which differ significantly in the number of embryos. We found a high agreement between hatching rate and number of embryos, concluding that the latter is a good proxy for fecundity.

  6. High hatching rates after cryopreservation of hydrated cysts of the brine shrimp A. franciscana.

    PubMed

    Yoshida, Toru; Arii, Yasuhiro; Hino, Katsuhiko; Sawatani, Ikuo; Tanaka, Midori; Takahashi, Rei; Bando, Toru; Mukai, Kazuhisa; Fukuo, Keisuke

    2011-01-01

    Cysts of Artemia franciscana are known to be extremely tolerant to UV and ionizing radiation, hypoxia, dryness, osmotic pressure, and temperatures. However, when cysts are hydrated, their resistance to extreme environmental conditions is markedly reduced, and they subsequently enter a developmental sequence. The hatching rate of hydrated cysts declined when they were rapidly frozen after a short period of hydration but slow freezing improved hatching rates after 6-h hydration (1.4 g H2O per g dry wt). We observed that trehalose content in hydrated cysts was greatly reduced up to 6-h time. DSC analysis showed different thermal profiles at two cooling rates, suggesting the formation of a minuscule ice crystal inside the cells. High hatching rates can be obtained from highly hydrated cysts at slow cooling rate.

  7. Hatch success and temperature-dependent development time in two broadly distributed topminnows (Fundulidae)

    NASA Astrophysics Data System (ADS)

    Schaefer, Jacob

    2012-07-01

    Metabolic scaling laws predict a variety of emergent properties of biological systems based on relationships among temperature, body size, and rates of physiological processes. These models have been criticized as being overly simplistic and not accounting for directional variability arising from evolutionary tradeoffs. I measured hatch success and egg development time at six temperatures for 12 populations throughout the latitudinal range of two broadly distributed topminnows ( Fundulus). I asked if hatch success and development time differed between the species and northern and southern populations. Hatch success reaction norms suggested that the more broadly (and northern) distributed Fundulus notatus was more eurythermic with a lower optima and broader performance breadth than Fundulus olivaceus. Temperature explained most variability in mass-corrected development time. Development time differed between the species, but not northern and southern populations. Deviations from predictions of universal scaling laws were most pronounced away from specie's thermal optima.

  8. Embryonic Development and Rates of Metabolic Activity in Early and Late Hatching Eggs of the Major Malaria Vector Anopheles gambiae

    PubMed Central

    Kaiser, Maria L.; Duncan, Frances D.; Brooke, Basil D.

    2014-01-01

    Anopheles gambiae eggs generally hatch at the completion of embryo development; two-three days post oviposition. However, staggered or delayed hatching has been observed whereby a single batch of eggs shows marked variation in time-to-hatch, with some eggs hatching 18 days post oviposition or later. The mechanism enabling delayed hatch has not been clearly elucidated but is likely mediated by environmental and genetic factors that either induce diapause or slow embryo development. This study aimed to compare metabolic activity and embryonic development between eggs collected from sub-colonies of the baseline Anopheles gambiae GAH colony previously selected for early or late time-to-hatch. Egg batches from early and late hatch sub-colonies as well as from the baseline colony were monitored for hatching. For both time-to-hatch selected sub-colonies and the baseline colony the majority of eggs hatched on day two post oviposition. Nevertheless, eggs produced by the late hatch sub-colony showed a significantly longer mean time to hatch than those produced by the early hatch sub-colony. The overall proportions that hatched were similar for all egg batches. CO2 output between eggs from early and late hatch sub-colonies showed significant differences only at 3 and 7 days post oviposition where eggs from the early hatch and the late hatch sub-colony were more metabolically active, respectively. No qualitative differences were observed in embryo development between the sub-colonies. It is concluded that all viable embryos develop to maturity at the same rate and that a small proportion then enter a state of diapause enabling them to hatch later. As it has previously been shown that it is possible to at least partially select for late hatch, this characteristic is likely to involve genetic as well as environmental factors. Delayed hatching in An. gambiae is likely an adaptation to maximise reproductive output despite the increased risk of desiccation in an unstable aquatic

  9. Egg Hatch Rate and Nymphal Survival of the Bed Bug (Hemiptera: Cimicidae) After Exposure to Insecticide Sprays.

    PubMed

    Hinson, K R; Benson, E P; Zungoli, P A; Bridges, W C; Ellis, B R

    2016-12-01

    Few studies have addressed the efficacy of insecticides used against eggs and first-instar nymphs of the bed bug, Cimex lectularius L. (Hemiptera: Cimicidae). Insect eggs are often resistant to insecticides; therefore, information on which products are effective is important. We evaluated the efficacy of four commonly used insecticide sprays applied directly to bed bug eggs. We also evaluated the efficacy of these insecticides to first-instar nymphs exposed to residuals resulting from directly spraying eggs. Temprid SC (beta-cyfluthrin, imidacloprid) was the most effective insecticide at preventing egg hatch (13% hatch rate) for pyrethroid-resistant, field-strain (Jersey City) bed bugs compared with a control (water [99% hatch rate]), Bedlam (MGK-264, sumithrin [84% hatch rate]), Demand CS (lambda-cyhalothrin [91% hatch rate]), and Phantom SC (chlorfenapyr [95% hatch rate]). Demand CS and Temprid SC were most effective at preventing egg hatch (0%) for an insecticide-susceptible (Harold Harlan) strain, followed by Bedlam (28%). Phantom SC produced a hatch rate similar to the control (97% and 96%, respectively). Harold Harlan-strain nymphs showed 100% survival for the control but 0% survival for Bedlam and Phantom SC. Jersey City-strain nymphs showed 100% survival for the control, 99% survival for Bedlam, 0% survival for Demand CS, 4% survival for Phantom SC, and 38% survival for Temprid SC. Demand CS was less effective at preventing hatch (91% hatch rate) of Jersey City-strain nymphs but was the only product to kill all nymphs (0% survival). One of the least effective products for preventing Jersey City-strain egg hatch (Phantom SC, 95% hatch rate) was the second most effective at killing nymphs, leaving only six of 141 alive. These findings indicate that survival of directly sprayed eggs and residually exposed, first-instar nymphs varies by strain, life stage, and product used.

  10. Heart rates increase after hatching in two species of Natricine snakes.

    PubMed

    Aubret, Fabien

    2013-11-29

    Experimental studies have shown heart rates to decrease from embryo to hatchling stage in turtles, remain steady in skinks, and increase in birds. However, no snake species has been studied in this regard. I recorded heart rate evolution trajectories from embryo to juvenile stage in 78 eggs from two species of European Natricine snakes. Unexpectedly, snakes behaved more like birds than turtles or lizards: heart rates increased after hatching in both N. maura and N. natrix, respectively by 43.92 ± 22.84% and 35.92 ± 24.52%. Heart rate shift was not related to an abrupt elevation of metabolism per se (snakes that increased their heart rates the most sharply grew the least after birth), but rather due to a number of smaller eggs that experienced lower than normal heart rates throughout the incubation and recovered a normal heart rate post-birth. This finding is discussed in the light of hatching synchrony benefits.

  11. Heart rates increase after hatching in two species of natricine snakes

    PubMed Central

    Aubret, Fabien

    2013-01-01

    Experimental studies have shown heart rates to decrease from embryo to hatchling stage in turtles, remain steady in skinks, and increase in birds. However, no snake species has been studied in this regard. I recorded heart rate evolution trajectories from embryo to juvenile stage in 78 eggs from two species of European Natricine snakes. Unexpectedly, snakes behaved more like birds than turtles or lizards: heart rates increased after hatching in both N. maura and N. natrix, respectively by 43.92 ± 22.84% and 35.92 ± 24.52%. Heart rate shift was not related to an abrupt elevation of metabolism per se (snakes that increased their heart rates the most sharply grew the least after birth), but rather due to a number of smaller eggs that experienced lower than normal heart rates throughout the incubation and recovered a normal heart rate post-birth. This finding is discussed in the light of hatching synchrony benefits. PMID:24287712

  12. Maintenance of mosquito vectors: effects of blood source on feeding, survival, fecundity, and egg hatching rates.

    PubMed

    Phasomkusolsil, Siriporn; Tawong, Jaruwan; Monkanna, Nantaporn; Pantuwatana, Kanchana; Damdangdee, Nuttapon; Khongtak, Weeraphan; Kertmanee, Yossasin; Evans, Brian P; Schuster, Anthony L

    2013-06-01

    Artificial membrane-feeding techniques have replaced direct feeding on animals for the maintenance of malaria and arbovirus vectors in many laboratories. Membrane feeding facilitates controlled experimentation of pathogen transmission during mosquito feeding. Sheep blood is commonly used due to its availability and low cost. We evaluated the impact of blood source (human, guinea pig, sheep, and hamster via direct feeding) on feeding rates, adult survival, fecundity, hatching rates, and developmental times for five species of laboratory-colonized mosquitoes (Anopheles dirus, An. cracens, An. minimus, An. sawadwongporni, and Ae. aegypti). We found that feeding rates differ among blood sources within mosquito species. Survival, fecundity, and hatching rates were lower in all Anopheles species and Ae. aegypti after membrane feeding on sheep blood. Survival rates seven days post-feeding on sheep blood were significantly lower (P<0.05) for An. dirus (84.2%), An. minimus (67.2%), An. sawadwongporni (51.5%), and An. cracens (35.5%) relative to other blood sources. An. minimus and An. sawadwongporni laid no eggs by seven days post-feeding with sheep blood, while An. dirus and An. cracens produced significantly fewer numbers of eggs and demonstrated significantly lower hatching rates relative to what was observed with the other blood sources. These findings support the conclusion that sheep blood is not a suitable blood source for laboratory rearing of Anopheles spp. © 2013 The Society for Vector Ecology.

  13. Interactions between hatch dates, growth rates, and mortality of Age-0 native Rainbow Smelt and nonnative Alewife in Lake Champlain

    USGS Publications Warehouse

    Parrish, Donna; Simonin, Paul W.; Rudstam, Lars G.; Pientka, Bernard; Sullivan, Patrick J.

    2016-01-01

    Timing of hatch in fish populations can be critical for first-year survival and, therefore, year-class strength and subsequent species interactions. We compared hatch timing, growth rates, and subsequent mortality of age-0 Rainbow Smelt Osmerus mordax and Alewife Alosa pseudoharengus, two common open-water fish species of northern North America. In our study site, Lake Champlain, Rainbow Smelt hatched (beginning May 26) almost a month earlier than Alewives (June 20). Abundance in the sampling area was highest in July for age-0 Rainbow Smelt and August for age-0 Alewives. Late-hatching individuals of both species grew faster than those hatching earlier (0.6 mm/d versus 0.4 for Rainbow Smelt; 0.7 mm/d versus 0.6 for Alewives). Mean mortality rate during the first 45 d of life was 3.4%/d for age-0 Rainbow Smelt and was 5.5%/d for age-0 Alewives. Alewife mortality rates did not differ with hatch timing but daily mortality rates of Rainbow Smelt were highest for early-hatching fish. Cannibalism is probably the primary mortality source for age-0 Rainbow Smelt in this lake. Therefore, hatching earlier may not be advantageous because the overlap of adult and age-0 Rainbow Smelt is highest earlier in the season. However, Alewives, first documented in Lake Champlain in 2003, may increase the mortality of age-0 Rainbow Smelt in the summer, which should favor selection for earlier hatching.

  14. Embryos in the Fast Lane: High-Temperature Heart Rates of Turtles Decline After Hatching

    PubMed Central

    Du, Wei-Guo; Zhao, Bo; Shine, Richard

    2010-01-01

    In ectotherms such as turtles, the relationship between cardiovascular function and temperature may be subject to different selective pressures in different life-history stages. Because embryos benefit by developing as rapidly as possible, and can “afford” to expend energy to do so (because they have access to the yolk for nutrition), they benefit from rapid heart (and thus, developmental) rates. In contrast, hatchlings do not have a guaranteed food supply, and maximal growth rates may not enhance fitness—and so, we might expect a lower heart rate, especially at high temperatures where metabolic costs are greatest. Our data on two species of emydid turtles, Chrysemys picta, and Graptemys pseudogeographica kohnii, support these predictions. Heart rates of embryos and hatchlings were similar at low temperatures, but heart rates at higher temperatures were much greater before than after hatching. PMID:20224773

  15. Seasonal predator removal relative to hatch rate of duck nests in waterfowl production areas

    USGS Publications Warehouse

    Sargeant, A.B.; Sovada, M.A.; Shaffer, T.L.

    1995-01-01

    These authors report that hatch rates of duck nests were related to removal of predators from waterfowl production areas. Cost effectiveness of such efforts is questioned. The prairie pothole region (PPR) is the primary breeding ground of several species of North American ducks (Bellrose 1980). Much habitat of breeding ducks in the PPR has been destroyed or degraded by intensive agriculture (e.g., Kiel et al. 1972, Bellrose 1980, Sugden and Beyersbergen 1984, Boyd 1985), resulting in high predation rates on duck nests (Sargeant and Raveling 1992). Because of predation, hatch rate (HR) of duck nests in Waterfowl Production Areas (WPA's) in the PPR is often less than the 15-20% suggested for stability of populations of the 5 most common species of dabbling ducks (e.g., Cowardin et al. 1985, Greenwood 1986, Klett et al. 1988, Greenwood et al. 1990). Managers seek ways to reduce depredations of duck clutches in WPA's, but little information is available concerning effects of predator removal. We evaluated seasonal (spring and early summer) removal of predators from WPA's in Minnesota and North Dakota. Our objectives were to compare HR in uplands of WPA's with and without predators removed and to determine functional aspects of conducting predator removal.

  16. Heart Rate Responses to Unaided Orion Side Hatch Egress in the Neutral Buoyancy Laboratory

    NASA Technical Reports Server (NTRS)

    English, Kirk L.; Hwang Emma Y.; Ryder, Jeffrey W.; Kelly, Cody; Walker, Thomas; Ploutz-Snyder, Lori L.

    2016-01-01

    NASA is developing the Orion capsule as a vehicle for transporting crewmembers to and from the International Space Station (ISS) and for future human space exploration missions. Orion and other commercial vehicles are designed to splash down in the ocean where nominally support personnel will assist crewmembers in egressing the vehicle. However, off-nominal scenarios will require crewmembers to egress the vehicle unaided, deploy survival equipment, and ingress a life raft. PURPOSE: To determine the heart rate (HR) responses to unaided Orion side hatch egress and raft ingress as a part of the NASA Crew Survival Engineering Team's evaluation of the PORT Orion mockup in the Neutral Buoyancy Laboratory (NBL). METHODS: Nineteen test subjects, including four astronauts (N=19, 14 males/5 females, 38.6+/-8.4 y, 174.4+/-9.6 cm, 75.7+/-13.1 kg), completed a graded maximal test on a cycle ergometer to determine VO2peak and HRpeak and were divided into five crews of four members each; one subject served on two crews. Each crew was required to deploy a life raft, egress the Orion vehicle from the side hatch, and ingress the life raft with two 8 kg emergency packs per crew. Each crew performed this activity one to three times; a total of ten full egresses were completed. Subjects wore a suit that was similar in form, mass, and function to the Modified Advanced Crew Escape Suit (MACES) including helmet, gloves, boots, supplemental O2 bottles, and a CO2-inflated life preserver (approx.18 kg); subjects began each trial seated supine in the PORT Orion mockup with seat belts and mockup O2 and communication connections and ended each trial with all four crewmembers inside the life raft. RESULTS: VO2peak was 40.8+/-6.8 mL/kg/min (3.1+/-0.7 L/min); HRpeak was 181+/-10 bpm. Total egress time across trials was 5.0+/-1.6 min (range: 2.8-8.0 min); all subjects were able to successfully complete all trials. Average maximum HR at activity start, at the hatch opening, in the water, and in the

  17. Effect of the presence of trophectoderm vesicles on blastocyst in relation to in vitro hatching, clinical pregnancy, and miscarriage rates.

    PubMed

    Araki, Yasuhisa; Matsui, Yuki; Iizumi, Ayaka; Tsuchiya, Syoutarou; Kaneko, Yumi; Sato, Kazufumi; Ozaki, Tomoya; Araki, Yasuyuki; Nishimura, Mitsuru

    2016-10-01

    Trophectoderm vesicles (TVs) are observed in some blastocysts that penetrate cells from the zona pellucida to the outer margin. Therefore, we compared this incidence in relation to hatching, pregnancy, and miscarriage rates between conventional in vitro fertilization (c-IVF) and intracytoplasmic sperm injection (ICSI). Vitrified/warmed blastocysts (n = 112) were derived from surplus embryos. The blastocysts were then observed using time-lapse cinematography to resolve the relationship between hatching and implantation. Another study was conducted that comprised 681 embryo transfer cycles in 533 patients who received a single vitrified/warmed blastocyst from our clinic. The incidence of TV was significantly higher in embryos inseminated by ICSI compared with c-IVF [ICSI: 51/56 (91 %); c-IVF: 25/56 (45 %); P < 0.01]. The successful hatching rate was significantly lower in ICSI than in c-IVF [ICSI: 11/56 (20 %); c-IVF: 29/56 (52 %); P < 0.01]. In addition, the hatching rate was significantly lower when TVs were present (14/76; 18 %) than in non-TV embryos (26/36; 72 %) (P < 0.01). In regard to the clinical study results, no significant differences were found between the groups in the pregnancy rate (TV present group: 107/183, 58.5 %; TV absent group: 273/498, 54.8 %) and miscarriage rate (TV present group: 21/107, 19.6 %; TV absent group: 53/273, 19.4 %). In vivo, we hypothesized that hatching and hatched would occur naturally by assisting protease action in the uterus; therefore, these results suggest that the presence of TV has no effect on pregnancy rates in the clinical setting.

  18. Hatching behavior in turtles.

    PubMed

    Spencer, Ricky-John; Janzen, Fredric J

    2011-07-01

    Incubation temperature plays a prominent role in shaping the phenotypes and fitness of embryos, including affecting developmental rates. In many taxa, including turtles, eggs are deposited in layers such that thermal gradients alter developmental rates within a nest. Despite this thermal effect, a nascent body of experimental work on environmentally cued hatching in turtles has revealed unexpected synchronicity in hatching behavior. This review discusses environmental cues for hatching, physiological mechanisms behind synchronous hatching, proximate and ultimate causes for this behavior, and future directions for research. Four freshwater turtle species have been investigated experimentally, with hatching in each species elicited by different environmental cues and responding via various physiological mechanisms. Hatching of groups of eggs in turtles apparently involves some level of embryo-embryo communication and thus is not a purely passive activity. Although turtles are not icons of complex social behavior, life-history theory predicts that the group environment of the nest can drive the evolution of environmentally cued hatching.

  19. Extended hatching periods in the subantarctic lithodid crabs Lithodes santolla and Paralomis granulosa (Crustacea: Decapoda: Lithodidae)

    NASA Astrophysics Data System (ADS)

    Thatje, S.; Calcagno, J. A.; Lovrich, G. A.; Sartoris, F. J.; Anger, K.

    2003-06-01

    Temporal pattern of hatching was studied in the subantarctic lithodid crabs Lithodes santolla (Molina) and Paralomis granulosa (Jaquinot) from the Argentine Beagle Channel. In both species, larval hatching occurred in low daily numbers over an extended period of up to several weeks, depending on hatch size. Low daily hatching activity and low oxygen-consumption rates in freshly hatched P. granulosa larvae are discussed as life history adaptations to, and/or physiological constraints by, the environmental conditions of high latitudes.

  20. Starting with a handicap: effects of asynchronous hatching on growth rate, oxidative stress and telomere dynamics in free-living great tits.

    PubMed

    Stier, Antoine; Massemin, Sylvie; Zahn, Sandrine; Tissier, Mathilde L; Criscuolo, François

    2015-12-01

    A trade-off between resource investment into growth rate and body self-maintenance is likely to occur, but the underlying molecular mediators of such a trade-off remain to be determined. In many altricial birds, hatching asynchrony creates a sibling competitive hierarchy within the brood, with first-hatched nestlings enjoying substantial advantages compared to last-hatched nestlings. We used this opportunity to test for a trade-off between growth and self-maintenance processes (oxidative stress, telomere erosion) in great tit nestlings, since resource availability and allocation are likely to differ between first-hatched and last-hatched nestlings. We found that despite their starting competitive handicap (i.e. being smaller/lighter before day 16), last-hatched nestlings exhibited growth rate and mass/size at fledging similar to first-hatched ones. However, last-hatched nestlings suffered more in terms of oxidative stress, and ended growth with shorter telomeres than first-hatched ones. Interestingly, growth rate was positively related to plasma antioxidant capacity and early life telomere length (i.e. at 7 days old), but among last-hatched nestlings, those exhibiting the faster body size growth were also those exhibiting the greatest telomere erosion. Last-hatched nestlings exhibited elevated levels of plasma testosterone (T), but only at day 7. T levels were positively associated with oxidative damage levels and plasma antioxidant capacity, the latter being only significant for first-hatched nestlings. Our results suggest that last-hatched nestlings present a specific trade-off between growth rate and self-maintenance processes, which is possibly driven by their need to compete with their older siblings and potentially mediated by elevated levels of T.

  1. The Effect of Elevated CO2 and Temperature on the Hatch Rate and Survival of Estuarine Forage Fish

    NASA Astrophysics Data System (ADS)

    Merlo, L. R.; Gobler, C.

    2016-02-01

    The World Oceans are acidifying and warming, yet little is known regarding how these processes will combine to impact fish populations. In estuaries, microbial respiration of eutrophication-enhanced organic matter can create elevated CO2 levels during late spring and summer seasons when thermal extremes can occur and temperate fish spawn. Here, we report on experiments that exposed fish embryos (e.g. Menidia beryllina, inland silverside) to normal and elevated CO2 (400 and 2,000 ppm) and the range of temperatures experienced within temperate estuaries during the spawning season (16 - 30C). Fish survival and growth rates were quantified from hatching through early life, larval stages. Temperature controlled egg hatching times, with elevated temperatures leading to more rapid hatch rates. Elevated levels of CO2 significantly depressed post-hatch survival of fish. Survival rates of fish exposed to elevated CO2 at lower than ideal temperatures were significantly lower than predicted by either variable individually indicating the ability of these stressors to synergistically interact. Since embryonic stages have been identified as being highly sensitive to acidification, this finding may be associated with the extended exposure of eggs to high CO2 at lower temperatures. The physiological mechanisms driving experimental trends and broader ecological implications of the study will be discussed.

  2. Bacterial isolation rate from fertile eggs, hatching eggs, and neonatal broilers with yolk sac infection.

    PubMed

    Cortés, Cecilia Rosario; Téllez Isaías, Guillermo; López Cuello, Carlos; Villaseca-Flores, Jorge Mateo; Anderson, Robin C; Eslava Campos, Carlos

    2004-01-01

    Yolk sac infection (YSI) is a major cause of mortality of broilers during the first week post-hatching. The aim of the present-study was to analyze the possible sources of fertile egg contamination and to establish the etiology of YSI. Sixty fertile eggs, sixty sawdust samples from the nest, sixty nonfertile 19 to 21 day old incubation eggs and liver and yolk sac samples from 216 dead, 1 to 7 day old chicks, were cultured. Five hundred and eighty eight colonies were isolated and further characterized using biochemical tests. Escherichia coli was the most common bacterium recovered from all samples except the sawdust and fertile eggs collected from the nest. Fertile egg contamination at breeder farm level was found to be minimal. In broilers, both mortality and the rate of E. coli isolation were increased with the time. These results suggest that egg contamination does not occur at the breeders farm, as previously has been reported. Bacterial contamination causing YSI in vertically integrated operations can occur at a latter stage. It can be considered that the main etiologic agent of YSI is E. coli, since YSI mortality was highly correlated with E. coli isolation.

  3. Characterization of hatch-size and growth rates of captive and wild-reared brown kiwi (Apteryx mantelli) chicks.

    PubMed

    Prier, Erica A; Gartrell, Brett D; Potter, Murray A; Lopez-Villalobos, Nicolas; McLennan, John

    2013-01-01

    Avian growth rate patterns represent a trade off between a tissue's functional maturity and its capacity for growth. At the time of hatch, the brown kiwi (Apteryx mantelli) limb has a high level of maturity in order for the chick to be able to kick its way out of the shell and walk and forage independently from an early age. Growth curves of limb segments, bill length and bodyweight are presented for captive-reared, BNZ Operation Nest Egg™ chicks over a period of 3 months from the point of hatch. Some parameters were slightly larger in the females than in males at time of hatch, including the bill length. Growth in bodyweight began to slow earlier in males than in females. Regressions of limb and bill measurements over time showed linear patterns of growth instead of a sigmoidal curve as seen in other birds, probably due to the short period of observation. Bodyweight and bill length were then compared to these morphometrics in a wild population of kiwi. Captive-reared chicks were found to hatch with shorter bills and to increase in bodyweight at a faster rate than the wild birds. Rapid weight gain has been implicated in developmental limb deformities in other precocial and long-legged birds and should be avoided in captive kiwi.

  4. Maternal vibration: an important cue for embryo hatching in a subsocial shield bug.

    PubMed

    Mukai, Hiromi; Hironaka, Mantaro; Tojo, Sumio; Nomakuchi, Shintaro

    2014-01-01

    Hatching care has been reported for many taxonomic groups, from invertebrates to vertebrates. The sophisticated care that occurs around hatching time is expected to have an adaptive function supporting the feeble young. However, details of the characteristics of the adaptive function of hatching care remain unclear. This study investigated the hatching care of the subsocial shield bug, Parastrachia japonensis (Heteroptera: Parastrachiidae) to verify its function. Results show that the P. japonensis mothers vibrated the egg mass intermittently while maintaining an egg-guarding posture. Then embryos started to emerge from their shells synchronously. Unlike such behaviors of closely related species, this vibrating behavior was faint, but lasted more than 6 h. To investigate the effect of this behavior on hatching synchrony and hatching success, we observed the hatching pattern and the hatching rate in control, mother-removed, and two artificial vibration groups. Control broods experienced continuous guarding from the mother. Intermittent artificial vibration broods were exposed to vibrations that matched the temporal pattern of maternal vibration produced by a motor. They showed synchronous hatching patterns and high hatching rates. However, for mother-removed broods, which were isolated from the mother, and when we provided continuous artificial vibration that did not match the temporal pattern of the maternal vibration, embryo hatching was not only asynchronous: some embryos failed to emerge from their shells. These results lead us to infer that hatching care in P. japonensis has two functions: hatching regulation and hatching assistance. Nevertheless, several points of observational and circumstantial evidence clearly contraindicate hatching assistance. A reduction in the hatching rate might result from dependence on maternal hatching care as a strong cue in P. japonensis. We conclude that the hatching care of P. japonensis regulates the hatching pattern and serves

  5. Hatch rate of channel catfish Ictalurus punctatus (Rafinesque 1818) eggs treated with 100 mg L-1 copper sulphate pentahydrate. Aquaculture Research

    USDA-ARS?s Scientific Manuscript database

    Catfish hatcheries use copper sulfate (CuSO4) as an economical control for saprolegniasis on eggs. This study determines hatch rate of channel catfish eggs in hatching troughs containing 23.8°C flow-through well water when treated with 100 mg/L CuSO4 (ten times the proposed therapeutic dose). Eggs...

  6. Cytokines and Blastocyst Hatching.

    PubMed

    Seshagiri, Polani B; Vani, Venkatappa; Madhulika, Pathak

    2016-03-01

    Blastocyst implantation into the uterine endometrium establishes early pregnancy. This event is regulated by blastocyst- and/or endometrium-derived molecular factors which include hormones, growth factors, cell adhesion molecules, cytokines and proteases. Their coordinated expression and function are critical for a viable pregnancy. A rate-limiting event that immediately precedes implantation is the hatching of blastocyst. Ironically, blastocyst hatching is tacitly linked to peri-implantation events, although it is a distinct developmental phenomenon. The exact molecular network regulating hatching is still unclear. A number of implantation-associated molecular factors are expressed in the pre-implanting blastocyst. Among others, cytokines, expressed by peri-implantation blastocysts, are thought to be important for hatching, making blastocysts implantation competent. Pro-inflammatory (IL-6, LIF, GM-CSF) and anti-inflammatory (IL-11, CSF-1) cytokines improve hatching rates; they modulate proteases (MMPs, tPAs, cathepsins and ISP1). However, functional involvement of cytokines and their specific mediation of hatching-associated proteases are unclear. There is a need to understand mechanistic roles of cytokines and proteases in blastocyst hatching. This review will assess the available knowledge on blastocyst-derived pro-inflammatory and anti-inflammatory cytokines and their role in potentially regulating blastocyst hatching. They have implications in our understanding of early embryonic loss and infertility in mammals, including humans.

  7. Laser assisted zona hatching does not improve live birth rate in patients undergoing their first ICSI cycles

    PubMed Central

    Razi, Mohammad Hossein; Halvaei, Iman; Razi, Yasamin

    2013-01-01

    Background: Routine use of assisted hatching (AH) following ICSI is a controversial issue in the literature. There are rare studies regarding the effect of laser assisted hatching (LAH) on live birth rate. Objective: Our main goal was to evaluate the effect of LAH on delivery rate as well as congenital anomaly in patients undergoing their first ICSI cycle. Materials and Methods: A total of 182 patients subjected to ICSI were randomly aliquot into two groups of experiment and control. In experiment group, the embryos were subjected to LAH to open a hole in ZP (about 10-12 µm) while in control group, the transferred embryos were intact with no AH. The patients were followed for clinical pregnancy and delivery rate as well as congenital anomaly. All the patients were infertile due to male factor infertility and LAH and embryo transfer were done on day 2. Results: Laboratory and clinical characteristics of two groups of experiment and control were the same. There were insignificant differences between two groups of experiment and control for clinical pregnancy rate (20% vs. 23.9%, respectively, p=0.3) and live birth rate (11.11% vs. 8.6%, respectively, p=0.6). Also no significant differences were observed between two groups of experiment and control for multiple pregnancy as well as congenital anomaly. Conclusion: Routine use of LAH in first ICSI cycle for male factor patients may have no beneficial effects on clinical pregnancy and live birth rate. PMID:24639729

  8. From facultative to obligatory parental care: Interspecific variation in offspring dependency on post-hatching care in burying beetles

    PubMed Central

    Capodeanu-Nägler, Alexandra; Keppner, Eva M.; Vogel, Heiko; Ayasse, Manfred; Eggert, Anne-Katrin; Sakaluk, Scott K.; Steiger, Sandra

    2016-01-01

    Studies on the evolution of parental care have focused primarily on the costs and benefits of parental care and the life-history attributes that favour it. However, once care evolves, offspring in some taxa appear to become increasingly dependent on their parents. Although offspring dependency is a central theme in family life, the evolutionary dynamics leading to it are not fully understood. Beetles of the genus Nicrophorus are well known for their elaborate biparental care, including provisioning of their young. By manipulating the occurrence of pre- or post-hatching care, we show that the offspring of three burying beetle species, N. orbicollis, N. pustulatus, and N. vespilloides, show striking variation in their reliance on parental care. Our results demonstrate that this variation within one genus arises through a differential dependency of larvae on parental feeding, but not on pre-hatching care. In N. pustulatus, larvae appear to be nutritionally independent of their parents, but in N. orbicollis, larvae do not survive in the absence of parental feeding. We consider evolutionary scenarios by which nutritional dependency may have evolved, highlighting the role of brood size regulation via infanticide in this genus. PMID:27378180

  9. Comparative analysis of hatching rates and clutch sizes of Nile crocodile (Crocodylus niloticus) eggs collected on- and off-farm in Zimbabwe.

    PubMed

    Khosa, Patricia; Imbayarwo-Chikosi, Venancio Edward; Hamandishe, Vimbai

    2012-04-01

    The Nile crocodile (Crocodylus niloticus) is a large aquatic reptile predominant in the tropics in Africa and Zimbabwe in particular. Clutch sizes and hatching rates of Nile crocodile eggs collected from the wild and on-farm in Lowveld, Highveld and Kariba regions of Zimbabwe were evaluated. A total of 274 egg records for the period 2000 to 2008 from 39 farms were collected from the Crocodile Farmers Association of Zimbabwe. The effect of source of eggs was analysed using the non-parametric one way analysis of variance procedure of SAS Version 9.1.3. Wilcoxon signed rank test for independent samples was used to compare the mean hatching rates and clutch sizes for eggs collected from the different sources by region. The degree of association between clutch sizes and the hatching rates by source and region was determined using the Spearman's rank correlation test. Source of eggs had no effect (P > 0.05) on hatching rates in all the regions but significantly influenced (P < 0.05) clutch sizes in Lowveld and Kariba. In these regions, clutch sizes in the wild were significantly (P < 0.05) higher than those on-farm. Correlation estimates between clutch size and hatching rates were weak and non-significant (P > 0.05) for the different sources of eggs in all regions. Full utilization of the wild resource would reduce challenges relating to shortage of captive breeders and high cost of rearing breeders and hence increase productivity.

  10. 76 FR 32188 - Hatch Solar Energy Center 1, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-03

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Hatch Solar Energy Center 1, LLC; Supplemental Notice That Initial... notice in the above-referenced proceeding of Hatch Solar Energy Center 1, LLC's application for market...

  11. Hatching behavior of eastern long-necked turtles (Chelodina longicollis): The influence of asynchronous environments on embryonic heart rate and phenotype.

    PubMed

    McGlashan, Jessica K; Loudon, Fiona K; Thompson, Michael B; Spencer, Ricky-John

    2015-10-01

    Variable temperatures within a nest cause asynchronous development within clutches of freshwater turtle embryos, yet synchronous hatching occurs and is thought to be an important survival strategy for hatchlings. Metabolic compensation and circadian rhythms in heart rates of embryonic turtles indicate the potential of communication between embryos in a nest. Heart rates were used to identify metabolic circadian rhythms in clutches of an Australian freshwater turtle (Chelodina longicollis) and determine whether embryos metabolically compensate and hatch synchronously when incubated in asynchronous environments. The effects of a group environment during incubation on egg development and incubation period were also investigated during the final 3 weeks of development. Chelodina longicollis hatch synchronously and metabolically compensate so that less advanced embryos catch up to more advanced clutch-mates. Heart rates of embryos remained stable from week 4-7 in asynchronous (M=89 bpm) and synchronous (M=92 bpm) groups and declined in the final 2 weeks of incubation (M=72 and 77 bpm). Circadian rhythms were present throughout development and diel heart rates of embryos in asynchronous groups showed less deviation from the mean (M=-0.5 bpm) than synchronous groups (M=-4 bpm). Eggs incubated in groups had a significantly shorter incubation period than eggs incubated individually. Phenotypic traits including size, performance, and growth of all hatchlings were not affected. Egg position within a turtle nest is important for coordinating development throughout incubation and facilitating synchronous hatching.

  12. Pre-hatching embryo-dependent and -independent programming of endometrial function in cattle

    PubMed Central

    Sponchiado, Mariana; Gomes, Nathália Souza; Fontes, Patrícia Kubo; Martins, Thiago; del Collado, Maite; Pastore, Athos de Assumpção; Pugliesi, Guilherme; Nogueira, Marcelo Fábio Gouveia

    2017-01-01

    The bovine pre-implantation embryo secretes bioactive molecules from early development stages, but effects on endometrial function are reported to start only after elongation. Here, we interrogated spatially defined regions of the endometrium transcriptome for responses to a day 7 embryo in vivo. We hypothesize that exposure to an embryo changes the abundance of specific transcripts in the cranial region of the pregnant uterine horn. Endometrium was collected from the uterotubal junction (UTJ), anterior (IA), medial (IM) and posterior (IP) regions of the uterine horn ipsilateral to the CL 7 days after estrus from sham-inseminated (Con) or artificially inseminated, confirmed pregnant (Preg) cows. Abundance of 86 transcripts was evaluated by qPCR using a microfluidic platform. Abundance of 12 transcripts was modulated in the Preg endometrium, including classical interferon-stimulated genes (ISG15, MX1, MX2 and OAS1Y), prostaglandin biosynthesis genes (PTGES, HPGD and AKR1C4), water channel (AQP4) and a solute transporter (SLC1A4) and this was in the UTJ and IA mainly. Additionally, for 71 transcripts, abundance varied according to region of the reproductive tract. Regulation included downregulation of genes associated with proliferation (IGF1, IGF2, IGF1R and IGF2R) and extracellular matrix remodeling (MMP14, MMP19 and MMP2) and upregulation of anti-adhesive genes (MUC1) in the cranial regions of uterine horn. Physical proximity to the embryo provides paracrine regulation of endometrial function. Embryo-independent regulation of the endometrial transcriptome may support subsequent stages of embryo development, such as elongation and implantation. We speculate that successful early embryo-dependent and -independent programming fine-tune endometrial functions that are important for maintenance of pregnancy in cattle. PMID:28423001

  13. Vitamin C supplementation enhances compact morulae formation but reduces the hatching blastocyst rate of bovine somatic cell nuclear transfer embryos.

    PubMed

    Li, Qian; Wang, Yong-Sheng; Wang, Li-Jun; Zhang, Hui; Li, Rui-Zhe; Cui, Chen-Chen; Li, Wen-Zhe; Zhang, Yong; Jin, Ya-Ping

    2014-08-01

    Vitamin C, an antioxidant that reduces reactive oxygen species (ROS) in cells, is capable of significantly improving the developmental competence of porcine and mouse somatic cell nuclear transfer (SCNT) embryos, both in vitro and in vivo. In the present study, the effects of vitamin C on the developmental competence of bovine SCNT embryos were investigated. The results indicated that vitamin C (40 μg/mL) positively affected the scavenging of intracellular ROS, cleavage rate at 24 h (76.67 vs. 68.26%, p<0.05), compact morulae formation (60.83 vs. 51.30%, p<0.05), and the blastomere apoptosis index (3.70 ± 1.41 vs. 4.43% ± 1.65, p<0.05) of bovine SCNT embryos. However, vitamin C supplementation did not significantly affect the blastocyst formation rate and proportion of inner cell mass over total cells per blastocyst on day 7. Moreover, vitamin C supplementation obviously impaired the total cell numbers per blastocyst (97.20 ± 11.35 vs. 88.57 ± 10.43, p<0.05) on day 7 and the hatching blastocysts formation rate on day 9 (26.51 vs. 50.65%, p<0.05) compared with that of the untreated group. Vitamin C supplementation preferentially improved the viability of bovine SCNT embryos prior to the blastocyst stage, but did not enhance the formation and quality of blastocysts in vitro. In conclusion, the effect of vitamin C on the development of bovine SCNT embryos is complex, and vitamin C is not a suitable antioxidant chemical for the in vitro culture of bovine SCNT embryos.

  14. The role of behavior in the dispersal of newly hatched gypsy moth larvae

    Treesearch

    Michael L. Mcmanus; Michael L. Mcmanus

    1973-01-01

    Newly hatched gypsy moth larvae are morphologically and behaviorally adapted for airborne dispersal. The diel periodicity of both hatching and dispersal from the egg mass and photopositive behavior assure that larvae are in optimal position for dispersal when air turbulence is maximal at midday. The rate of larval activity depends upon ambient temperature and relative...

  15. Comparison of three lines of broiler breeders differing in ascites susceptibility or growth rate. 1. Relationship between acoustic resonance data and embryonic or hatching parameters.

    PubMed

    Tona, K; Kemps, B; Bruggeman, V; Bamelis, F; De Smit, L; Onagbesan, O; De Baerdemaeker, J; Decuypere, E

    2005-09-01

    Ascites is a prevalent cardiovascular disease among modern broilers with negative impacts on production and animal welfare. The peak of mortality due to ascites occurs at the end of the growing period, but the etiology of this problem may start during embryonic development. A few recent reports have demonstrated that the signs of ascites susceptibility are manifested during the late stages of incubation. In the current study, we used a nondestructive method based on egg acoustic resonance parameters [resonant frequency (RF) and damping] to establish a relationship between embryo physiological events during early development in broiler eggs and susceptibility to ascites. The hatching eggs of 3 broiler lines differing in ascites susceptibility were used for this study: ascites-resistant dam line (DAR), ascites-sensitive dam line (DAS), and ascites-sensitive sire line (SASL). These lines were selected on the basis of fast growth, high breast meat yield, and ascites induction at low temperatures such that the order of ascites susceptibility in terms of mortality was SASL > DAS > DAR. Eggs were incubated under standard conditions in forced-draft incubators. We measured egg weights at setting, albumen pH, Haugh units (HU) at setting, and embryo weights at d 11 and 18, at internal pipping (IP), and at hatch. The durations of IP, external pipping (EP), and hatching were also determined. At 2 hourly periods during incubation, egg RF and damping were also measured. There were differences in egg weights between DAR and SASL vs. DAS, but albumen HU, albumen pH, and the ratio of yolk weight to egg weight were similar. There were differences in RF, damping, embryonic growth rates, and hatching events. Changes in resonant frequency and damping, which certainly suggest eggshell differences among lines, were not totally related to variations in physiological events during early and late embryonic development. A comparison between DAR and DAS, between DAS and SASL, or DAR and SASL

  16. Glassfrog embryos hatch early after parental desertion.

    PubMed

    Delia, Jesse R J; Ramírez-Bautista, Aurelio; Summers, Kyle

    2014-06-22

    Both parental care and hatching plasticity can improve embryo survival. Research has found that parents can alter hatching time owing to a direct effect of care on embryogenesis or via forms of care that cue the hatching process. Because parental care alters conditions critical for offspring development, hatching plasticity could allow embryos to exploit variation in parental behaviour. However, this interaction of parental care and hatching plasticity remains largely unexplored. We tested the hypothesis that embryos hatch early to cope with paternal abandonment in the glassfrog Hyalinobatrachium fleischmanni (Centrolenidae). We conducted male-removal experiments in a wild population, and examined embryos' response to conditions with and without fathers. Embryos hatched early when abandoned, but extended development in the egg stage when fathers continued care. Paternal care had no effect on developmental rate. Rather, hatching plasticity was due to embryos actively hatching at different developmental stages, probably in response to deteriorating conditions without fathers. Our experimental results are supported by a significant correlation between the natural timing of abandonment and hatching in an unmanipulated population. This study demonstrates that embryos can respond to conditions resulting from parental abandonment, and provides insights into how variation in care can affect selection on egg-stage adaptations.

  17. Glassfrog embryos hatch early after parental desertion

    PubMed Central

    Delia, Jesse R. J.; Ramírez-Bautista, Aurelio; Summers, Kyle

    2014-01-01

    Both parental care and hatching plasticity can improve embryo survival. Research has found that parents can alter hatching time owing to a direct effect of care on embryogenesis or via forms of care that cue the hatching process. Because parental care alters conditions critical for offspring development, hatching plasticity could allow embryos to exploit variation in parental behaviour. However, this interaction of parental care and hatching plasticity remains largely unexplored. We tested the hypothesis that embryos hatch early to cope with paternal abandonment in the glassfrog Hyalinobatrachium fleischmanni (Centrolenidae). We conducted male-removal experiments in a wild population, and examined embryos' response to conditions with and without fathers. Embryos hatched early when abandoned, but extended development in the egg stage when fathers continued care. Paternal care had no effect on developmental rate. Rather, hatching plasticity was due to embryos actively hatching at different developmental stages, probably in response to deteriorating conditions without fathers. Our experimental results are supported by a significant correlation between the natural timing of abandonment and hatching in an unmanipulated population. This study demonstrates that embryos can respond to conditions resulting from parental abandonment, and provides insights into how variation in care can affect selection on egg-stage adaptations. PMID:24789892

  18. [Laser assisted hatching: Rouen University Hospital outcomes].

    PubMed

    Blessmann-Roset, J; Rives, N; Clavier, B; Milazzo, J-P; Mazurier, S; Mousset-Siméon, N; Macé, B

    2009-04-01

    Despite technical progress in In Vitro Fertilisation (IVF) procedure, embryo implantation rate remains low. Assisted hatching has been proposed to facilitate natural embryo hatching and implantation. Our study has evaluated whether laser assisted hatching improves implantation, pregnancy and live birth rates in different cases. We studied retrospectively 143 IVF cycles concerning more than 38 years old women, 166 IVF cycles after two previous implantation failures and 180 frozen-thawed embryo transfers. Population characteristics were comparable in hatched and control groups. Implantation, pregnancy and live birth rates in women more than 38 years old were comparable with or without assisted hatching. Concerning repeated implantation failures, even if implantation, pregnancy and live birth rates were higher in assisted hatching group (FIV or ICSI), the differences were not significant. After frozen-thawed embryo transfers, implantation rate was significantly better with assisted hatching (19.14% vs 8.84% [p=0.02]). Assisted hatching improves embryo implantation rate after frozen-thawed embryo transfer.

  19. Post-hatching development of mitochondrial function, organ mass and metabolic rate in two ectotherms, the American alligator (Alligator mississippiensis) and the common snapping turtle (Chelydra serpentina).

    PubMed

    Sirsat, Sarah K G; Sirsat, Tushar S; Price, Edwin R; Dzialowski, Edward M

    2016-04-15

    The ontogeny of endothermy in birds is associated with disproportionate growth of thermogenic organs and increased mitochondrial oxidative capacity. However, no similar study has been made of the development of these traits in ectotherms. For comparison, we therefore investigated the metabolism, growth and muscle mitochondrial function in hatchlings of a turtle and a crocodilian, two ectotherms that never develop endothermy. Metabolic rate did not increase substantially in either species by 30 days post-hatching. Yolk-free body mass and heart mass did not change through 30 days in alligators and heart mass was a constant proportion of body mass, even after 1 year. Yolk-free body mass and liver mass grew 36% and 27%, respectively, in turtles during the first 30 days post-hatch. The mass-specific oxidative phosphorylation capacity of mitochondria, assessed using permeabilized muscle fibers, increased by a non-significant 47% in alligator thigh and a non-significant 50% in turtle thigh over 30 days, but did not increase in the heart. This developmental trajectory of mitochondrial function is slower and shallower than that previously observed in ducks, which demonstrate a 90% increase in mass-specific oxidative phosphorylation capacity in thigh muscles over just a few days, a 60% increase in mass-specific oxidative phosphorylation capacity of the heart over a few days, and disproportionate growth of the heart and other organs. Our data thus support the hypothesis that these developmental changes in ducks represent mechanistic drivers for attaining endothermy. © 2016. Published by The Company of Biologists Ltd.

  20. Post-hatching development of mitochondrial function, organ mass and metabolic rate in two ectotherms, the American alligator (Alligator mississippiensis) and the common snapping turtle (Chelydra serpentina)

    PubMed Central

    Sirsat, Sarah K. G.; Sirsat, Tushar S.; Price, Edwin R.; Dzialowski, Edward M.

    2016-01-01

    ABSTRACT The ontogeny of endothermy in birds is associated with disproportionate growth of thermogenic organs and increased mitochondrial oxidative capacity. However, no similar study has been made of the development of these traits in ectotherms. For comparison, we therefore investigated the metabolism, growth and muscle mitochondrial function in hatchlings of a turtle and a crocodilian, two ectotherms that never develop endothermy. Metabolic rate did not increase substantially in either species by 30 days post-hatching. Yolk-free body mass and heart mass did not change through 30 days in alligators and heart mass was a constant proportion of body mass, even after 1 year. Yolk-free body mass and liver mass grew 36% and 27%, respectively, in turtles during the first 30 days post-hatch. The mass-specific oxidative phosphorylation capacity of mitochondria, assessed using permeabilized muscle fibers, increased by a non-significant 47% in alligator thigh and a non-significant 50% in turtle thigh over 30 days, but did not increase in the heart. This developmental trajectory of mitochondrial function is slower and shallower than that previously observed in ducks, which demonstrate a 90% increase in mass-specific oxidative phosphorylation capacity in thigh muscles over just a few days, a 60% increase in mass-specific oxidative phosphorylation capacity of the heart over a few days, and disproportionate growth of the heart and other organs. Our data thus support the hypothesis that these developmental changes in ducks represent mechanistic drivers for attaining endothermy. PMID:26962048

  1. Time-dependent rates of molecular evolution.

    PubMed

    Ho, Simon Y W; Lanfear, Robert; Bromham, Lindell; Phillips, Matthew J; Soubrier, Julien; Rodrigo, Allen G; Cooper, Alan

    2011-08-01

    For over half a century, it has been known that the rate of morphological evolution appears to vary with the time frame of measurement. Rates of microevolutionary change, measured between successive generations, were found to be far higher than rates of macroevolutionary change inferred from the fossil record. More recently, it has been suggested that rates of molecular evolution are also time dependent, with the estimated rate depending on the timescale of measurement. This followed surprising observations that estimates of mutation rates, obtained in studies of pedigrees and laboratory mutation-accumulation lines, exceeded long-term substitution rates by an order of magnitude or more. Although a range of studies have provided evidence for such a pattern, the hypothesis remains relatively contentious. Furthermore, there is ongoing discussion about the factors that can cause molecular rate estimates to be dependent on time. Here we present an overview of our current understanding of time-dependent rates. We provide a summary of the evidence for time-dependent rates in animals, bacteria and viruses. We review the various biological and methodological factors that can cause rates to be time dependent, including the effects of natural selection, calibration errors, model misspecification and other artefacts. We also describe the challenges in calibrating estimates of molecular rates, particularly on the intermediate timescales that are critical for an accurate characterization of time-dependent rates. This has important consequences for the use of molecular-clock methods to estimate timescales of recent evolutionary events. © 2011 Blackwell Publishing Ltd.

  2. Laser-assisted hatching in assisted reproduction.

    PubMed

    Montag, M; van der Ven, H

    1999-09-01

    The use of a 1.48 um diode laser for assisted hatching was investigated in animal experimentation. Laser assisted hatching was offered to patients with advanced maternal age to evaluate a possible benefit. Using the Fertilase(r) system we investigated the impact of openings with different size in the zona of mouse embryos on the hatching process, as well as that of two openings. Laser-drilling was performed at the blastocyst stage to look for differences in timing and efficacy of hatching. The possible benefit of assisted hatching was studied in 24 couples with advanced maternal age (38.8+2.1 years) and compared to a control group (37.8+2.5 years) treated in the same time period but without assisted hatching. A certain diameter of a laser drilled opening in the zona pellucida is necessary for efficient hatching. When two openings are present in the zona, the embryo will use both openings for hatching and subsequently become trapped. Laser-drilling at th e expanded blastocyst stage causes an immediate collapse of treated blastocysts and the onset of hatching is retarded. Assisted hatching in 24 patients with advanced maternal age resulted in a significant increase (p<0.01) in the implantation rate when compared to 24 untreated patients. The use of a 1.48 microm diode laser to drill an opening into the zona pellucida provides a good alternate to conventionally applied techniques. The procedure is efficient and safe as long as it is applied properly. In a human in vitro fertilization program, selected patients will have a benefit form assisted hatching.

  3. In vitro embryo development and blastocyst hatching rates following vitrification of river buffalo embryos produced from oocytes recovered from slaughterhouse ovaries or live animals by ovum pick-up.

    PubMed

    Manjunatha, B M; Gupta, P S P; Ravindra, J P; Devaraj, M; Nandi, S

    2008-03-03

    The present study was undertaken to determine whether the source of oocytes (ovum pick up versus slaughterhouse ovaries) affected in vitro embryo production and embryo survival (as measured by blastocyst hatching rates) following vitrification in buffaloes (Bubalus bubalis). Oocytes recovered from live buffaloes (n=6) by ovum pick up (OPU) and by manual aspiration from slaughterhouse ovaries were in vitro matured, fertilized and cultured to blastocyst stage under same culture conditions. Vitrification of blastocysts was carried out in two steps at 24 degrees C. Embryos were equilibrated in 10% EG+10% DMSO+0.3 M sucrose in base medium for 4 min. Subsequently, the embryos were transferred into 25% EG+25% DMSO+0.3 M sucrose in base medium for 45 s and then the embryos were loaded into straws and immersed in liquid nitrogen. Following warming, blastocysts were cultured in vitro for 48 h to assess hatching. Oocytes derived from live animals by OPU resulted in a significantly higher blastocyst yield then those derived from slaughterhouse ovaries (30.6+/-4.3 versus 18.5+/-1.8). Blastocyst hatching rates following vitrification of buffalo embryos produced from the oocytes collected from live animals by OPU was significantly higher than the oocytes collected from slaughterhouse ovaries (52.8+/-4.2 versus 40.2+/-4.4). In conclusion, the present study showed that source of oocytes (OPU versus slaughterhouse ovaries) affects the in vitro embryo development and blastocyst hatching rates following vitrification of embryos in buffaloes.

  4. Effect of L-carnitine on in vitro developmental rate, the zona pellucida and hatching of blastocysts and their cell numbers in mouse embryos

    PubMed Central

    Khanmohammadi, Nasrin; Movahedin, Mansoureh; Safari, Manouchehr; Sameni, Hamid Reza; Yousefi, Behpour; Jafari, Behnaz; Zarbakhsh, Sam

    2016-01-01

    L-carnitine (LC) is an antioxidant with the ability to promote the growth in vitro embryo. Objective: The goal was to evaluate the effect of LC on some indicators of embryo development and blastocyst quality including zona pellucid (ZP) thickness, the hatching of blastocysts and their cell numbers. Materials and Methods: Mouse embryos were randomly divided into five groups and incubated with different concentrations of LC (I; 0, II; 0.5, III; 1, IV; 2 and V; 4 mg/ml) from 2-cell to hatched blastocyst. The percentage of blastocysts and hatched blastocysts was calculated. Blastocysts ZP thickness was measured and the number of blastocyst cells was counted using Hoechst and propidium iodide (PI) staining. Results: The results showed concentration of 0.5 mg/ml of LC had an antioxidant effect as in this group, the percentage of blastocysts and hatched blactocysts (p=0.01), the ZP thickness (p=0.00) and the number of blastocyst inner cell mass were significantly more favorable than the control group (p=0.03); and concentration of 4 mg/ml of LC had a toxic effect on embryo development and blastocyst quality (p=0.00). Conclusion: The results suggest that LC may increase the number of blastocyst cells, which probably helps to expand the blastocyst and thinning of the ZP thickness and, therefore, creating a successful hatching for implantation. PMID:27921089

  5. Heart rate dependency of JT interval sections.

    PubMed

    Hnatkova, Katerina; Johannesen, Lars; Vicente, Jose; Malik, Marek

    2017-08-09

    Little experience exists with the heart rate correction of J-Tpeak and Tpeak-Tend intervals. In a population of 176 female and 176 male healthy subjects aged 32.3±9.8 and 33.1±8.4years, respectively, curve-linear and linear relationship to heart rate was investigated for different sections of the JT interval defined by the proportions of the area under the vector magnitude of the reconstructed 3D vectorcardiographic loop. The duration of the JT sub-section between approximately just before the T peak and almost the T end was found heart rate independent. Most of the JT heart rate dependency relates to the beginning of the interval. The duration of the terminal T wave tail is only weakly heart rate dependent. The Tpeak-Tend is only minimally heart rate dependent and in studies not showing substantial heart rate changes does not need to be heart rate corrected. For any correction formula that has linear additive properties, heart rate correction of JT and JTpeak intervals is practically the same as of the QT interval. However, this does not apply to the formulas in the form of Int/RR(a) since they do not have linear additive properties. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Effects of transgenic sterilization constructs and their repressor compounds on hatch, developmental rate and early survival of electroporated channel catfish embryos and fry.

    PubMed

    Su, Baofeng; Shang, Mei; Li, Chao; Perera, Dayan A; Pinkert, Carl A; Irwin, Michael H; Peatman, Eric; Grewe, Peter; Patil, Jawahar G; Dunham, Rex A

    2015-04-01

    Channel catfish (Ictalurus punctatus) embryos were electroporated with sterilization constructs targeting primordial germ cell proteins or with buffer. Some embryos then were treated with repressor compounds, cadmium chloride, copper sulfate, sodium chloride or doxycycline, to prevent expression of the transgene constructs. Promoters included channel catfish nanos and vasa, salmon transferrin (TF), modified yeast Saccharomyces cerevisiae copper transport protein (MCTR) and zebrafish racemase (RM). Knock-down systems were the Tet-off (nanos and vasa constructs), MCTR, RM and TF systems. Knock-down genes included shRNAi targeting 5' nanos (N1), 3' nanos (N2) or dead end (DND), or double-stranded nanos RNA (dsRNA) for overexpression of nanos mRNA. These constructs previously were demonstrated to knock down nanos, vasa and dead end, with the repressors having variable success. Exogenous DNA affected percentage hatch (% hatch), as all 14 constructs, except for the TF dsRNA, TF N1 (T), RM DND (C), vasa DND (C), vasa N1 (C) and vasa N2 (C), had lower % hatch than the control electroporated with buffer. The MCTR and RM DND (T) constructs resulted in delayed hatch, and the vasa and nanos constructs had minimal effects on time of hatch (P < 0.05). Cadmium chloride appeared to counteract the slow development caused by the TF constructs in two TF treatments (P < 0.05). The 4 ppt sodium chloride treatment for the RM system decreased % hatch (P < 0.05) and slowed development. In the case of nanos constructs, doxycycline greatly delayed hatch (P < 0.05). Adverse effects of the transgenes and repressors continued for several treatments for the first 6 days after hatch, but only in a few treatments during the next 10 days. Repressors and gene expression impacted the yield of putative transgenic channel catfish fry, and need to be considered and accounted for in the hatchery phase of producing transgenically sterilized catfish fry and their fertile counterparts. This fry output

  7. Hatching Behavior of Potato Cyst Nematodes from the Canary Islands

    PubMed Central

    Gonzalez, J. A.; Phillips, M. S.

    1996-01-01

    The present work investigated early hatching differences in naturally occuring field populations and newly reared populations of potato cyst nematodes from the Canary Islands. Hatching behavior of the two species appears to be distinct, with more juveniles hatched from G. pallida that hatch earlier and over a shorter time than G. rostochiensis. The hatching rate of 3-year-old PCN populations was more than double (mean 44.5% ñ 1) that shown by newly reared populations (mean 19.1% ñ 12.5), and those that could be classified as pathotype Pa 1 (Pa 1 and P 13) were found to hatch particularly poorly. Significant differences were also observed in the juveniles released in tap water between newly reared populations of both species, with mean hatch significantly higher for G. rostochiensis. The results are discussed in relation to the implication that these findings may have for competition between the two species of PCN in the field. PMID:19277163

  8. Effect of short-term exposure to methyl-tert-butyl ether and tert-butyl alcohol on the hatch rate and development of the African catfish, Clarias gariepinus.

    PubMed

    Moreels, David; Lodewijks, Pieter; Zegers, Hans; Rurangwa, Eugène; Vromant, Nico; Bastiaens, Leen; Diels, Ludo; Springael, Dirk; Merckx, Roel; Ollevier, Frans

    2006-02-01

    Methyl tert-butyl ether (MTBE), a synthetic chemical used as a fuel additive, has been detected more frequently in the environment than previously. In this study, we examine the effects of MTBE (up to 100 mg/L) and its primary metabolite tertbutyl alcohol (TBA) (up to 1,400 mg/L) on the hatch rate and larval development of the African catfish Clarias gariepinus. Exposure to higher MTBE concentrations resulted in deformed eyes, mouthparts, and spinal cord and in increased larval mortality. Methyl tert-butyl ether exposure had no significant impact on egg viability, whereas TBA induced a decline of hatch rate. The MTBE can be regarded as a pollutant with toxicological effects on catfish larvae at concentrations above 50 mg/L. Although such concentrations greatly surpass present-day concentrations found in surface water (0.088 mg/L), concentrations up to 200 mg/L have been detected in groundwater.

  9. Convexity, gauge-dependence and tunneling rates

    NASA Astrophysics Data System (ADS)

    Plascencia, Alexis D.; Tamarit, Carlos

    2016-10-01

    We clarify issues of convexity, gauge-dependence and radiative corrections in relation to tunneling rates. Despite the gauge dependence of the effective action at zero and finite temperature, it is shown that tunneling and nucleation rates remain independent of the choice of gauge-fixing. Taking as a starting point the functional that defines the transition amplitude from a false vacuum onto itself, it is shown that decay rates are exactly determined by a non-convex, false vacuum effective action evaluated at an extremum. The latter can be viewed as a generalized bounce configuration, and gauge-independence follows from the appropriate Nielsen identities. This holds for any election of gauge-fixing that leads to an invertible Faddeev-Popov matrix.

  10. The load dependence of rate constants.

    PubMed

    Walcott, Sam

    2008-06-07

    As experimental techniques in biophysics have progressed at the single molecule level, there has been considerable interest in understanding how external mechanical influences (such as load) affect chemical reactions. The majority of biophysical studies investigating load-dependent kinetics use an equation where the rate constant exponentially depends on force, which is sometimes called Bell's equation. This equation requires the determination of two parameters that describe the potential energy-strain function: k(0), which is the reaction rate in the absence of load, and x(c), which is the difference in strain between the reactant and transition states. However, there have been theoretical studies based on Kramers' theory suggesting that the rate constant should have load-dependent pre-exponential terms and nonlinear load-dependent terms in the exponential. Kramers' theory requires an exact knowledge of the potential energy-strain function, which is in general not known for an experimental system. Here, we derive a general approximation of Kramers' theory where the potential energy-strain function is described by five parameters, which can, for small loads, be reduced to four-, three-, and finally to two parameters (Bell's equation). We then use an idealized physical system to validate our approximations to Kramers' theory and show how they can predict parameters of interest (such as k(0) and x(c)) better than Bell's equation. Finally, we show previously published experimental data that are not well fitted by Bell's equation but are adequately fitted by these more exact equations.

  11. Hatching Eggs in the Classroom.

    ERIC Educational Resources Information Center

    Smith, Robert W.

    1984-01-01

    This article provides detailed instructions on how to hatch chicken eggs. Sections include: (1) making the incubator; (2) making the brooder; (3) guidelines for hatching eggs; (4) from incubator to brooder; and (5) recommended readings. (JMK)

  12. Hatching Eggs in the Classroom.

    ERIC Educational Resources Information Center

    Smith, Robert W.

    1984-01-01

    This article provides detailed instructions on how to hatch chicken eggs. Sections include: (1) making the incubator; (2) making the brooder; (3) guidelines for hatching eggs; (4) from incubator to brooder; and (5) recommended readings. (JMK)

  13. Mechanism Guides Hatch Through Hatchway

    NASA Technical Reports Server (NTRS)

    Barron, Daniel R.; Kennedy, Steven E.

    1993-01-01

    Elliptical hatch designed to move through hatchway to make pressure-assisted seal with either side of bulkhead. Compact three-degree-of-freedom mechanism guides hatch through hatchway or holds hatch off to one side to facilitate passage of crew and/or equipment. Hatches and mechanisms used in submarines, pressure chambers (including hyperbaric treatment chambers), vacuum chambers, and vacuum-or-pressure test chambers.

  14. Mechanism Guides Hatch Through Hatchway

    NASA Technical Reports Server (NTRS)

    Barron, Daniel R.; Kennedy, Steven E.

    1993-01-01

    Elliptical hatch designed to move through hatchway to make pressure-assisted seal with either side of bulkhead. Compact three-degree-of-freedom mechanism guides hatch through hatchway or holds hatch off to one side to facilitate passage of crew and/or equipment. Hatches and mechanisms used in submarines, pressure chambers (including hyperbaric treatment chambers), vacuum chambers, and vacuum-or-pressure test chambers.

  15. Extremely low frequency magnetic field and the hatching rate of Fasciola hepatica eggs, the fecundity and survival of liver fluke-infected snail, Lymnaea truncatula.

    PubMed

    Kołodziejczyk, Lidia; Kuźna-Grygiel, Wanda; Gonet, Bolesław; Podraza, Wojciech

    2010-01-01

    Eggs of Fasciola hepatica were exposed for 10 days to extremely low frequency magnetic field (ELFMF) at the frequency of 50 Hz and density of 2 mT (rms). The results show an accelerated hatching of F. hepatica eggs in relation to control (non-exposed) group. The host snails, Lymnaea truncatula, were divided into three groups; those of groups I and II were infected with the miracidia of F. hepatica hatched from control egg culture, whereas those of group III were infected with miracidia hatched from eggs affected by ELFMF. Thereafter, snails of groups II and III were exposed to ELFMF for 53 days, whereas those of group I were not exposed. At day 14 post infection, a significant decrease was observed in the number of cocoons laid by snails of group III, compared with control. Also, significant mortality in group III snails was observed 42 days post infection. The increased mortality and a lower number of cocoons laid by group III snails have probably resulted from enhanced stimulation of metacercarial parthenogenetic reproduction in consequence of infecting the molluscs with miracidia reared under ELFMF.

  16. Rate-dependent spallation properties of tantalum

    SciTech Connect

    Johnson, J.N.; Hixson, R.S.; Tonks, D.L.; Zurek, A.K.

    1995-09-01

    Spallation experiments are conducted on high-purity tantalum using VISAR instrumentation for impact stresses of 9.5 GPa and 6.0 GPa. The high-amplitude experiment exhibits very rapid initial spall separation, while the low-amplitude shot is only slightly above the threshold for void growth and thus exhibits distinct rate-dependent spallation behavior. These experiments are analyzed in terms of simple tensile fracture criteria, a standard rate-dependent void-growth model, and a rate-dependent void growth model in which the expected plastic volume strain makes no contribution to the relaxation of the mean stress. Recovery tests and VISAR measurements suggest an additional resistance to spallation that follows the rapid coalescence of voids; this effect is termed the secondary spall resistance and is due to the convoluted nature of the spall plane and the resulting interlocking fracture pattern that is developed and for which the stress remains unrelieved until the spall planes have separated several hundred microns.

  17. Rates of oxygen uptake increase independently of changes in heart rate in late stages of development and at hatching in the green iguana, Iguana iguana.

    PubMed

    Sartori, Marina R; Abe, Augusto S; Crossley, Dane A; Taylor, Edwin W

    2017-03-01

    Oxygen consumption (VO2), heart rate (fH), heart mass (Mh) and body mass (Mb) were measured during embryonic incubation and in hatchlings of green iguana (Iguana iguana). Mean fH and VO2 were unvarying in early stage embryos. VO2 increased exponentially during the later stages of embryonic development, doubling by the end of incubation, while fH was constant, resulting in a 2.7-fold increase in oxygen pulse. Compared to late stage embryos, the mean inactive level of VO2 in hatchlings was 1.7 fold higher, while fH was reduced by half resulting in a further 3.6 fold increase in oxygen pulse. There was an overall negative correlation between mean fH and VO2 when data from hatchlings was included. Thus, predicting metabolic rate as VO2 from measurements of fH is not possible in embryonic reptiles. Convective transport of oxygen to supply metabolism during embryonic incubation was more reliably indicated as an index of cardiac output (COi) derived from the product of fH and Mh. However, a thorough analysis of factors determining rates of oxygen supply during development and eclosion in reptiles will require cannulation of blood vessels that proved impossible in the present study, to determine oxygen carrying capacity by the blood and arteriovenous oxygen content difference (A-V diff), plus patterns of blood flow. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Spread of hatch and delayed feed access affect post hatch performance of female broiler chicks up to day 5.

    PubMed

    Wang, Y; Li, Y; Willems, E; Willemsen, H; Franssens, L; Koppenol, A; Guo, X; Tona, K; Decuypere, E; Buyse, J; Everaert, N

    2014-04-01

    It is not rare that newly hatched chicks remain without feed for about 24 to 48 h before they are placed on farms due to a series of logistic operations. Furthermore, the spread in hatching time can also mount up to 30 to 48 h for late v. early hatchers. In other words, the practice is a complex combination of spread of hatch and delayed feed access. The present study was aimed to investigate the combined effects of hatching time with a delay in feed access of 48 h, starting from their hatch-time (biological age). When chicks had access to feed immediately after hatch, late hatchers had a higher feed intake and relative growth rate up to day 5 compared with their early hatched counterparts. Feed deprivation during the first 48 h resulted in retarded early growth rate, which was further aggravated by an impaired feed intake after refeeding. In addition, the differential effects of hatching time on relative growth rate and feed intake observed in immediately fed chicks were eliminated by the 48 h feed delay. The yolk utilization after hatch was faster for the late hatchers up to biological day 2 regardless of the feeding treatments. Hatching muscle glycogen content was higher in the late hatchers compared with that of their early counterparts at hatch and at biological day 2 independent of feeding treatment. Moreover, the liver glycogen content of the late hatchers was also higher at hatch. For the immediately fed chicks, the proportional breast muscle weight of the late hatchers was higher at biological day 2 and 5. For the starved chicks, on the other hand, this effect was only observed after they had access to feed (biological day 5). The different plasma T3 levels at hatch may have contributed to the different post hatch performance. It is concluded that the spread of hatch influenced post hatch performance, especially appetite and growth at least until day 5. Moreover, the delay in feed access interacted with the hatching time and caused adverse effects on the

  19. Corticosterone stimulates hatching of late-term tree lizard embryos.

    PubMed Central

    Weiss, Stacey L.; Johnston, Gwynne; Moore, Michael C.

    2007-01-01

    The regulation of hatching in oviparous animals is important for successful reproduction and survival, but is poorly understood. We unexpectedly found that RU-486, a progesterone and glucocorticoid antagonist, interferes with hatching of viable tree lizard (Urosaurus ornatus) embryos in a dose-dependent manner and hypothesized that embryonic glucocorticoids regulate hatching. To test this hypothesis, we treated eggs with corticosterone (CORT) or vehicle on Day 30 (85%) of incubation, left other eggs untreated, and observed relative hatch order and hatch time. In one study, the CORT egg hatched first in 9 of 11 clutches. In a second study, the CORT egg hatched first in 9 of 12 clutches, before vehicle-treated eggs in 10 of 12 clutches, and before untreated eggs in 7 of 9 clutches. On average, CORT eggs hatched 18.2h before vehicle-treated eggs and 11.6h before untreated eggs. Thus, CORT accelerates hatching of near-term embryos and RU-486 appears to block this effect. CORT may mobilize energy substrates that fuel hatching and/or accelerate lung development, and may provide a mechanism by which stressed embryos escape environmental stressors. PMID:17208477

  20. Time-Dependent Rate Phenomenon in Viruses

    PubMed Central

    Aiewsakun, Pakorn

    2016-01-01

    ABSTRACT Among the most fundamental questions in viral evolutionary biology are how fast viruses evolve and how evolutionary rates differ among viruses and fluctuate through time. Traditionally, viruses are loosely classed into two groups: slow-evolving DNA viruses and fast-evolving RNA viruses. As viral evolutionary rate estimates become more available, it appears that the rates are negatively correlated with the measurement timescales and that the boundary between the rates of DNA and RNA viruses might not be as clear as previously thought. In this study, we collected 396 viral evolutionary rate estimates across almost all viral genome types and replication strategies, and we examined their rate dynamics. We showed that the time-dependent rate phenomenon exists across multiple levels of viral taxonomy, from the Baltimore classification viral groups to genera. We also showed that, by taking the rate decay dynamics into account, a clear division between the rates of DNA and RNA viruses as well as reverse-transcribing viruses could be recovered. Surprisingly, despite large differences in their biology, our analyses suggested that the rate decay speed is independent of viral types and thus might be useful for better estimation of the evolutionary time scale of any virus. To illustrate this, we used our model to reestimate the evolutionary timescales of extant lentiviruses, which were previously suggested to be very young by standard phylogenetic analyses. Our analyses suggested that these viruses are millions of years old, in agreement with paleovirological evidence, and therefore, for the first time, reconciled molecular analyses of ancient and extant viruses. IMPORTANCE This work provides direct evidence that viral evolutionary rate estimates decay with their measurement timescales and that the rate decay speeds do not differ significantly among viruses despite the vast differences in their molecular features. After adjustment for the rate decay dynamics, the

  1. Determination of Time Dependent Virus Inactivation Rates

    NASA Astrophysics Data System (ADS)

    Chrysikopoulos, C. V.; Vogler, E. T.

    2003-12-01

    A methodology is developed for estimating temporally variable virus inactivation rate coefficients from experimental virus inactivation data. The methodology consists of a technique for slope estimation of normalized virus inactivation data in conjunction with a resampling parameter estimation procedure. The slope estimation technique is based on a relatively flexible geostatistical method known as universal kriging. Drift coefficients are obtained by nonlinear fitting of bootstrap samples and the corresponding confidence intervals are obtained by bootstrap percentiles. The proposed methodology yields more accurate time dependent virus inactivation rate coefficients than those estimated by fitting virus inactivation data to a first-order inactivation model. The methodology is successfully applied to a set of poliovirus batch inactivation data. Furthermore, the importance of accurate inactivation rate coefficient determination on virus transport in water saturated porous media is demonstrated with model simulations.

  2. Photos above SM Hatch

    NASA Image and Video Library

    2013-01-02

    View of Yuri Alexievich Gagarin (first space traveler) photo and other photos,above Service Module (SM) hatch. The blue and white rosette on the left with the writing пора в космос is the symbol and name of the Russian television program for children that covers cosmonautic and International Space Station (ISS) topics. Photo was taken during Expedition 34.

  3. 29 CFR 1918.31 - Hatch coverings.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 'tween-decks unless all hatch beams are in place under the hatch covers. (c) Missing, broken, or poorly... covers and hatch beams not of uniform size shall be placed only in the hatch, deck, and section in which...

  4. Ovulation Order Mediates a Trade-Off between Pre-Hatching and Post-Hatching Viability in an Altricial Bird

    PubMed Central

    Sockman, Keith W.

    2008-01-01

    Simultaneously dependent siblings often compete for parentally provided resources. This competition may lead to mortality, the probability of which may be a function, in part, of the individual offspring's production order. In birds, serial ovulation followed by hatching asynchrony of simultaneous dependents leads to differences in post-hatching survival that largely depend on ovulation (laying) order. This has led to the widespread assumption that early-laid eggs are of greater value and therefore should possess different maternally manipulated characteristics than later-laid eggs. However, this perspective ignores the potential effect of laying order on pre-hatching viability, an effect which some studies suggest should offset the effect of laying order on post-hatching viability. I examined the relationship between laying order and hatching and fledging probability in wild, free-living Lincoln's sparrows (Melospiza lincolnii). In broods with complete hatching success, first-laid and therefore first-hatched offspring had the highest probability of fledging, and fledging probability declined with increasing laying order. However, first-laid eggs were less likely than later-laid eggs to hatch. This effect of laying order on pre-hatching viability seemed to offset that on post-hatching viability, and, consistently, maternal investment in egg size varied little if at all with respect to laying order. These results suggest that ovulation order mediates a trade-off between pre-hatching and post-hatching viability and should encourage a re-evaluation of the solitary role post-embryonic survival often plays when researchers make assumptions about the value of propagules based on the order in which they are produced. PMID:18335056

  5. Time-dependent freezing rate parcel model

    NASA Astrophysics Data System (ADS)

    Vali, G.; Snider, J. R.

    2015-02-01

    The time-dependent freezing rate (TDFR) model here described represents the formation of ice particles by immersion freezing within an air parcel. The air parcel trajectory follows an adiabatic ascent and includes a period in time when the parcel remains stationary at the top of its ascent. The description of the ice nucleating particles (INPs) in the air parcel is taken from laboratory experiments with cloud and precipitation samples and is assumed to represent the INP content of the cloud droplets in the parcel. Time dependence is included to account for variations in updraft velocity and for the continued formation of ice particles under isothermal conditions. The magnitudes of these factors are assessed on the basis of laboratory measurements. Results show that both factors give rise to three-fold variations in ice concentration for a realistic range of the input parameters. Refinements of the parameters specifying time dependence and INP concentrations are needed to make the results more specific to different atmospheric aerosol types. The simple model framework described in this paper can be adapted to more elaborate cloud models. The results here presented can help guide decisions on whether to include a time-dependent ice nucleation scheme or a simpler singular description in models.

  6. Time-dependent freezing rate parcel model

    NASA Astrophysics Data System (ADS)

    Vali, G.; Snider, J. R.

    2014-11-01

    The Time-Dependent Freezing Rate (TDFR) model here described represents the formation of ice particles by immersion freezing within an air parcel. The air parcel trajectory follows an adiabatic ascent and includes a period at time with the parcel remaining stationary at the top of its ascent. The description of the ice nucleating particles (INPs) in the air parcel is taken from laboratory experiments with cloud and precipitation samples and is assumed to represent the INP content of the cloud droplets in the parcel. Time-dependence is included to account for variations in updraft velocity and for the continued formation of ice particles at isothermal conditions. The magnitudes of these factors are assessed on the basis of laboratory measurements. Results show that both factors give rise to factors of about 3 variations in ice concentration for a realistic range of the input parameters. Refinements of the parameters specifying time-dependence and INP concentrations are needed to make the results more specific to different atmospheric aerosol types. The simple model framework described in this paper can be adapted to more elaborate cloud models. The results here presented can help guide decisions on whether to include a time-dependent ice nucleation scheme or a simpler singular description in models.

  7. Aspects of hatching success and chick survival in Gull-billed Terns in coastal Virginia

    USGS Publications Warehouse

    Eyler, T.B.; Erwin, R.M.; Stotts, D.B.; Hatfield, J.S.

    1999-01-01

    Because of a long-term population decline in Gull-billed Terns (Sterna nilotica) nesting along the coast of Virginia, we began a three year study in 1994 to monitor hatching success and survival of Gull-billed Tern chicks at several Virginia colony sites. Colonies were located on either small, storm-deposited shellpiles along marsh fringes or large, sandshell overwash fans of barrier islands. Nests were monitored one to three times a week for hatching success, and enclosures were installed around selected nests to monitor chick survival from hatching to about two weeks of age. Hatching success was lower in marsh colonies than island colonies, and was lower in 1995 than in 1994 and 1996, primarily because of flooding. The average brood size of nests where at least one chick hatched was 1.99 chicks. Survival rates of chicks to 14 days depended on hatch order and year but not brood size (one vs. two or more) or time of season. A-chicks had higher survival rates than B-chicks and third-hatched C-chicks (0.661 compared to 0.442 and 0.357, respectively). The year effect was significant only for A-chicks, with lower survival in 1994 (0.50) than in 1995 (0.765) or 1996 (0.758). Overall, productivity was low (0.53 chick per nest) compared to estimates for colonies in Denmark, and was attributable to nest flooding by spring and storm-driven high tides and chick predation, presumably mostly by Great Horned Owls (Bubo virginianus).

  8. Environmentally cued hatching in reptiles.

    PubMed

    Doody, J S

    2011-07-01

    Evidence is accumulating for the widespread occurrence of environmentally cued hatching (ECH) in animals, but its diversity and distribution across taxa are unknown. Herein I review three types of ECH in reptiles: early hatching, delayed hatching, and synchronous hatching. ECH is currently known from 43 species, including turtles, crocodilians, lizards, snakes, tuatara, and possibly worm lizards. Early hatching caused by physical disturbance (e.g., vibrations) is the most commonly reported ECH across all groups; although it apparently serves an antipredator function in some species, its adaptive value is unknown in most. Delayed hatching, characterized by metabolic depression or embryonic aestivation, and sometimes followed by a hypoxic cue (flooding), occurs in some turtles and possibly in monitor lizards and crocodilians; in some of these species delayed hatching serves to defer hatching from the dry season until the more favorable conditions of the wet season. Synchronous hatching, whereby sibling eggs hatch synchronously despite vertical thermal gradients in the nest, occurs in some turtles and crocodilians. Although vibrations and vocalizations in hatching-competent embryos can stimulate synchronous hatching, cues promoting developmentally less advanced embryos to catch up with more advanced embryos have not been confirmed. Synchronous hatching may serve to dilute predation risk by promoting synchronous emergence or reduce the period in which smells associated with hatching can attract predators to unhatched eggs. Within species, advancing our understanding of ECH requires three types of studies: (1) experiments identifying hatching cues and the plastic hatching period, (2) experiments disentangling hypotheses about multiple hatching cues, and (3) investigations into the environmental context in which ECH might evolve in different species (major predators or abiotic influences on the egg, embryo, and hatchling). Among species and groups, surveys for ECH are

  9. OA-7 Hatch Opening

    NASA Image and Video Library

    2017-03-02

    Inside the Payload Hazardous Servicing Facility at NASA's Kennedy Space Center in Florida, technicians open the hatch on the Orbital ATK Cygnus pressurized cargo module to prepare for late stowage of supplies and hardware. The Orbital ATK CRS-7 commercial resupply services mission to the International Space Station is scheduled to launch atop a United Launch Alliance Atlas V rocket from Space Launch Complex 41 at Cape Canaveral Air Force Station targeted for March 24, 2017. Cygnus will deliver 7,600 pounds of supplies, equipment and scientific research materials to the space station.

  10. Heart Rate Dependency of Large Artery Stiffness.

    PubMed

    Tan, Isabella; Spronck, Bart; Kiat, Hosen; Barin, Edward; Reesink, Koen D; Delhaas, Tammo; Avolio, Alberto P; Butlin, Mark

    2016-07-01

    Carotid-femoral pulse wave velocity (cfPWV) quantifies large artery stiffness, it is used in hemodynamic research and is considered a useful cardiovascular clinical marker. cfPWV is blood pressure (BP) dependent. Intrinsic heart rate (HR) dependency of cfPWV is unknown because increasing HR is commonly accompanied by increasing BP. This study aims to quantify cfPWV dependency on acute, sympathovagal-independent changes in HR, independent of BP. Individuals (n=52, age 40-93 years, 11 female) with in situ cardiac pacemakers or cardioverter defibrillators were paced at 60, 70, 80, 90, and 100 bpm. BP and cfPWV were measured at each HR. Both cfPWV (mean [95% CI], 0.31 [0.26-0.37] m/s per 10 bpm; P<0.001) and central aortic diastolic pressure (3.78 [3.40-4.17] mm Hg/10 bpm; P<0.001) increased with HR. The HR effect on cfPWV was isolated by correcting the BP effects by 3 different methods: (1) statistically, by a linear mixed model; (2) mathematically, using an exponential relationship between BP and cross-sectional lumen area; and (3) using measured BP dependency of cfPWV derived from changes in BP induced by orthostatic changes (seated and supine) in a subset of subjects (n=17). The BP-independent effects of HR on cfPWV were quantified as 0.20 [0.11-0.28] m/s per 10 bpm (P<0.001, method 1), 0.16 [0.11-0.22] m/s per 10 bpm (P<0.001, method 2), and 0.16 [0.11-0.21] m/s per 10 bpm (P<0.001, method 3). With a mean HR dependency in the range of 0.16 to 0.20 m/s per 10 bpm, cfPWV may be considered to have minimal physiologically relevant changes for small changes in HR, but larger differences in HR must be considered as contributing to significant differences in cfPWV.

  11. [Assisted hatching following embryo implantation failure].

    PubMed

    Carballo Mondragón, Esperanza; Durán Monterrosas, Leonor; Campos Cañas, Jorge A; González de Jesús, Patricia; Kably Ambe, Alberto

    2012-08-01

    Assisted hatching in reproduction techniques has improved the successful implantation rates in certain groups of patients with poor prognosis. This study focuses on its effect in groups of patients with previous implantation failure and according to age groups. Compare the pregnancy rates of patients who turned to this technique following an implantation failure using in vitro fertilization with those of patients who did not use assisted hatching before another attempt of in vitro fertilization and according to specific age groups. Cases of patients using assisted hatching in our Center between January 2008 and December 2009 were studied. The results were compared in terms of age in three groups: group I, >35 years; group II, 35-39 years, and group III, > 40 years. Patients in group II had better pregnancy rate (30%) than those in groups I and III (16.98 and 20.83%, respectively). When comparing the results of the group of patients using assisted hatching with those of the group that did not, the first reported a 20% pregnancy rate versus no pregnancy in the other group.

  12. Hatch securing mechanism

    NASA Astrophysics Data System (ADS)

    Culling, Robert K.

    1992-09-01

    The invention is a hatch securing mechanism having a base attached to a hatchway and a hasp attached to a hatch lid. The base has an apertured retainer and a pinway element, the hasp being held between the retainer and pinway element during closure of the lid. A latch pin translatable in the pinway element has an angled tip which slides against a bevelled surface of the hasp to force the hasp into tighter, locked engagement with the base. The latch pin has a helical groove segment about the pin's axis, and a stud fixed to the pinway element engages the groove segment. The interaction of the stud and groove segment effects translation of the latch pin when the pin is manually rotated. The action of the latch pin also compresses an elastically deformable seal between the door and door frame so that the seal is increasingly effective against explosive blast pressures. The invention includes a lock mechanism for keeping the latch pin in a hasp retaining position unless the pin is manually moved.

  13. Forced collapse of the blastocoel enhances survival of cryotop vitrified bovine hatching/hatched blastocysts derived from in vitro fertilization and somatic cell nuclear transfer.

    PubMed

    Min, Sung-Hun; Lee, Enok; Son, Hyeong-Hoon; Yeon, Ji-Yeong; Koo, Deog-Bon

    2013-04-01

    Freezing of bovine blastocysts has been widely used to improve the feasibility of cattle production by the embryo transfer technique. However, the low survival of vitrified-warmed embryos and their further development are crucial problems. Particularly, the production of offspring in vitrified-warmed bovine hatching/hatched blastocysts derived from in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT) is very low. Thus, we examined the effects of forced blastocoel collapse (FBC) before vitrification of bovine IVF- and SCNT-derived hatching/hatched embryos on the survival rate and apoptosis index after warming. Under optimal conditions, the overall survival rates in vitrified-warmed bovine IVF- and SCNT-derived hatching/hatched blastocysts were higher in FBC groups than in non-FBC groups (p<0.05). The total cell numbers of vitrified-warmed hatching/hatched blastocysts were higher in FBC groups than in non-FBC groups (p<0.05). Otherwise, the number of apoptotic positive cells of vitrified-warmed hatching/hatched blastocysts was lower in FBC groups than in non-FBC groups (p<0.05). Taken together, these findings suggest that forced collapse of the blastocoel using a pulled Pasteur pipette is an effective pretreatment technique for vitrification of bovine IVF- and SCNT-derived hatching/hatched blastocysts.

  14. Localization in inelastic rate dependent shearing deformations

    NASA Astrophysics Data System (ADS)

    Katsaounis, Theodoros; Lee, Min-Gi; Tzavaras, Athanasios

    2017-01-01

    Metals deformed at high strain rates can exhibit failure through formation of shear bands, a phenomenon often attributed to Hadamard instability and localization of the strain into an emerging coherent structure. We verify formation of shear bands for a nonlinear model exhibiting strain softening and strain rate sensitivity. The effects of strain softening and strain rate sensitivity are first assessed by linearized analysis, indicating that the combined effect leads to Turing instability. For the nonlinear model a class of self-similar solutions is constructed, that depicts a coherent localizing structure and the formation of a shear band. This solution is associated to a heteroclinic orbit of a dynamical system. The orbit is constructed numerically and yields explicit shear localizing solutions.

  15. Station Crew Opens Dragon's Hatch

    NASA Image and Video Library

    The hatch between the newly arrived SpaceX Dragon spacecraft and the Harmony module of the International Space Station was opened by NASA Astronaut Don Pettit at 5:53 am EDT as the station flew 253...

  16. Behnken in Interdeck Access Hatch

    NASA Image and Video Library

    2010-02-08

    S130-E-005218 (8 Feb. 2010) --- NASA astronaut Robert Behnken, STS-130 mission specialist, smiles for the camera while in the hatch which connects the flight deck and middeck of space shuttle Endeavour during flight day one activities.

  17. Station Crew Opens Dragon Hatch

    NASA Image and Video Library

    Expedition 33 Commander Suni Williams and Flight Engineer Aki Hoshide opened the hatch to the SpaceX Dragon cargo ship at 1:40 p.m. EDT Wednesday, Oct. 10, marking a milestone for the first commerc...

  18. Cooling-rate dependence of thermoremanent magnetisation

    NASA Astrophysics Data System (ADS)

    Fox, J. M. W.; Aitken, M. J.

    1980-01-01

    In using the thermoremanent magnetisation (TRM) of material heated in antiquity (usually pottery, bricks, stones or lava) to evaluate the magnitude of the geomagnetic field at the time of heating, little attention (apart from an observation by Thellier1) has been given to the possibility that results are affected by the rate at which the sample is cooling while the TRM is being acquired. We report here an experimental observation of the effect in archaeological baked clay; it parallels the theoretical prediction of Dodson and McClelland-Brown2 in respect of geological material.

  19. NSA AERI Hatch Correction Data Set

    DOE Data Explorer

    Turner, David

    2012-03-23

    From 2000-2008, the NSA AERI hatch was determined to be indicated as open too frequently. Analysis suggests that the hatch was actually opening and closing properly but that its status was not being correctly reported by the hatch controller to the datastream. An algorithm was written to determine the hatch status from the observed

  20. The effect of overwing hatch placement on evacuation from smaller transport aircraft.

    PubMed

    Wilson, Rebecca L; Muir, Helen C

    2009-08-01

    Overwing exits are installed on a number of smaller transport aircraft. With a traditional overwing exit, once released, the hatch is not attached to the fuselage and will fall into the cabin. To operate, the hatch has to be brought inwards, manoeuvred and placed in a location where it does not obstruct egress. Accidents and experimental studies have shown that the hatch is not always disposed of into an appropriate location. Evacuation trials from a smaller transport aircraft cabin were conducted. The placement of the exit hatch was manipulated. The results indicated that hatch placement had a significant effect on passenger evacuation rates from a smaller transport aircraft, with the internal placement tested resulting in slower evacuation rates. The study has highlighted the importance of operators disposing of the hatch into a location whereby it does not impede egress. One way to ensure this would be the installation of an automatically disposed hatch.

  1. Hatching of amphibian embryos: the physiological trigger.

    PubMed

    Petranka, J W; Just, J J; Crawford, E C

    1982-07-16

    Marbled salamander embryos hatch in water if the environmental oxygen pressure is 86 torr or less, but do not hatch if the environmental oxygen pressure is equivalent to that of air. Under hypoxic conditions, embryos hatch in aqueous and nonaqueous media with equal success. Increasing carbon dioxide pressure does not induce hatching, but does decrease the time to hatching by altering environmental pH.

  2. A cicada that ensures its fitness during climate warming by synchronizing its hatching time with the rainy season.

    PubMed

    Moriyama, Minoru; Numata, Hideharu

    2011-12-01

    A shift in phenology due to climate change is associated with some recent changes in populations, as it can disrupt the synchrony between organisms' requirements and resource availability. This conceptual framework has been developed mostly in systems of trophic interactions. Many coincidental changes, however, are involved in trophic interactions, preventing us from describing the direct impact of phenological shifts on fitness consequences. Here we address the phenological relationship in a simple non-trophic interaction to document a causal process of a warming-driven fitness change in a cicada, Cryptotympana facialis, whose numbers increased dramatically in Osaka, Japan in the late 20th century. We show that synchrony of the rainy season and hatching time may have a substantial influence on hatching success, by 1) shifting the time of completion of embryonic development, and 2) supplying water at various intervals. We estimate the change in hatching time over the last eleven decades (1901-2009) based on meteorological records and the temperature-dependent rate of C. facialis embryogenesis. Our estimate shows that hatching had initially occurred after the rainy season, and that warming had advanced it into the rainy season in the late 20th century. The probability of hatching success was markedly variable, and often very low before this synchronization occurred, but became stably high thereafter. Our findings suggest that the stabilizing effect of this synchrony on fitness was indispensable to the recent population increase of C. facialis.

  3. Spawning and hatching of endangered Gila Chub in captivity

    USGS Publications Warehouse

    Schultz, Andrew A.; Bonar, Scott A.

    2016-01-01

    Information on reproductive characteristics of the endangered Gila Chub Gila intermedia is largely limited and qualitative, and culture techniques and requirements are virtually unknown. Here we provide the first published data on spawning and selected reproductive and developmental characteristics of Gila Chub. Fish were brought to the laboratory in March 2003 from Sabino Creek, Arizona (12.3°C). Fish were then warmed slowly and spawned at 14.9°C, 10 d after collection. Following this initial spawning, Gila Chub spawned consistently in the laboratory without hormonal, chemical, photoperiod, temperature, or substrate manipulation during all times of the year. Spawns were noted at temperatures ranging from about 15°C to 26°C; however, we noted that Gila Chub spawned less frequently at temperatures above 24°C. Multiple spawning attempts per year per individual are probable. There was a strong, inverse relationship between time to hatch and incubation temperature. The hatch rate of eggs was high (mean = 99.43%), and larval Gila Chub accepted a variety of natural and formulated diets at first feeding. The future of Gila Chub may someday depend in part on hatchery propagation to provide specimens for restocking formerly occupied habitats and establishing refuge populations. Information from our study can aid future efforts to successfully spawn and rear Gila Chub and related species.

  4. Circadian rhythms of embryonic development and hatching in fish: a comparative study of zebrafish (diurnal), Senegalese sole (nocturnal), and Somalian cavefish (blind).

    PubMed

    Villamizar, Natalia; Blanco-Vives, Borja; Oliveira, Catarina; Dinis, Maria Teresa; Di Rosa, Viviana; Negrini, Pietro; Bertolucci, Cristiano; Sánchez-Vázquez, Francisco Javier

    2013-08-01

    During early development, most organisms display rhythmic physiological processes that are shaped by daily changes in their surrounding environment (i.e., light and temperature cycles). In fish, the effects of daily photocycles and their interaction with temperature during early developmental stages remain largely unexplored. We investigated the existence of circadian rhythms in embryonic development and hatching of three teleost species with different daily patterns of behavior: diurnal (zebrafish), nocturnal (Senegalese sole), and blind, not entrained by light (Somalian cavefish). To this end, fertilized eggs were exposed to three light regimes: 12 h of light: 12 h of darkness cycle (LD), continuous light (LL), or continuous darkness (DD); and three species-appropriate temperature treatments: 24°C, 28°C, or 32°C for zebrafish and cavefish and 18°C, 21°C, or 24°C for sole. The results pointed to the existence of daily rhythms of embryonic development and hatching synchronized to the LD cycle, with different acrophases, depending on the species: zebrafish embryos advanced their developmental stage during the light phase, whereas sole did so during the dark phase. In cavefish, embryogenesis occurred within 24 h post fertilization (hpf) at the same pace during day or night. The hatching rhythms appeared to be controlled by a clock mechanism that restricted or "gated" hatching to a particular time of day/night (window), so that embryos that reached a certain developmental state by that time hatch, whereas those that have not wait until the next available window. Under LL and DD conditions, hatching rhythms and the gating phenomenon persisted in cavefish, in zebrafish they split into ultradian bouts of hatching occurring at 12-18-h intervals, whereas in sole DD and LL produced a 24-h delay and advance, respectively. Hatching rates were best under the LD cycle and the reported optimal temperature for each species (95.2±2.7% of the zebrafish and 83.3±0.1% of the

  5. Assisted hatching on assisted conception (IVF & ICSI).

    PubMed

    Seif, M M W; Edi-Osagie, E C O; Farquhar, C; Hooper, L; Blake, D; McGinlay, P

    2006-01-25

    Failure of implantation and conception may result from an inability of the blastocyst to escape from its outer coat, know as the zona pellucida. In vitro culture conditions and/or advancing maternal age may alter the architecture of the zona pellucida and result in hatching difficulties. Artificial disruption of this coat is known as assisted hatching (AH) has been proposed as a method of improving the success of assisted conception. To determine whether assisted hatching (AH) of embryos facilitates live births and clinical pregnancy and whether it impacts on negative outcomes (such as multiple pregnancy and miscarriage). We searched the Cochrane Menstrual Disorders and Subfertility Group trials register (1 June 2005), the Cochrane Controlled Trials Register (Cochrane Library Issue 2, 2005), MEDLINE (1996 to June 2003), EMBASE (1980 to June 2005) and reference lists of articles. Authors were contacted for missing and/or unpublished data. Trials were identified and independently screened by two reviewers. Randomised controlled trials of AH (mechanical, chemical or laser disruption of the zona pellucida prior to embryo replacement) versus no AH that reported live birth, clinical pregnancy or implantation rates were included. Qualitative assessments and data extraction were performed independently by two reviewers. Outcomes were extracted as rates and combined using random effects meta-analysis, sensitivity analysis, sub grouping and meta-regression where appropriate. Twenty-three randomised controlled trials consisting of 2668 women reported on 849 pregnancy outcomes. There was no significant difference in the odds of live births in the AH compared with control groups (6 RCTs; OR 1.19 95% CI 0.81 to 1.73; 163 births from 516 women). Women undergoing assisted hatching were significantly more likely to achieve clinical pregnancy (23 RCTs, OR 1.33, 95% CI 1.12 to 1.57). Miscarriage rates per woman were similar in both groups (12 RCTs OR 1.23 (95% CI 0.73 to 2

  6. Assisted hatching on assisted conception (IVF & ICSI).

    PubMed

    Seif, M M W; Edi-Osagie, E C O; Farquhar, C; Hooper, L; Blake, D; McGinlay, P

    2005-10-19

    Failure of implantation and conception may result from an inability of the blastocyst to escape from its outer coat, know as the zona pellucida. In vitro culture conditions and/or advancing maternal age may alter the architecture of the zona pellucida and result in hatching difficulties. Artificial disruption of this coat is known as assisted hatching (AH) has been proposed as a method of improving the success of assisted conception. To determine whether assisted hatching (AH) of embryos facilitates live births and clinical pregnancy and whether it impacts on negative outcomes (such as multiple pregnancy and miscarriage). We searched the Cochrane Menstrual Disorders and Subfertility Group trials register (1 June 2005), the Cochrane Controlled Trials Register (Cochrane Library Issue 2, 2005), MEDLINE (1996 to June 2003), EMBASE (1980 to June 2005) and reference lists of articles. Authors were contacted for missing and/or unpublished data. Trials were identified and independently screened by two reviewers. Randomised controlled trials of AH (mechanical, chemical or laser disruption of the zona pellucida prior to embryo replacement) versus no AH that reported live birth, clinical pregnancy or implantation rates were included. Qualitative assessments and data extraction were performed independently by two reviewers. Outcomes were extracted as rates and combined using random effects meta-analysis, sensitivity analysis, sub grouping and meta-regression where appropriate. Twenty-three randomised controlled trials consisting of 2668 women reported on 849 pregnancy outcomes. There was no significant difference in the odds of live births in the AH compared with control groups (6 RCTs; OR 1.19 95% CI 0.81 to 1.73; 163 births from 516 women). Women undergoing assisted hatching were significantly more likely to achieve clinical pregnancy (23 RCTs, OR 1.33, 95% CI 1.12 to 1.57). Miscarriage rates per woman were similar in both groups (12 RCTs OR 1.23 (95% CI 0.73 to 2

  7. Hatching the Cleidoic Egg: The Role of Thyroid Hormones

    PubMed Central

    De Groef, Bert; Grommen, Sylvia V.H.; Darras, Veerle M.

    2013-01-01

    A major life stage transition in birds and other oviparous sauropsids is the hatching of the cleidoic egg. Not unlike amphibian metamorphosis, hatching in these species can be regarded as a transition from a relatively well-protected “aqueous” environment to a more hazardous and terrestrial life outside the egg, a transition in which thyroid hormones (THs) (often in concert with glucocorticoids) play an important role. In precocial birds such as the chicken, the perihatch period is characterized by peak values of THs. THs are implicated in the control of muscle development, lung maturation and the switch from chorioallantoic to pulmonary respiration, yolk sac retraction, gut development and induction of hepatic genes to accommodate the change in dietary energy source, initiation of thermoregulation, and the final stages of brain maturation as well as early post-hatch imprinting behavior. There is evidence that, at least for some of these processes, THs may have similar roles in non-avian sauropsids. In altricial birds such as passerines on the other hand, THs do not rise significantly until well after hatching and peak values coincide with the development of endothermy. It is not known how hatching-associated processes are regulated by hormones in these animals or how this developmental mode evolved from TH-dependent precocial hatching. PMID:23755041

  8. Effects of geolocators on hatching success, return rates, breeding movements, and change in body mass in 16 species of Arctic-breeding shorebirds.

    PubMed

    Weiser, Emily L; Lanctot, Richard B; Brown, Stephen C; Alves, José A; Battley, Phil F; Bentzen, Rebecca; Bêty, Joël; Bishop, Mary Anne; Boldenow, Megan; Bollache, Loïc; Casler, Bruce; Christie, Maureen; Coleman, Jonathan T; Conklin, Jesse R; English, Willow B; Gates, H River; Gilg, Olivier; Giroux, Marie-Andrée; Gosbell, Ken; Hassell, Chris; Helmericks, Jim; Johnson, Andrew; Katrínardóttir, Borgný; Koivula, Kari; Kwon, Eunbi; Lamarre, Jean-Francois; Lang, Johannes; Lank, David B; Lecomte, Nicolas; Liebezeit, Joe; Loverti, Vanessa; McKinnon, Laura; Minton, Clive; Mizrahi, David; Nol, Erica; Pakanen, Veli-Matti; Perz, Johanna; Porter, Ron; Rausch, Jennie; Reneerkens, Jeroen; Rönkä, Nelli; Saalfeld, Sarah; Senner, Nathan; Sittler, Benoît; Smith, Paul A; Sowl, Kristine; Taylor, Audrey; Ward, David H; Yezerinac, Stephen; Sandercock, Brett K

    2016-01-01

    Geolocators are useful for tracking movements of long-distance migrants, but potential negative effects on birds have not been well studied. We tested for effects of geolocators (0.8-2.0 g total, representing 0.1-3.9 % of mean body mass) on 16 species of migratory shorebirds, including five species with 2-4 subspecies each for a total of 23 study taxa. Study species spanned a range of body sizes (26-1091 g) and eight genera, and were tagged at 23 breeding and eight nonbreeding sites. We compared breeding performance and return rates of birds with geolocators to control groups while controlling for potential confounding variables. We detected negative effects of tags for three small-bodied species. Geolocators reduced annual return rates for two of 23 taxa: by 63 % for semipalmated sandpipers and by 43 % for the arcticola subspecies of dunlin. High resighting effort for geolocator birds could have masked additional negative effects. Geolocators were more likely to negatively affect return rates if the total mass of geolocators and color markers was 2.5-5.8 % of body mass than if tags were 0.3-2.3 % of body mass. Carrying a geolocator reduced nest success by 42 % for semipalmated sandpipers and tripled the probability of partial clutch failure in semipalmated and western sandpipers. Geolocators mounted perpendicular to the leg on a flag had stronger negative effects on nest success than geolocators mounted parallel to the leg on a band. However, parallel-band geolocators were more likely to reduce return rates and cause injuries to the leg. No effects of geolocators were found on breeding movements or changes in body mass. Among-site variation in geolocator effect size was high, suggesting that local factors were important. Negative effects of geolocators occurred only for three of the smallest species in our dataset, but were substantial when present. Future studies could mitigate impacts of tags by reducing protruding parts and minimizing use of additional

  9. Mechanism of reverse rate-dependent action of cardioactive agents.

    PubMed

    Bányász, T; Bárándi, L; Harmati, G; Virág, L; Szentandrássy, N; Márton, I; Zaza, A; Varró, A; Nánási, P P

    2011-01-01

    Class 3 antiarrhythmic agents exhibit reverse rate-dependent lengthening of the action potential duration (APD), i.e. changes in APD are greater at longer than at shorter cycle lengths. In spite of the several theories developed to explain this reverse rate-dependency, its mechanism has been clarified only recently. The aim of the present study is to elucidate the mechanisms responsible for reverse rate-dependency in mammalian ventricular myocardium. Action potentials were recorded using conventional sharp microelectrodes from human, canine, rabbit, guinea pig, and rat ventricular myocardium in a rate-dependent manner. Rate-dependent drug-effects of various origin were studied using agents known to lengthen or shorten action potentials allowing thus to determine the drug-induced changes in APD as a function of the cycle length. Both drug-induced lengthening and shortening of action potentials displayed reverse rate-dependency in human, canine, and guinea pig preparations, but not in rabbit and rat myocardium. Similar results were obtained when repolarization was modified by injection of inward or outward current pulses in isolated canine cardiomyocytes. In contrast to reverse rate-dependence, drug-induced changes in APD well correlated with baseline APD values (i.e. that measured before the superfusion of drug or injection of current) in all of the preparations studied. Since the net membrane current (I(net)), determined from the action potential waveform at the middle of the plateau, was inversely proportional to APD, and consequently to cycle length, it is concluded that that reverse rate-dependency may simply reflect the inverse relationship linking I(net) to APD. In summary, reverse rate-dependency is an intrinsic property of drug action in the hearts of species showing positive APD - cycle length relationship, including humans. This implies that development of a pure K(+) channel blocking agent without reverse rate-dependent effects is not likely to be

  10. A rate-dependent constitutive model for molybdenum

    NASA Astrophysics Data System (ADS)

    Steinberg, Daniel J.

    1994-07-01

    The Steinberg-Guinan-Lund rate-dependent constitutive model has been successfully applied to molybdenum. The model reproduces yield strength vs strain-rate and temperature data and also successfully simulates rate-dependent phenomena, such as shock-smearing, precursor decay, and precursor on reshock, as observed in one-dimensional gas-gun experiments. The spall strength of molybdenum was determined to be 1.5 GPa.

  11. Item Response Models for Local Dependence among Multiple Ratings

    ERIC Educational Resources Information Center

    Wang, Wen-Chung; Su, Chi-Ming; Qiu, Xue-Lan

    2014-01-01

    Ratings given to the same item response may have a stronger correlation than those given to different item responses, especially when raters interact with one another before giving ratings. The rater bundle model was developed to account for such local dependence by forming multiple ratings given to an item response as a bundle and assigning…

  12. Item Response Models for Local Dependence among Multiple Ratings

    ERIC Educational Resources Information Center

    Wang, Wen-Chung; Su, Chi-Ming; Qiu, Xue-Lan

    2014-01-01

    Ratings given to the same item response may have a stronger correlation than those given to different item responses, especially when raters interact with one another before giving ratings. The rater bundle model was developed to account for such local dependence by forming multiple ratings given to an item response as a bundle and assigning…

  13. Cross section dependence of event rates at neutrino telescopes.

    PubMed

    Hussain, S; Marfatia, D; McKay, D W; Seckel, D

    2006-10-20

    We examine the dependence of event rates at neutrino telescopes on the neutrino-nucleon cross section for neutrinos with energy above 1 PeV, and contrast the results with those for cosmic ray experiments. Scaling of the standard model cross sections leaves the rate of upward events essentially unchanged. Details, such as detector depth and cross section inelasticity, can influence rates. Numerical estimates of upward shower, muon, and tau event rates in the IceCube detector confirm these results.

  14. Hatching asynchrony in American Goldfinches: an experimental study

    USGS Publications Warehouse

    Skagen, Susan Knight

    1987-01-01

    I examined Lack's (1954, 1968) hypothesis that asynchronous hatching is an adaptive response to food shortage during the breeding season by comparing growth and survival of nestlings in asynchronous and artificially created synchronous broods of American Goldfinches (Carduelis tristis). I also examined the effects of seasonal and environmental factors on nestling growth and survival and on hatching asynchrony. Nestlings in asynchronous broods were more likely to diverge in mass and did so at a faster rate than those in synchronous broods. The lightest nestlings of asynchronous broods grew more slowly than their heavier nestmates and than all nestlings in synchronous broods. Brood reduction occurred more frequently in asynchronous broods. Survival and growth rates decreased throughout the breeding season and during inclement weather. Hatching intervals increased during the season. When brood reduction or differential growth among nestmates occurred in asynchronous broods, suggesting that the energy available for growth was limiting, heavy nestlings in asynchronous broods grew nonsignificantly faster than heavy nestlings in concurrent synchronous broods. This trend implies that when insufficient food is delivered to nestlings, asynchronous hatching may provide a slight advantage for older nestlings. Growth rates of all nestlings, however, were greatest in highly synchronous broods. Explanations other than growth of young must be invoked to explain why extreme synchrony is not more common in goldfinches. I discuss constraints on the normal pattern of hatching asynchrony characteristic of this species. The proximate mechanism for differential feeding and brood reduction is discussed.

  15. Optimal False Discovery Rate Control for Dependent Data

    PubMed Central

    Xie, Jichun; Cai, T. Tony; Maris, John; Li, Hongzhe

    2013-01-01

    This paper considers the problem of optimal false discovery rate control when the test statistics are dependent. An optimal joint oracle procedure, which minimizes the false non-discovery rate subject to a constraint on the false discovery rate is developed. A data-driven marginal plug-in procedure is then proposed to approximate the optimal joint procedure for multivariate normal data. It is shown that the marginal procedure is asymptotically optimal for multivariate normal data with a short-range dependent covariance structure. Numerical results show that the marginal procedure controls false discovery rate and leads to a smaller false non-discovery rate than several commonly used p-value based false discovery rate controlling methods. The procedure is illustrated by an application to a genome-wide association study of neuroblastoma and it identifies a few more genetic variants that are potentially associated with neuroblastoma than several p-value-based false discovery rate controlling procedures. PMID:23378870

  16. Egg storage duration and hatch window affect gene expression of nutrient transporters and intestine morphological parameters of early hatched broiler chicks.

    PubMed

    Yalcin, S; Gursel, I; Bilgen, G; Izzetoglu, G T; Horuluoglu, B H; Gucluer, G

    2016-05-01

    In recent years, researchers have given emphasis on the differences in physiological parameters between early and late hatched chicks within a hatch window. Considering the importance of intestine development in newly hatched chicks, however, changes in gene expression of nutrient transporters in the jejunum of early hatched chicks within a hatch window have not been studied yet. This study was conducted to determine the effects of egg storage duration before incubation and hatch window on intestinal development and expression of PepT1 (H+-dependent peptide transporter) and SGLT1 (sodium-glucose co-transporter) genes in the jejunum of early hatched broiler chicks within a 30 h of hatch window. A total of 1218 eggs obtained from 38-week-old Ross 308 broiler breeder flocks were stored for 3 (ES3) or 14 days (ES14) and incubated at the same conditions. Eggs were checked between 475 and 480 h of incubation and 40 chicks from each egg storage duration were weighed; chick length and rectal temperature were measured. The chicks were sampled to evaluate morphological parameters and PepT1 and SGLT1 expression. The remaining chicks that hatched between 475 and 480 h were placed back in the incubator and the same measurements were conducted with those chicks at the end of hatch window at 510 h of incubation. Chick length, chick dry matter content, rectal temperature and weight of small intestine segments increased, whereas chick weight decreased during the hatch window. The increase in the jejunum length and villus width and area during the hatch window were higher for ES3 than ES14 chicks. PepT1 expression was higher for ES3 chicks compared with ES14. There was a 10.2 and 17.6-fold increase in PepT1 and SGLT1 expression of ES3 chicks at the end of hatch window, whereas it was only 2.3 and 3.3-fold, respectively, for ES14 chicks. These results suggested that egg storage duration affected development of early hatched chicks during 30 h of hatch window. It can be concluded that

  17. Rate dependent constitutive models for fiber reinforced polymer composites

    NASA Technical Reports Server (NTRS)

    Gates, Thomas S.

    1990-01-01

    A literature survey was conducted to assess the state-of-the-art in rate dependent constitutive models for continuous fiber reinforced polymer matrix composite (PMC) materials. Several recent models which include formulations for describing plasticity, viscoelasticity, viscoplasticity, and rate-dependent phenomenon such as creep and stress relaxation are outlined and compared. When appropriate, these comparisons include brief descriptions of the mathematical formulations, the test procedures required for generating material constants, and details of available data comparing test results to analytical predictions.

  18. Strain rate dependence in plasticized and un-plasticized PVC

    NASA Astrophysics Data System (ADS)

    Kendall, M. J.; Siviour, C. R.

    2012-08-01

    An experimental and analytical investigation has been made into the mechanical behaviour of two poly (vinyl chloride) (PVC) polymers - an un-plasticized PVC and a diisononyl phthalate (DINP)-plasticized PVC. Measurements of the compressive stress-strain behaviour of the PVCs at strain rates ranging from 10-3 to 103s-1 and temperatures from - 60 to 100∘C are presented. Dynamic Mechanical Analysis was also performed in order to understand the material transitions observed in compression testing as the strain rate is increased. This investigation develops a better understanding of the interplay between the temperature dependence and rate dependence of polymers, with a focus on locating the temperature and rate-dependent material transitions that occur during high rate testing.

  19. The effect of moisture stress upon the hatching of Nematodirus battus larvae.

    PubMed

    Parkin, J T

    1975-04-01

    An experiment was carried out to investigate the effect of soil moisture stress upon the hatching behaviour of Nematodirus battus. The method involved the use of polyethylene glycol solutions to maintain a steady osmotic pressure around a soil containing N. battus eggs, which were ready to hatch. Different concentrations of polyethylene glycol (creating different moisture stresses) were found to affect the numbers and the rate of egg hatching markedly.

  20. 38 CFR 3.650 - Rate for additional dependent.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ....650 Rate for additional dependent. (a) Running awards. Except as provided in paragraph (c) of this...: (1) Where benefits would be payable from a date prior to the date of filing claim, the reduction will be effective from the date of potential entitlement of the additional dependent. (2) Where...

  1. 38 CFR 3.650 - Rate for additional dependent.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ....650 Rate for additional dependent. (a) Running awards. Except as provided in paragraph (c) of this...: (1) Where benefits would be payable from a date prior to the date of filing claim, the reduction will be effective from the date of potential entitlement of the additional dependent. (2) Where...

  2. Calculating Sputter Rate Angular Dependence Using Optical Profilometry (Preprint)

    DTIC Science & Technology

    2007-07-26

    This work attempts to determine angular dependence curves for sputter rates of a material based on a single experimental measurement. An aluminum...angular dependence curve to match the given erosion profile. The calculated profile matched well with the experimental profile; however, neither matched...the optimization routine, the angular dependence curve was input to the COLISEUM plasma modeling code, which generated the same erosion profile as the experimental data.

  3. Differential effects of egg albumen content on barn swallow nestlings in relation to hatch order.

    PubMed

    Ferrari, R P; Martinelli, R; Saino, N

    2006-05-01

    In diverse animal taxa, egg mass variation mediates maternal effects with long-term consequences for offspring ontogeny and fitness. Patterns of egg mass variation with laying order differ considerably among birds, but no study has experimentally investigated the function of variation in albumen or yolk egg content in the wild. In barn swallows (Hirundo rustica), absolute and relative albumen mass increased with egg laying order. Experimental albumen removal delayed hatching, had larger negative effects on growth of late-hatched nestlings, and reduced nestling survival. Laying order positively predicted hatch order. Because nestling competitive ability depends on size, and albumen egg content influences hatchling size, present results suggest that by increasing albumen content of late eggs mothers reduce hatching asynchrony and enhance growth particularly of late-hatched nestlings. Thus, variation in albumen mass with laying order may function to mitigate the negative phenotypic consequences of hatching late in species that adopt a 'brood-survival' strategy.

  4. Associations of resting heart rate with endothelium-dependent vasodilation and shear rate.

    PubMed

    Laosiripisan, Jitanan; Parkhurst, Kristin L; Tanaka, Hirofumi

    2017-01-01

    Heart rate is an independent risk factor for cardiovascular disease and a hemodynamic factor that can modulate blood flow as it affects the frequency of shear stimuli acting on the arterial wall. However, the association between heart rate and endothelium-dependent vasodilation remains highly controversial. We determined the association between heart rate at rest and endothelium-dependent vasodilation in 98 apparently healthy adults (18-63 years). The mild and positive association between heart rate and flow-mediated dilation (FMD) was no longer significant when age and sex or baseline diameter were controlled for. The path analyses revealed that heart rate was not directly related to FMD but the association was indirectly mediated by shear rate, which was confirmed by a bias-corrected bootstrap 95% CIs (0.0157-0.1056). We concluded that even though heart rate and endothelium-dependent vasodilation were associated with shear rate, there was no independent relation between heart rate and FMD.

  5. Continuum modeling of rate-dependent granular flows in SPH

    NASA Astrophysics Data System (ADS)

    Hurley, Ryan C.; Andrade, José E.

    2017-01-01

    We discuss a constitutive law for modeling rate-dependent granular flows that has been implemented in smoothed particle hydrodynamics (SPH). We model granular materials using a viscoplastic constitutive law that produces a Drucker-Prager-like yield condition in the limit of vanishing flow. A friction law for non-steady flows, incorporating rate-dependence and dilation, is derived and implemented within the constitutive law. We compare our SPH simulations with experimental data, demonstrating that they can capture both steady and non-steady dynamic flow behavior, notably including transient column collapse profiles. This technique may therefore be attractive for modeling the time-dependent evolution of natural and industrial flows.

  6. Rate-dependent extensional "dynamic ligaments" using shear thickening fluids

    NASA Astrophysics Data System (ADS)

    Nenno, Paul T.; Wetzel, Eric D.

    2014-04-01

    A novel "dynamic ligament" smart material that exhibits a strongly rate-dependent response in extension is developed and characterized. The devices, based on elastomeric polymers and shear thickening fluids, exhibit low resistance to extension at rates below 10 mm/s, but when stretched at 100 mm/s or higher resist with up to 7 × higher force. A link between the shear thickening fluid's rheology and the dynamic ligament's tensile performance is presented to explain the rate-dependent response. Future recommendations for improving device performance are presented, along with a host of different potential application areas including safety equipment, adaptive braces, sporting goods, and military equipment.

  7. 78 FR 6173 - Diana Del Grosso, Ray Smith, Joseph Hatch, Cheryl Hatch, Kathleen Kelley, Andrew Wilklund, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-29

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF TRANSPORTATION Surface Transportation Board Diana Del Grosso, Ray Smith, Joseph Hatch, Cheryl Hatch, Kathleen... Smith, Joseph Hatch, Cheryl Hatch, Kathleen Kelley, Andrew Wilklund, and Richard Kosiba (Petitioners...

  8. Evolution of density- and patch-size-dependent dispersal rates.

    PubMed Central

    Poethke, Hans Joachim; Hovestadt, Thomas

    2002-01-01

    Based on a marginal value approach, we derive a nonlinear expression for evolutionarily stable (ES) dispersal rates in a metapopulation with global dispersal. For the general case of density-dependent population growth, our analysis shows that individual dispersal rates should decrease with patch capacity and-beyond a certain threshold-increase with population density. We performed a number of spatially explicit, individual-based simulation experiments to test these predictions and to explore further the relevance of variation in the rate of population increase, density dependence, environmental fluctuations and dispersal mortality on the evolution of dispersal rates. They confirm the predictions of our analytical approach. In addition, they show that dispersal rates in metapopulations mostly depend on dispersal mortality and inter-patch variation in population density. The latter is dominantly driven by environmental fluctuations and the rate of population increase. These conclusions are not altered by the introduction of neighbourhood dispersal. With patch capacities in the order of 100 individuals, kin competition seems to be of negligible importance for ES dispersal rates except when overall dispersal rates are low. PMID:11916481

  9. Extreme-value dependence: An application to exchange rate markets

    NASA Astrophysics Data System (ADS)

    Fernandez, Viviana

    2007-04-01

    Extreme value theory (EVT) focuses on modeling the tail behavior of a loss distribution using only extreme values rather than the whole data set. For a sample of 10 countries with dirty/free float regimes, we investigate whether paired currencies exhibit a pattern of asymptotic dependence. That is, whether an extremely large appreciation or depreciation in the nominal exchange rate of one country might transmit to another. In general, after controlling for volatility clustering and inertia in returns, we do not find evidence of extreme-value dependence between paired exchange rates. However, for asymptotic-independent paired returns, we find that tail dependency of exchange rates is stronger under large appreciations than under large depreciations.

  10. Rate Dependent Deformation and Strength Analysis of Polymer Matrix Composites

    NASA Technical Reports Server (NTRS)

    Goldberg, Robert K.; Stouffer, Donald C.

    1999-01-01

    A research program is being undertaken to develop rate dependent deformation and failure models for the analysis of polymer matrix composite materials. In previous work in this program, strain-rate dependent inelastic constitutive equations used to analyze polymers have been implemented into a mechanics of materials based composite micromechanics method. In the current work, modifications to the micromechanics model have been implemented to improve the calculation of the effective inelastic strain. Additionally, modifications to the polymer constitutive model are discussed in which pressure dependence is incorporated into the equations in order to improve the calculation of constituent and composite shear stresses. The Hashin failure criterion is implemented into the analysis method to allow for the calculation of ply level failure stresses. The deformation response and failure stresses for two representative uniaxial polymer matrix composites, IM7/977-2 and AS4-PEEK, are predicted for varying strain rates and fiber orientations. The predicted results compare favorably to experimentally obtained values.

  11. The dependence of homogeneous nucleation rate on supersaturation.

    PubMed

    Girshick, Steven L

    2014-07-14

    The claim that classical nucleation theory (CNT) correctly predicts the dependence on supersaturation of the steady-state rate of homogeneous nucleation is reexamined in light of recent experimental studies of nucleation of a range of substances, including water, argon, nitrogen, and several 1-alcohols. Based on these studies (which include, for water, a compilation of nine different studies), it is concluded that the dependence of nucleation rate on supersaturation is not correctly predicted by CNT. It is shown that CNT's incorrect prediction of the supersaturation dependence of nucleation rate is due to its incorrect prediction of the Gibbs free energy change associated with formation of small clusters from the monomer vapor, evaluated at the substance's equilibrium vapor pressure, even though that free energy change is itself a function only of temperature.

  12. Growth-rate-dependent dynamics of a bacterial genetic oscillator

    NASA Astrophysics Data System (ADS)

    Osella, Matteo; Lagomarsino, Marco Cosentino

    2013-01-01

    Gene networks exhibiting oscillatory dynamics are widespread in biology. The minimal regulatory designs giving rise to oscillations have been implemented synthetically and studied by mathematical modeling. However, most of the available analyses generally neglect the coupling of regulatory circuits with the cellular “chassis” in which the circuits are embedded. For example, the intracellular macromolecular composition of fast-growing bacteria changes with growth rate. As a consequence, important parameters of gene expression, such as ribosome concentration or cell volume, are growth-rate dependent, ultimately coupling the dynamics of genetic circuits with cell physiology. This work addresses the effects of growth rate on the dynamics of a paradigmatic example of genetic oscillator, the repressilator. Making use of empirical growth-rate dependencies of parameters in bacteria, we show that the repressilator dynamics can switch between oscillations and convergence to a fixed point depending on the cellular state of growth, and thus on the nutrients it is fed. The physical support of the circuit (type of plasmid or gene positions on the chromosome) also plays an important role in determining the oscillation stability and the growth-rate dependence of period and amplitude. This analysis has potential application in the field of synthetic biology, and suggests that the coupling between endogenous genetic oscillators and cell physiology can have substantial consequences for their functionality.

  13. Strain Rate Dependent Modeling of Polymer Matrix Composites

    NASA Technical Reports Server (NTRS)

    Goldberg, Robert K.; Stouffer, Donald C.

    1999-01-01

    A research program is in progress to develop strain rate dependent deformation and failure models for the analysis of polymer matrix composites subject to high strain rate impact loads. Strain rate dependent inelastic constitutive equations have been developed to model the polymer matrix, and have been incorporated into a micromechanics approach to analyze polymer matrix composites. The Hashin failure criterion has been implemented within the micromechanics results to predict ply failure strengths. The deformation model has been implemented within LS-DYNA, a commercially available transient dynamic finite element code. The deformation response and ply failure stresses for the representative polymer matrix composite AS4/PEEK have been predicted for a variety of fiber orientations and strain rates. The predicted results compare favorably to experimentally obtained values.

  14. Strain rate dependency of laser sintered polyamide 12

    NASA Astrophysics Data System (ADS)

    Cook, J. E. T.; Goodridge, R. D.; Siviour, C. R.

    2015-09-01

    Parts processed by Additive Manufacturing can now be found across a wide range of applications, such as those in the aerospace and automotive industry in which the mechanical response must be optimised. Many of these applications are subjected to high rate or impact loading, yet it is believed that there is no prior research on the strain rate dependence in these materials. This research investigates the effect of strain rate and laser energy density on laser sintered polyamide 12. In the study presented here, parts produced using four different laser sintered energy densities were exposed to uniaxial compression tests at strain rates ranging from 10-3 to 10+3 s-1 at room temperature, and the dependence on these parameters is presented.

  15. Heartbeat, embryo communication and hatching synchrony in snake eggs

    PubMed Central

    Aubret, Fabien; Blanvillain, Gaëlle; Bignon, Florent; Kok, Philippe J. R.

    2016-01-01

    Communication is central to life at all levels of complexity, from cells to organs, through to organisms and communities. Turtle eggs were recently shown to communicate with each other in order to synchronise their development and generate beneficial hatching synchrony. Yet the mechanism underlying embryo to embryo communication remains unknown. Here we show that within a clutch, developing snake embryos use heart beats emanating from neighbouring eggs as a clue for their metabolic level, in order to synchronise development and ultimately hatching. Eggs of the water snake Natrix maura increased heart rates and hatched earlier than control eggs in response to being incubated in physical contact with more advanced eggs. The former produced shorter and slower swimming young than their control siblings. Our results suggest potential fitness consequences of embryo to embryo communication and describe a novel driver for the evolution of egg-clustering behaviour in animals. PMID:26988725

  16. Immunological development in nestling American kestrels Falco sparverius: post-hatching ontogeny of the antibody response.

    PubMed

    Smits, Judit E G; Bortolotti, Gary R

    2008-12-01

    Avian research involving examination of immune function or testing of immunocompetence in wild birds has been based upon information on Galliforms, (chicken and quail) even though they are precocial, whereas most wild species with which ecologists, biologists and toxicologists work are altricial; blind, naked and completely dependent at hatching. Here we begin to address this gap in knowledge, offering insight into the early, post-hatching, humoral immune response in an altricial bird, the American kestrel (Falco sparverius). Over two breeding seasons, nestling kestrels were immunized with a non-pathogenic antigen, dinitrophenol keyhole limpet hemocyanin (DNP-KLH), between 3 and 9 days post-hatching and boostered 6 days later. Background levels, primary and secondary immune responses were measured using an enzyme linked immunosorbent assay. The specificity of our laboratory produced rabbit, anti-kestrel antibody was determined using a double immunodiffusion assay. Results showed the rabbit antiserum to have specific anti-kestrel IgG activity. Birds as young as three days old could successfully mount an antibody response, the magnitude of which increased with age at first vaccination. Early immunization did not compromise growth rate, nor did it affect the maximum secondary response. Comparatively, adult kestrels immunized during the same season and following the same protocol, had antibody levels four times higher than those of the nestlings.

  17. Induction of egg hatching by high humidity in the cicada Cryptotympana facialis.

    PubMed

    Moriyama, Minoru; Numata, Hideharu

    2006-01-01

    The timing of egg hatching in Cryptotympana facialis was examined in relation to short-term weather conditions. The brief underwater submergence, once a week, of dead twigs bearing cicada egg nests resulted in high hatching rates both at 25 degrees C and under outdoor conditions protected from rainfall. Under outdoor conditions with natural rainfall, most eggs hatched on rainy days. There was a significant positive correlation between the number of hatching eggs and daily relative humidity (RH). When eggs picked from twigs were exposed to various humidity levels, many eggs hatched quickly at higher humidity without direct contact with liquid water. Newly hatched nymphs showed a low tolerance to desiccation; at 81% RH at 25 degrees C, most of them died within 6 h. Under outdoor conditions, most nymphs died within 2 h on sunny days, whereas nymphs survived longer on rainy days. When newly hatched nymphs were released on dry ground, only 24% of them succeeded in burrowing into the soil, and many were killed by ants or desiccation. However, 92% of nymphs released onto wet ground successfully burrowed into it. The direct induction of hatching by high humidity ensures the survival and establishment in the soil of newly hatched nymphs in this species.

  18. Rate-dependent deformation of rocks in the brittle regime

    NASA Astrophysics Data System (ADS)

    Baud, P.; Brantut, N.; Heap, M. J.; Meredith, P. G.

    2013-12-01

    Rate-dependent brittle deformation of rocks, a phenomenon relevant for long-term interseismic phases of deformation, is poorly understood quantitatively. Rate-dependence can arise from chemically-activated, subcritical crack growth, which is known to occur in the presence of aqueous fluids. Here we attempt to establish quantitative links between this small scale process and its macroscopic manifestations. We performed a series of brittle deformation experiments in porous sandstones, in creep (constant stress) and constant strain rate conditions, in order to investigate the relationship between their short- and long-term mechanical behaviors. Elastic wave velocities measurements indicate that the amount of microcracking follows the amount of inelastic strain in a trend which does not depend upon the timescale involved. The comparison of stress-strain curves between constant strain rate and creep tests allows us to define a stress difference between the two, which can be viewed as a difference in energy release rate. We empirically show that the creep strain rates are proportional to an exponential function of this stress difference. We then establish a general method to estimate empirical micromechanical functions relating the applied stresses to mode I stress intensity factors at microcrack tips, and we determine the relationship between creep strain rates and stress intensity factors in our sandstone creep experiments. We finally provide an estimate of the sub-critical crack growth law parameters, and find that they match -within the experimental errors and approximations of the method- the typical values observed in independent single crack tests. Our approach provides a comprehensive and unifying explanation for the origin and the macroscopic manifestation of time-dependent brittle deformation in brittle rocks.

  19. Velocity of chloroplast avoidance movement is fluence rate dependent.

    PubMed

    Kagawa, Takatoshi; Wada, Masamitsu

    2004-06-01

    In Arabidopsis leaves, chloroplast movement is fluence rate dependent. At optimal, lower light fluences, chloroplasts accumulate at the cell surface to maximize photosynthetic potential. Under high fluence rates, chloroplasts avoid incident light to escape photodamage. In this paper, we examine the phenomenon of chloroplast avoidance movement in greater detail and demonstrate a proportional relationship between fluence rate and the velocity of chloroplast avoidance. In addition we show that the amount of light-activated phototropin2, the photoreceptor for the avoidance response, likely plays a role in this phenomenon, as heterozygous mutant plants show a reduced avoidance velocity compared to that of homozygous wild type plants.

  20. Temperature dependence of nucleation rate in a binary solid solution

    NASA Astrophysics Data System (ADS)

    Wang, H. Y.; Philippe, T.; Duguay, S.; Blavette, D.

    2012-12-01

    The influence of regression (partial dissolution) effects on the temperature dependence of nucleation rate in a binary solid solution has been studied theoretically. The results of the analysis are compared with the predictions of the simplest Volmer-Weber theory. Regression effects are shown to have a strong influence on the shape of the curve of nucleation rate versus temperature. The temperature TM at which the maximum rate of nucleation occurs is found to be lowered, particularly for low interfacial energy (coherent precipitation) and high-mobility species (e.g. interstitial atoms).

  1. Worldwide Spacecraft Crew Hatch History

    NASA Technical Reports Server (NTRS)

    Johnson, Gary

    2009-01-01

    The JSC Flight Safety Office has developed this compilation of historical information on spacecraft crew hatches to assist the Safety Tech Authority in the evaluation and analysis of worldwide spacecraft crew hatch design and performance. The document is prepared by SAIC s Gary Johnson, former NASA JSC S&MA Associate Director for Technical. Mr. Johnson s previous experience brings expert knowledge to assess the relevancy of data presented. He has experience with six (6) of the NASA spacecraft programs that are covered in this document: Apollo; Skylab; Apollo Soyuz Test Project (ASTP), Space Shuttle, ISS and the Shuttle/Mir Program. Mr. Johnson is also intimately familiar with the JSC Design and Procedures Standard, JPR 8080.5, having been one of its original developers. The observations and findings are presented first by country and organized within each country section by program in chronological order of emergence. A host of reference sources used to augment the personal observations and comments of the author are named within the text and/or listed in the reference section of this document. Careful attention to the selection and inclusion of photos, drawings and diagrams is used to give visual association and clarity to the topic areas examined.

  2. Temperature-dependence of biomass accumulation rates during secondary succession.

    PubMed

    Anderson, Kristina J; Allen, Andrew P; Gillooly, James F; Brown, James H

    2006-06-01

    Rates of ecosystem recovery following disturbance affect many ecological processes, including carbon cycling in the biosphere. Here, we present a model that predicts the temperature dependence of the biomass accumulation rate following disturbances in forests. Model predictions are derived based on allometric and biochemical principles that govern plant energetics and are tested using a global database of 91 studies of secondary succession compiled from the literature. The rate of biomass accumulation during secondary succession increases with average growing season temperature as predicted based on the biochemical kinetics of photosynthesis in chloroplasts. In addition, the rate of biomass accumulation is greater in angiosperm-dominated communities than in gymnosperm-dominated ones and greater in plantations than in naturally regenerating stands. By linking the temperature-dependence of photosynthesis to the rate of whole-ecosystem biomass accumulation during secondary succession, our model and results provide one example of how emergent, ecosystem-level rate processes can be predicted based on the kinetics of individual metabolic rate.

  3. The Accretion Rate Dependence of Burst Oscillation Amplitude

    NASA Astrophysics Data System (ADS)

    Ootes, Laura S.; Watts, Anna L.; Galloway, Duncan K.; Wijnands, Rudy

    2017-01-01

    Neutron stars in low-mass X-ray binaries exhibit oscillations during thermonuclear bursts, attributed to asymmetric brightness patterns on the burning surfaces. All models that have been proposed to explain the origin of these asymmetries (spreading hotspots, surface waves, and cooling wakes) depend on the accretion rate. By analysis of archival RXTE data of six oscillation sources, we investigate the accretion rate dependence of the amplitude of burst oscillations. This more than doubles the size of the sample analyzed previously by Muno et al., who found indications for a relationship between accretion rate and oscillation amplitudes. We find that burst oscillation signals can be detected at all observed accretion rates. Moreover, oscillations at low accretion rates are found to have relatively small amplitudes ({A}{{rms}}≤slant 0.10) while oscillations detected in bursts observed at high accretion rates cover a broad spread in amplitudes (0.05≤slant {A}{{rms}}≤slant 0.20). In this paper we present the results of our analysis and discuss these in the light of current burst oscillation models. Additionally, we investigate the bursts of two sources without previously detected oscillations. Despite the fact that these sources have been observed at accretion rates where burst oscillations might be expected, we find their behavior not to be anomalous compared to oscillation sources.

  4. Plasma corticosterone in American kestrel siblings: effects of age, hatching order, and hatching asynchrony.

    PubMed

    Love, Oliver P; Bird, David M; Shutt, Laird J

    2003-04-01

    Although it is well documented that hatching asynchrony in birds can lead to competitive and developmental hierarchies, potentially greatly affecting growth and survival of nestlings, hatching asynchrony may also precipitate modulations in neuroendocrine development or function. Here we examine sibling variation in adrenocortical function in postnatally developing, asynchronously hatching American kestrels (Falco sparverius) by measurements of baseline and stress-induced levels of corticosterone at ages 10, 16, 22, and 28 days posthatching. There was a significant effect of hatching order on both baseline and stress-induced corticosterone levels during development and these effects grew stronger through development. First-hatched chicks exhibited higher baseline levels than later-hatched chicks throughout development and higher stress-induced levels during the latter half of development. Furthermore, there was significant hatching span (difference in days between first- and last-hatched chicks) x hatching order interaction on both baseline and stress-induced corticosterone levels during development. Hatching span was also positively correlated with both measures of corticosterone and body mass in first-hatched chicks, but was negatively correlated with these factors through most of the development in last-hatched chicks. It is known that hatching asynchrony creates mass and size hierarchies within kestrel broods and we suggest that hierarchies in adrenocortical function among siblings may be one physiological mechanism by which these competitive hierarchies are maintained.

  5. Micromechanical modeling of rate-dependent behavior of Connective tissues.

    PubMed

    Fallah, A; Ahmadian, M T; Firozbakhsh, K; Aghdam, M M

    2017-03-07

    In this paper, a constitutive and micromechanical model for prediction of rate-dependent behavior of connective tissues (CTs) is presented. Connective tissues are considered as nonlinear viscoelastic material. The rate-dependent behavior of CTs is incorporated into model using the well-known quasi-linear viscoelasticity (QLV) theory. A planar wavy representative volume element (RVE) is considered based on the tissue microstructure histological evidences. The presented model parameters are identified based on the available experiments in the literature. The presented constitutive model introduced to ABAQUS by means of UMAT subroutine. Results show that, monotonic uniaxial test predictions of the presented model at different strain rates for rat tail tendon (RTT) and human patellar tendon (HPT) are in good agreement with experimental data. Results of incremental stress-relaxation test are also presented to investigate both instantaneous and viscoelastic behavior of connective tissues. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Fault Scaling Relationships Depend on the Average Geological Slip Rate

    NASA Astrophysics Data System (ADS)

    Anderson, J. G.; Biasi, G. P.; Wesnousky, S. G.

    2016-12-01

    This study addresses whether knowing the geological slip rates on a fault in addition to the rupture length improves estimates of magnitude (Mw) of continental earthquakes that rupture the surface, based on a database of 80 events that includes 57 strike-slip, 12 reverse, and 11 normal faulting events. Three functional forms are tested to relate rupture length L to magnitude Mw: linear, bilinear, and a shape with constant static stress drop. The slip rate dependence is tested as a perturbation to the estimates of magnitude from rupture length. When the data are subdivided by fault mechanism, magnitude predictions from rupture length are improved for strike-slip faults when slip rate is included, but not for reverse or normal faults. This conclusion is robust, independent of the functional form used to relate L to Mw. Our preferred model is the constant stress drop model, because teleseismic observations of earthquakes favor that result. Because a dependence on slip rate is only significant for strike-slip events, a combined relationship for all rupture mechanisms is not appropriate. The observed effect of slip rate for strike-slip faults implies that the static stress drop, on average, tends to decrease as the fault slip rate increases.

  7. Sleep-Dependent Modulation of Metabolic Rate in Drosophila.

    PubMed

    Stahl, Bethany A; Slocumb, Melissa E; Chaitin, Hersh; DiAngelo, Justin R; Keene, Alex C

    2017-08-01

    Dysregulation of sleep is associated with metabolic diseases, and metabolic rate (MR) is acutely regulated by sleep-wake behavior. In humans and rodent models, sleep loss is associated with obesity, reduced metabolic rate, and negative energy balance, yet little is known about the neural mechanisms governing interactions between sleep and metabolism. We have developed a system to simultaneously measure sleep and MR in individual Drosophila, allowing for interrogation of neural systems governing interactions between sleep and metabolic rate. Like mammals, MR in flies is reduced during sleep and increased during sleep deprivation suggesting sleep-dependent regulation of MR is conserved across phyla. The reduction of MR during sleep is not simply a consequence of inactivity because MR is reduced ~30 minutes following the onset of sleep, raising the possibility that CO2 production provides a metric to distinguish different sleep states in the fruit fly. To examine the relationship between sleep and metabolism, we determined basal and sleep-dependent changes in MR is reduced in starved flies, suggesting that starvation inhibits normal sleep-associated effects on metabolic rate. Further, translin mutant flies that fail to suppress sleep during starvation demonstrate a lower basal metabolic rate, but this rate was further reduced in response to starvation, revealing that regulation of starvation-induced changes in MR and sleep duration are genetically distinct. Therefore, this system provides the unique ability to simultaneously measure sleep and oxidative metabolism, providing novel insight into the physiological changes associated with sleep and wakefulness in the fruit fly.

  8. High resolution Ge/Li/ spectrometer reduces rate-dependent distortions at high counting rates

    NASA Technical Reports Server (NTRS)

    Brenner, R.; Larsen, R. N.; Mann, H. M.; Rudnick, S. J.; Sherman, I. S.; Strauss, M. G.

    1968-01-01

    Modified spectrometer system with a low-noise preamplifier reduces rate-dependent distortions at high counting rates, 25,000 counts per second. Pole-zero cancellation minimizes pulse undershoots due to multiple time constants, baseline restoration improves resolution and prevents spectral shifts.

  9. Scale dependence of immigration rates: models, metrics and data.

    PubMed

    Englund, Göran; Hambäck, Peter A

    2007-01-01

    1. We examine the relationship between immigration rate and patch area for different types of movement behaviours and detection modes. Theoretical models suggest that the scale dependence of the immigration rate per unit area (I/A) can be described by a power model I/A = i*Area(zeta), where zeta describes the strength of the scale dependence. 2. Three types of scaling were identified. Area scaling (zeta = 0) is expected for passively dispersed organisms that have the same probability of landing anywhere in the patch. Perimeter scaling (-0.30 > zeta > -0.45) is expected when patches are detected from a very short distance and immigrants arrive over the patch boundary, whereas diameter scaling (zeta = -0.5) is expected if patches are detected from a long distance or if search is approximately linear. 3. A meta-analysis of published empirical studies of the scale dependence of immigration rates in terrestrial insects suggests that butterflies show diameter scaling, aphids show area scaling, and the scaling of beetle immigration is highly variable. We conclude that the scaling of immigration rates in many cases can be predicted from search behaviour and the mode of patch detection.

  10. The role of landscape features and density dependence in growth andfledging rates of Piping Plovers in North Dakota, USA

    USGS Publications Warehouse

    Anteau, Michael J.; Wiltermuth, Mark T.; Sherfy, Mark H.; Shaffer, Terry L.; Pearse, Aaron T.

    2014-01-01

    For species with precocial young, survival from hatching to fledging is a key factor influencing recruitment. Furthermore, growth rates of precocial chicks are an indicator of forage quality and habitat suitability of brood-rearing areas. We examined how growth and fledging rates of Piping Plover (Charadrius melodus) chicks were influenced by landscape features, such as hatchling density (hatchlings per hectare of remotely sensed habitat [H ha-1]), island vs. mainland, and wind fetch (exposure to waves) at 2-km segments (n ¼ 15) of Lake Sakakawea, North Dakota, during 2007–2008. Hatchling growth was comparable with published estimates for other habitats. Models for fledging rate (fledged young per segment) assuming density dependence had more support (wi ¼ 96%) than those assuming density independence (wi ¼ 4%). Density-dependent processes appeared to influence fledging rate only at densities .5 H ha-1, which occurred in 19% of the segments we sampled. When areas with densities .5 H ha-1 were excluded, density-dependence and density-independence models were equally supported (wi ¼ 52% and 48%, respectively). Fledging rate declined as the wind fetch of a segment increased. Fledging rate on mainland shorelines was 4.3 times greater than that on islands. Previous work has indicated that plovers prefer islands for nesting, but our results suggest that this preference is not optimal and could lead to an ecological trap for chicks. While other researchers have found nesting-habitat requirements to be gravelly areas on exposed beaches without fine-grain substrates, our results suggest that chicks fledge at lower rates in these habitats. Thus, breeding plovers likely require complexes of these nesting habitats along with protected areas with fine, nutrient-rich substrate for foraging by hatchlings.

  11. Inclination Dependence of Estimated Galaxy Masses and Star Formation Rates

    NASA Astrophysics Data System (ADS)

    Hernandez, Betsy; Maller, Ariyeh; McKernan, Barry; Ford, Saavik

    2016-01-01

    We examine the inclination dependence of inferred star formation rates and galaxy mass estimates in the Sloan Digital Sky Survey by combining the disk/bulge de-convolved catalog of Simard et al 2011 with stellar mass estimates catalog of Mendel et al 2014 and star formation rates measured from spectra by Brinchmann et al 2004. We know that optical star formation indicators are reddened by dust, but calculated star formation rates and stellar mass estimates should account for this. However, we find that face-on galaxies have a higher calculated average star formation rates than edge-on galaxies. We also find edge-on galaxies have ,on average, slightly smaller but similar estimated masses to face-on galaxies, suggesting that there are issues with the applied dust corrections for both models.

  12. Rate and state dependent seismicity during fluid injection in rocks

    NASA Astrophysics Data System (ADS)

    Wenzel, Friedemann

    2014-05-01

    Dieterich (1994) developed a theoretical frame of seismicity evolution from a background seismicity due to stress changes in a medium. The theory assumes a volume density of seismic faults with a specific initial slip velocity distribution upon which the stress changes act. Each fault then follows the rate and state dependent frictional law where instabilities develop, but not as Coulomb failure. The evolution is expressed in the form of a differntial equation, which can be adapted for the case of fluid pressure changes resulting from injection and even linearized to allow for analytic insight into the properties of the solution. For a constant injection rate the seismic activity increases at a given distance from the injection point once the pressure exceeds a threshold value. If the presusure rate is high enough the seismic activity becomes proportional to the pressure rate in accordance with criticality theory of Shapiro (2002). Once the rate drops the seismicity reduced to lower levels. Shut off and variable injection rates must be evaluated numerically but lead to results comparable to the criticality theory. The presentation outlines the physical concept of the rate and state approach in comparison to the criticality approach and shows the main analytic and numerical results.

  13. Transcriptional dynamics with time-dependent reaction rates

    NASA Astrophysics Data System (ADS)

    Nandi, Shubhendu; Ghosh, Anandamohan

    2015-02-01

    Transcription is the first step in the process of gene regulation that controls cell response to varying environmental conditions. Transcription is a stochastic process, involving synthesis and degradation of mRNAs, that can be modeled as a birth-death process. We consider a generic stochastic model, where the fluctuating environment is encoded in the time-dependent reaction rates. We obtain an exact analytical expression for the mRNA probability distribution and are able to analyze the response for arbitrary time-dependent protocols. Our analytical results and stochastic simulations confirm that the transcriptional machinery primarily act as a low-pass filter. We also show that depending on the system parameters, the mRNA levels in a cell population can show synchronous/asynchronous fluctuations and can deviate from Poisson statistics.

  14. Ataxia rating scales are age-dependent in healthy children.

    PubMed

    Brandsma, Rick; Spits, Anne H; Kuiper, Marieke J; Lunsing, Roelinka J; Burger, Huibert; Kremer, Hubertus P; Sival, Deborah A

    2014-06-01

    To investigate ataxia rating scales in children for reliability and the effect of age and sex. Three independent neuropaediatric observers cross-sectionally scored a set of paediatric ataxia rating scales in a group of 52 healthy children (26 males, 26 females) aged 4 to 16 years (mean age 10y 5mo SD 3y 11mo). The investigated scales involved the commonly applied International Cooperative Ataxia Rating Scale (ICARS), the Scale for Assessment and Rating of Ataxia (SARA), the Brief Ataxia Rating Scale (BARS), and PEG-board tests. We investigated the interrelatedness between individual ataxia scales, the influence of age and sex, inter- and intra-observer agreement, and test-retest reliability. Spearman's rank correlations revealed strong correlations between ICARS, SARA BARS, and PEG-board test (all p<0.001). ICARS, SARA, BARS and PEG-board test outcomes were age-dependent until 12.5, 10, 11, and 11.5 years of age respectively. Intraclass correlation coefficients (ICCs) varied between moderate and almost perfect (interobserver agreement: 0.85, 0.72, and 0.69; intraobserver agreement: 0.92, 0.94, and 0.70; and test-retest reliability: 0.95, 0.50, and 0.71; for ICARS, SARA, and BARS respectively). Interobserver variability decreased after the sixth year of life. In healthy children, ataxia rating scales are reliable, but should include age-dependent interpretation in children up to 12 years of age. To enable longitudinal interpretation of quantitative ataxia rating scales in children, European paediatric normative values are necessary. © 2014 Mac Keith Press.

  15. Medium-dependent control of the bacterial growth rate.

    PubMed

    Ehrenberg, Måns; Bremer, Hans; Dennis, Patrick P

    2013-04-01

    By combining results from previous studies of nutritional up-shifts we here re-investigate how bacteria adapt to different nutritional environments by adjusting their macromolecular composition for optimal growth. We demonstrate that, in contrast to a commonly held view the macromolecular composition of bacteria does not depend on the growth rate as an independent variable, but on three factors: (i) the genetic background (i.e. the strain used), (ii) the physiological history of the bacteria used for inoculation of a given growth medium, and (iii) the kind of nutrients in the growth medium. These factors determine the ribosome concentration and the average rate of protein synthesis per ribosome, and thus the growth rate. Immediately after a nutritional up-shift, the average number of ribosomes in the bacterial population increases exponentially with time at a rate which eventually is attained as the final post-shift growth rate of all cell components. After a nutritional up-shift from one minimal medium to another minimal medium of higher nutritional quality, ribosome and RNA polymerase syntheses are co-regulated and immediately increase by the same factor equal to the increase in the final growth rate. However, after an up-shift from a minimal medium to a medium containing all 20 amino acids, RNA polymerase and ribosome syntheses are no longer coregulated; a smaller rate of synthesis of RNA polymerase is compensated by a gradual increase in the fraction of free RNA polymerase, possibly due to a gradual saturation of mRNA promoters. We have also analyzed data from a recent publication, in which it was concluded that the macromolecular composition in terms of RNA/protein and RNA/DNA ratios is solely determined by the effector molecule ppGpp. Our analysis indicates that this is true only in special cases and that, in general, medium adaptation also depends on factors other than ppGpp.

  16. Can Artemia Hatching Assay Be a (Sensitive) Alternative Tool to Acute Toxicity Test?

    PubMed

    Rotini, A; Manfra, L; Canepa, S; Tornambè, A; Migliore, L

    2015-12-01

    Artemia sp. is extensively used in ecotoxicity testing, despite criticisms inherent to both acute and long-term tests. Alternative endpoints and procedures should be considered to support the use of this biological model. The hatching process comprises several developmental steps and the cyst hatchability seems acceptable as endpoint criterion. In this study, we assessed the reliability of the hatching assay on A. franciscana by comparing with acute and long-term mortality tests, using two chemicals: Diethylene Glycol (DEG), Sodium Dodecyl Sulphate (SDS). Both DEG and SDS tests demonstrated a dose dependent hatching inhibition. The hatching test resulted more sensitive than acute mortality test and less sensitive than the long-term one. Results demonstrate the reliability and high sensitivity of this hatching assay on a short time lag and support its useful application in first-tier risk assessment procedures.

  17. 29 CFR 1918.43 - Handling hatch beams and covers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Handling hatch beams and covers. 1918.43 Section 1918.43... § 1918.43 Handling hatch beams and covers. Paragraphs (f)(2), (g), and (h) of this section apply only to... side of the hatch. (2) On seagoing vessels, hatch boards or similar covers removed from the hatch beams...

  18. Time-Dependent Behaviors of Granite: Loading-Rate Dependence, Creep, and Relaxation

    NASA Astrophysics Data System (ADS)

    Hashiba, K.; Fukui, K.

    2016-07-01

    To assess the long-term stability of underground structures, it is important to understand the time-dependent behaviors of rocks, such as their loading-rate dependence, creep, and relaxation. However, there have been fewer studies on crystalline rocks than on tuff, mudstone, and rock salt, because the high strength of crystalline rocks makes the detection of their time-dependent behaviors much more difficult. Moreover, studies on the relaxation, temporal change of stress and strain (TCSS) conditions, and relations between various time-dependent behaviors are scarce for not only granites, but also other rocks. In this study, previous reports on the time-dependent behaviors of granites were reviewed and various laboratory tests were conducted using Toki granite. These tests included an alternating-loading-rate test, creep test, relaxation test, and TCSS test. The results showed that the degree of time dependence of Toki granite is similar to other granites, and that the TCSS resembles the stress-relaxation curve and creep-strain curve. A viscoelastic constitutive model, proposed in a previous study, was modified to investigate the relations between the time-dependent behaviors in the pre- and post-peak regions. The modified model reproduced the stress-strain curve, creep, relaxation, and the results of the TCSS test. Based on a comparison of the results of the laboratory tests and numerical simulations, close relations between the time-dependent behaviors were revealed quantitatively.

  19. The temperature-dependence of elementary reaction rates: beyond Arrhenius.

    PubMed

    Smith, Ian W M

    2008-04-01

    The rates of chemical reactions and the dependence of their rate constants on temperature are of central importance in chemistry. Advances in the temperature-range and accuracy of kinetic measurements, principally inspired by the need to provide data for models of combustion, atmospheric, and astrophysical chemistry, show up the inadequacy of the venerable Arrhenius equation--at least, over wide ranges of temperature. This critical review will address the question of how to reach an understanding of the factors that control the rates of 'non-Arrhenius' reactions. It makes use of a number of recent kinetic measurements and shows how developments in advanced forms of transition state theory provide satisfactory explanations of complex kinetic behaviour (72 references).

  20. Anesthetic Diffusion Through Lipid Membranes Depends on the Protonation Rate

    PubMed Central

    Pérez-Isidoro, Rosendo; Sierra-Valdez, F. J.; Ruiz-Suárez, J. C.

    2014-01-01

    Hundreds of substances possess anesthetic action. However, despite decades of research and tests, a golden rule is required to reconcile the diverse hypothesis behind anesthesia. What makes an anesthetic to be local or general in the first place? The specific targets on proteins, the solubility in lipids, the diffusivity, potency, action time? Here we show that there could be a new player equally or even more important to disentangle the riddle: the protonation rate. Indeed, such rate modulates the diffusion speed of anesthetics into lipid membranes; low protonation rates enhance the diffusion for local anesthetics while high ones reduce it. We show also that there is a pH and membrane phase dependence on the local anesthetic diffusion across multiple lipid bilayers. Based on our findings we incorporate a new clue that may advance our understanding of the anesthetic phenomenon. PMID:25520016

  1. Anesthetic diffusion through lipid membranes depends on the protonation rate.

    PubMed

    Pérez-Isidoro, Rosendo; Sierra-Valdez, F J; Ruiz-Suárez, J C

    2014-12-18

    Hundreds of substances possess anesthetic action. However, despite decades of research and tests, a golden rule is required to reconcile the diverse hypothesis behind anesthesia. What makes an anesthetic to be local or general in the first place? The specific targets on proteins, the solubility in lipids, the diffusivity, potency, action time? Here we show that there could be a new player equally or even more important to disentangle the riddle: the protonation rate. Indeed, such rate modulates the diffusion speed of anesthetics into lipid membranes; low protonation rates enhance the diffusion for local anesthetics while high ones reduce it. We show also that there is a pH and membrane phase dependence on the local anesthetic diffusion across multiple lipid bilayers. Based on our findings we incorporate a new clue that may advance our understanding of the anesthetic phenomenon.

  2. On the Temperature Dependence of Enzyme-Catalyzed Rates.

    PubMed

    Arcus, Vickery L; Prentice, Erica J; Hobbs, Joanne K; Mulholland, Adrian J; Van der Kamp, Marc W; Pudney, Christopher R; Parker, Emily J; Schipper, Louis A

    2016-03-29

    One of the critical variables that determine the rate of any reaction is temperature. For biological systems, the effects of temperature are convoluted with myriad (and often opposing) contributions from enzyme catalysis, protein stability, and temperature-dependent regulation, for example. We have coined the phrase "macromolecular rate theory (MMRT)" to describe the temperature dependence of enzyme-catalyzed rates independent of stability or regulatory processes. Central to MMRT is the observation that enzyme-catalyzed reactions occur with significant values of ΔCp(‡) that are in general negative. That is, the heat capacity (Cp) for the enzyme-substrate complex is generally larger than the Cp for the enzyme-transition state complex. Consistent with a classical description of enzyme catalysis, a negative value for ΔCp(‡) is the result of the enzyme binding relatively weakly to the substrate and very tightly to the transition state. This observation of negative ΔCp(‡) has important implications for the temperature dependence of enzyme-catalyzed rates. Here, we lay out the fundamentals of MMRT. We present a number of hypotheses that arise directly from MMRT including a theoretical justification for the large size of enzymes and the basis for their optimum temperatures. We rationalize the behavior of psychrophilic enzymes and describe a "psychrophilic trap" which places limits on the evolution of enzymes in low temperature environments. One of the defining characteristics of biology is catalysis of chemical reactions by enzymes, and enzymes drive much of metabolism. Therefore, we also expect to see characteristics of MMRT at the level of cells, whole organisms, and even ecosystems.

  3. Dyar's Rule and the Investment Principle: optimal moulting strategies if feeding rate is size-dependent and growth is discontinuous

    PubMed Central

    Hutchinson, J. M. C.; McNamara, J. M.; Houston, A. I.; Vollrath, F.

    1997-01-01

    We consider animals whose feeding rate depends on the size of structures that grow only by moulting (e.g. spiders' legs). Our Investment Principle predicts optimum size increases at each moult; under simplifying assumptions these are a function of the scaling of feeding rate with size, the efficiency of moulting and the optimum size increase at the preceding moult. We show how to test this quantitatively, and make the qualitative prediction that size increases and instar durations change monotonically through development. Thus, this version of the model does not predict that proportional size increases necessarily remain constant, which is the pattern described by Dyar's Rule. A literature survey shows that in nature size increases tend to decline and instar durations to increase, but exceptions to monotonicity occur frequently: we consider how relaxing certain assumptions of the model could explain this. Having specified various functions relating fitness to adult size and time of emergence, we calculate (using dynamic programming) the effect of manipulating food availability, time of hatching and size of the initial (or some intermediate) instar. The associated norms of reaction depend on the fitness function and differ from those when growth follows Dyar's Rule or is continuous. We go on to consider optimization of the number of instars. The Investment Principle then predicts upper and lower limits to observed size increases and explains why increases usually change little or decline through development. This is thus a new adaptive explanation for Dyar's Rule and for the most common deviation from the Rule.

  4. Culture, feeding, and growth of alewives hatched in the laboratory

    USGS Publications Warehouse

    Heinrich, John W.

    1981-01-01

    Alewives (Alosa pseudoharengus) were reared from the egg to the early juvenile life stage. The major obstacle to rearing alewives from the egg- providing an acceptable food that facilitates first feeding- was overcome by presenting a mixture of wild zooplankton to the larvae twice daily, beginning on the day of hatching. Initial feeding by larvae held at 20A?C was observed 2 days after hatching, when the yolk was nearly absorbed. Comparison of stomach contents and the wild zooplankton composition suggested that the diet of larvae during the first 15 days of life shifted with changes in the availability of food but remained within a fairly narrow range of food sizes. Larvae hatched at a mean total length of 3.8 mm and grew at an average rate of 0.62 mm per day, to a mean of 35.5 mm after 50 days. At 50 days most fish had transformed into juveniles. The daily instantaneous mortality coefficient was 0.018. About half of the mortality occurred during the first 13 days after hatching.

  5. Strain rate dependency of oceanic intraplate earthquake b-values at extremely low strain rates

    NASA Astrophysics Data System (ADS)

    Sasajima, Ryohei; Ito, Takeo

    2016-06-01

    We discovered a clear positive dependence of oceanic intraplate earthquake (OCEQ) b-values on the age of the oceanic lithosphere. OCEQ b-values in the youngest (<10 Ma) oceanic lithosphere are around 1.0, while those in middle to old (>20 Ma) oceanic lithosphere exceed 1.5, which is significantly higher than the average worldwide earthquake b-value (around 1.0). On the other hand, the b-value of intraplate earthquakes in the Ninety East-Sumatra orogen, where oceanic lithosphere has an anomalously higher strain rate compared with normal oceanic lithosphere, is 0.93, which is significantly lower than the OCEQ b-value (about 1.9) with the same age (50-110 Ma). Thus, the variation in b-values relates to the strain rate of the oceanic lithosphere and is not caused by a difference in thermal structure. We revealed a negative strain rate dependency of the b-value at extremely low strain rates (<2 × 10-10/year), which can clearly explain the above b-values. We propose that the OCEQ b-value depends strongly on strain rate (either directly or indirectly) at extremely low strain rates. The high OCEQ b-values (>1.5) in oceanic lithosphere >20 Ma old imply that future improvement in seismic observation will capture many smaller magnitude OCEQs, which will provide valuable information on the evolution of the oceanic lithosphere and the driving mechanism of plate tectonics.

  6. Temperature Dependent Rate Coefficients for the OH + Pinonaldehyde Reaction

    NASA Astrophysics Data System (ADS)

    Davis, M. E.; Talukdar, R.; Notte, G.; Ellison, G. B.; Ravishankara, A. R.; Burkholder, J. B.

    2005-12-01

    The biogenic emission of monoterpenes is an important source of volatile organic compounds (VOCs) to the atmosphere, approximately 10% of the biogenic hydrocarbons emitted yearly. The oxidation of alpha-pinene, the most abundant monoterpene in the atmosphere, by OH leads to the formation of pinonaldehyde (3-acetyl-2,2-dimethyl-cyclobutyl-ethanal) as a major oxidation product formed in yields > 50%. The atmospheric oxidation of pinonaldehyde will impact radical cycling, ozone formation and air quality on a regional scale. Previous laboratory studies of the OH + pinonaldehyde rate coefficient have used relative rate methods and were limited to room temperature. The reported rate coefficients are in poor agreement with values ranging from 4.0 to 9.1 × 10-11 cm#3 molecule-1 s-1. In this study we have measured absolute rate coefficients to resolve these discrepancies and have extended the measurements to include the temperature dependence. The rate coefficient for the gas phase reaction of OH with pinonaldehyde was measured over the temperature range 297 to 374 K and between 55 and 96 Torr under pseudo first order conditions in OH. Laser-induced fluorescence (LIF) was used to monitor the OH radical which was produced by pulsed laser photolysis. The pinonaldehyde concentration was determined in situ using Fourier transform infrared (FTIR) and UV (185 nm) absorption spectroscopy. The rate coefficient for the OH + pinonaldehyde reaction will be presented. Our results will be compared with previous rate coefficient measurements and the discrepancies and the atmospheric implications of these measurements will be discussed.

  7. A rate-dependent Hosford-Coulomb model for predicting ductile fracture at high strain rates

    NASA Astrophysics Data System (ADS)

    Marcadet, Stephane J.; Roth, Christian C.; Erice, Borja; Mohr, Dirk

    2015-09-01

    The Hosford-Coulomb model incorporates the important effect of the Lode angle parameter in addition to the stress triaxiality to predict the initiation of ductile fracture. A strain-rate dependent extension of the Hosford-Coulomb model is presented to describe the results from low, intermediate and high strain rate fracture experiments on advanced high strength steels (DP590 and TRIP780). The model predictions agree well with the experimental observation of an increase in ductility as function of strain rate for stress states ranging from uniaxial to equi-biaxial tension.

  8. Measurement of Force-Dependent Release Rates of Cytoskeletal Motors.

    PubMed

    Can, Sinan; Yildiz, Ahmet

    2017-01-01

    Optical tweezers permit measuring motor-filament rupture forces with piconewton sensitivity. For deeper structural and mechanistic understanding of motors, different structural constraints can be induced by pulling motor proteins at various positions and manipulating the direction of the exerted force. Here, we present an optical-trapping approach to investigate the effect of the magnitude and direction of tension applied to the linker element of cytoskeletal motors on motor-filament interactions. Using this approach, force-dependent microtubule release rates of monomeric kinesins can be directly measured by pulling on kinesin's "neck linker" with a constant force.

  9. Temperature dependences of rate coefficients for electron catalyzed mutual neutralization.

    PubMed

    Shuman, Nicholas S; Miller, Thomas M; Friedman, Jeffrey F; Viggiano, Albert A; Maeda, Satoshi; Morokuma, Keiji

    2011-07-14

    The flowing afterglow technique of variable electron and neutral density attachment mass spectrometry (VENDAMS) has recently yielded evidence for a novel plasma charge loss process, electron catalyzed mutual neutralization (ECMN), i.e., A(+) + B(-) + e(-) → A + B + e(-). Here, rate constants for ECMN of two polyatomic species (POCl(3)(-) and POCl(2)(-)) and one diatomic species (Br(2)(-)) each with two monatomic cations (Ar(+)and Kr(+)) are measured using VENDAMS over the temperature range 300 K-500 K. All rate constants show a steep negative temperature dependence, consistent with that expected for a three body process involving two ions and an electron. No variation in rate constants as a function of the cation type is observed outside of uncertainty; however, rate constants of the polyatomic anions (~1 × 10(-18) cm(6) s(-1) at 300 K) are measurably higher than that for Br(2)(-) [(5.5 ± 2) × 10(-19) cm(6) s(-1) at 300 K].

  10. Temperature dependences of rate coefficients for electron catalyzed mutual neutralization

    SciTech Connect

    Shuman, Nicholas S.; Miller, Thomas M.; Friedman, Jeffrey F.; Viggiano, Albert A.; Maeda, Satoshi; Morokuma, Keiji

    2011-07-14

    The flowing afterglow technique of variable electron and neutral density attachment mass spectrometry (VENDAMS) has recently yielded evidence for a novel plasma charge loss process, electron catalyzed mutual neutralization (ECMN), i.e., A{sup +}+ B{sup -}+ e{sup -}{yields} A + B + e{sup -}. Here, rate constants for ECMN of two polyatomic species (POCl{sub 3}{sup -} and POCl{sub 2}{sup -}) and one diatomic species (Br{sub 2}{sup -}) each with two monatomic cations (Ar{sup +}and Kr{sup +}) are measured using VENDAMS over the temperature range 300 K-500 K. All rate constants show a steep negative temperature dependence, consistent with that expected for a three body process involving two ions and an electron. No variation in rate constants as a function of the cation type is observed outside of uncertainty; however, rate constants of the polyatomic anions ({approx}1 x 10{sup -18} cm{sup 6} s{sup -1} at 300 K) are measurably higher than that for Br{sub 2}{sup -}[(5.5 {+-} 2) x 10{sup -19} cm{sup 6} s{sup -1} at 300 K].

  11. Temperature dependences of rate coefficients for electron catalyzed mutual neutralization

    NASA Astrophysics Data System (ADS)

    Shuman, Nicholas S.; Miller, Thomas M.; Friedman, Jeffrey F.; Viggiano, Albert A.; Maeda, Satoshi; Morokuma, Keiji

    2011-07-01

    The flowing afterglow technique of variable electron and neutral density attachment mass spectrometry (VENDAMS) has recently yielded evidence for a novel plasma charge loss process, electron catalyzed mutual neutralization (ECMN), i.e., A+ + B- + e- → A + B + e-. Here, rate constants for ECMN of two polyatomic species (POCl3- and POCl2-) and one diatomic species (Br2-) each with two monatomic cations (Ar+and Kr+) are measured using VENDAMS over the temperature range 300 K-500 K. All rate constants show a steep negative temperature dependence, consistent with that expected for a three body process involving two ions and an electron. No variation in rate constants as a function of the cation type is observed outside of uncertainty; however, rate constants of the polyatomic anions (˜1 × 10-18 cm6 s-1 at 300 K) are measurably higher than that for Br2- [(5.5 ± 2) × 10-19 cm6 s-1 at 300 K].

  12. Scale dependence of rock friction at high work rate.

    PubMed

    Yamashita, Futoshi; Fukuyama, Eiichi; Mizoguchi, Kazuo; Takizawa, Shigeru; Xu, Shiqing; Kawakata, Hironori

    2015-12-10

    Determination of the frictional properties of rocks is crucial for an understanding of earthquake mechanics, because most earthquakes are caused by frictional sliding along faults. Prior studies using rotary shear apparatus revealed a marked decrease in frictional strength, which can cause a large stress drop and strong shaking, with increasing slip rate and increasing work rate. (The mechanical work rate per unit area equals the product of the shear stress and the slip rate.) However, those important findings were obtained in experiments using rock specimens with dimensions of only several centimetres, which are much smaller than the dimensions of a natural fault (of the order of 1,000 metres). Here we use a large-scale biaxial friction apparatus with metre-sized rock specimens to investigate scale-dependent rock friction. The experiments show that rock friction in metre-sized rock specimens starts to decrease at a work rate that is one order of magnitude smaller than that in centimetre-sized rock specimens. Mechanical, visual and material observations suggest that slip-evolved stress heterogeneity on the fault accounts for the difference. On the basis of these observations, we propose that stress-concentrated areas exist in which frictional slip produces more wear materials (gouge) than in areas outside, resulting in further stress concentrations at these areas. Shear stress on the fault is primarily sustained by stress-concentrated areas that undergo a high work rate, so those areas should weaken rapidly and cause the macroscopic frictional strength to decrease abruptly. To verify this idea, we conducted numerical simulations assuming that local friction follows the frictional properties observed on centimetre-sized rock specimens. The simulations reproduced the macroscopic frictional properties observed on the metre-sized rock specimens. Given that localized stress concentrations commonly occur naturally, our results suggest that a natural fault may lose its

  13. Acute and chronic eggshell temperature manipulations during hatching term influence hatchability, broiler performance, and ascites incidence.

    PubMed

    Sozcu, A; Ipek, A

    2015-02-01

    The aim of the current study was to determine how a control temperature and acute and chronic high eggshell temperatures during the last three days of incubation, can affect hatchability, chick quality, and organ development on day of hatch as well as broiler performance and ascites incidence in later life. The eggshell temperature manipulations were applied during hatching term (days 19 to 21) as follows: control EST (37.3 to 38.0°C), acute high eggshell temperature manipulations (38.4- to 39.0°C for three hours daily) and chronic high eggshell temperature manipulations (38.4 to 39.0°C). The lowest hatchability and the highest cull chick rate were in the chronic high eggshell temperature manipulations group. Lower chick quality parameters correlated with lower chick weights and heavier residual yolk sac weights that were in the chronic high eggshell temperature manipulations group depending on hatch time. The live weights on the 1(st) day of the growing period were higher in the control and acute high eggshell temperature manipulations groups than the chronic high eggshell temperature manipulations group. At 6 wk of age, live weights of broilers were the highest in the control than in the acute and chronic high eggshell temperature manipulations groups. The total mortality was 2.5, 9.2, and 13.3%, the mortality due to ascites was 2.1, 8.3, and 12.9% in the control, acute ,and chronic high eggshell temperature manipulations groups, respectively. The right ventricular/total ventricular ratios for the control, acute and chronic high eggshell temperature manipulations groups were 0.22, 0.28, and 0.30%, respectively. In conclusion, short-term and long-term higher temperatures during the hatching term affect embryo development, incubation results, broiler performance, and ascites incidence. Although the acute high eggshell temperature manipulations did not affect the chick quality parameters at hatch, it negatively affected incubation results and broiler performance

  14. Pulse structure dependence of proton spin polarization rate

    NASA Astrophysics Data System (ADS)

    Kawahara, Tomomi; Uesaka, Tomohiro; Shimizu, Youhei; Sakaguchi, Satoshi; Wakui, Takashi

    2009-10-01

    A polarized proton solid target for RI beam experiments has been developed at Center for Nuclear Study, University of Tokyo [1]. The proton is polarized by transferring population difference in photo-excited triplet states of aromatic molecule. Through this method proton polarization of about 20% have been obtained at 0.1 T and in 100 K. Although this target has been successfully applied to RI beam experiments [2,3], further improvement in the polarization is desirable for future applications. To pursuit possible improvement in photo-excitation power, we have examined pulse-structure dependence of proton polarization rate. The excitation light is provided by a cw Ar-ion laser and pulsed by an optical chopper. We have found that proton polarization depends strongly on the pulse structure and the optimum condition is found to be a duty factor of 50% and a repetition frequency of 10 kHz. At this condition, the polarization rate can be increased by a factor 2.5 or more compared with the old settings, where a duty factor and a repetition frequency were 5% and 2.5 kHz, respectively. [1] T. Wakui et al., Nucl. Instrum. Methods A 550 (2005) 521. [2] M. Hatano et al., Eur. Phys. J. A 25 (2005) 255. [3] S. Sakaguchi et al., CNS Annual Report 2006 (2007).

  15. Interpretation of the temperature dependence of equilibrium and rate constants.

    PubMed

    Winzor, Donald J; Jackson, Craig M

    2006-01-01

    The objective of this review is to draw attention to potential pitfalls in attempts to glean mechanistic information from the magnitudes of standard enthalpies and entropies derived from the temperature dependence of equilibrium and rate constants for protein interactions. Problems arise because the minimalist model that suffices to describe the energy differences between initial and final states usually comprises a set of linked equilibria, each of which is characterized by its own energetics. For example, because the overall standard enthalpy is a composite of those individual values, a positive magnitude for DeltaH(o) can still arise despite all reactions within the subset being characterized by negative enthalpy changes: designation of the reaction as being entropy driven is thus equivocal. An experimenter must always bear in mind the fact that any mechanistic interpretation of the magnitudes of thermodynamic parameters refers to the reaction model rather than the experimental system. For the same reason there is little point in subjecting the temperature dependence of rate constants for protein interactions to transition-state analysis. If comparisons with reported values of standard enthalpy and entropy of activation are needed, they are readily calculated from the empirical Arrhenius parameters.

  16. Prey behavior, age-dependent vulnerability, and predation rates.

    PubMed

    Lingle, Susan; Feldman, Alex; Boyce, Mark S; Wilson, W Finbarr

    2008-11-01

    Variation in the temporal pattern of vulnerability can provide important insights into predator-prey relationships and the evolution of antipredator behavior. We illustrate these points with a system that has coyotes (Canis latrans) as a predator and two species of congeneric deer (Odocoileus spp.) as prey. The deer employ different antipredator tactics (aggressive defense vs. flight) that result in contrasting patterns of age-dependent vulnerability in their probability of being captured when encountered by coyotes. We use long-term survival data and a simple mathematical model to show that (1) species differences in age-dependent vulnerability are reflected in seasonal predation rates and (2) seasonal variation in prey vulnerability and predator hunt activity, which can be associated with the availability of alternative prey, interact to shape seasonal and annual predation rates for each prey species. Shifting hunt activity from summer to winter, or vice versa, alleviated annual mortality on one species and focused it on the other. Our results indicate that seasonal variation in prey vulnerability and hunt activity interact to influence the impact that a predator has on any particular type of prey. Furthermore, these results indicate that seasonal variation in predation pressure is an important selection pressure shaping prey defenses.

  17. Hybrid colored noise process with space-dependent switching rates

    NASA Astrophysics Data System (ADS)

    Bressloff, Paul C.; Lawley, Sean D.

    2017-07-01

    A fundamental issue in the theory of continuous stochastic process is the interpretation of multiplicative white noise, which is often referred to as the Itô-Stratonovich dilemma. From a physical perspective, this reflects the need to introduce additional constraints in order to specify the nature of the noise, whereas from a mathematical perspective it reflects an ambiguity in the formulation of stochastic differential equations (SDEs). Recently, we have identified a mechanism for obtaining an Itô SDE based on a form of temporal disorder. Motivated by switching processes in molecular biology, we considered a Brownian particle that randomly switches between two distinct conformational states with different diffusivities. In each state, the particle undergoes normal diffusion (additive noise) so there is no ambiguity in the interpretation of the noise. However, if the switching rates depend on position, then in the fast switching limit one obtains Brownian motion with a space-dependent diffusivity of the Itô form. In this paper, we extend our theory to include colored additive noise. We show that the nature of the effective multiplicative noise process obtained by taking both the white-noise limit (κ →0 ) and fast switching limit (ɛ →0 ) depends on the order the two limits are taken. If the white-noise limit is taken first, then we obtain Itô, and if the fast switching limit is taken first, then we obtain Stratonovich. Moreover, the form of the effective diffusion coefficient differs in the two cases. The latter result holds even in the case of space-independent transition rates, where one obtains additive noise processes with different diffusion coefficients. Finally, we show that yet another form of multiplicative noise is obtained in the simultaneous limit ɛ ,κ →0 with ɛ /κ2 fixed.

  18. Honeybee flight metabolic rate: does it depend upon air temperature?

    PubMed

    Woods, William A; Heinrich, Bernd; Stevenson, Robert D

    2005-03-01

    Differing conclusions have been reached as to how or whether varying heat production has a thermoregulatory function in flying honeybees Apis mellifera. We investigated the effects of air temperature on flight metabolic rate, water loss, wingbeat frequency, body segment temperatures and behavior of honeybees flying in transparent containment outdoors. For periods of voluntary, uninterrupted, self-sustaining flight, metabolic rate was independent of air temperature between 19 and 37 degrees C. Thorax temperatures (T(th)) were very stable, with a slope of thorax temperature on air temperature of 0.18. Evaporative heat loss increased from 51 mW g(-1) at 25 degrees C to 158 mW g(-1) at 37 degrees C and appeared to account for head and abdomen temperature excess falling sharply over the same air temperature range. As air temperature increased from 19 to 37 degrees C, wingbeat frequency showed a slight but significant increase, and metabolic expenditure per wingbeat showed a corresponding slight but significant decrease. Bees spent an average of 52% of the measurement period in flight, with 19 of 78 bees sustaining uninterrupted voluntary flight for periods of >1 min. The fraction of time spent flying declined as air temperature increased. As the fraction of time spent flying decreased, the slope of metabolic rate on air temperature became more steeply negative, and was significant for bees flying less than 80% of the time. In a separate experiment, there was a significant inverse relationship of metabolic rate and air temperature for bees requiring frequent or constant agitation to remain airborne, but no dependence for bees that flew with little or no agitation; bees were less likely to require agitation during outdoor than indoor measurements. A recent hypothesis explaining differences between studies in the slope of flight metabolic rate on air temperature in terms of differences in metabolic capacity and thorax temperature is supported for honeybees in voluntary

  19. Exercise training improves heart rate variability after methamphetamine dependency.

    PubMed

    Dolezal, Brett Andrew; Chudzynski, Joy; Dickerson, Daniel; Mooney, Larissa; Rawson, Richard A; Garfinkel, Alan; Cooper, Christopher B

    2014-06-01

    Heart rate variability (HRV) reflects a healthy autonomic nervous system and is increased with physical training. Methamphetamine dependence (MD) causes autonomic dysfunction and diminished HRV. We compared recently abstinent methamphetamine-dependent participants with age-matched, drug-free controls (DF) and also investigated whether HRV can be improved with exercise training in the methamphetamine-dependent participants. In 50 participants (MD = 28; DF = 22), resting heart rate (HR; R-R intervals) was recorded over 5 min while seated using a monitor affixed to a chest strap. Previously reported time domain (SDNN, RMSSD, pNN50) and frequency domain (LFnu, HFnu, LF/HF) parameters of HRV were calculated with customized software. MD were randomized to thrice-weekly exercise training (ME = 14) or equal attention without training (MC = 14) over 8 wk. Groups were compared using paired and unpaired t-tests. Statistical significance was set at P ≤ 0.05. Participant characteristics were matched between groups (mean ± SD): age = 33 ± 6 yr; body mass = 82.7 ± 12 kg, body mass index = 26.8 ± 4.1 kg·min. Compared with DF, the MD group had significantly higher resting HR (P < 0.05), LFnu, and LF/HF (P < 0.001) as well as lower SDNN, RMSSD, pNN50, and HFnu (all P < 0.001). At randomization, HRV indices were similar between ME and MC groups. However, after training, the ME group significantly (all P < 0.001) increased SDNN (+14.7 ± 2.0 ms, +34%), RMSSD (+19.6 ± 4.2 ms, +63%), pNN50 (+22.6% ± 2.7%, +173%), HFnu (+14.2 ± 1.9, +60%), and decreased HR (-5.2 ± 1.1 bpm, -7%), LFnu (-9.6 ± 1.5, -16%), and LF/HF (-0.7 ± 0.3, -19%). These measures did not change from baseline in the MC group. HRV, based on several conventional indices, was diminished in recently abstinent, methamphetamine-dependent individuals. Moreover, physical training yielded a marked increase in HRV, representing increased vagal modulation or improved autonomic balance.

  20. 9 CFR 91.29 - Hatches.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ....25 (e) and (f) are met and sufficient space shall be left clear on such hatches for passageway across... stowed, sufficient space shall be left clear for the proper removal and handling of such hay and feed...

  1. Hoshide in intra-deck hatch

    NASA Image and Video Library

    2008-06-01

    S124-E-005419 (1 June 2008) --- Japan Aerospace Exploration Agency (JAXA) astronaut Akihiko Hoshide, STS-124 mission specialist, smiles for a photo while in the hatch which connects the flight deck and middeck of Space Shuttle Discovery.

  2. Hatches Open, Expedition 32 Expands to Six

    NASA Image and Video Library

    The hatches between the Soyuz and the Rassvet module opened Tuesday at 3:23 a.m. when Flight Engineers Suni Williams, Yuri Malenchenko and Aki Hoshide entered the International Space Station. Exped...

  3. Ultraviolet variability of quasars: dependence on the accretion rate

    NASA Astrophysics Data System (ADS)

    Meusinger, H.; Weiss, V.

    2013-12-01

    Aims: Although the variability in the ultraviolet and optical domain is one of the major characteristics of quasars, the dominant underlying mechanisms are still poorly understood. There is a broad consensus on the relationship between the strength of the variability and such quantities as time-lag, wavelength, luminosity, and redshift. However, evidence on a dependence on the fundamental parameters of the accretion process is still inconclusive. This paper is focused on the correlation between the ultraviolet quasar long-term variability and the accretion rate. Methods: We compiled a catalogue of about 4000 quasars including individual estimators for the variability strength derived from the multi-epoch photometry in the SDSS Stripe 82, virial black hole masses M derived from the Mg ii line, and mass accretion rates Ṁ from the Davis-Laor scaling relation. Several statistical tests were applied to evaluate the correlations of the variability with luminosity, mass, Eddington ratio, and accretion rate. Results: We confirm the existence of significant anti-correlations between the variability estimator V and the accretion rate Ṁ, the Eddington ratio ɛ, and the bolometric luminosity Lbol, respectively. The Eddington ratio is tightly correlated with Ṁ. A weak, statistically not significant positive trend is indicated for the dependence of V on M. As a side product, we find a strong correlation of the radiative efficiency η with M in our sample. We show via numerical simulations that this trend is most likely produced by selection effects in combination with the mass errors and the use of the scaling relation for Ṁ. The anti-correlations of V with Ṁ, ɛ, and Lbol cannot be explained in such a way. The strongest anti-correlation is found between V and Ṁ. However, it is difficult to decide which of the quantities L,ɛ, and Ṁ is intrinsically correlated with V and which of the observed correlations of V are produced by the L - ɛ - Ṁ relation. A V -

  4. Modified Sediment Rating Curve Approach for Supply-dependent Conditions

    NASA Astrophysics Data System (ADS)

    Wright, S. A.; Topping, D. J.; Rubin, D. M.; Melis, T. S.

    2007-12-01

    particularly suited to such an approach because it is substantially sediment supply-limited such that transport rates are dependent on both flow and sediment supply; also, there is a rich dataset available for constraining the empirical parameters and testing the hybrid model. Though more empirical in nature than the morphodynamic models, this modified sediment rating curve approach may have broad potential application because its simplicity allows for relatively rapid evaluation of long-term sediment budgets under a range of flow regimes and sediment supply conditions.

  5. Characterizing heart rate variability by scale-dependent Lyapunov exponent

    NASA Astrophysics Data System (ADS)

    Hu, Jing; Gao, Jianbo; Tung, Wen-wen

    2009-06-01

    Previous studies on heart rate variability (HRV) using chaos theory, fractal scaling analysis, and many other methods, while fruitful in many aspects, have produced much confusion in the literature. Especially the issue of whether normal HRV is chaotic or stochastic remains highly controversial. Here, we employ a new multiscale complexity measure, the scale-dependent Lyapunov exponent (SDLE), to characterize HRV. SDLE has been shown to readily characterize major models of complex time series including deterministic chaos, noisy chaos, stochastic oscillations, random 1/f processes, random Levy processes, and complex time series with multiple scaling behaviors. Here we use SDLE to characterize the relative importance of nonlinear, chaotic, and stochastic dynamics in HRV of healthy, congestive heart failure, and atrial fibrillation subjects. We show that while HRV data of all these three types are mostly stochastic, the stochasticity is different among the three groups.

  6. Potential pitfalls of strain rate imaging: angle dependency

    NASA Technical Reports Server (NTRS)

    Castro, P. L.; Greenberg, N. L.; Drinko, J.; Garcia, M. J.; Thomas, J. D.

    2000-01-01

    Strain Rate Imaging (SRI) is a new echocardiographic technique that allows for the real-time determination of myocardial SR, which may be used for the early and accurate detection of coronary artery disease. We sought to study whether SR is affected by scan line alignment in a computer simulation and an in vivo experiment. Through the computer simulation and the in vivo experiment we generated and validated safe scanning sectors within the ultrasound scan sector and showed that while SRI will be an extremely valuable tool in detecting coronary artery disease there are potential pitfalls for the unwary clinician. Only after accounting for these affects due to angle dependency, can clinicians utilize SRI's potential as a valuable tool in detecting coronary artery disease.

  7. Objective and subjective memory ratings in cannabis-dependent adolescents.

    PubMed

    McClure, Erin A; Lydiard, Jessica B; Goddard, Scott D; Gray, Kevin M

    2015-01-01

    Cannabis is the most widely used illicit substance worldwide, with an estimated 160 million users. Among adolescents, rates of cannabis use are increasing, while the perception of detrimental effects of cannabis use is declining. Difficulty with memory is one of the most frequently noted cognitive deficits associated with cannabis use, but little data exist exploring how well users can identify their own memory deficits, if present. The current secondary analysis sought to characterize objective verbal and visual memory performance via a neurocognitive battery in cannabis-dependent adolescents enrolled in a pharmacotherapeutic cannabis cessation clinical trial (N = 112) and compare this to a single self-reported item assessing difficulties with memory loss. Exploratory analyses also assessed dose-dependent effects of cannabis on memory performance. A small portion of the study sample (10%) endorsed a "serious problem" with memory loss. Those participants reporting "no problem" or "serious problem" scored similarly on visual and verbal memory tasks on the neurocognitive battery. Exploratory analyses suggested a potential relationship between days of cannabis use, amount of cannabis used, and gender with memory performance. This preliminary and exploratory analysis suggests that a sub-set of cannabis users may not accurately perceive difficulties with memory. Further work should test this hypothesis with the use of a control group, comprehensive self-reports of memory problems, and adult populations that may have more years of cannabis use and more severe cognitive deficits. © American Academy of Addiction Psychiatry.

  8. Objective and subjective memory ratings in cannabis-dependent adolescents

    PubMed Central

    McClure, Erin A.; Lydiard, Jessica B.; Goddard, Scott D.; Gray, Kevin M.

    2015-01-01

    Background and Objectives Cannabis is the most widely used illicit substance worldwide, with an estimated 160 million users. Among adolescents, rates of cannabis use are increasing, while the perception of detrimental effects of cannabis use is declining. Difficulty with memory is one of the most frequently noted cognitive deficits associated with cannabis use, but little data exists exploring how well users can identify their own memory deficits, if present. Methods The current secondary analysis sought to characterize objective verbal and visual memory performance via a neurocognitive battery in cannabis-dependent adolescents enrolled in a pharmacotherapeutic cannabis cessation clinical trial (N=112) and compare this to a single self-reported item assessing difficulties with memory loss. Exploratory analyses also assessed dose-dependent effects of cannabis on memory performance. Results A small portion of the study sample (10%) endorsed a “serious problem” with memory loss. Those participants reporting “no problem” or “serious problem” scored similarly on visual and verbal memory tasks on the neurocognitive battery. Exploratory analyses suggested a potential relationship between days of cannabis use, amount of cannabis used, and gender with memory performance. Conclusions and Scientific Significance This preliminary and exploratory analysis suggests that a sub-set of cannabis users may not accurately perceive difficulties with memory. Further work should test this hypothesis with the use of a control group, comprehensive self-reports of memory problems, and adult populations that may have more years of cannabis use and more severe cognitive deficits. PMID:25823635

  9. A STELLAR-MASS-DEPENDENT DROP IN PLANET OCCURRENCE RATES

    SciTech Connect

    Mulders, Gijs D.; Pascucci, Ilaria; Apai, Dániel

    2015-01-10

    The Kepler spacecraft has discovered a large number of planets with up to one-year periods and down to terrestrial sizes. While the majority of the target stars are main-sequence dwarfs of spectral type F, G, and K, Kepler covers stars with effective temperatures as low as 2500 K, which corresponds to M stars. These cooler stars allow characterization of small planets near the habitable zone, yet it is not clear if this population is representative of that around FGK stars. In this paper, we calculate the occurrence of planets around stars of different spectral types as a function of planet radius and distance from the star and show that they are significantly different from each other. We further identify two trends. First, the occurrence of Earth- to Neptune-sized planets (1-4 R {sub ⊕}) is successively higher toward later spectral types at all orbital periods probed by Kepler; planets around M stars occur twice as frequently as around G stars, and thrice as frequently as around F stars. Second, a drop in planet occurrence is evident at all spectral types inward of a ∼10 day orbital period, with a plateau further out. By assigning to each spectral type a median stellar mass, we show that the distance from the star where this drop occurs is stellar mass dependent, and scales with semi-major axis as the cube root of stellar mass. By comparing different mechanisms of planet formation, trapping, and destruction, we find that this scaling best matches the location of the pre-main-sequence co-rotation radius, indicating efficient trapping of migrating planets or planetary building blocks close to the star. These results demonstrate the stellar-mass dependence of the planet population, both in terms of occurrence rate and of orbital distribution. The prominent stellar-mass dependence of the inner boundary of the planet population shows that the formation or migration of planets is sensitive to the stellar parameters.

  10. Shear-rate-dependent transport coefficients in granular suspensions

    NASA Astrophysics Data System (ADS)

    Garzó, Vicente

    2017-06-01

    A recent model for monodisperse granular suspensions is used to analyze transport properties in spatially inhomogeneous states close to the simple (or uniform) shear flow. The kinetic equation is based on the inelastic Boltzmann (for low-density gases) with the presence of a viscous drag force that models the influence of the interstitial gas phase on the dynamics of grains. A normal solution is obtained via a Chapman-Enskog-like expansion around a (local) shear flow distribution which retains all the hydrodynamic orders in the shear rate. To first order in the expansion, the transport coefficients characterizing momentum and heat transport around shear flow are given in terms of the solutions of a set of coupled linear integral equations which are approximately solved by using a kinetic model of the Boltzmann equation. To simplify the analysis, the steady-state conditions when viscous heating is compensated by the cooling terms arising from viscous friction and collisional dissipation are considered to get the explicit forms of the set of generalized transport coefficients. The shear-rate dependence of some of the transport coefficients of the set is illustrated for several values of the coefficient of restitution.

  11. Shear-rate-dependent transport coefficients in granular suspensions.

    PubMed

    Garzó, Vicente

    2017-06-01

    A recent model for monodisperse granular suspensions is used to analyze transport properties in spatially inhomogeneous states close to the simple (or uniform) shear flow. The kinetic equation is based on the inelastic Boltzmann (for low-density gases) with the presence of a viscous drag force that models the influence of the interstitial gas phase on the dynamics of grains. A normal solution is obtained via a Chapman-Enskog-like expansion around a (local) shear flow distribution which retains all the hydrodynamic orders in the shear rate. To first order in the expansion, the transport coefficients characterizing momentum and heat transport around shear flow are given in terms of the solutions of a set of coupled linear integral equations which are approximately solved by using a kinetic model of the Boltzmann equation. To simplify the analysis, the steady-state conditions when viscous heating is compensated by the cooling terms arising from viscous friction and collisional dissipation are considered to get the explicit forms of the set of generalized transport coefficients. The shear-rate dependence of some of the transport coefficients of the set is illustrated for several values of the coefficient of restitution.

  12. Assessing Wind Farm Reliability Using Weather Dependent Failure Rates

    NASA Astrophysics Data System (ADS)

    Wilson, G.; McMillan, D.

    2014-06-01

    Using reliability data comprising of two modern, large scale wind farm sites and wind data from two onsite met masts, a model is developed which calculates wind speed dependant failure rates which are used to populate a Markov Chain. Monte Carlo simulation is then exercised to simulate three wind farms which are subjected to controlled wind speed conditions from three separate potential UK sites. The model then calculates and compares wind farm reliability due to corrective maintenance and component failure rates influenced by the wind speed of each of the sites. Results show that the components affected most by changes in average daily wind speed are the control system and the yaw system. A comparison between this model and a more simple estimation of site yield is undertaken. The model takes into account the effects of the wind speed on the cost of operation and maintenance and also includes the impact of longer periods of downtime in the winter months and shorter periods in the summer. By taking these factors into account a more detailed site assessment can be undertaken. There is significant value to this model for operators and manufacturers.

  13. Activation of peroxisome proliferators-activated receptor δ (PPARδ) promotes blastocyst hatching in mice.

    PubMed

    Kang, Hee Jung; Hwang, Soo Jin; Yoon, Jung Ah; Jun, Jin Hyun; Lim, Hyunjung Jade; Yoon, Tae Ki; Song, Haengseok

    2011-10-01

    Prostaglandins participate in a variety of female reproductive processes, including ovulation, fertilization, embryo implantation and parturition. In particular, maternal prostacyclin (PGI(2)) is critical for embryo implantation and the action of PGI(2) is not mediated via its G-protein-coupled membrane receptor, IP, but its nuclear receptor, peroxisome-proliferator-activated receptor δ (PPARδ). Recently, several studies have shown that PGI(2) enhances blastocyst development and/or hatching rate in vitro, and subsequently implantation and live birth rates in mice. However, the mechanism by which PGI(2) improves preimplantation embryo development in vitro remains unclear. Using molecular, pharmacologic and genetic approaches, we show that PGI(2)-induced PPARδ activation accelerates blastocyst hatching in mice. mRNAs for PPARδ, retinoid X receptor (heterodimeric partners of PPARδ) and PGI(2) synthase (PGIS) are temporally induced after zygotic gene activation, and their expression reaches maximum levels at the blastocyst stage, suggesting that functional complex of PPARδ can be formed in the blastocyst. Carbaprostacyclin (a stable analogue of PGI(2)) and GW501516 (a PPARδ selective agonist) significantly accelerated blastocyst hatching but did not increase total cell number of cultured blastocysts. Whereas U51605 (a PGIS inhibitor) interfered with blastocyst hatching, GW501516 restored U51605-induced retarded hatching. In contrast to the improvement of blastocyst hatching by PPARδ agonists, PPAR antagonists significantly inhibited blastocyst hatching. Furthermore, deletion of PPARδ at early stages of preimplantation mouse embryos caused delay of blastocyst hatching, but did not impair blastocyst development. Taken together, PGI(2)-induced PPARδ activation accelerates blastocyst hatching in mice.

  14. Exercise Training Improves Heart Rate Variability after Methamphetamine Dependency

    PubMed Central

    Dolezal, Brett A.; Chudzynski, Joy; Dickerson, Daniel; Mooney, Larissa; Rawson, Richard A.; Garfinkel, Alan; Cooper, Christopher B.

    2014-01-01

    Purpose Heart rate variability (HRV) reflects a healthy autonomic nervous system and is increased with physical training. Methamphetamine dependence (MD) causes autonomic dysfunction and diminished HRV. We compared recently abstinent MD participants with age-matched, drug free controls (DF) and also investigated whether HRV can be improved with exercise training in the MD participants. Methods In 50 participants (MD=28; DF=22) resting heart rate (R-R intervals) was recorded over 5 min while seated using a monitor affixed to a chest strap. Previously reported time-domain (SDNN, RMSSD, pNN50) and frequency-domain (LFnu, HFnu, LF/HF) parameters of HRV were calculated with customized software. MD were randomized to thrice weekly exercise training (ME=14) or equal attention without training (MC=14) over 8 weeks. Groups were compared using paired and unpaired t-tests. Statistical significance was set at P≤0.05. Results Participant characteristics were matched between groups: age 33±6 years; body mass 82.7±12 kg, BMI 26.8±4.1 kg•min−2, mean±SD. Compared with DF, the MD group had significantly higher resting heart rate (P<0.05), LFnu, and LF/HF (P<0.001) as well as lower SDNN, RMSSD, pNN50 and HFnu (all P<0.001). At randomization, HRV indices were similar between ME and MC groups. However, after training, the ME group significantly (all P<0.001) increased SDNN (+14.7±2.0 ms, +34%), RMSSD (+19.6±4.2 ms, +63%), pNN50 (+22.6±2.7%, +173%), HFnu (+14.2±1.9, +60%) and decreased HR (−5.2±1.1 beats·min−1, −7%), LFnu (−9.6±1.5, −16%) and LF/HF (−0.7±0.3, −19%). These measures did not change from baseline in the MC group. Conclusion HRV, based on several conventional indices, was diminished in recently abstinent, methamphetamine dependent individuals. Moreover, physical training yielded a marked increase of HRV representing increased vagal modulation or improved autonomic balance. PMID:24162556

  15. DnaK-Dependent Accelerated Evolutionary Rate in Prokaryotes

    PubMed Central

    Kadibalban, A. Samer; Bogumil, David; Landan, Giddy; Dagan, Tal

    2016-01-01

    Many proteins depend on an interaction with molecular chaperones in order to fold into a functional tertiary structure. Previous studies showed that protein interaction with the GroEL/GroES chaperonine and Hsp90 chaperone can buffer the impact of slightly deleterious mutations in the protein sequence. This capacity of GroEL/GroES to prevent protein misfolding has been shown to accelerate the evolution of its client proteins. Whether other bacterial chaperones have a similar effect on their client proteins is currently unknown. Here, we study the impact of DnaK (Hsp70) chaperone on the evolution of its client proteins. Evolutionary parameters were derived from comparison of the Escherichia coli proteome to 1,808,565 orthologous proteins in 1,149 proteobacterial genomes. Our analysis reveals a significant positive correlation between protein binding frequency with DnaK and evolutionary rate. Proteins with high binding affinity to DnaK evolve on average 4.3-fold faster than proteins in the lowest binding affinity class at the genus resolution. Differences in evolutionary rates of DnaK interactor classes are still significant after adjusting for possible effects caused by protein expression level. Furthermore, we observe an additive effect of DnaK and GroEL chaperones on the evolutionary rates of their common interactors. Finally, we found pronounced similarities in the physicochemical profiles that characterize proteins belonging to DnaK and GroEL interactomes. Our results thus implicate DnaK-mediated folding as a major component in shaping protein evolutionary dynamics in bacteria and supply further evidence for the long-term manifestation of chaperone-mediated folding on genome evolution. PMID:27189986

  16. Hatching asynchrony aggravates inbreeding depression in a songbird (Serinus canaria): an inbreeding-environment interaction.

    PubMed

    de Boer, Raïssa A; Eens, Marcel; Fransen, Erik; Müller, Wendt

    2015-04-01

    Understanding how the intensity of inbreeding depression is influenced by stressful environmental conditions is an important area of enquiry in various fields of biology. In birds, environmental stress during early development is often related to hatching asynchrony; differences in age, and thus size, impose a gradient in conditions ranging from benign (first hatched chick) to harsh (last hatched chick). Here, we compared the effect of hatching order on growth rate in inbred (parents are full siblings) and outbred (parents are unrelated) canary chicks (Serinus canaria). We found that inbreeding depression was more severe under more stressful conditions, being most evident in later hatched chicks. Thus, consideration of inbreeding-environment interactions is of vital importance for our understanding of the biological significance of inbreeding depression and hatching asynchrony. The latter is particularly relevant given that hatching asynchrony is a widespread phenomenon, occurring in many bird species. The exact causes of the observed inbreeding-environment interaction are as yet unknown, but may be related to a decrease in maternal investment in egg contents with laying position (i.e. prehatching environment), or to performance of the chicks during sibling competition and/or their resilience to food shortage (i.e. posthatching environment).

  17. Slower heart rate and altered rate dependence of ventricular repolarization in patients with lone atrial fibrillation.

    PubMed

    Maury, Philippe; Caudron, Guillaume; Bouisset, Frédéric; Fourcade, Joëlle; Duparc, Alexandre; Mondoly, Pierre; Rollin, Anne; Hascoët, Sébastien; Detis, Nicolas; Cardin, Christelle; Delay, Marc; Lairez, Olivier; Roncalli, Jérome; Galinier, Michel; Carrié, Didier; Elbaz, Meyer; Ferrières, Jean; Fauvel, Jean-Marie; Zimmermann, Marc

    2013-01-01

    Electrophysiological alterations in atrial fibrillation (AF) may be genetically based and may lead to changes in ventricular repolarization. Short QT syndrome is a rare channelopathy with abbreviated ventricular repolarization and a propensity for AF. To determine if minor unrecognized forms of short QT syndrome can explain some cases of lone AF. We prospectively compared QT intervals in 66 patients with idiopathic lone AF and 132 age- and sex-matched controls. QT intervals were measured during sinus rhythm in each of the 12 surface electrocardiogram leads and corrected using Bazett's formula (QTc). QT intervals were also corrected using other formulae. Uncorrected QT and heart rate regression lines were compared between AF patients and controls. AF patients presented with a slower resting heart rate (64 ± 10 beats per minute [bpm] vs 69 ± 9 bpm; P=0.0006). QTc intervals were shorter in AF patients in 11/12 electrocardiogram leads (significant in 7/12, borderline in 2/12; mean QTc 381 ± 21 ms vs 388 ± 22 ms; P=0.02). QTc intervals were also shorter in AF patients, significantly or not, using other correction formulae. For similar heart rates, uncorrected QT intervals were shorter in patients when heart rates were greater than 70 bpm and longer when heart rates were less than 60 bpm. AF patients displayed steeper QT/heart rate regression line slopes than controls (P=0.009). Heart rate is significantly slower and the rate dependence of ventricular repolarization is significantly altered in patients with lone AF compared with controls. Further study is warranted to determine if AF induces subsequent ventricular repolarization changes or if these modifications are caused by an underlying primary electrical disease. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  18. Feeding activity in groups of newly hatched broiler chicks: effects of strain and hatching time.

    PubMed

    Nielsen, B L; Juul-Madsen, H R; Steenfeldt, S; Kjaer, J B; Sørensen, P

    2010-07-01

    The feeding activity of 2 strains of broiler chickens was investigated during their first week of life in relation to their hatching time. Fast (Ross 308) and slow-growing (LB) strains were allocated to 1 of 3 (early, middle, or late hatch) single-strain groups of 80 to 100 as-hatched birds in 4 replicates divided into 2 time-separated blocks. Behavioral observations differed between blocks and were carried out at intervals on d 1 to 6, and the percentage of birds feeding (from trough or paper), drinking, or being otherwise active (block 2 only) were registered. A higher mortality caused by flip-over was seen among the late-hatching birds from the slow-growing strain. The percentage of birds engaged in feeding activity was similar for the 2 strains, but LB birds began to eat from the paper later and were observed eating from the trough less than Ross 308 birds, which in turn were less active than LB, especially in the early and middle hatch groups. Early hatch groups were observed feeding from the paper more than the middle and late hatch groups. Drinking behavior mirrored feeding from the trough, indicating that drinking was prandial. Within strain, no effect of hatch time was found on live weight at hatch, but the feeding behavior of early hatched birds led to a small, transient weight advantage on d 3 after hatch. The transition from feeding on paper to feeding only from the trough may have less effect on birds that feed from the trough sooner, such as the fast-growing strain.

  19. ENVIRONMENTAL DEPENDENCE OF THE STAR FORMATION RATE AND THE SPECIFIC STAR FORMATION RATE AT FIXED MORPHOLOGY

    SciTech Connect

    Deng Xinfa

    2010-09-20

    From the Main galaxy sample of the Sloan Digital Sky Survey Data Release 7, I construct two volume-limited samples with luminosities -20.5 {<=} M{sub r} {<=} -18.5 and -22.5{<=}M{sub r} {<=}-20.5, respectively, to explore the environmental dependence of the star formation rate (SFR) and the specific star formation rate (SSFR) at fixed morphology. It is found that in these two volume-limited samples, galaxies in the lowest density regime preferentially have higher SFR and SSFR than galaxies in the densest regime. I divide each volume-limited Main galaxy sample into two distinct populations, the early type and the late type, and observe that the environmental dependence of the SFR and SSFR of galaxies remains true at fixed morphology: the SFR and SSFR of galaxies in the densest regime is still preferentially lower than that of the ones in the lowest density regime with the same morphological type. I also note that the environmental dependence of the SFR and SSFR of late-type galaxies is stronger than that of early-type galaxies.

  20. Comparison of hatching mode in pelagic and demersal eggs of two closely related species in the order pleuronectiformes.

    PubMed

    Kawaguchi, Mari; Sano, Kaori; Yoshizaki, Norio; Shimizu, Daisuke; Fujinami, Yuichiro; Noda, Tsutomu; Yasumasu, Shigeki

    2014-11-01

    We compared several characteristics of the pelagic eggs of Verasper variegatus with those of demersal eggs of Pseudopleuronectes yokohamae, both in the order Pleuronectiformes (halibuts or flatfishes). V. variegatus eggs had about twice the diameter of P. yokohamae eggs. However, the total egg protein weight of P. yokohamae was similar to that of V. variegatus. The specific gravity of P. yokohamae eggs was calculated to be 7-fold that of V. variegatus. The difference in size is the main feature distinguishing the two types of egg. The thickness of the egg envelope of P. yokohamae- more than twice that of V. variegatus-must affect the manner of hatching. The amount of hatching enzyme synthesized in pre-hatching embryo was estimated to be larger in P. yokohamae than V. variegatus. The distribution of hatching gland cells differed between the species. In V. variegates embryos, these were located on the yolk sac as a narrow ring-shaped belt, resulting in cleavage of the egg envelope into two parts by digesting a limited region of the egg envelope, called "rim-hatching". The hatching gland cells of P. yokohamae embryos were distributed all over the surface of the yolk sac, forming a hole through which the embryo could escape. Thus, the location of the hatching gland cells in pre-hatching embryos varied during the evolution of the Pleuronectiformes, depending on the egg type and manner of hatching.

  1. Spreading rate dependence of gravity anomalies along oceanic transform faults.

    PubMed

    Gregg, Patricia M; Lin, Jian; Behn, Mark D; Montési, Laurent G J

    2007-07-12

    Mid-ocean ridge morphology and crustal accretion are known to depend on the spreading rate of the ridge. Slow-spreading mid-ocean-ridge segments exhibit significant crustal thinning towards transform and non-transform offsets, which is thought to arise from a three-dimensional process of buoyant mantle upwelling and melt migration focused beneath the centres of ridge segments. In contrast, fast-spreading mid-ocean ridges are characterized by smaller, segment-scale variations in crustal thickness, which reflect more uniform mantle upwelling beneath the ridge axis. Here we present a systematic study of the residual mantle Bouguer gravity anomaly of 19 oceanic transform faults that reveals a strong correlation between gravity signature and spreading rate. Previous studies have shown that slow-slipping transform faults are marked by more positive gravity anomalies than their adjacent ridge segments, but our analysis reveals that intermediate and fast-slipping transform faults exhibit more negative gravity anomalies than their adjacent ridge segments. This finding indicates that there is a mass deficit at intermediate- and fast-slipping transform faults, which could reflect increased rock porosity, serpentinization of mantle peridotite, and/or crustal thickening. The most negative anomalies correspond to topographic highs flanking the transform faults, rather than to transform troughs (where deformation is probably focused and porosity and alteration are expected to be greatest), indicating that crustal thickening could be an important contributor to the negative gravity anomalies observed. This finding in turn suggests that three-dimensional magma accretion may occur near intermediate- and fast-slipping transform faults.

  2. Antioxidants in eggs of great tits Parus major from Chernobyl and hatching success.

    PubMed

    Møller, Anders Pape; Karadas, Filis; Mousseau, Timothy A

    2008-08-01

    Antioxidants are powerful protectors against the damaging effects of free radicals that constitute the inevitable by-products of aerobic metabolism. Growing embryos are particularly susceptible to the damaging effects of free radicals produced during rapid growth, and mothers of many species provide protection against such damage by allocating antioxidants to their eggs. Birds living in radioactively contaminated areas use dietary antioxidants to cope with the damaging effects of radiation, but females also allocate dietary antioxidants to eggs, potentially enforcing a physiological trade-off between self-maintenance and reproductive investment. Here we tested whether female great tits Parus major breeding in radioactively contaminated study areas near Chernobyl allocated less dietary antioxidants to eggs, and whether such reduced allocation of dietary antioxidants to eggs had fitness consequences. Concentrations of total yolk carotenoids and vitamins A and E were depressed near Chernobyl compared to concentrations in a less contaminated Ukrainian study area and a French control study area, and all antioxidants showed dose-dependent relationships with all three dietary antioxidants decreasing with increasing level of radiation at nest boxes. These effects held even when controlling statistically for potentially confounding habitat variables and covariation among antioxidants. Laying date was advanced and clutch size increased at nest boxes with high dose rates. Hatching success increased with increasing concentration of vitamin E, implying that hatching success decreased at boxes with high levels of radiation, eventually eliminating and even reversing the higher potential reproductive output associated with early reproduction and large clutch size. These findings are consistent with the hypothesis that radioactive contamination reduced levels of dietary antioxidants in yolks, with negative consequences for hatching success and reproductive success.

  3. Physiological and fitness correlates of experimentally altered hatching asynchrony magnitude in chicks of a wild seabird.

    PubMed

    Merkling, Thomas; Chastel, Olivier; Blanchard, Pierrick; Trouvé, Colette; Hatch, Scott A; Danchin, Etienne

    2014-03-01

    Nest-bound chicks depend entirely on their parents for food, often leading to high sibling competition. Asynchronous hatching, resulting from the onset of incubation before clutch completion, facilitates the establishment of within-nest hierarchy, with younger chicks being subject to lower feeding and growth rates. Because social and nutritional stresses affect baseline stress hormone levels in birds, younger chicks are expected to have higher levels of corticosterone than their siblings. As previous studies showed that hatching asynchrony magnitude influences the course of sibling competition, it should also affect baseline corticosterone. We measured baseline corticosterone at age 5 days in nestling black-legged kittiwakes (Rissa tridactyla) in 3 types of experimental broods: synchronous, asynchronous, and highly asynchronous. Sexual dimorphism takes place during chick-rearing and might also influence baseline corticosterone, we thus included chick sex in our analyses and also monitored chick growth and survival. Baseline corticosterone did not differ among A-chicks, but was higher in B-chicks from highly asynchronous broods compared with the other brood types, in line with the presumed increase in nutritional stress. In asynchronous broods, A-chicks had higher baseline corticosterone than their siblings, contrary to our expectations. We interpret that result as a cost of dominance among A-chicks. In line with previous studies, mass gain was negatively correlated with baseline corticosterone levels. We found that baseline corticosterone predicted survival in a sex-specific way. Regardless of hatching rank, males with higher baseline corticosterone suffered higher mortality, suggesting that males were more sensitive to high level of stress, independently of its cause. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Temperature Dependence of the O + HO2 Rate Coefficient

    NASA Technical Reports Server (NTRS)

    Nicovich, J. M.; Wine, P. H.

    1997-01-01

    A pulsed laser photolysis technique has been employed to investigate the kinetics of the radical-radical reaction O((sup 3)P) + HO2 OH + O2 over the temperature range 266-391 K in 80 Torr of N2 diluent gas. O((sup 3)P) was produced by 248.5-nm KrF laser photolysis of O3 followed by rapid quenching of O(1D) to O((sup 3)P) while HO2 was produced by simultaneous photolysis of H2O2 to create OH radicals which, in turn, reacted with H2O2 to yield HO2. The O((sup 3)P) temporal profile was monitored by using time-resolved resonance fluorescence spectroscopy. The HO2 concentration was calculated based on experimentally measured parameters. The following Arrhenius expression describes our experimental results: k(sub 1)(T) equals (2.91 +/- 0.70) x 10(exp -11) exp[(228 +/- 75)/T] where the errors are 2 sigma and represent precision only. The absolute uncertainty in k, at any temperature within the range 266-391 K is estimated to be +/- 22 percent. Our results are in excellent agreement with a discharge flow study of the temperature dependence of k(sub 1) in 1 Torr of He diluent reported by Keyser, and significantly reduce the uncertainty in the rate of this important stratospheric reaction at subambient temperatures.

  5. Temperature Dependence of the O + HO2 Rate Coefficient

    NASA Technical Reports Server (NTRS)

    Nicovich, J. M.; Wine, P. H.

    1997-01-01

    A pulsed laser photolysis technique has been employed to investigate the kinetics of the radical-radical reaction O((sup 3)P) + HO2 OH + O2 over the temperature range 266-391 K in 80 Torr of N2 diluent gas. O((sup 3)P) was produced by 248.5-nm KrF laser photolysis of O3 followed by rapid quenching of O(1D) to O((sup 3)P) while HO2 was produced by simultaneous photolysis of H2O2 to create OH radicals which, in turn, reacted with H2O2 to yield HO2. The O((sup 3)P) temporal profile was monitored by using time-resolved resonance fluorescence spectroscopy. The HO2 concentration was calculated based on experimentally measured parameters. The following Arrhenius expression describes our experimental results: k(sub 1)(T) equals (2.91 +/- 0.70) x 10(exp -11) exp[(228 +/- 75)/T] where the errors are 2 sigma and represent precision only. The absolute uncertainty in k, at any temperature within the range 266-391 K is estimated to be +/- 22 percent. Our results are in excellent agreement with a discharge flow study of the temperature dependence of k(sub 1) in 1 Torr of He diluent reported by Keyser, and significantly reduce the uncertainty in the rate of this important stratospheric reaction at subambient temperatures.

  6. Thermal effects in laser-assisted embryo hatching

    NASA Astrophysics Data System (ADS)

    Douglas-Hamilton, Diarmaid H.; Conia, Jerome D.

    2000-08-01

    Diode lasers [(lambda) equals 1480 nm] are used with in-vitro fertilization [IVF] as a promoter of embryo hatching. A focused laser beam is applied in vitro to form a channel in the zona pellucida (shell) of the pre-embryo. After transfer into the uterus, the embryo hatches: it extrudes itself through the channel and implants into the uterine wall. Laser-assisted hatching can result in improving implantation and pregnancy success rates. We present examples of zone pellucida ablation using animal models. In using the laser it is vital not to damage pre-embryo cells, e.g. by overheating. In order to define safe regimes we have derived some thermal side-effects of zona pellucida removal. The temperature profile in the beam and vicinity is predicted as function of laser pulse duration and power. In a crossed-beam experiment a HeNe laser probe detects the temperature-induced change in refractive index. We find that the diode laser beam produces superheated water approaching 200 C on the beam axis. Thermal histories during and following the laser pulse are given for regions in the neighborhood of the beam. We conclude that an optimum regime exists with pulse duration

  7. Hatching and fledging times from grassland passerine nests

    USGS Publications Warehouse

    Pietz, P.J.; Granfors, D.A.; Grant, T.A.; Ribic, C.A.; Thompson, F. R.; Pietz, P.J.

    2012-01-01

    Accurate estimates of fledging age are needed in field studies to avoid inducing premature fledging or missing the fledging event. Both may lead to misinterpretation of nest fate. Correctly assessing nest fate and length of the nestling period can be critical for accurate calculation of nest survival rates. For researchers who mark nestlings, knowing the age at which their activities may cause young to leave nests prematurely could prevent introducing bias to their studies. We obtained estimates of fledging age using data from grassland bird nests monitored from hatching through fledging with video-surveillance systems in North Dakota and Minnesota during 1996–2001. We compared these values to those obtained from traditional nest visits and from available literature. Mean and modal fledging ages for video-monitored nests were generally similar to those for visited nests, although Clay-colored Sparrows (Spizella pallida) typically fledged 1 day earlier from visited nests. Average fledging ages from both video and nest visits occurred within ranges reported in the literature, but expanded by 1–2 days the upper age limit for Clay-colored Sparrows and the lower age limit for Bobolinks (Dolichonyx oryzivorus). Video showed that eggs hatched throughout the day whereas most young fledged in the morning (06:30–12:30 CDT). Length of the hatching period for a clutch was usually >1 day and was positively correlated with clutch size. Length of the fledging period for a brood was usually <1 day, and in nearly half the nests, fledging was completed within <2 hr. Video surveillance has proven to be a useful tool for providing new information and for corroborating published statements related to hatching and fledging chronology. Comparison of data collected from video and nest visits showed that carefully conducted nest visits generally can provide reliable data for deriving estimates of survival.

  8. Killifish Hatching and Orientation experiment MA-161

    NASA Technical Reports Server (NTRS)

    Scheld, H. W.; Boyd, J. F.; Bozarth, G. A.; Conner, J. A.; Eichler, V. B.; Fuller, P. M.; Hoffman, R. B.; Keefe, J. R.; Kuchnow, K. P.; Oppenheimer, J. M.

    1976-01-01

    The killifish Fundulus heteroclitus was used as a model system for study of embryonic development and vestibular adaptation in orbital flight. Juvenile fish in a zero gravity environment exhibited looping swimming activity similar to that observed during the Skylab 3 mission. Hatchings from a 336 hour egg stage were also observed to loop. At splashdown, both juveniles and hatchings exhibited a typical diving response suggesting relatively normal vestibular function. Juveniles exhibited swimming patterns suggestive of abnormal swim bladders. The embryos exhibited no abnormalities resulting from development in a zero gravity environment.

  9. Killifish Hatching and Orientation experiment MA-161

    NASA Technical Reports Server (NTRS)

    Scheld, H. W.; Boyd, J. F.; Bozarth, G. A.; Conner, J. A.; Eichler, V. B.; Fuller, P. M.; Hoffman, R. B.; Keefe, J. R.; Kuchnow, K. P.; Oppenheimer, J. M.

    1976-01-01

    The killifish Fundulus heteroclitus was used as a model system for study of embryonic development and vestibular adaptation in orbital flight. Juvenile fish in a zero gravity environment exhibited looping swimming activity similar to that observed during the Skylab 3 mission. Hatchings from a 336 hour egg stage were also observed to loop. At splashdown, both juveniles and hatchings exhibited a typical diving response suggesting relatively normal vestibular function. Juveniles exhibited swimming patterns suggestive of abnormal swim bladders. The embryos exhibited no abnormalities resulting from development in a zero gravity environment.

  10. Effects of copper on the survival, hatching, and reproduction of a pulmonate snail (Physa acuta).

    PubMed

    Gao, Lei; Doan, Hai; Nidumolu, Bhanu; Kumar, Anupama; Gonzago, Debra

    2017-10-01

    Acute and chronic bioassays provide essential basis for establishment of environmental quality standards. The effects of Cu on a pulmonate snail, Physa acuta, were investigated at a number of sublethal and lethal endpoints. Cu exposure suppressed movement and triggered an escape response in P. acuta at low and high concentrations, respectively, exerting acute toxic effects on adult snails exposed to a 96 h LC50 of 23.8 μg L(-1). Following 16 d exposure of Cu to the egg masses, successful hatching decreased with increasing Cu concentration. High Cu concentrations (12.5 and 25 μg L(-1)) resulted in inhibition of eye and shell development at the veliger stage, and a deformed shell, abnormal eyes, and different morphological shapes with lesions and hemorrhages were observed after 9 days of exposure. A large number of eggs exposed to 2.5-25 μg L(-1) Cu remained in the veliger and hippo stages for 2-7 days, with no further development. Results from reproduction tests showed that adult snails exposed to various Cu treatments produced more than three broods, with the total number of eggs ranging from 770 to 1,289, revealing little difference between the control and Cu-treated groups (p > 0.05). However, snails exposed to 12.5 and 25 μg L(-1) Cu produced polynuclear eggs in one egg capsule. The hatching success rate and shell length of the filial generation were significantly reduced in a dose-dependent manner (p < 0.05). The shell length of newly hatched snails was shorter in the reproduction test than in the hatching test, indicating inherent Cu toxicity in the filial generation from the exposed parent strain. The present study provides essential data regarding Cu toxicity in pulmonate snail P. acuta. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Base metal thermocouples drift rate dependence from thermoelement diameter

    NASA Astrophysics Data System (ADS)

    Pavlasek, P.; Duris, S.; Palencar, R.

    2015-02-01

    testing was used to establish the relation between the level of EMF drift and the lead diameter of the thermocouple thermoelements. Furthermore this data was also used to create a drift function which mathematically expresses the dependency between the drift rate and the diameter of the thermocouple leads.

  12. Variation in incubation periods and egg metabolism in mallards: Intrinsic mechanisms to promote hatch synchrony

    USGS Publications Warehouse

    MacCluskie, Margaret C.; Flint, Paul L.; Sedinger, James S.

    1997-01-01

    We investigated factors affecting incubation time and metabolic rates of Mallard (Anas platyrhynchos) eggs incubated under constant environmental conditions. Time required to reach the star-pipped stage of hatch varied significantly among females, but not with laying sequence or egg size. Metabolic rate of eggs varied positively with position in the laying sequence and tended to vary among females. Metabolic rate did not vary with egg volume or incubation length. Our results indicate metabolic rate may act as one synchronization mechanism for hatch. The role of maternal effects in development time should be considered in subsequent studies of incubation time in ducks.

  13. External gills and adaptive embryo behavior facilitate synchronous development and hatching plasticity under respiratory constraint.

    PubMed

    Rogge, Jessica R; Warkentin, Karen M

    2008-11-01

    Plasticity in hatching timing allows embryos to balance egg- and larval-stage risks, and depends on the ability of hatching-competent embryos to continue developing in the egg. Hypoxia can slow development, kill embryos and induce premature hatching. For terrestrial eggs of red-eyed treefrogs, the embryonic period can extend approximately 50% longer than development to hatching competence, and development is synchronous across perivitelline oxygen levels (PO2) ranging from 0.5-16.5 kPa. Embryos maintain large external gills until hatching, then gills regress rapidly. We assessed the respiratory value of external gills using gill manipulations and closed-system respirometry. Embryos without external gills were oxygen limited in air and hatched at an external PO2 of 17 kPa, whereas embryos with gills regulated their metabolism and remained in the egg at substantially lower PO2. By contrast, tadpoles gained no respiratory benefit from external gills. We videotaped behavior and manipulated embryos to test if they position gills near the air-exposed portion of the egg surface, where PO2 is highest. Active embryos remained stationary for minutes in gills-at-surface positions. After manipulations and spontaneous movements that positioned gills in the O2-poor region of the egg, however, they returned their gills to the air-exposed surface within seconds. Even neural tube stage embryos, capable only of ciliary rotation, positioned their developing head in the region of highest PO2. Such behavior may be critical both to delay hatching after hatching competence and to obtain sufficient oxygen for normal, synchronous development at earlier stages.

  14. Effects of Selected Nematicides on Hatching of Heterodera schachtii.

    PubMed

    Steele, A E

    1983-07-01

    Aldicarb, carbofuran, fensulfothion, and phenamiphos were tested in concentrations of 1-100 mug/ml for their effects on hatching of Heterodera schachtii. Exposure of cysts to 1 mug aldicarb or carbofuran/ml stimulated hatch whereas phenamiphos and, to a lesser degree, fensulfothion inhibited hatch. Addition of aldicarb to sugarbeet root diffusate or 4 mM zinc chloride suppressed activities of these hatching agents. Transfer of cysts previously treated with aldicarb or carbofuran to zinc chloride or water rapidly initiated hatch which finally exceeded the hatch from cysts not treated with the nematicides.

  15. Mechanical Hatching Egg Sanitization: A Fresh Look

    USDA-ARS?s Scientific Manuscript database

    Three to four decades ago, hatching egg sanitization was done by immersion of eggs in an egg-gathering basket (plastic-coated metal wire) into a small vat with a heating element and disinfectant solution. This procedure failed miserably for several reasons. First, the eggs were not subjected to the...

  16. Problems associated with incubation and hatching

    USGS Publications Warehouse

    Olsen, G.H.

    1989-01-01

    There are numerous problems in incubation and hatching that can result in a dead embryo. Many of these problems can be prevented if the proper diagnosis of embryo mortality is made and the client instructed on how to prevent the probem in the future. This session is designed to give the avian practitioner an introduction to this area.

  17. In vitro hatching of Trichuris suis eggs.

    PubMed

    Vejzagić, Nermina; Thamsborg, Stig Milan; Kringel, Helene; Roepstorff, Allan; Bruun, Johan Musaeus; Kapel, Christian M O

    2015-07-01

    Eggs of the pig whipworm, Trichuris suis ova (TSO), are currently tested in human clinical trials for their potential immunomodulatory capacity. The biological potency of TSO (egg viability and infectivity) is traditionally assessed in Göttingen minipigs as the establishment of intestinal larvae after inoculation with a known number of eggs. To minimize testing in animal models, development of an in vitro egg hatching assay is proposed as a reliable, cost-effective, and a faster alternative to test the egg viability. The present study aimed to investigate the influence of different chemical, physical, and biological factors on egg hatching. Thus, in a series of experiments and in different combinations, the eggs were stimulated with glass beads, artificial gastric juice, bile salt and trypsin solution, fermentation gut medium, or stimulated with mucosal scrapings from the ileum and the large intestine of the infected and uninfected Göttingen minipig. Mechanical stimulation with glass beads presented a simple and reproducible method for egg hatching. However, incubation of eggs with mucosal scrapings from the ileum, caecum, and colon for 24 h at 38 °C significantly increased hatching.

  18. 9 CFR 91.29 - Hatches.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EXPORTATION....25 (e) and (f) are met and sufficient space shall be left clear on such hatches for passageway across... stowed, sufficient space shall be left clear for the proper removal and handling of such hay and feed and...

  19. 9 CFR 91.29 - Hatches.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EXPORTATION....25 (e) and (f) are met and sufficient space shall be left clear on such hatches for passageway across... stowed, sufficient space shall be left clear for the proper removal and handling of such hay and feed and...

  20. Temperature-dependent rate models of vascular cambium cell mortality

    Treesearch

    Matthew B. Dickinson; Edward A. Johnson

    2004-01-01

    We use two rate-process models to describe cell mortality at elevated temperatures as a means of understanding vascular cambium cell death during surface fires. In the models, cell death is caused by irreversible damage to cellular molecules that occurs at rates that increase exponentially with temperature. The models differ in whether cells show cumulative effects of...

  1. Effect of drying period and soil moisture on egg hatch of the tadpole shrimp (Notostraca: Triopsidae).

    PubMed

    Fry, L L; Mulla, M S

    1992-02-01

    Tadpole shrimp (Triops spp.) are potential biological control agents against larval mosquitoes in temporary ponds and flood-irrigated fields. In some rice field situations, however, they may become pests that uproot and eat young rice plants. In cursory observations, it has been reported that tadpole shrimp eggs do not readily hatch on flooding when the soil or substrate containing eggs is moist before flooding. The relationship between drying (moisture content) of soil and tadpole shrimp hatch was determined in studies conducted in mesocosms at the University of California Aquatic and Vector Control Research facilities at Riverside and at Oasis in the Coachella Valley of southern California. In laboratory hatching trials, an increase in hatch of Triops longicaudatus (LeConte) with declining soil moisture content was demonstrated (t = 8.4, P less than 0.001; r2 = 0.76). In field trials in mesocosms at Riverside, egg hatch increased with increased drying period and declining soil moisture content (G = 29.8, P less than 0.01). No hatch of eggs occurred after 3 d of drying, when soil moisture content was high, but a high level of hatching occurred after 7 and 14 d of drying, when soil moisture declined to low levels. At Oasis, soil moisture did not decrease with drying time because of porous soil and capillary action of water from adjacent flooded mesocosms and thick vegetation covering the pond bottoms. Therefore, hatch rates at Oasis were not associated with the length of the drying period (G = 35, P greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Egg hatching of two locusts, Schistocerca gregaria and Locusta migratoria, in response to light and temperature cycles.

    PubMed

    Nishide, Yudai; Tanaka, Seiji; Saeki, Shinjiro

    2015-05-01

    The present study showed that the eggs of the desert locust, Schistocerca gregaria, and the migratory locust, Locusta migratoria, responded to photoperiod by hatching when placed on sand in the laboratory. S. gregaria mainly hatched during the dark phase and L. migratoria during the light phase. The importance of light as a hatching cue depended on the magnitude of the temperature change during the thermoperiod; photoperiod played a more important role in the control of hatching time in both species when the magnitude of the temperature change was small. In addition, the eggs of the two species that were covered with sand did not respond to photoperiod and hatched during both the light and dark phases, indicating that light did not penetrate through the sand. Because locust eggs are normally laid as egg pods and a foam plug is deposited between the egg mass and the ground surface, we tested a possibility that naturally deposited eggs perceived light through the foam plug. The eggs that were deposited and left undisturbed in the sand hatched during the light and dark phases at similar frequencies. These results suggest that the eggs of both locust species responded to light and controlled their hatching timing accordingly but would not use light as a hatching cue in the field. The evolutionary significance of the ability of eggs to respond to light in these locusts was discussed.

  3. A voter model with time dependent flip rates

    NASA Astrophysics Data System (ADS)

    Baxter, G. J.

    2011-09-01

    We introduce time variation in the flip rates of the voter model. This type of generalization may be applied to other diffusion-like models in which interaction rates at the microscopic level may change with time, for example in models of language change, allowing the representation of changes in speakers' learning rates over their lifetime. The mean time taken to reach consensus varies in a nontrivial way with the rate of change of the flip rates, varying between bounds given by the mean consensus times for static homogeneous (the original voter model) and static heterogeneous flip rates. By considering the mean time between interactions for each agent, we derive excellent estimates of the mean consensus times and exit probabilities for any timescale of flip rate variation. The scaling of consensus times with population size on complex networks is correctly predicted, and is as would be expected for the ordinary voter model. Heterogeneity in the initial distribution of opinions has a strong effect, considerably reducing the mean time to consensus, while increasing the probability of survival of the opinion which initially occupies the most slowly changing agents. The mean times taken to reach consensus for different states are very different. An opinion originally held by the fastest changing agents has a smaller chance of succeeding, and takes much longer to do so than an evenly distributed opinion.

  4. Dependence of the Brittle Ductile Transition on Strain-Rate-Dependent Critical Homologous Temperature

    NASA Astrophysics Data System (ADS)

    Davis, Paul M.

    2017-02-01

    Earthquakes mainly occur in crust or mantle that is below a critical temperature for the tectonic strain-rate, \\dot{e}_t, such that stress builds up to the breaking point before it can relax due to creep. Then long-range stress correlation gives rise to power law seismicity including large events. The limiting temperature depends on pressure, which is taken into account by finding a critical homologous temperature THc = T/TM above which earthquakes are rarely observed (where T, TM are temperature and average melting temperature of constituent minerals). We find that THc for ocean plates is ∼0.55. For California earthquakes, it is also close to 0.55. The uppermost mantle layer of oceanic plates of thickness ∼50 km is composed of harzburgite and depleted peridotite from which basalt has been removed to form ocean crust. Thus it has a higher melting temperature than the peridotite of the surrounding mantle, or the lower halves of plates. Thicknesses of seismicity in deep subduction zones, determined from 2D polynomial fits to a relocated catalog, are ∼50 km, which suggests that the earthquake channel is confined to this layer. We construct models to find homologous temperatures in slabs, and find that seismicity thicknesses are also, on average, confined to TH ≤ 0.55 ± 0.05. The associated rheology is compared with that obtained from flexure models of ocean lithosphere. The brittle-ductile transition occurs where viscosity drops from high values in the cold cores of slabs to values of 1022 to 1023 Pa s, i.e., where creep strain-rates become comparable to tectonic rates. The cutoff for deep earthquakes is not sharp. However they appear unlikely to occur if homologous temperature is high TH > 0.55. Exceptions to the rule are anomalously deep earthquakes such as those beneath the Iceland and the Hawaiian hotspots, and the Newport Inglewood Fault. These are smaller events with short-range stress correlation, and can be explained if strain-rates are 2 to 3 orders

  5. Dependence of the brittle ductile transition on strain-rate-dependent critical homologous temperature

    NASA Astrophysics Data System (ADS)

    Davis, Paul M.

    2017-05-01

    Earthquakes mainly occur in crust or mantle that is below a critical temperature for the tectonic strain-rate, \\dot{e}_t, such that stress builds up to the breaking point before it can relax due to creep. Then long-range stress correlation gives rise to power law seismicity including large events. The limiting temperature depends on pressure, which is taken into account by finding a critical homologous temperature THc = T/TM above which earthquakes are rarely observed (where T, TM are temperature and average melting temperature of constituent minerals). We find that THc for ocean plates is ∼0.55. For California earthquakes, it is also close to 0.55. The uppermost mantle layer of oceanic plates of thickness ∼50 km is composed of harzburgite and depleted peridotite from which basalt has been removed to form ocean crust. Thus it has a higher melting temperature than the peridotite of the surrounding mantle, or the lower halves of plates. Thicknesses of seismicity in deep subduction zones, determined from 2-D polynomial fits to a relocated catalogue, are ∼50 km, which suggests that the earthquake channel is confined to this layer. We construct models to find homologous temperatures in slabs, and find that seismicity thicknesses are also, on average, confined to TH ≤ 0.55 ± 0.05. The associated rheology is compared with that obtained from flexure models of ocean lithosphere. The brittle-ductile transition occurs where viscosity drops from high values in the cold cores of slabs to values of 1022-1023 Pa s, that is, where creep strain-rates become comparable to tectonic rates. The cut-off for deep earthquakes is not sharp. However they appear unlikely to occur if homologous temperature is high TH > 0.55. Exceptions to the rule are anomalously deep earthquakes such as those beneath the Iceland and the Hawaiian hotspots, and the Newport Inglewood Fault. These are smaller events with short-range stress correlation, and can be explained if strain-rates are two to

  6. Rate dependence of swelling in lithium-ion cells

    SciTech Connect

    Oh, KY; Siegel, JB; Secondo, L; Kim, SU; Samad, NA; Qin, JW; Anderson, D; Garikipati, K; Knobloch, A; Epureanu, BI; Monroe, CW; Stefanopoulou, A

    2014-12-01

    Swelling of a commercial 5 Ah lithium-ion cell with a nickel/manganese/cobalt-oxide cathode is investigated as a function of the charge state and the charge/discharge rate. In combination with sensitive displacement measurements, knowledge of the electrode configuration within this prismatic cell's interior allows macroscopic deformations of the casing to be correlated to electrochemical and mechanical transformations in individual anode/separator/cathode layers. Thermal expansion and interior charge state are both found to cause significant swelling. At low rates, where thermal expansion is negligible, the electrode sandwich dilates by as much as 1.5% as the charge state swings from 0% to 100% because of lithium-ion intercalation. At high rates a comparably large residual swelling was observed at the end of discharge. Thermal expansion caused by joule heating at high discharge rate results in battery swelling. The changes in displacement with respect to capacity at low rate correlate well with the potential changes known to accompany phase transitions in the electrode materials. Although the potential response changes minimally with the C-rate, the extent of swelling varies significantly, suggesting that measurements of swelling may provide a sensitive gauge for characterizing dynamic operating states. (C) 2014 Elsevier B.V. All rights reserved.

  7. Rate-dependent fracture characteristics of lumbar vertebral bodies.

    PubMed

    Stemper, Brian D; Yoganandan, Narayan; Baisden, Jamie L; Umale, Sagar; Shah, Alok S; Shender, Barry S; Paskoff, Glenn R

    2015-01-01

    Experimental testing incorporating lumbar columns and isolated components is essential to advance the understanding of injury tolerance and for the development of safety enhancements. This study incorporated a whole column axial acceleration model and an isolated vertebral body model to quantify compression rates during realistic loading and compressive tolerance of vertebrae. Eight lumbar columns and 53 vertebral bodies from 23 PMHS were used. Three-factor ANOVA was used to determine significant differences (p<0.05) in physiologic and failure biomechanics based on compression rate, spinal level, and gender. Results demonstrated a significant increase in ultimate force (i.e., fracture) from lower to higher compression rates. Ultimate stress also increased with compression rate. Displacement and strain to failure were consistent at both compression rates. Differences in ultimate mechanics between vertebral bodies obtained from males and females demonstrated non-significant trends, with female vertebral bodies having lower ultimate force that would be associated with decreased injury tolerance. This was likely a result of smaller vertebrae in that population. Combined with existing literature, results presented in this manuscript contribute to the understanding of lumbar spine tolerance during axial loading events that occur in both military and civilian environments with regard to effects of compression rate and gender.

  8. Standard operating procedures for standardized mass rearing of the dengue and chikungunya vectors Aedes aegypti and Aedes albopictus (Diptera: Culicidae) - II - Egg storage and hatching.

    PubMed

    Zheng, Min-Lin; Zhang, Dong-Jing; Damiens, David D; Lees, Rosemary Susan; Gilles, Jeremie R L

    2015-06-26

    Management of large quantities of eggs will be a crucial aspect of the efficient and sustainable mass production of mosquitoes for programmes with a Sterile Insect Technique component. The efficiency of different hatching media and effectiveness of long term storage methods are presented here. The effect on hatch rate of storage duration and three hatching media was analysed: deionized water, boiled deionized water and a bacterial broth, using Two-way ANOVA and Post hoc Tukey tests, and the Pearson correlation coefficient was used to find the effect on the proportion of collapsed eggs. Two long term storage methods were also tested: conventional storage (egg paper strips stored in zip lock bags within a sealed plastic box), and water storage (egg papers in a covered plastic cup with deionized water). Regression analyses were used to find the effect of water storage and storage duration on hatch rate. Both species hatched most efficiently in bacterial broth. Few eggs hatched in deionized water, and pre-boiling the water increased the hatch rate of Ae. aegypti, but not Ae. albopictus. A hatch rate greater than 80% was obtained after 10 weeks of conventional storage in Ae. aegypti and 11 weeks in Ae. albopictus. After this period, hatching decreased dramatically; no eggs hatched after 24 weeks. Storing eggs in water produced an 85% hatch rate after 5 months in both species. A small but significant proportion of eggs hatched in the water, probably due to combined effects of natural deoxygenation of the water over time and the natural instalment hatching typical of the species. The demonstrated efficiency of the bacterial broth hatching medium for both Ae. albopictus and Ae. aegypti facilitates mass production of these two important vector species in the same facility, with use of a common hatching medium reducing cost and operational complexity. Similarly the increased hatch rate of eggs stored in water would allow greater flexibility of egg management in a large

  9. 46 CFR 174.220 - Hatches and coamings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... PERTAINING TO SPECIFIC VESSEL TYPES Special Rules Pertaining to Offshore Supply Vessels § 174.220 Hatches and... securing-devices; and (2) Be attached to the hatch frame or coaming by hinges, captive chains, or other...

  10. 1. VIEW OF THE ENTRANCE TO THE HATCH ADIT (FEATURE ...

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

    1. VIEW OF THE ENTRANCE TO THE HATCH ADIT (FEATURE B-28), FACING WEST. (OCTOBER, 1995) - Nevada Lucky Tiger Mill & Mine, Hatch Adit, East slope of Buckskin Mountain, Paradise Valley, Humboldt County, NV

  11. Monitoring the hatch time of individual chicken embryos.

    PubMed

    Romanini, C E B; Exadaktylos, V; Tong, Q; McGonnel, I; Demmers, T G M; Bergoug, H; Eterradossi, N; Roulston, N; Garain, P; Bahr, C; Berckmans, D

    2013-02-01

    This study investigated variations in eggshell temperature (T(egg)) during the hatching process of broiler eggs. Temperature sensors monitored embryo temperature by registering T(egg) every minute. Measurements carried out on a sample of 40 focal eggs revealed temperature drops between 2 to 6°C during the last 3 d of incubation. Video cameras recorded the hatching process and served as the gold standard reference for manually labeling the hatch times of chicks. Comparison between T(egg) drops and the hatch time of individuals revealed a time synchronization with 99% correlation coefficient and an absolute average time difference up to 25 min. Our findings suggest that attaching temperature sensors to eggshells is a precise tool for monitoring the hatch time of individual chicks. Individual hatch monitoring registers the biological age of chicks and facilitates an accurate and reliable means to count hatching results and manage the hatch window.

  12. Prebreeding survival of Roseate Terns Sterna dougallii varies with sex, hatching order and hatching date

    USGS Publications Warehouse

    Nisbet, Ian C.T.; Monticelli, David; Spendelow, Jeffrey A.; Szczys, Patricia

    2016-01-01

    Unequal sex ratios can reduce the productivity of animal populations and are especially prevalent among endangered species. A cohort of 333 Roseate Tern Sterna dougallii chicks at a site where the adult sex ratio was skewed towards females was sexed at hatching and followed through fledging and return to the breeding area, and subsequently during adulthood. The entire regional metapopulation was sampled for returning birds. Prebreeding survival (from fledging to age 3 years) was lower in males than in females, but only among B-chicks (second in hatching order). Prebreeding survival also declined with hatching date. The proportion of females in this cohort increased from 54.6% at hatching to 56.2% at fledging and to an estimated 58.0% among survivors at age 3 years. This was more than sufficient to explain the degree of skew in the sex ratio of the adult population, but changes in this degree of skew during the study period make it difficult to identify the influence of a single cohort of recruits. Many studies of prebreeding survival in other bird species have identified effects of sex, hatching order or hatching date, but no previous study has tested for effects of all three factors simultaneously.

  13. Rate dependent of strength in metallic glasses at different temperatures

    PubMed Central

    Wang, Y. W.; Bian, X. L.; Wu, S. W.; Hussain, I.; Jia, Y. D.; Yi, J.; Wang, G.

    2016-01-01

    The correlation between the strength at the macroscale and the elastic deformation as well as shear cracking behavior at the microscale of bulk metallic glasses (BMGs) is investigated. The temperatures of 298 K and 77 K as well as the strain rate ranging from 10−6 s−1 to 10−2 s−1 are applied to the BMGs, in which the mechanical responses of the BMGs are profiled through the compression tests. The yield strength is associated with the activation of the elementary deformation unit, which is insensitive to the strain rate. The maximum compressive strength is linked to the crack propagation during shear fracture process, which is influenced by the strain rate. The cryogenic temperature of 77 K significantly improves the yield strength and the maximum compressive strength of the BMGs. PMID:27270688

  14. Dependence of rate constants on vibrational temperatures - An Arrhenius description

    NASA Technical Reports Server (NTRS)

    Ford, D. I.; Johnson, R. E.

    1988-01-01

    An interpretation of the variation of rate constants with vibrational temperature is proposed which introduces parameters analogous to those of the classical Arrhenius expression. The constancy of vibrational activation energy is studied for the dissociaton of NO, the ion-molecular reaction of O(+) with N2, and the atom exchange reaction of I with H2. It is found that when a Boltzmann distribution for vibrational states is applicable, the variation of the rate constant with the vibrational temperature can be used to define a vibrational activation energy. The method has application to exchange reactions where a vibrational energy threshold exists.

  15. Dependence of rate constants on vibrational temperatures - An Arrhenius description

    NASA Technical Reports Server (NTRS)

    Ford, D. I.; Johnson, R. E.

    1988-01-01

    An interpretation of the variation of rate constants with vibrational temperature is proposed which introduces parameters analogous to those of the classical Arrhenius expression. The constancy of vibrational activation energy is studied for the dissociaton of NO, the ion-molecular reaction of O(+) with N2, and the atom exchange reaction of I with H2. It is found that when a Boltzmann distribution for vibrational states is applicable, the variation of the rate constant with the vibrational temperature can be used to define a vibrational activation energy. The method has application to exchange reactions where a vibrational energy threshold exists.

  16. DEPENDENCE OF INTERSTELLAR TURBULENT PRESSURE ON SUPERNOVA RATE

    SciTech Connect

    Joung, M. Ryan; Mac Low, Mordecai-Mark; Bryan, Greg L. E-mail: mordecai@amnh.or

    2009-10-10

    Feedback from massive stars is one of the least understood aspects of galaxy formation. We perform a suite of vertically stratified local interstellar medium (ISM) models in which supernova (SN) rates and vertical gas column densities are systematically varied based on the Schmidt-Kennicutt law. Our simulations have a sufficiently high spatial resolution (1.95 pc) to follow the hydrodynamic interactions among multiple SNe that structure the interstellar medium. At a given SN rate, we find that the mean mass-weighted sound speed and velocity dispersion decrease as the inverse square root of gas density. The sum of thermal and turbulent pressures is nearly constant in the midplane, so the effective equation of state is isobaric. In contrast, across our four models having SN rates that range from 1 to 512 times the Galactic SN rate, the mass-weighted velocity dispersion remains in the range 4-6 km s{sup -1}. Hence, gas averaged over approx100 pc regions follows P propor to rho{sup a}lpha with alpha approx 1, indicating that the effective equation of state on this scale is close to isothermal. Simulated H I emission lines have widths of 10-18 km s{sup -1}, comparable to observed values. In our highest SN rate model, superbubble blow-outs occur, and the turbulent pressure on large scales is approx>4 times higher than the thermal pressure. We find a tight correlation between the thermal and turbulent pressures averaged over approx100 pc regions in the midplane of each model, as well as across the four ISM models. We construct a subgrid model for turbulent pressure based on analytic arguments and explicitly calibrate it against our stratified ISM simulations. The subgrid model provides a simple yet physically motivated way to include SN feedback in cosmological simulations.

  17. Dependence of Interstellar Turbulent Pressure on Supernova Rate

    NASA Astrophysics Data System (ADS)

    Joung, M. Ryan; Mac Low, Mordecai-Mark; Bryan, Greg L.

    2009-10-01

    Feedback from massive stars is one of the least understood aspects of galaxy formation. We perform a suite of vertically stratified local interstellar medium (ISM) models in which supernova (SN) rates and vertical gas column densities are systematically varied based on the Schmidt-Kennicutt law. Our simulations have a sufficiently high spatial resolution (1.95 pc) to follow the hydrodynamic interactions among multiple SNe that structure the interstellar medium. At a given SN rate, we find that the mean mass-weighted sound speed and velocity dispersion decrease as the inverse square root of gas density. The sum of thermal and turbulent pressures is nearly constant in the midplane, so the effective equation of state is isobaric. In contrast, across our four models having SN rates that range from 1 to 512 times the Galactic SN rate, the mass-weighted velocity dispersion remains in the range 4-6 km s-1. Hence, gas averaged over ~100 pc regions follows P vprop ρα with α ≈ 1, indicating that the effective equation of state on this scale is close to isothermal. Simulated H I emission lines have widths of 10-18 km s-1, comparable to observed values. In our highest SN rate model, superbubble blow-outs occur, and the turbulent pressure on large scales is gsim4 times higher than the thermal pressure. We find a tight correlation between the thermal and turbulent pressures averaged over ~100 pc regions in the midplane of each model, as well as across the four ISM models. We construct a subgrid model for turbulent pressure based on analytic arguments and explicitly calibrate it against our stratified ISM simulations. The subgrid model provides a simple yet physically motivated way to include SN feedback in cosmological simulations.

  18. Larger rate dependence of late sodium current in cardiac Purkinje cells: A potential link to arrhythmogenesis.

    PubMed

    Li, Wei; Yu, Ying; Hou, Jian-Wen; Zhou, Zhi-Wen; Guo, Kai; Zhang, Peng-Pai; Wang, Zhi-Quan; Yan, Jian-Hua; Sun, Jian; Zhou, Qing; Wang, Yue-Peng; Li, Yi-Gang

    2017-03-01

    Purkinje cells (PCs) have a steeper rate dependence of repolarization and are more susceptible to arrhythmic activity than do ventricular myocytes (VMs). Late sodium current (INaL) is rate dependent and contributes to rate dependence of repolarization. This study sought to test our hypothesis that PCs have a larger rate dependence of INaL, contributing to their steeper rate dependence of repolarization and higher susceptibility to arrhythmic activity, than do VMs. INaL was recorded in isolated rabbit PCs and VMs with the whole-cell patch clamp technique. Action potential was examined using the microelectrode technique. Compared with VMs, PCs exhibited a significantly larger rate dependence of INaL with a larger INaL to basic cycle length (BCL) slope. Moreover, PCs had a larger rate dependence of INaL decay and slower recovery kinetics. Interestingly, the larger rate dependence of INaL matched to a steeper rate dependence of action potential duration (APD) in PCs. The INaL blocker tetrodotoxin significantly blunted, while the INaL enhancer anemone toxin (ATX-II) significantly increased, the rate dependence of INaL and APD in PCs and VMs. In the presence of ATX-II, the rate dependence of INaL in PCs was markedly larger than that in VMs, causing a much steeper rate dependence of APD in PCs. Accordingly, PCs exhibited greater rate-dependent electrical instability and were more prone to ATX-II-induced early afterdepolarizations, which were completely inhibited by the INaL inhibitor ranolazine. PCs have a significantly larger rate dependence of INaL than do VMs because of distinctive INaL decay and recovery kinetics, which contributes to their larger rate adaptation, and simultaneously predisposes them to a higher risk of arrhythmogenesis. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  19. Section BB Hatch Coating; Framing Plan on Line C Lodging ...

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

    Section B-B Hatch Coating; Framing Plan on Line C Lodging Knees at Hatch; Elevation A-A Hull Framing; Section at Hatch Frame 36, Starboard Looking Aft; Midship Section Frame 37, Port Looking Aft - Steam Schooner WAPAMA, Kaiser Shipyard No. 3 (Shoal Point), Richmond, Contra Costa County, CA

  20. 9 CFR 147.22 - Hatching egg sanitation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Hatching egg sanitation. 147.22... Procedures § 147.22 Hatching egg sanitation. Hatching eggs should be collected from the nests at frequent... practices should be observed: (a) Cleaned and disinfected containers, such as egg flats, should be used...

  1. 9 CFR 147.22 - Hatching egg sanitation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Hatching egg sanitation. 147.22... Procedures § 147.22 Hatching egg sanitation. Hatching eggs should be collected from the nests at frequent... practices should be observed: (a) Cleaned and disinfected containers, such as egg flats, should be used...

  2. 9 CFR 147.22 - Hatching egg sanitation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Hatching egg sanitation. 147.22... Procedures § 147.22 Hatching egg sanitation. Hatching eggs should be collected from the nests at frequent... practices should be observed: (a) Cleaned and disinfected containers, such as egg flats, should be used...

  3. 9 CFR 147.22 - Hatching egg sanitation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Hatching egg sanitation. 147.22... Procedures § 147.22 Hatching egg sanitation. Hatching eggs should be collected from the nests at frequent... practices should be observed: (a) Cleaned and disinfected containers, such as egg flats, should be used...

  4. 9 CFR 147.22 - Hatching egg sanitation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Hatching egg sanitation. 147.22... Procedures § 147.22 Hatching egg sanitation. Hatching eggs should be collected from the nests at frequent... practices should be observed: (a) Cleaned and disinfected containers, such as egg flats, should be used...

  5. Consequences of Hatch Phenology on Stages of Fish Recruitment

    PubMed Central

    Bogner, David M.; Wuellner, Melissa R.

    2016-01-01

    Little is known about how hatch phenology (e.g., the start, peak, and duration of hatching) could influence subsequent recruitment of freshwater fishes into a population. We used two commonly sympatric fish species that exhibit different hatching phenologies to examine recruitment across multiple life stages. Nine yellow perch (Perca flavescens) and bluegill (Lepomis macrochirus) annual cohorts were sampled from 2004 through 2013 across larval, age-0, age-1, and age-2 life stages in a Nebraska (U.S.A.) Sandhill lake. Yellow perch hatched earlier in the season and displayed a more truncated hatch duration compared to bluegill. The timing of hatch influenced recruitment dynamics for both species but important hatching metrics were not similar between species across life stages. A longer hatch duration resulted in greater larval yellow perch abundance but greater age-1 bluegill abundance. In contrast, bluegill larval and age-0 abundances were greater during years when hatching duration was shorter and commenced earlier, whereas age-0 yellow perch abundance was greater when hatching occurred earlier. As a result of hatch phenology, yellow perch recruitment variability was minimized sooner (age-0 life stage) than bluegill (age-1 life stage). Collectively, hatch phenology influenced recruitment dynamics across multiple life stages but was unique for each species. Understanding the complexities of when progeny enter an environment and how this influences eventual recruitment into a population will be critical in the face of ongoing climate change. PMID:27764216

  6. 46 CFR 185.610 - Watertight doors and watertight hatches.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Watertight doors and watertight hatches. 185.610 Section... (UNDER 100 GROSS TONS) OPERATIONS Markings Required § 185.610 Watertight doors and watertight hatches. Watertight doors and watertight hatches must be marked on both sides in clearly legible letters at least 25...

  7. 46 CFR 169.747 - Watertight doors and hatches.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Watertight doors and hatches. 169.747 Section 169.747... Vessel Control, Miscellaneous Systems, and Equipment Markings § 169.747 Watertight doors and hatches. Each watertight door and watertight hatch must be marked on both sides in at least 1-inch letters...

  8. 46 CFR 185.610 - Watertight doors and watertight hatches.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Watertight doors and watertight hatches. 185.610 Section... (UNDER 100 GROSS TONS) OPERATIONS Markings Required § 185.610 Watertight doors and watertight hatches. Watertight doors and watertight hatches must be marked on both sides in clearly legible letters at least 25...

  9. 46 CFR 169.747 - Watertight doors and hatches.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Watertight doors and hatches. 169.747 Section 169.747... Vessel Control, Miscellaneous Systems, and Equipment Markings § 169.747 Watertight doors and hatches. Each watertight door and watertight hatch must be marked on both sides in at least 1-inch letters...

  10. 29 CFR 1918.43 - Handling hatch beams and covers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... apply in cases where hatch beams are of such design that: (1) The width of the flange is 50 percent or more of the height of the web; and (2) The flange rests flat on the deck when the hatch beam is stood... position, unless the design of the system otherwise prevents unintentional movement. (h) Hatches shall not...

  11. Temperature and strain-rate dependent fracture strength of graphynes

    NASA Astrophysics Data System (ADS)

    Zhang, Ying-Yan; Pei, Qing-Xiang; Mai, Yiu-Wing; Gu, Yuan-Tong

    2014-10-01

    Graphyne is an allotrope of graphene. The mechanical properties of graphynes (α-, β-, γ- and 6,6,12-graphynes) under uniaxial tension deformation at different temperatures and strain rates are studied using molecular dynamics simulations. It is found that graphynes are more sensitive to temperature changes than graphene in terms of fracture strength and Young's modulus. The temperature sensitivity of the different graphynes is proportionally related to the percentage of acetylenic linkages in their structures, with the α-graphyne (having 100% of acetylenic linkages) being most sensitive to temperature. For the same graphyne, temperature exerts a more pronounced effect on the Young's modulus than fracture strength, which is different from that of graphene. The mechanical properties of graphynes are also sensitive to strain rate, in particular at higher temperatures.

  12. Long-range dependencies in heart rate signals—revisited

    NASA Astrophysics Data System (ADS)

    Makowiec, Danuta; Gałaşka, Rafał; Dudkowska, Aleksandra; Rynkiewicz, Andrzej; Zwierz, Marcin

    2006-09-01

    The arguments are given that local exponents obtained in multifractal analysis by two methods: wavelet transform modulus maxima (WTMM) and multifractal detrended fluctuation analysis (MDFA) allow to separate statistically hearts of healthy people and subjects suffering from reduced left ventricle systolic function (NYHA I-III class). Proposed indices of fractality suggest that a signal of human heart rate is a mixture of two processes: monofractal and multifractal ones.

  13. Asynchronous hatching provides females with a means for increasing male care but incurs a cost by reducing offspring fitness.

    PubMed

    Ford, L E; Smiseth, P T

    2016-02-01

    In species with biparental care, sexual conflict occurs because the benefit of care depends on the total amount of care provided by the two parents while the cost of care depends on each parent's own contribution. Asynchronous hatching may play a role in mediating the resolution of this conflict over parental care. The sexual conflict hypothesis for the evolution of asynchronous hatching suggests that females adjust hatching patterns in order to increase male parental effort relative to female effort. We tested this hypothesis in the burying beetle Nicrophorus vespilloides by setting up experimental broods with three different hatching patterns: synchronous, asynchronous and highly asynchronous broods. As predicted, we found that males provided care for longer in asynchronous broods whereas the opposite was true of females. However, we did not find any benefit to females of reducing their duration of care in terms of increased lifespan or reduced mass loss during breeding. We found substantial negative effects of hatching asynchrony on offspring fitness as larval mass was lower and fewer larvae survived to dispersal in highly asynchronous broods compared to synchronous or asynchronous broods. Our results suggest that, even though females can increase male parental effort by hatching their broods more asynchronously, females pay a substantial cost from doing so in terms of reducing offspring growth and survival. Thus, females should be under selection to produce a hatching pattern that provides the best possible trade-off between the benefits of increased male parental effort and the costs due to reduced offspring fitness.

  14. Hatching asynchrony in Burrowing Owls is influenced by clutch size and hatching success but not by food.

    PubMed

    Wellicome, Troy I

    2005-01-01

    In most animals, siblings from a given reproductive event emerge over a very short period of time. In contrast, many species of birds hatch their young asynchronously over a period of days or weeks, handicapping last-hatched chicks with an age and size disadvantage. Numerous studies have examined the adaptive significance of this atypical hatching pattern, but few have attempted to explain the considerable intrapopulation variation that exists in hatching asynchrony. I explored proximate determinants of hatching asynchrony by monitoring 112 Burrowing Owl (Athene cunicularia) nests in the grasslands of southern Saskatchewan, Canada, over 4 years. Age disparities between first- and last-hatched siblings (i.e., hatching spans) varied considerably, ranging between 1 and 7 days (mode = 4 days). These hatching spans increased with increased hatching success. Hatching spans also increased with larger clutches, but the increase was less than predicted given the increased time required to lay more eggs. Hatching span was unrelated to number of prey cached in the nest during egg laying (an index of food availability), and was unaltered by a year of super-abundant prey. Furthermore, pairs given extra food during laying had hatching spans equal to those of unsupplemented control pairs. These results were inconsistent with both the energy constraint and facultative manipulation hypotheses, which predict that hatching asynchrony should vary with the level of food during laying, when incubation onset is determined. Burrowing Owls were apparently free of food limitation early in breeding, yet may not have been able to optimize hatching spans because food conditions during laying were largely unrelated to food conditions during brooding. Thus, one of the premises for facultative manipulation of hatching asynchrony-that laying females are able to forecast post-hatch food conditions-may not have been met for this population of Burrowing Owls.

  15. Causes of hatching failure in endangered birds

    PubMed Central

    Hemmings, N.; West, M.; Birkhead, T. R.

    2012-01-01

    About 10 per cent of birds' eggs fail to hatch, but the incidence of failure can be much higher in endangered species. Most studies fail to distinguish between infertility (due to a lack of sperm) and embryo mortality as the cause of hatching failure, yet doing so is crucial in order to understand the underlying problem. Using newly validated techniques to visualize sperm and embryonic tissue, we assessed the fertility status of unhatched eggs of five endangered species, including both wild and captive birds. All eggs were classified as ‘infertile’ when collected, but most were actually fertile with numerous sperm on the ovum. Eggs of captive birds had fewer sperm and were more likely to be infertile than those of wild birds. Our findings raise important questions regarding the management of captive breeding programmes. PMID:22977070

  16. Density dependence, whitebark pine, and vital rates of grizzly bears

    USGS Publications Warehouse

    van Manen, Frank T.; Haroldson, Mark A.; Bjornlie, Daniel D; Ebinger, Michael R.; Thompson, Daniel J.; Costello, Cecily M; White, Gary C.

    2016-01-01

    Understanding factors influencing changes in population trajectory is important for effective wildlife management, particularly for populations of conservation concern. Annual population growth of the grizzly bear (Ursus arctos) population in the Greater Yellowstone Ecosystem, USA has slowed from 4.2–7.6% during 1983–2001 to 0.3–2.2% during 2002–2011. Substantial changes in availability of a key food source and bear population density have occurred. Whitebark pine (Pinus albicaulis), the seeds of which are a valuable but variable fall food for grizzly bears, has experienced substantial mortality primarily due to a mountain pine beetle (Dendroctonus ponderosae) outbreak that started in the early 2000s. Positive growth rates of grizzly bears have resulted in populations reaching high densities in some areas and have contributed to continued range expansion. We tested research hypotheses to examine if changes in vital rates detected during the past decade were more associated with whitebark pine decline or, alternatively, increasing grizzly bear density. We focused our assessment on known-fate data to estimate survival of cubs-of-the-year (cubs), yearlings, and independent bears (≥2 yrs), and reproductive transition of females from having no offspring to having cubs. We used spatially and temporally explicit indices for grizzly bear density and whitebark pine mortality as individual covariates. Models indicated moderate support for an increase in survival of independent male bears over 1983–2012, whereas independent female survival did not change. Cub survival, yearling survival, and reproductive transition from no offspring to cubs all changed during the 30-year study period, with lower rates evident during the last 10–15 years. Cub survival and reproductive transition were negatively associated with an index of grizzly bear density, indicating greater declines where bear densities were higher. Our analyses did not support a similar relationship for the

  17. Dependence of transmon qubit relaxation rate on readout drive power

    NASA Astrophysics Data System (ADS)

    Mundhada, S. O.; Shankar, S.; Narla, A.; Zalys-Geller, E.; Girvin, S. M.; Devoret, M. H.

    In circuit QED experiments, microwave drives are applied to the readout mode for qubit measurement, control and to realize various multi-photon processes. These microwave drives have been observed to detrimentally affect the qubit mode by increasing the qubit relaxation rates for both upward and downward transitions. These transitions demolish the qubit state during a measurement, limiting the maximum measurement strength and thus the readout fidelity and speed. Here, we experimentally investigate this effect for transmon qubits coupled to different realizations of the readout mode: 3-dimensional microwave cavities, strip-line resonators and nonlinear readout modes in a waveguide. Work supported by: NSF, ARO, AFOSR and YINQE.

  18. STS-96 Astronauts Adjust Unity Hatch

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Aboard the International Space Station (ISS), astronauts Rick D. Husband and Tamara E. Jernigan adjust the hatch for the U.S. built Unity node. The task was part of an overall effort of seven crew members to prepare the existing portion of the International Space Station (ISS). Launched on May 27, 1999, aboard the Orbiter Discovery, the STS-96 mission was the second ISS assembly flight and the first shuttle mission to dock with the station.

  19. STS-96 Astronauts Adjust Unity Hatch

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Aboard the International Space Station (ISS), astronauts Rick D. Husband and Tamara E. Jernigan adjust the hatch for the U.S. built Unity node. The task was part of an overall effort of seven crew members to prepare the existing portion of the International Space Station (ISS). Launched on May 27, 1999, aboard the Orbiter Discovery, the STS-96 mission was the second ISS assembly flight and the first shuttle mission to dock with the station.

  20. Size and rate dependent necking in thin metallic films

    NASA Astrophysics Data System (ADS)

    Pardoen, T.

    2014-01-01

    The control of the ductility of thin metallic films is a major issue in a variety of technologies involving flexible electronics, MEMS and deformable coatings. An enhanced closed form 1D imperfection based localization analysis is developed in order to investigate the mechanics of diffuse necking in metallic films. The model relies on a description of the localization process in a finite length specimen using either a 2- or 3-zone model, under plane stress or plane strain tension conditions. A strain gradient plasticity contribution to the stabilization of the localization process is taken into account in the hardening response through a simple estimate of the deformation gradient inside the necking zone. The model, with gradient plasticity effects, is validated towards 2D finite element simulations. The response of the material involves both strain-hardening and rate sensitivity, as well as possible creep relaxation. The plastic flow parameters are related to the grain size and film thickness. The model shows, in agreement with experiments, that the ductility can either drop to small values for very small grain sizes and/or film thickness due to the high strength and to the presence of imperfections, or can remain constant or even increase owing to an increased rate sensitivity resulting from thermally activated mechanisms. This last stabilization effect can be reinforced by gradient plasticity effects if allowed by the dominant deformation mechanism.

  1. Texture-dependent anaerobic microsites constrain soil carbon oxidation rates

    NASA Astrophysics Data System (ADS)

    Keiluweit, Marco; Fendorf, Scott

    2016-04-01

    Soil texture, which is a product of parent material, climate and other soil forming factors, is a predictor for long-term storage of soil organic carbon (SOC) storage in many soil ecosystems. Positive correlation between texture (particularly clay content) and SOC storage have long been attributed to protective associations between clay minerals and organic compounds that prevent microbial and enzymatic access - a mechanism commonly referred to as 'mineral protection'. Texture therefore acts as the primary proxy for mineral protection in terrestrial ecosystem models used to assess SOC storage and its sensitivity to global change impacts. Here we show that this protective effect of texture is not only due to mineral protection, but also to the formation of anaerobic microsites. Combining micro-scale laboratory experiments with field-scale observations, we find that oxygen diffusion limitations within clay-rich domains create anaerobic microsites within seemingly well-aerated soils, shifting microbial metabolism to less efficient anaerobic SOC oxidation pathways. Kinetic and thermodynamic constraints reduce SOC oxidation rates within these anaerobic microsites by an order of magnitude relative to aerobic rates, and caused the preservation of bioavailable, polymeric and reduced organic compounds. Lifting these metabolic constraints through increased soil aeration (e.g., through changes in precipitation patterns or land use) may stimulate microbial oxidation of this inherently bioavailable SOC pool. Models that attribute the effects of texture merely to 'mineral protection' may therefore underestimate the vulnerability of soil C to global change impacts.

  2. Enzyme surface rigidity tunes the temperature dependence of catalytic rates

    PubMed Central

    Isaksen, Geir Villy; Åqvist, Johan; Brandsdal, Bjørn Olav

    2016-01-01

    The structural origin of enzyme adaptation to low temperature, allowing efficient catalysis of chemical reactions even near the freezing point of water, remains a fundamental puzzle in biocatalysis. A remarkable universal fingerprint shared by all cold-active enzymes is a reduction of the activation enthalpy accompanied by a more negative entropy, which alleviates the exponential decrease in chemical reaction rates caused by lowering of the temperature. Herein, we explore the role of protein surface mobility in determining this enthalpy–entropy balance. The effects of modifying surface rigidity in cold- and warm-active trypsins are demonstrated here by calculation of high-precision Arrhenius plots and thermodynamic activation parameters for the peptide hydrolysis reaction, using extensive computer simulations. The protein surface flexibility is systematically varied by applying positional restraints, causing the remarkable effect of turning the cold-active trypsin into a variant with mesophilic characteristics without changing the amino acid sequence. Furthermore, we show that just restraining a key surface loop causes the same effect as a point mutation in that loop between the cold- and warm-active trypsin. Importantly, changes in the activation enthalpy–entropy balance of up to 10 kcal/mol are almost perfectly balanced at room temperature, whereas they yield significantly higher rates at low temperatures for the cold-adapted enzyme. PMID:27354533

  3. Binary accretion rates: dependence on temperature and mass ratio

    NASA Astrophysics Data System (ADS)

    Young, M. D.; Clarke, C. J.

    2015-09-01

    We perform a series of 2D smoothed particle hydrodynamics simulations of gas accretion on to binaries via a circumbinary disc, for a range of gas temperatures and binary mass ratios (q). We show that increasing the gas temperature increases the accretion rate on to the primary for all values of the binary mass ratio: for example, for q = 0.1 and a fixed binary separation, an increase of normalized sound speed by a factor of 5 (from our `cold' to `hot' simulations) changes the fraction of the accreted gas that flows on to the primary from 10 to ˜40 per cent. We present a simple parametrization for the average accretion rate of each binary component accurate to within a few per cent and argue that this parametrization (rather than those in the literature based on warmer simulations) is relevant to supermassive black hole accretion and all but the widest stellar binaries. We present trajectories for the growth of q during circumbinary disc accretion and argue that the period distribution of stellar `twin' binaries is strong evidence for the importance of circumbinary accretion. We also show that our parametrization of binary accretion increases the minimum mass ratio needed for spin alignment of supermassive black holes to q ˜ 0.4, with potentially important implications for the magnitude of velocity kicks acquired during black hole mergers.

  4. Strain Rate Dependant Material Model for Orthotropic Metals

    NASA Astrophysics Data System (ADS)

    Vignjevic, Rade

    2016-08-01

    In manufacturing processes anisotropic metals are often exposed to the loading with high strain rates in the range from 102 s-1 to 106 s-1 (e.g. stamping, cold spraying and explosive forming). These types of loading often involve generation and propagation of shock waves within the material. The material behaviour under such a complex loading needs to be accurately modelled, in order to optimise the manufacturing process and achieve appropriate properties of the manufactured component. The presented research is related to development and validation of a thermodynamically consistent physically based constitutive model for metals under high rate loading. The model is capable of modelling damage, failure and formation and propagation of shock waves in anisotropic metals. The model has two main parts: the strength part which defines the material response to shear deformation and an equation of state (EOS) which defines the material response to isotropic volumetric deformation [1]. The constitutive model was implemented into the transient nonlinear finite element code DYNA3D [2] and our in house SPH code. Limited model validation was performed by simulating a number of high velocity material characterisation and validation impact tests. The new damage model was developed in the framework of configurational continuum mechanics and irreversible thermodynamics with internal state variables. The use of the multiplicative decomposition of deformation gradient makes the model applicable to arbitrary plastic and damage deformations. To account for the physical mechanisms of failure, the concept of thermally activated damage initially proposed by Tuller and Bucher [3], Klepaczko [4] was adopted as the basis for the new damage evolution model. This makes the proposed damage/failure model compatible with the Mechanical Threshold Strength (MTS) model Follansbee and Kocks [5], 1988; Chen and Gray [6] which was used to control evolution of flow stress during plastic deformation. In

  5. Effects of interaction of incubator CO2 levels and mixing hatching eggs of different embryo growth trajectory on embryo physiological and hatching parameters.

    PubMed

    Tona, K; Everaert, N; Willemsen, H; Gbeassor, M; Decuypere, E; Buyse, J

    2013-01-01

    1. Two experiments were designed to investigate the effects of mixing eggs of different genotype and incubating with different CO2 concentrations on embryonic parameters. Half of the eggs were incubated in a CO2 controlled incubator (VCO2) during the first 10 d of incubation and the other half was incubated at standard incubation ventilation rate (SV). 2. From 10 to 18 d of incubation, thick albumen and embryos were weighed. Blood samples were collected at d 18 of incubation, at internal pipping and at hatch for determination of triiodothyronine (T3), thyroxine (T4) and corticosterone concentration. During the last 2 d of incubation, hatching events of individual eggs were monitored every 2 h. 3. From 4 to 5 d of incubation in the SV group of Experiment 1, pH values of Ross strain chickens were lower than those of Isa Brown. From d 12 of incubation onwards, Ross embryos grew faster than those of Isa Brown. At 14 and 16 d of incubation, Ross eggs in the CO2 controlled incubator had lower albumen weights compared to all other treatments. 4. T3 concentrations in Ross embryos were higher than those of Isa Brown embryos. Chicken weight at hatch was in the following order: Isa Brown SV < Isa Brown VCO2 = Ross SV < Ross VCO2. 5. In Experiment 2, incubation time of VCO2 eggs until internal pipping, external pipping and hatch was significantly shorter than that of SV eggs. 6. It was concluded that mixing of hatching eggs of differential embryo developmental trajectory affects their hatching process.

  6. The Luminosity Dependence of the Galaxy Merger Rate

    NASA Astrophysics Data System (ADS)

    Patton, D. R.; Atfield, J. E.

    2008-09-01

    We measure the number of companions per galaxy (Nc) as a function of r-band absolute magnitude for both the Sloan Digital Sky Survey and the Croton and coworkers semianalytic catalog applied to the Millennium Run simulation. For close pairs with projected separations of 5-20 h-1 kpc, velocity differences less than 500 km s-1, and luminosity ratios between 1:2 and 2:1, we find good agreement between the observations and simulations, with Nc consistently close to 0.02 over the range -22 < Mr < - 18. For larger pair separations, Nc(Mr) instead becomes increasingly steep toward the faint end, implying that luminosity-dependent clustering plays an important role on small scales. Using the simulations to assess and correct for projection effects, we infer that the real-space Nc(Mr) for close pairs peaks at about M* and declines by at least a factor of 2 as Mr becomes fainter. Conversely, by measuring the number density of close companions, we estimate that at least 90% of all major mergers occur between galaxies which are fainter than L*. Finally, measurements of the luminosity density of close companions indicate that L* galaxies likely dominate in terms of the overall importance of major mergers in the evolution of galaxy populations at low redshift.

  7. Hatching asynchrony vs. foraging efficiency: the response to food availability in specialist vs. generalist tit species.

    PubMed

    Barrientos, R; Bueno-Enciso, J; Sanz, J J

    2016-11-28

    Breeding mistiming is increasingly frequent in several ecosystems in the face of current climate change. Species belonging to higher trophic levels must employ mechanisms to reduce it. One of these mechanisms is hatching asynchrony, with the eggs in a clutch hatching over a period of several days. Some authors have suggested it to be adaptive when food is unpredictable. However, these birds can also suffer associated costs. We tested whether a species with higher foraging efficiency avoid hatching asynchrony compared to its sister species. We studied hatching asynchrony and nestling provisioning in relation to food availability in sympatric populations of blue and great tits. For the first time, we show that sister species respond to food availability with different strategies. Blue tit feeding rates readily responded to the abundance of their main prey, and also reduced the impact of nestling size hierarchy on mean nestling weight, consequently increasing fledging rate. Our results suggest that levels of hatching asynchrony seem to be influenced by species-specific life history traits, as generalist foragers rely less on it. They also highlight the importance of multi-species approaches when studying the response of organisms to environmental unpredictability.

  8. Hatching asynchrony vs. foraging efficiency: the response to food availability in specialist vs. generalist tit species

    PubMed Central

    Barrientos, R.; Bueno-Enciso, J.; Sanz, J. J.

    2016-01-01

    Breeding mistiming is increasingly frequent in several ecosystems in the face of current climate change. Species belonging to higher trophic levels must employ mechanisms to reduce it. One of these mechanisms is hatching asynchrony, with the eggs in a clutch hatching over a period of several days. Some authors have suggested it to be adaptive when food is unpredictable. However, these birds can also suffer associated costs. We tested whether a species with higher foraging efficiency avoid hatching asynchrony compared to its sister species. We studied hatching asynchrony and nestling provisioning in relation to food availability in sympatric populations of blue and great tits. For the first time, we show that sister species respond to food availability with different strategies. Blue tit feeding rates readily responded to the abundance of their main prey, and also reduced the impact of nestling size hierarchy on mean nestling weight, consequently increasing fledging rate. Our results suggest that levels of hatching asynchrony seem to be influenced by species-specific life history traits, as generalist foragers rely less on it. They also highlight the importance of multi-species approaches when studying the response of organisms to environmental unpredictability. PMID:27892941

  9. Strain Rate Dependency of Fracture Toughness, Energy Release Rate and Geomechanical Attributes of Select Indian Shales

    NASA Astrophysics Data System (ADS)

    Mahanta, B.; Vishal, V.; Singh, T. N.; Ranjith, P.

    2016-12-01

    In addition to modern improved technology, it requires detailed understanding of rock fractures for the purpose of enhanced energy extraction through hydraulic fracturing of gas shales and geothermal energy systems. The understanding of rock fracture behavior, patterns and properties such as fracture toughness; energy release rate; strength and deformation attributes during fracturing hold significance. Environmental factors like temperature, pressure, humidity, water vapor and experimental condition such as strain rate influence the estimation of these properties. In this study, the effects of strain rates on fracture toughness, energy release rate as well as geomechanical properties like uniaxial compressive strength, Young's modulus, failure strain, tensile strength, and brittleness index of gas shales were investigated. In addition to the rock-mechanical parameters, the fracture toughness and the energy release rates were measured for three different modes viz. mode I, mixed mode (I-II) and mode II. Petrographic and X-ray diffraction (XRD) analyses were performed to identify the mineral composition of the shale samples. Scanning electron microscope (SEM) analyses were conducted to have an insight about the strain rate effects on micro-structure of the rock. The results suggest that the fracture toughness; the energy release rate as well as other geomechanical properties are a function of strain rates. At high strain rates, the strength and stiffness of shale increases which in turn increases the fracture toughness and the energy release rate of shale that may be due to stress redistribution during grain fracturing. The fracture toughness and the strain energy release rates for all the modes (I/I-II/II) are comparable at lower strain rates, but they vary considerably at higher strain rates. In all the cases, mode I and mode II fracturing requires minimum and maximum applied energy, respectively. Mode I energy release rate is maximum, compared to the other modes.

  10. Discovery of Spin-Rate-Dependent Asteroid Thermal Inertia

    NASA Astrophysics Data System (ADS)

    Harris, Alan; Drube, Line

    2016-10-01

    Knowledge of the surface thermal inertia of an asteroid can provide insight into surface structure: porous material has a lower thermal inertia than rock. Using WISE/NEOWISE data and our new asteroid thermal-inertia estimator we show that the thermal inertia of main-belt asteroids (MBAs) appears to increase with spin period. Similar behavior is found in the case of thermophysically-modeled thermal inertia values of near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. On the basis of a picture of depth-dependent thermal inertia our results suggest that, in general, thermal inertia values representative of solid rock are reached some tens of centimeters to meters below the surface in the case of MBAs (the median diameter in our dataset = 24 km). In the case of the much smaller (km-sized) NEOs a thinner porous surface layer is indicated, with large pieces of solid rock possibly existing just a meter or less below the surface. These conclusions are consistent with our understanding from in-situ measurements of the surfaces of the Moon, and a few asteroids, and suggest a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids. Our results have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles ("kinetic impactors") in planetary defense.

  11. Ram Load Simulation of Wing Skin-Spar Joints: New Rate-dependent Cohesive Model

    DTIC Science & Technology

    2006-01-06

    carbon - fiber composites are modeled in order to validate the rate-dependent cohesive model. Also, in order to provide a methodology to obtain data to determine material constants for this rate-dependent cohesive zone model, a simple inexpensive experimental apparatus for high rate DCB (Double Cantilever Beam) sample testing was

  12. The effect of artificial shrinkage and assisted hatching on the development of mouse blastocysts and cell number after vitrification

    PubMed Central

    Kim, Hye Jin; Lee, Ki Hwan; Park, Sung Baek; Choi, Young Bae

    2015-01-01

    Objective The goal of this study was to ascertain optimal assisted hatching (AH) method in frozen embryo transfer. We compared the effect of depending on whether mechanical or laser-AH was performed before or after the vitrification of embryo development rate and blastocyst cell numbers. Methods In order to induce superovulation, pregnant mare's serum gonadotropin followed by human chorionic gonadotropin were injected into 4- to 5-week-old female mice. 2-cell embryos were then collected by flushing out the oviducts. The Expanded blastocysts were recovered after the collected embryos were incubated for 48 hours, and were then subjected to artificial shrinkage (AS) and cross-mechanical AH (cMAH) or quarter-laser zona thinning-AH (qLZT-AH) were carried out using the expanded blastocysts before or after vitrification. After 48 hours of incubation, followed by vitrification and thawing (V-T), and blastocysts were fluorescence stained and observed. Results The rate of formation of hatched blastocysts after 24 and 72 hours of incubation was significantly higher in the AS/qLZT-AH/V-T group than in the other groups (p<0.05). The cell number of the inner cell mass was higher in AS/V-T/non-AH and AS/V-T/cMAH groups than those of others (p<0.05). In the control group, the number of trophectoderm and the total cell number were higher than in the AS-AH group (p<0.05). Conclusion The above results suggest that AS and AH in vitrification of expanded blastocysts lead to the more efficient formation of hatched blastocysts in mice. PMID:26473108

  13. The effect of artificial shrinkage and assisted hatching on the development of mouse blastocysts and cell number after vitrification.

    PubMed

    Kim, Hye Jin; Lee, Ki Hwan; Park, Sung Baek; Choi, Young Bae; Yang, Jung Bo

    2015-09-01

    The goal of this study was to ascertain optimal assisted hatching (AH) method in frozen embryo transfer. We compared the effect of depending on whether mechanical or laser-AH was performed before or after the vitrification of embryo development rate and blastocyst cell numbers. In order to induce superovulation, pregnant mare's serum gonadotropin followed by human chorionic gonadotropin were injected into 4- to 5-week-old female mice. 2-cell embryos were then collected by flushing out the oviducts. The Expanded blastocysts were recovered after the collected embryos were incubated for 48 hours, and were then subjected to artificial shrinkage (AS) and cross-mechanical AH (cMAH) or quarter-laser zona thinning-AH (qLZT-AH) were carried out using the expanded blastocysts before or after vitrification. After 48 hours of incubation, followed by vitrification and thawing (V-T), and blastocysts were fluorescence stained and observed. The rate of formation of hatched blastocysts after 24 and 72 hours of incubation was significantly higher in the AS/qLZT-AH/V-T group than in the other groups (p<0.05). The cell number of the inner cell mass was higher in AS/V-T/non-AH and AS/V-T/cMAH groups than those of others (p<0.05). In the control group, the number of trophectoderm and the total cell number were higher than in the AS-AH group (p<0.05). The above results suggest that AS and AH in vitrification of expanded blastocysts lead to the more efficient formation of hatched blastocysts in mice.

  14. Female promiscuity and maternally dependent offspring growth rates in mammals.

    PubMed

    Garratt, Michael; Brooks, Robert C; Lemaître, Jean-François; Gaillard, Jean-Michel

    2014-04-01

    Conflicts between family members are expected to influence the duration and intensity of parental care. In mammals, the majority of this care occurs as resource transfer from mothers to offspring during gestation and lactation. Mating systems can have a strong influence on the severity of familial conflict--where female promiscuity is prevalent, conflict is expected to be higher between family members, causing offspring to demand more resources. If offspring are capable of manipulating their mothers and receive resources in proportion to their demands, resource transfer should increase with elevated promiscuity. We tested this prediction, unexplored across mammals, using a comparative approach. The total durations of gestation and lactation were not related to testes mass, a reliable proxy of female promiscuity across taxa. Offspring growth during gestation, however, and weaning mass, were positively correlated with testes mass, suggesting that offspring gain resources from their mothers at faster rates when familial conflict is greater. During gestation, the relationship between offspring growth and testes mass was also related to placenta morphology, with a stronger relationship between testes mass and growth observed in species with a less invasive placenta. Familial conflict could have a pervasive influence on patterns of parental care in mammals.

  15. Strain-rate dependence for Ni/Al hybrid foams

    NASA Astrophysics Data System (ADS)

    Jung, Anne; Larcher, Martin; Jirousek, Ondrej; Koudelka, Petr; Solomos, George

    2015-09-01

    Shock absorption often needs stiff but lightweight materials that exhibit a large kinetic energy absorption capability. Open-cell metal foams are artificial structures, which due to their plateau stress, including a strong hysteresis, can in principle absorb large amounts of energy. However, their plateau stress is too low for many applications. In this study, we use highly novel and promising Ni/Al hybrid foams which consist of standard, open-cell aluminium foams, where nanocrystalline nickel is deposited by electrodeposition as coating on the strut surface. The mechanical behaviour of cellular materials, including their behaviour under higher strain-rates, is governed by their microstructure due to the properties of the strut material, pore/strut geometry and mass distribution over the struts. Micro-inertia effects are strongly related to the microstructure. For a conclusive model, the exact real microstructure is needed. In this study a micro-focus computer tomography (μCT) system has been used for the analysis of the microstructure of the foam samples and for the development of a microstructural Finite Element (micro-FE) mesh. The microstructural FE models have been used to model the mechanical behaviour of the Ni/Al hybrid foams under dynamic loading conditions. The simulations are validated by quasi-static compression tests and dynamic split Hopkinson pressure bar tests.

  16. Induced hatching to avoid infectious egg disease in whitefish.

    PubMed

    Wedekind, Claus

    2002-01-08

    Reacting to a threat before physical contact, e.g., induced by air- or water-borne substances, appears to be an elegant way of defense. The reaction may be behavioral, developmental, morphological, or physiological, and it can involve a shift in niche or life history. Hatching from eggs is a shift in niche and in life history. From niche shift and life history models, one would predict that the timing of hatching is, to some degree, phenotypically plastic, i.e., early or delayed hatching is likely to be inducible. Temporary increased larval mortality (e.g., increased predation on larvae) would favor delayed hatching, while relatively high egg mortality would favor early hatching. Here, I show experimentally that eggs of the whitefish (Coregonus sp.) hatch earlier in the presence of a virulent egg parasite and that this early hatching is induced by water-borne cues emitted from infected eggs.

  17. Laser assisted zona hatching does not lead to immediate impairment in human embryo quality and metabolism.

    PubMed

    Uppangala, Shubhashree; D'Souza, Fiona; Pudakalakatti, Shivanand; Atreya, Hanudatta S; Raval, Keyur; Kalthur, Guruprasad; Adiga, Satish Kumar

    2016-12-01

    Laser assisted zona hatching (LAH) is a routinely used therapeutic intervention in assisted reproductive technology for patients with poor prognosis. However, results are not conclusive in demonstrating the benefits of zona hatching in improving the pregnancy rate. Recent observations on LAH induced genetic instability in animal embryos prompted us to look into the effects of laser assisted zona hatching on the human preimplantation embryo quality and metabolic uptake using high resolution nuclear magnetic resonance (NMR) technology. This experimental prospective study included fifty embryos from twenty-five patients undergoing intra cytoplasmic sperm injection. Embryo quality assessment followed by profiling of spent media for the non-invasive evaluation of metabolites was performed using NMR spectroscopy 24 hours after laser treatment and compared with that of non-treated sibling embryos. Both cell number and embryo quality on day 3 of development did not vary significantly between the two groups at 24 hours post laser treatment interval. Time lapse monitoring of the embryos for 24 hours did not reveal blastomere fragmentation adjacent to the point of laser treatment. Similarly, principal component analysis of metabolites did not demonstrate any variation across the groups. These results suggest that laser assisted zona hatching does not affect human preimplantation embryo morphology and metabolism at least until 24 hours post laser assisted zona hatching. However, studies are required to elucidate laser induced metabolic and developmental changes at extended time periods. AH: assisted hatching; ART: assisted reproductive technology; DNA: deoxy-ribo nucleic acid; LAH: laser assisted hatching; MHz: megahertz; NMR: nuclear magnetic resonance; PCA: principal component analysis; PGD: preimplantation genetic diagnosis; TLM: time lapse monitoring.

  18. Characterization of Nonlinear Rate Dependent Response of Shape Memory Polymers

    NASA Technical Reports Server (NTRS)

    Volk, Brent; Lagoudas, Dimitris C.; Chen, Yi-Chao; Whitley, Karen S.

    2007-01-01

    the material while it was above its glass transition temperature. After deforming the material to a specified applied strain, the material was then cooled to below the glass transition temperature (Tg) while retaining the deformed shape. Finally, the specimen was heated again to above the transition temperature, and the resulting shape recovery profile was measured. Results show that strain recovery occurs at a nonlinear rate with respect to time. Results also indicate that the ratio of recoverable strain/applied strain increases as the applied strain increases.

  19. Early transition of the digestive system to exogenous nutrition in domestic post-hatch birds.

    PubMed

    Pinchasov, Y

    1995-03-01

    The effect of early transition of the digestive system to exogenous nutrition was examined in three experiments with growing birds. A nutrient mixture (0.5 ml) of glucose, starch and oil (1:1:0.5, by vol) was orally administered immediately after hatch to turkey poults (Meleagris gallopavo) having immediate or delayed access to feed (Expt 1). Increasing amounts (0, 0.25 and 0.5 ml) of this mixture were administered immediately after hatch to turkey poults (Expt 2), or to broiler chicks (Gallus domesticus; Expt 3). The relative weights of the gastrointestinal tract (GIT) and its ingesta content, and the amylolytic capability of the pancreas were examined during the immediate post-hatch period (to 30 h). Oral administration of nutrients immediately after hatching only slightly influenced the growth of the pancreas and its amylolytic activity, but significantly increased GIT weight in both species, in a dose-dependent manner. It is suggested that early post-hatching exposure of the digestive system by the forced administration of nutrient mixture induces anatomical and metabolic changes in the digestive system slightly earlier than in birds with late access to feed. This increases GIT content and plasma glucose levels, resulting in enhanced feed consumption and growth promotion.

  20. The instantaneous rate dependence in low temperature laboratory rock friction and rock deformation experiments

    USGS Publications Warehouse

    Beeler, N.M.; Tullis, T.E.; Kronenberg, A.K.; Reinen, L.A.

    2007-01-01

    Earthquake occurrence probabilities that account for stress transfer and time-dependent failure depend on the product of the effective normal stress and a lab-derived dimensionless coefficient a. This coefficient describes the instantaneous dependence of fault strength on deformation rate, and determines the duration of precursory slip. Although an instantaneous rate dependence is observed for fracture, friction, crack growth, and low temperature plasticity in laboratory experiments, the physical origin of this effect during earthquake faulting is obscure. We examine this rate dependence in laboratory experiments on different rock types using a normalization scheme modified from one proposed by Tullis and Weeks [1987]. We compare the instantaneous rate dependence in rock friction with rate dependence measurements from higher temperature dislocation glide experiments. The same normalization scheme is used to compare rate dependence in friction to rock fracture and to low-temperature crack growth tests. For particular weak phyllosilicate minerals, the instantaneous friction rate dependence is consistent with dislocation glide. In intact rock failure tests, for each rock type considered, the instantaneous rate dependence is the same size as for friction, suggesting a common physical origin. During subcritical crack growth in strong quartzofeldspathic and carbonate rock where glide is not possible, the instantaneous rate dependence measured during failure or creep tests at high stress has long been thought to be due to crack growth; however, direct comparison between crack growth and friction tests shows poor agreement. The crack growth rate dependence appears to be higher than the rate dependence of friction and fracture by a factor of two to three for all rock types considered. Copyright 2007 by the American Geophysical Union.

  1. Laboratory oviposition, fecundity and egg hatching ability of colonized Anopheles albimanus from southwestern Mexico.

    PubMed

    Ramsey, J M; Salinas, E; Lopez, J R; del Angel-Cabañas, G; Martinez, L; Bown, D N

    1988-12-01

    Fecundity, oviposition patterns and egg hatching characteristics were studied in two colonies of Anopheles albimanus isolated from the Pacific coast of southern Mexico. Fecundity was inversely proportional to the cage space available to the female and was influenced by the bloodmeal source, feeding method and previous feeding history. The length of the gonotrophic cycle decreased with succeeding experience from a mean 6.6 in the first to 2.6 days for the fifth cycle. Oviposition timing was also dependent on availability of oviposition substrate. Hatching success of eggs increased significantly when the oviposition site was witheld until 48 hr post-bloodmeal.

  2. EVALUATION REINFORCER MAGNITUDE AND RATE DEPENDENCY OF RESISTANCE TO CHANGE MECHANIMS

    PubMed Central

    Pinkston, Jonathan W.; Ginsburg, Brett C.; Lamb, R. J.

    2015-01-01

    In many circumstances, reinforcer magnitude appears to modulate the rate-dependent effects of drugs, such that when schedules arrange for relatively larger reinforcer magnitude, rate dependency is attenuated compared to behavior maintained by smaller magnitudes. The current literature on resistance to change suggests that increased reinforcer density strengthens operant behavior, and such strengthening effects appear to extend to the temporal control of behavior. As rate dependency may be understood as a loss of temporal control, the effects of reinforcer magnitude on rate dependency may be due to increased resistance to disruption of temporally controlled behavior. In the present experiments, pigeons earned different magnitudes of grain during signaled components of a multiple fixed-interval schedule. Three drugs, clonidine, haloperidol, and morphine, were examined: all three decreased overall rates of key pecking; however, only the effects of clonidine were attenuated as reinforcer magnitude increased. An analysis of within-interval performance found rate-dependent effects for clonidine and morphine, but those effects were not modulated by reinforcer magnitude. Additionally, we included prefeeding and extinction conditions, standard tests used to measure resistance to change. In general, rate-decreasing effects of prefeeding and extinction were attenuated by increasing reinforcer magnitudes. Rate-dependent analyses of prefeeding showed rate-dependency following those tests, but in no case were these effects modulated by reinforcer magnitude. The results suggest a resistance-to-change interpretation of the effects of reinforcer magnitude on rate dependency is not viable. PMID:25115595

  3. Reinforcer magnitude and rate dependency: evaluation of resistance-to-change mechanisms.

    PubMed

    Pinkston, Jonathan W; Ginsburg, Brett C; Lamb, Richard J

    2014-10-01

    Under many circumstances, reinforcer magnitude appears to modulate the rate-dependent effects of drugs such that when schedules arrange for relatively larger reinforcer magnitudes rate dependency is attenuated compared with behavior maintained by smaller magnitudes. The current literature on resistance to change suggests that increased reinforcer density strengthens operant behavior, and such strengthening effects appear to extend to the temporal control of behavior. As rate dependency may be understood as a loss of temporal control, the effects of reinforcer magnitude on rate dependency may be due to increased resistance to disruption of temporally controlled behavior. In the present experiments, pigeons earned different magnitudes of grain during signaled components of a multiple FI schedule. Three drugs, clonidine, haloperidol, and morphine, were examined. All three decreased overall rates of key pecking; however, only the effects of clonidine were attenuated as reinforcer magnitude increased. An analysis of within-interval performance found rate-dependent effects for clonidine and morphine; however, these effects were not modulated by reinforcer magnitude. In addition, we included prefeeding and extinction conditions, standard tests used to measure resistance to change. In general, rate-decreasing effects of prefeeding and extinction were attenuated by increasing reinforcer magnitudes. Rate-dependent analyses of prefeeding showed rate-dependency following those tests, but in no case were these effects modulated by reinforcer magnitude. The results suggest that a resistance-to-change interpretation of the effects of reinforcer magnitude on rate dependency is not viable.

  4. Effects of hatching time for larval ambystomatid salamanders

    USGS Publications Warehouse

    Boone, M.D.; Scott, D.E.; Niewiarowski, P.H.

    2002-01-01

    In aquatic communities, the phenology of breeding may influence species interactions. In the early-breeding marbled salamander, Ambystoma opacum, timing of pond filling may determine whether interactions among larvae are competitive or predatory. The objectives of our studies were to determine how time of egg hatching affected size, larval period, and survival to metamorphosis in A. opacum, and if early-hatching in A. opacum influenced the competitive and predator-prey relationships with smaller larvae of the mole salamander, Ambystoma talpoideum. Salamander larvae were reared from hatching through metamorphosis in large, outdoor enclosures located in a natural temporary pond in Aiken County, South Carolina, in two experiments. In study 1, we reared early- and late-hatching A. opacum larvae separately from hatching through metamorphosis. In study 2, we examined how early- versus late-hatching A. opacum affected a syntopic species, A. talpoideum. In general, early-hatching A. opacum were larger and older at metamorphosis, had greater survival, and left the pond earlier than late-hatching larvae. Ambystoma talpoideum reared in the presence of early-hatching A. opacum had lower survival than in controls, suggesting that A. opacum may predate upon A. talpoideum when they gain a growth advantage over later-hatching larvae. Our studies demonstrate that time of pond filling and phenology of breeding may influence population dynamics and alter the nature of relationships that develop among species.

  5. Modeling of viscoplastic rate-dependent hardening-softening behavior of hot mix asphalt in compression

    NASA Astrophysics Data System (ADS)

    Yun, Taeyoung; Kim, Y. Richard

    2011-02-01

    The objective of this paper is to model viscoplastic rate-dependent hardening-softening behavior that is experimentally observed from hot mix asphalt (HMA) under repetitive creep and recovery loading in compression. A differential equation is utilized to incorporate the effects of the stress history into yield stress, and an internal variable representing rate dependence in the equation is set as a function of the viscoplastic strain rate to address the change in rate dependence of the material due to gradual hardening. Also, a separate rate-dependent function concept is adopted to describe the difference in rate dependence of the yield stress during unloading and loading. The developed viscoplastic model is applied using the time-temperature superposition principle and shows good agreement with the measured viscoplastic responses of HMA under repetitive creep and recovery loading with various load levels and rest periods.

  6. Measurement of generation-dependent proliferation rates and death rates during mouse erythroid progenitor cell differentiation.

    PubMed

    Akbarian, Vahe; Wang, Weijia; Audet, Julie

    2012-05-01

    Herein, we describe an experimental and computational approach to perform quantitative carboxyfluorescein diacetate succinimidyl ester (CFSE) cell-division tracking in cultures of primary colony-forming unit-erythroid (CFU-E) cells, a hematopoietic progenitor cell type, which is an important target for the treatment of blood disorders and for the manufacture of red blood cells. CFSE labeling of CFU-Es isolated from mouse fetal livers was performed to examine the effects of stem cell factor (SCF) and erythropoietin (EPO) in culture. We used a dynamic model of proliferation based on the Smith-Martin representation of the cell cycle to extract proliferation rates and death rates from CFSE time-series. However, we found that to accurately represent the cell population dynamics in differentiation cultures of CFU-Es, it was necessary to develop a model with generation-specific rate parameters. The generation-specific rates of proliferation and death were extracted for six generations (G(0) -G(5) ) and they revealed that, although SCF alone or EPO alone supported similar total cell outputs in culture, stimulation with EPO resulted in significantly higher proliferation rates from G(2) to G(5) and higher death rates in G(2) , G(3) , and G(5) compared with SCF. In addition, proliferation rates tended to increase from G(1) to G(5) in cultures supplemented with EPO and EPO + SCF, while they remained lower and more constant across generations with SCF. The results are consistent with the notion that SCF promotes CFU-E self-renewal while EPO promotes CFU-E differentiation in culture.

  7. Culture system for embryos of blue-breasted quail from the blastoderm stage to hatching.

    PubMed

    Ono, Tamao; Nakane, Yoshifumi; Wadayama, Takahiro; Tsudzuki, Masaoki; Arisawa, Kenjiro; Ninomiya, Shoko; Suzuki, Toshihiko; Mizutani, Makoto; Kagami, Hiroshi

    2005-01-01

    The blue-breasted quail (Coturnix chinensis), the smallest species in the order Galliforms, is a candidate model animal for avian developmental engineering because it is precocious and prolific. This species requires 17 days to hatch and 8 to 9 weeks to mature to an adult body weight of about 50 g, whereas the Japanese quail (Coturnix japonica) requires 16 days to hatch and 6 to 8 weeks to mature to an adult body weight of 100 to 150 g. The early embryo is the most challenging embryonic stage in terms of culture and manipulation for avian biotechnology. We have evaluated various conditions for the culture of blue-breasted quail embryos from the blastoderm stage to hatching. A hatchability rate of 26% (10/39) is among the best of the various culture conditions examined in the present study and the embryo culture system should facilitate advances in avian biotechnology.

  8. Flight Test Techniques for Quantifying Pitch Rate and Angle of Attack Rate Dependencies

    NASA Technical Reports Server (NTRS)

    Grauer, Jared A.; Morelli, Eugene A.; Murri, Daniel G.

    2017-01-01

    Three different types of maneuvers were designed to separately quantify pitch rate and angle of attack rate contributions to the nondimensional aerodynamic pitching moment coefficient. These maneuvers combined pilot inputs and automatic multisine excitations, and were own with the subscale T-2 and Bat-4 airplanes using the NASA AirSTAR flight test facility. Stability and control derivatives, in particular C(sub mq) and C(sub m alpha(.)) were accurately estimated from the flight test data. These maneuvers can be performed with many types of aircraft, and the results can be used to increase simulation prediction fidelity and facilitate more accurate comparisons with wind tunnel experiments or numerical investigations.

  9. Triazole Fungicides Inhibit Zebrafish Hatching by Blocking the Secretory Function of Hatching Gland Cells.

    PubMed

    De la Paz, Javiera F; Beiza, Natalia; Paredes-Zúñiga, Susana; Hoare, Misque S; Allende, Miguel L

    2017-04-04

    In animals, hatching represents the transition point from a developing embryo to a free-living individual, the larva. This process is finely regulated by many endogenous and environmental factors and has been shown to be sensitive to a variety of chemical agents. It is commonly evaluated in bioassays in order to establish the effects of different agents on early development and reproductive capabilities in fish and other aquatic animals. In fish, the breakdown of the chorion is achieved by the secretion of choriolysin by hatching gland cells (HGCs) into the perivitelline space (PVS), coupled with spontaneous movements of the developing larva. In this work, we used zebrafish to assay the effects of a family of widely used agrochemicals-triazoles Triadimefon (FON), Triadimenol (NOL) and free triazole (1,2,4-T)-on hatching success. We found a strong inhibition of hatching by triazole exposure which was correlated with morphological changes and a reduction in the secretory function of the HGCs. As a consequence, the release of choriolytic enzymes by HGCs was reduced. We also found that HGC secretion reduction after exposure to FON can be rescued by co-incubation with a dopamine D2 receptor antagonist but not by antagonists of the D1-like receptors. This suggests a specific pathway through which this family of fungicides may be impairing a critical event in the fish life cycle.

  10. A generalized Prandtl-Ishlinskii model for characterizing the rate-independent and rate-dependent hysteresis of piezoelectric actuators.

    PubMed

    Gan, Jinqiang; Zhang, Xianmin; Wu, Heng

    2016-03-01

    In this paper, a generalized hysteresis model is developed to describe both rate-independent and rate-dependent hysteresis in piezoelectric actuators. Based on the classical Prandtl-Ishlinskii (P-I) model, the developed model adds a quadratic polynomial and makes other small changes. When it is used to describe rate-independent hysteresis, the parameters of the model are constants, which can be identified by self-adaptive particle swarm optimization. The effectiveness of this rate-independent modified P-I model is demonstrated by comparing simulation results of the developed model and the classic Prandtl-Ishlinskii model. Simulation results suggest that the rate-independent modified P-I model can describe hysteresis more precisely. Compared with the classical P-I model, the rate-independent modified P-I model reduces modeling error by more than 50%. When it is used to describe rate-independent hysteresis, a one-side operator is adopted and the parameters are functions with input frequency. The results of the experiments and simulations have shown that the proposed models can accurately describe both rate-independent and rate-dependent hysteresis in piezoelectric actuators.

  11. Dynamics of a Hogg-Huberman Model with Time Dependent Reevaluation Rates

    NASA Astrophysics Data System (ADS)

    Tanaka, Toshijiro; Kurihara, Tetsuya; Inoue, Masayoshi

    2006-05-01

    The dynamical behavior of the Hogg-Huberman model with time-dependent reevaluation rates is studied. The time dependence of the reevaluation rate that agents using one of resources decide to consider their resource choice is obtained in terms of states of the system. It is seen that the change of fraction of agents using one resource is suppressed to be smaller than that in the case of a fixed reevaluation rate and the chaos control in the system associated with time-dependent reevaluation rates can be performed by the system itself.

  12. Strain-rate-dependent non-linear tensile properties of the superficial zone of articular cartilage.

    PubMed

    Ahsanizadeh, Sahand; Li, LePing

    2015-11-01

    The tensile properties of articular cartilage play an important role in the compressive behavior and integrity of the tissue. The stress-strain relationship of cartilage in compression was observed previously to depend on the strain-rate. This strain-rate dependence has been thought to originate mainly from fluid pressurization. However, it was not clear to what extent the tensile properties of cartilage contribute to the strain-rate dependence in compressive behavior of cartilage. The aim of the present study was to quantify the strain-rate dependent stress-strain relationship and hysteresis of articular cartilage in tension. Uniaxial tensile tests were performed to examine the strain-rate dependent non-linear tensile properties of the superficial zone of bovine knee cartilage. Tensile specimens were oriented in the fiber direction indicated by the India ink method. Seven strain-rates were used in the measurement ranging from 0.1 to 80%/s, which corresponded to nearly static to impact joint loadings. The experimental data showed substantial strain-rate and strain-magnitude dependent load response: for a given strain-magnitude, the tensile stress could vary by a factor of 1.95 while the modulus by a factor of 1.58 with strain-rate; for a given strain-rate, the modulus at 15% strain could be over four times the initial modulus at no strain. The energy loss in cartilage tension upon unloading exhibited a complex variation with the strain-rate. The strain-rate dependence of cartilage in tension observed from the present study is relatively weaker than that in compression observed previously, but is considerable to contribute to the strain-rate dependent load response in compression.

  13. Intraspecific priority effects modify compensatory responses to changes in hatching phenology in an amphibian.

    PubMed

    Murillo-Rincón, Andrea P; Kolter, Nora A; Laurila, Anssi; Orizaola, Germán

    2017-01-01

    In seasonal environments, modifications in the phenology of life-history events can alter the strength of time constraints experienced by organisms. Offspring can compensate for a change in timing of hatching by modifying their growth and development trajectories. However, intra- and interspecific interactions may affect these compensatory responses, in particular if differences in phenology between cohorts lead to significant priority effects (i.e. the competitive advantage that early-hatching individuals have over late-hatching ones). Here, we conducted a factorial experiment to determine whether intraspecific priority effects can alter compensatory phenotypic responses to hatching delay in a synchronic breeder by rearing moor frog (Rana arvalis) tadpoles in different combinations of phenological delay and food abundance. Tadpoles compensated for the hatching delay by speeding up their development, but only when reared in groups of individuals with identical hatching phenology. In mixed phenology groups, strong competitive effects by non-delayed tadpoles prevented the compensatory responses and delayed larvae metamorphosed later than in single phenology treatments. Non-delayed individuals gained advantage from developing with delayed larvae by increasing their developmental and growth rates as compared to single phenology groups. Food shortage prolonged larval period and reduced mass at metamorphosis in all treatments, but it did not prevent compensatory developmental responses in larvae reared in single phenology groups. This study demonstrates that strong intraspecific priority effects can constrain the compensatory growth and developmental responses to phenological change, and that priority effects can be an important factor explaining the maintenance of synchronic life histories (i.e. explosive breeding) in seasonal environments. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

  14. Tainted resurrection: metal pollution is linked with reduced hatching and high juvenile mortality in Daphnia egg banks.

    PubMed

    Rogalski, Mary A

    2015-05-01

    Many taxa, from plants to zooplankton, produce long-lasting dormant propagules capable of temporal dispersal. In some cases, propagules can persist for decades or even centuries before emerging from seed and egg banks. Despite impressive longevity, relatively little is known about how the chemical environment experienced before or during dormancy affects the fate and performance of individuals. This study examines the hatching rate and developmental success of Daphnia hatched from diapausing eggs isolated from sediments from four lakes that experienced varying levels of metal contamination. Two hundred seventy-three animals were hatched from lake sediments deposited over the past century. Hatching rate was negatively influenced by metal contamination and sediment age. There was a robust positive relationship between sediment metal concentrations and juvenile mortality in Daphnia hatching from those sediments. The negative effect of metals on Daphnia hatching and juvenile survival may stem from metal bioaccumulation, genetic effects, or reduced maternal investment in diapausing embryos. Regardless of the specific mechanism driving this trend, exposure to metals may impose strong selection on Daphnia diapausing egg banks.

  15. Alcohol-Dependent Individuals Discount Sex at Higher Rates than Controls

    PubMed Central

    Jarmolowicz, David P.; Bickel, Warren K.; Gatchalian, Kirstin M.

    2016-01-01

    Background Research on delay discounting has expanded our understanding of substance dependence in many ways. Recently, orderly discounting of sexual rewards has been demonstrated in both substance-dependent individuals, and healthy controls. Less clear, however, is if rates of sexual discounting are higher than controls in alcohol-dependent-individuals. Methods 20 Alcohol-dependent individuals and 21 healthy control participants completed two delay-discounting tasks. One task involved monetary rewards, whereas the other involved the discounting of sexual rewards (i.e., number of sex acts). Results Alcohol dependent individuals discounted sexual rewards at significantly higher rates than did controls. There was a trend towards, but not a similarly significant relation for the discounting of monetary rewards. Conclusions Rates of sexual discounting are elevated in alcohol dependent individuals. If this relation is replicated in other at risk populations, the rapid devaluation of sexual rewards may be a behavioral marker of impulsive sexual choices. PMID:23312341

  16. Growth-rate dependent global effects on gene expression in bacteria

    PubMed Central

    Klumpp, Stefan; Zhang, Zhongge; Hwa, Terence

    2010-01-01

    Summary Bacterial gene expression depends not only on specific regulations but also directly on bacterial growth, because important global parameters such as the abundance of RNA polymerases and ribosomes are all growth-rate dependent. Understanding these global effects is necessary for a quantitative understanding of gene regulation and for the robust design of synthetic genetic circuits. The observed growth-rate dependence of constitutive gene expression can be explained by a simple model using the measured growth-rate dependence of the relevant cellular parameters. More complex growth dependences for genetic circuits involving activators, repressors and feedback control were analyzed, and salient features were verified experimentally using synthetic circuits. The results suggest a novel feedback mechanism mediated by general growth-dependent effects and not requiring explicit gene regulation, if the expressed protein affects cell growth. This mechanism can lead to growth bistability and promote the acquisition of important physiological functions such as antibiotic resistance and tolerance (persistence). PMID:20064380

  17. Reinforcement magnitude modulation of rate dependent effects in pigeons and rats.

    PubMed

    Ginsburg, Brett C; Pinkston, Jonathan W; Lamb, R J

    2011-08-01

    Response rate can influence the behavioral effects of many drugs. Reinforcement magnitude may also influence drug effects. Further, reinforcement magnitude can influence rate-dependent effects. For example, in an earlier report, we showed that rate-dependent effects of two antidepressants depended on reinforcement magnitude. The ability of reinforcement magnitude to interact with rate-dependency has not been well characterized. It is not known whether our previous results are specific to antidepressants or generalize to other drug classes. Here, we further examine rate-magnitude interactions by studying effects of two stimulants (d-amphetamine [0.32-5.6 mg/kg] and cocaine [0.32-10 mg/kg]) and two sedatives (chlordiazepoxide [1.78-32 mg/kg] and pentobarbital [1.0-17.8 mg/kg]) in pigeons responding under a 3-component multiple fixed-interval (FI) 300-s schedule maintained by 2-, 4-, or 8-s of food access. We also examine the effects of d-amphetamine [0.32-3.2 mg/kg] and pentobarbital [1.8-10 mg/kg] in rats responding under a similar multiple FI300-s schedule maintained by 2- or 10- food pellet (45 mg) delivery. In pigeons, cocaine and, to a lesser extent, chlordiazepoxide exerted rate-dependent effects that were diminished by increasing durations of food access. The relationship was less apparent for pentobarbital, and not present for d-amphetamine. In rats, rate-dependent effects of pentobarbital and d-amphetamine were not modulated by reinforcement magnitude. In conclusion, some drugs appear to exert rate-dependent effect which are diminished when reinforcement magnitude is relatively high. Subsequent analysis of the rate-dependency data suggest the effects of reinforcement magnitude may be due to a diminution of drug-induced increases in low-rate behavior that occurs early in the fixed-interval.

  18. Does Impulsivity Change Rate Dependently Following Stimulant Administration? A Translational Selective Review and Reanalysis

    PubMed Central

    Bickel, W. K.; Quisenberry, A. J.; Snider, S. E.

    2015-01-01

    Rationale Rate dependence refers to an orderly relationship between a baseline measure of behavior and the change in that behavior following an intervention. The most frequently observed rate-dependent effect is an inverse relationship between the baseline rate of behavior and response rates following an intervention. A previous report of rate dependence in delay discounting suggests that the discounting of delayed reinforcers, and perhaps, other impulsivity measures, may change rate dependently following acute and chronic administration of potentially therapeutic medications in both preclinical and clinical studies. Objective The aim of the current paper was to review the effects of stimulants on delay discounting and other impulsivity tasks. Methods All studies identified from the literature were required to include: 1) an objective measure of impulsivity, 2) administration of amphetamine, methylphenidate, or modafinil, 3) presentation of a pre- and post- drug administration impulsivity measure, and 4) the report of individual drug effects or results in groups split by baseline or vehicle impulsivity. Twenty-five research reports were then re-analyzed for evidence consistent with rate dependence. Results Of the total possible instances, 67% produced results consistent with rate dependence. Specifically, 72%, 45%, and 80% of the data sets were consistent with rate dependence following amphetamine, methylphenidate, and modafinil administration, respectively. Conclusions These results suggest rate dependence is a more robust phenomenon than reported in the literature. Impulsivity studies should consider this quantitative signature as a process to determine the effects of variables and as a potential prognostic tool to evaluate the effectiveness future interventions. PMID:26581504

  19. Time-dependent Kramers escape rate in overdamped system with power-law distribution

    NASA Astrophysics Data System (ADS)

    Zhou, Yanjun; Yin, Cangtao

    2016-05-01

    The probability distribution of Brownian particles moving in an overdamped complex system follows the generalized Smoluchowski equation, which can be rigorously proven that the exact time-dependent solution for this equation follows Tsallis form. Time-dependent escape rate in overdamped system with power-law distributions is then established based on the flux over population theory. The stationary state escape rate in overdamped system with power-law distribution which has been obtained before based on mean first passage time theory is recovered from time-dependent escape rate as time toward infinity.

  20. Rate dependence of grain boundary sliding via time-scaling atomistic simulations

    NASA Astrophysics Data System (ADS)

    Hammami, Farah; Kulkarni, Yashashree

    2017-02-01

    Approaching experimentally relevant strain rates has been a long-standing challenge for molecular dynamics method which captures phenomena typically on the scale of nanoseconds or at strain rates of 107 s-1 and higher. Here, we use grain boundary sliding in nanostructures as a paradigmatic problem to investigate rate dependence using atomistic simulations. We employ a combination of time-scaling computational approaches, including the autonomous basin climbing method, the nudged elastic band method, and kinetic Monte Carlo, to access strain rates ranging from 0.5 s-1 to 107 s-1. Combined with a standard linear solid model for viscoelastic behavior, our simulations reveal that grain boundary sliding exhibits noticeable rate dependence only below strain rates on the order of 10 s-1 but is rate independent and consistent with molecular dynamics at higher strain rates.

  1. Design and properties of a rate-dependent ‘dynamic ligament’ containing shear thickening fluid

    NASA Astrophysics Data System (ADS)

    Nenno, Paul T.; Wetzel, Eric D.

    2014-12-01

    A ‘dynamic ligament’ device that exhibits a discontinuous, rate-dependent tensile response is developed and characterized. The device, based on a shear thickening fluid (STF) and flexible ribbons enclosed in elastomeric tubing, exhibits low resistance to extension at rates below 10 mm s-1, but when stretched at 100 mm s-1 or higher resists with more than tenfold higher force. A link between the rheology of the STF and the tensile performance of the dynamic ligament is presented to explain the rate-dependent response. Visualization experiments show evidence of void formation and dilation in the STF during high rate extension.

  2. Yield strength dependence on strain rate of molybdenum-alloy nanofibers

    SciTech Connect

    Loya, P. E.; Peng, C.; Zhang, P.; Zhang, J.; Lou, J.; Xia, Y. Z.; Bei, H.; George, E. P.; Gao, Y. F.

    2014-06-23

    The yield strength dependence on strain rate was studied for molybdenum-alloy nanofibers with varying initial dislocation density at three different pre-strain levels. In-situ tensile experiments at three displacement rates were carried out in a scanning electron microscope. Yield strength and its scatter decreased as a function of the pre-strain level for different displacement rates. A statistical model was used to analyze the results, and a negative strain rate dependence was inferred from the yield experiments. This finding suggests the need for theoretical investigations since classical models such as dynamic strain aging may have limitations at such nanoscales.

  3. Biomolecular origin of the rate-dependent deformation of prismatic enamel

    NASA Astrophysics Data System (ADS)

    Zhou, Jikou; Hsiung, Luke L.

    2006-07-01

    Penetration deformation of columnar prismatic enamel was investigated using instrumented nanoindentation testing that was carried out at three constant strain rates (0.05, 0.005, and 0.0005s-1). Enamel demonstrated better resistance to penetration deformation and greater elastic modulus values were measured at higher strain rates. The origin of rate-dependent deformation was rationalized to be the shear deformation of nanoscale protein matrix surrounding each hydroxyapatite crystal rod. The shear modulus of protein matrix was determined. It depends on strain rate in a format Gp=0.213+0.021lnɛ˙.

  4. Displacement rate dependence of irradiation creep as predicted by the production bias model

    SciTech Connect

    Woo, C.H.

    1996-04-01

    Recently, it has been shown that the non-swelling component of irradiation creep of austenitic stainless steels is relatively independent of temperature but is sensitive to the displacement rate. An earlier model of Lewthwaite and Mosedale anticipated the sensitivity of displacement rate and attributed it to the flux sensitivity of point defect recombination. The point-defect recombination process does not yield the observed temperature dependence, however, although it does predict an inverse dependence of the creep rate on the square root of the displacement rate that was experimentally observed at relatively low temperatures.

  5. Rate dependent inelastic behavior of polycrystalline solids using a dislocation model

    SciTech Connect

    Werne, R.W.; Kelly, J.M.

    1980-02-26

    A rate dependent theory of polycrystalline plasticity is presented in which the solid is modeled as an isotropic continuum with internal variables. The rate of plastic deformation is shown to be a function of the deviatoric portion of the Cauchy stress tensor as well as two scalar internal variables. The scalar internal variables, which are the dislocation density and mobile fraction, are governed by rate equations which reflect the evolution of microstructural processes. The model has been incorporated into a two dimensional finite element code and several example multidimensional problems are presented which exhibit the rate dependence of the material model.

  6. Coordinate-dependent diffusion coefficients: Decay rate in open quantum systems

    SciTech Connect

    Sargsyan, V. V.; Palchikov, Yu. V.; Antonenko, N. V.; Kanokov, Z.; Adamian, G. G.

    2007-06-15

    Based on a master equation for the reduced density matrix of an open quantum collective system, the influence of coordinate-dependent microscopical diffusion coefficients on the decay rate from a metastable state is treated. For various frictions and temperatures larger than a crossover temperature, the quasistationary decay rates obtained with the coordinate-dependent microscopical set of diffusion coefficients are compared with those obtained with the coordinate-independent microscopical set of diffusion coefficients and coordinate-independent and -dependent phenomenological sets of diffusion coefficients. Neglecting the coordinate dependence of diffusion coefficients, one can strongly overestimate or underestimate the decay rate at low temperature. The coordinate-dependent phenomenological diffusion coefficient in momentum are shown to be suitable for applications.

  7. Exploration of mechanisms underlying the strain-rate-dependent mechanical property of single chondrocytes

    SciTech Connect

    Nguyen, Trung Dung; Gu, YuanTong

    2014-05-05

    Based on the characterization by Atomic Force Microscopy, we report that the mechanical property of single chondrocytes has dependency on the strain-rates. By comparing the mechanical deformation responses and the Young's moduli of living and fixed chondrocytes at four different strain-rates, we explore the deformation mechanisms underlying this dependency property. We found that the strain-rate-dependent mechanical property of living cells is governed by both of the cellular cytoskeleton and the intracellular fluid when the fixed chondrocytes are mainly governed by their intracellular fluid, which is called the consolidation-dependent deformation behavior. Finally, we report that the porohyperelastic constitutive material model which can capture the consolidation-dependent behavior of both living and fixed chondrocytes is a potential candidature to study living cell biomechanics.

  8. 29 CFR 780.211 - Contract production of hatching eggs.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Contract production of hatching eggs. 780.211 Section 780... eggs. It is common practice for hatcherymen to enter into arrangements with farmer poultry raisers for the production of hatching eggs which the hatchery agrees to buy. Ordinarily, the farmer furnishes...

  9. 29 CFR 780.211 - Contract production of hatching eggs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Contract production of hatching eggs. 780.211 Section 780... eggs. It is common practice for hatcherymen to enter into arrangements with farmer poultry raisers for the production of hatching eggs which the hatchery agrees to buy. Ordinarily, the farmer furnishes...

  10. 29 CFR 780.211 - Contract production of hatching eggs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Contract production of hatching eggs. 780.211 Section 780... eggs. It is common practice for hatcherymen to enter into arrangements with farmer poultry raisers for the production of hatching eggs which the hatchery agrees to buy. Ordinarily, the farmer furnishes...

  11. 29 CFR 780.211 - Contract production of hatching eggs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Contract production of hatching eggs. 780.211 Section 780... eggs. It is common practice for hatcherymen to enter into arrangements with farmer poultry raisers for the production of hatching eggs which the hatchery agrees to buy. Ordinarily, the farmer furnishes...

  12. 29 CFR 780.211 - Contract production of hatching eggs.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Contract production of hatching eggs. 780.211 Section 780... eggs. It is common practice for hatcherymen to enter into arrangements with farmer poultry raisers for the production of hatching eggs which the hatchery agrees to buy. Ordinarily, the farmer furnishes...

  13. 14. VIEW OF NORTHSOUTH ROAD WHICH PARALLELS ROAD TO HATCH ...

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

    14. VIEW OF NORTH-SOUTH ROAD WHICH PARALLELS ROAD TO HATCH ADIT (FEATURE B-28). NOTE MODERN 'LAY DOWN' FENCE ON ROAD. ROAD LIES TO THE WEST OF THE HATCH ADIT AND PHOTOGRAPH IS VIEW TO THE SOUTH. (OCTOBER, 1995) - Nevada Lucky Tiger Mill & Mine, East slope of Buckskin Mountain, Paradise Valley, Humboldt County, NV

  14. 46 CFR 131.520 - Hatches and other openings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Hatches and other openings. 131.520 Section 131.520 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Tests, Drills, and Inspections § 131.520 Hatches and other openings. Before any vessel leaves protected waters...

  15. Effect of storage environment on hatching of Globodera ellingtonae

    USDA-ARS?s Scientific Manuscript database

    Globodera spp. eggs go through a diapause stage in which development remains dormant until favorable hatching conditions are reached. Because of the regulatory concerns with Globodera spp., it is often only possible to rear eggs for research in the greenhouse. However, hatch is often lower for green...

  16. 46 CFR 196.15-20 - Hatches and other openings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Hatches and other openings. 196.15-20 Section 196.15-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS OPERATIONS Test, Drills, and Inspections § 196.15-20 Hatches and other openings. (a) It shall be the...

  17. 46 CFR 131.893 - Watertight doors and watertight hatches.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Watertight doors and watertight hatches. 131.893 Section... OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.893 Watertight doors and watertight hatches. Each watertight door in a bulkhead that must be watertight in compliance with the requirements in...

  18. 46 CFR 131.893 - Watertight doors and watertight hatches.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Watertight doors and watertight hatches. 131.893 Section... OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.893 Watertight doors and watertight hatches. Each watertight door in a bulkhead that must be watertight in compliance with the requirements in...

  19. 46 CFR 122.610 - Watertight doors and watertight hatches.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Watertight doors and watertight hatches. 122.610 Section... Markings Required § 122.610 Watertight doors and watertight hatches. Watertight doors and watertight...: “WATERTIGHT DOOR—KEEP CLOSED” or “WATERTIGHT HATCH—KEEP CLOSED”, unless such markings are deemed unnecessary...

  20. 46 CFR 122.610 - Watertight doors and watertight hatches.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Watertight doors and watertight hatches. 122.610 Section... Markings Required § 122.610 Watertight doors and watertight hatches. Watertight doors and watertight...: “WATERTIGHT DOOR—KEEP CLOSED” or “WATERTIGHT HATCH—KEEP CLOSED”, unless such markings are deemed unnecessary...

  1. 46 CFR 108.145 - Hatches and tonnage openings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Hatches and tonnage openings. 108.145 Section 108.145 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Structural Fire Protection § 108.145 Hatches and tonnage...

  2. 46 CFR 108.145 - Hatches and tonnage openings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Hatches and tonnage openings. 108.145 Section 108.145 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Structural Fire Protection § 108.145 Hatches and tonnage...

  3. 46 CFR 108.145 - Hatches and tonnage openings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Hatches and tonnage openings. 108.145 Section 108.145 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Structural Fire Protection § 108.145 Hatches and tonnage...

  4. 46 CFR 108.145 - Hatches and tonnage openings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Hatches and tonnage openings. 108.145 Section 108.145 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Structural Fire Protection § 108.145 Hatches and...

  5. 46 CFR 108.145 - Hatches and tonnage openings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Hatches and tonnage openings. 108.145 Section 108.145 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Structural Fire Protection § 108.145 Hatches and...

  6. Efficient rate-distortion optimized media streaming for tree-reducible packet dependencies

    NASA Astrophysics Data System (ADS)

    Röder, Martin; Cardinal, Jean; Hamzaoui, Raouf

    2006-01-01

    In packetized media streaming systems, packet dependencies are often modeled as a directed acyclic graph called the dependency graph. We consider the situation where the dependency graph is reducible to a tree. This occurs, for instance, in MPEG1 video streams that are packetized at the frame level. Other video coding standards such as H.264 also allow tree-reducible dependencies. We propose in this context efficient dynamic programming algorithms for finding rate-distortion optimal transmission policies. The proposed algorithms are much faster than previous exact algorithms developed for arbitrary dependency graphs.

  7. Solvent viscosity dependence of the folding rate of a small protein: distributed computing study.

    PubMed

    Zagrovic, Bojan; Pande, Vijay

    2003-09-01

    By using distributed computing techniques and a supercluster of more than 20,000 processors we simulated folding of a 20-residue Trp Cage miniprotein in atomistic detail with implicit GB/SA solvent at a variety of solvent viscosities (gamma). This allowed us to analyze the dependence of folding rates on viscosity. In particular, we focused on the low-viscosity regime (values below the viscosity of water). In accordance with Kramers' theory, we observe approximately linear dependence of the folding rate on 1/gamma for values from 1-10(-1)x that of water viscosity. However, for the regime between 10(-4)-10(-1)x that of water viscosity we observe power-law dependence of the form k approximately gamma(-1/5). These results suggest that estimating folding rates from molecular simulations run at low viscosity under the assumption of linear dependence of rate on inverse viscosity may lead to erroneous results.

  8. Current dependence of spin torque switching rate based on Fokker-Planck approach

    SciTech Connect

    Taniguchi, Tomohiro Imamura, Hiroshi

    2014-05-07

    The spin torque switching rate of an in-plane magnetized system in the presence of an applied field is derived by solving the Fokker-Planck equation. It is found that three scaling currents are necessary to describe the current dependence of the switching rate in the low-current limit. The dependences of these scaling currents on the applied field strength are also studied.

  9. Rate-Dependent Homogenization Based Continuum Plasticity Damage Model for Dendritic Cast Aluminum Alloys

    DTIC Science & Technology

    2011-01-01

    The overall framework of this rate-dependent HCPD model follows the structure of the anisotropic Gursen- Tvergaard-Needleman( GTN ) type elasto...with evolving porosity. The HCPD model follows the Gurson-Tvergaard-Needleman or GTN models framework established in [14, 15, 16, 17] that account for...this method. In [32, 33] the VCFEM model has been extended for rate-dependent elastic- viscoplastic porous ductile material. Micromechanical analysis

  10. Effect of laser-assisted multi-point zona thinning on development and hatching of cleavage embryos in mice.

    PubMed

    Lee, Young Seok; Park, Min Jung; Park, Sea Hee; Koo, Ja Seong; Moon, Hwa Sook; Joo, Bo Sun

    2015-06-01

    This study aimed to examine the effect of laser-assisted zona thinning (LAZT) at one or four-points on the blastocyst formation and hatching process in mice with respect to female age. Eight-cell or morula embryos collected from superovulated C57BL female mice with different ages (6-11 and 28-31 weeks) were treated with LAZT at one-point (LAZT1) or four-points (LAZT4). The zona pellucida was thinned to more than 70% of its initial thickness by making two holes of 15-20 µm. In the young mice, LAZT resulted in a significant increase in early hatching and hatching rates compared to the control group (p<0.05). However, in the old mice, LAZT significantly increased blastocyst formation as well as early hatching and hatching compared to the controls (p<0.05). These effects were more remarkable in LAZT4 than in LAZT1 and in aged mice than in young ones. These results show that multi-point LAZT leads to a significant improvement of blastocyst formation and hatching in mice compared to controls.

  11. Drugs and punished responding I: rate-dependent effects under multiple schedules1

    PubMed Central

    McMillan, D. E.

    1973-01-01

    The effects of drugs were studied in pigeons whose responses were punished with electric shock during one component of a multiple fixed-interval 5-min fixed-interval 5-min schedule of food presentation. Most of the drugs analyzed for rate-dependent effects increased low rates of both punished and unpunished responding, while increasing higher rates less, or decreasing them; however, low rates of punished responding sometimes were increased more by pentobarbital, diazepam, and chlordiazepoxide than were matched rates of unpunished responding. In contrast, d-amphetamine and chlorpromazine usually increased low rates of unpunished responding more than matched rates of punished responding. These two drugs also decreased high rates of unpunished responding less than they decreased high rates of punished responding. Thus, the effects of drugs on punished responding depend on the control rate of punished responding; however, the rate-dependent effects of drugs on punished responding are not always the same as they are for unpunished responding. PMID:4706233

  12. PRESSURE AND TEMPERATURE DEPENDENT DEFLAGRATION RATE MEASUREMENTS OF LLM-105 AND TATB BASED EXPLOSIVES

    SciTech Connect

    Glascoe, E A; Tan, N; Koerner, J; Lorenz, K T; Maienschein, J L

    2009-11-10

    The pressure dependent deflagration rates of LLM-105 and TATB based formulations were measured in the LLNL high pressure strand burner. The role of binder amount, explosive type, and thermal damage and their effects on the deflagration rate will be discussed. Two different formulations of LLM-105 and three formulations of TATB were studied and results indicate that binder amount and type play a minor role in the deflagration behavior. This is in sharp contrast to the HMX based formulations which strongly depend on binder amount and type. The effect of preheating these samples was considerably more dramatic. In the case of LLM-105, preheating the sample appears to have little effect on the deflagration rate. In contrast, preheating TATB formulations causes the deflagration rate to accelerate and become erratic. The thermal and mechanical properties of these formulations will be discussed in the context of their pressure and temperature dependent deflagration rates.

  13. Modeling the influence of physical heterogeneity on the time dependence of anorthite weathering rates

    NASA Astrophysics Data System (ADS)

    Jung, H.; Navarre-Sitchler, A.

    2016-12-01

    Several orders of magnitude difference between laboratory measured and field estimated weathering rates is a well-known knowledge gap that hampers extrapolating laboratory-measured weathering rates to natural systems. The influence of hydrologic heterogeneity has been recognized as an important factor affecting this discrepancy, but it has not been quantitatively linked to the time dependence of weathering rates. We evaluate the impact of heterogeneous fluid flow on the time dependence of anorthite weathering rate with fully coupled reactive transport simulator, Crunchflow. Simulations performed in correlated random permeability fields with log-normal distribution are compared to homogeneous permeability fields. Preliminary results reveal that flux-weighted weathering rates measured at the outlet of the domain are constant and independent to the degree of heterogeneity when the weathering front reside inside of the domain. However, the weathering rate starts to decrease with different reduction rate depending on the degree of heterogeneity after the front leaves the domain. The higher the degree of heterogeneity (i.e. the higher variance of the permeability distribution) the earlier the weathering front exits the domain and thus the earlier the reduction in weathering rate is observed, but the rate of reduction in weathering rate of this case is lower than the case with a low degree of heterogeneity. This is because of the development of a larger area of initially non-reactive zones that participate in the dissolution reaction at later time for the higher degree of heterogeneity case. The differences in the rate and timing of reduction lead to the reversal of the weathering rate over time. We are expecting this type of conceptual modeling approach to help elucidate hydrologic controls on the time dependence of effective reaction rates at field scales and improve the application of laboratory measured rates to numerical simulations of field scale systems.

  14. Inbreeding coefficient and heterozygosity-fitness correlations in unhatched and hatched song sparrow nestmates.

    PubMed

    Taylor, Sabrina S; Sardell, Rebecca J; Reid, Jane M; Bucher, Thomas; Taylor, Nathan G; Arcese, Peter; Keller, Lukas F

    2010-10-01

    Heterozygosity-fitness correlations use molecular measures of heterozygosity as proxy estimates of individual inbreeding coefficients (f) to examine relationships between inbreeding and fitness traits. Heterozygosity-fitness correlations partly depend on the assumption that individual heterozygosity and f are strongly and negatively correlated. Although theory predicts that this relationship will be strongest when mean f and variance in f are high, few studies of heterozygosity-fitness correlations include estimates of f based on pedigrees, which allow for more thorough examinations of the relationship between f, heterozygosity and fitness in nature. We examined relationships between pedigree-based estimates of f, multilocus heterozygosity (MLH) and the probability of survival to hatch in song sparrow nestmates. f and MLH were weakly, but significantly negatively correlated. Inbreeding coefficient predicted the probability of survival to hatch. In contrast, MLH did not predict the probability of survival to hatch nor did it account for residual variation in survival to hatch after statistically controlling for the effects of f. These results are consistent with the expectation that heterozygosity-f correlations will be weak when mean and variance in f are low. Our results also provide empirical support for recent simulation studies, which show that variation in MLH among siblings with equal f can be large and may obscure MLH-fitness relationships.

  15. MicroRNA-276 promotes egg-hatching synchrony by up-regulating brm in locusts

    PubMed Central

    He, Jing; Chen, Qianquan; Wei, Yuanyuan; Jiang, Feng; Yang, Meiling; Hao, Shuguang; Guo, Xiaojiao; Chen, Dahua; Kang, Le

    2016-01-01

    Developmental synchrony, the basis of uniform swarming, migration, and sexual maturation, is an important strategy for social animals to adapt to variable environments. However, the molecular mechanisms underlying developmental synchrony are largely unexplored. The migratory locust exhibits polyphenism between gregarious and solitarious individuals, with the former displaying more synchronous sexual maturation and migration than the latter. Here, we found that the egg-hatching time of gregarious locusts was more uniform compared with solitarious locusts and that microRNA-276 (miR-276) was expressed significantly higher in both ovaries and eggs of gregarious locusts than in solitarious locusts. Interestingly, inhibiting miR-276 in gregarious females and overexpressing it in solitarious females, respectively, caused more heterochronic and synchronous hatching of progeny eggs. Moreover, miR-276 directly targeted a transcription coactivator gene, brahma (brm), resulting in its up-regulation. Knockdown of brm not only resulted in asynchronous egg hatching in gregarious locusts but also impaired the miR-276–induced synchronous egg hatching in solitarious locusts. Mechanistically, miR-276 mediated brm activation in a manner that depended on the secondary structure of brm, namely, a stem-loop around the binding site of miR-276. Collectively, our results unravel a mechanism by which miR-276 enhances brm expression to promote developmental synchrony and provide insight into regulation of developmental homeostasis and population sustaining that are closely related to biological synchrony. PMID:26729868

  16. Angle-dependent strong-field molecular ionization rates with tuned range-separated time-dependent density functional theory

    NASA Astrophysics Data System (ADS)

    Sissay, Adonay; Abanador, Paul; Mauger, François; Gaarde, Mette; Schafer, Kenneth J.; Lopata, Kenneth

    2016-09-01

    Strong-field ionization and the resulting electronic dynamics are important for a range of processes such as high harmonic generation, photodamage, charge resonance enhanced ionization, and ionization-triggered charge migration. Modeling ionization dynamics in molecular systems from first-principles can be challenging due to the large spatial extent of the wavefunction which stresses the accuracy of basis sets, and the intense fields which require non-perturbative time-dependent electronic structure methods. In this paper, we develop a time-dependent density functional theory approach which uses a Gaussian-type orbital (GTO) basis set to capture strong-field ionization rates and dynamics in atoms and small molecules. This involves propagating the electronic density matrix in time with a time-dependent laser potential and a spatial non-Hermitian complex absorbing potential which is projected onto an atom-centered basis set to remove ionized charge from the simulation. For the density functional theory (DFT) functional we use a tuned range-separated functional LC-PBE*, which has the correct asymptotic 1/r form of the potential and a reduced delocalization error compared to traditional DFT functionals. Ionization rates are computed for hydrogen, molecular nitrogen, and iodoacetylene under various field frequencies, intensities, and polarizations (angle-dependent ionization), and the results are shown to quantitatively agree with time-dependent Schrödinger equation and strong-field approximation calculations. This tuned DFT with GTO method opens the door to predictive all-electron time-dependent density functional theory simulations of ionization and ionization-triggered dynamics in molecular systems using tuned range-separated hybrid functionals.

  17. Participation Rates in the Aid to Families with Dependent Children Program: Trends for 1967 through 1984.

    ERIC Educational Resources Information Center

    Ruggles, Patricia; Michel, Richard C.

    This report examines participation rates in the Aid to Families with Dependent Children (AFDC) program. TRIM2, a microsimulation model that simulated the eligibility and benefit rules of the AFDC program on a state-by-state basis, showed that there had been a dramatic decline after 1981 in the rate at which AFDC families were applying for and…

  18. Factors Affecting Growth of Tengmalm's Owl (Aegolius funereus) Nestlings: Prey Abundance, Sex and Hatching Order.

    PubMed

    Zárybnická, Markéta; Riegert, Jan; Brejšková, Lucie; Šindelář, Jiří; Kouba, Marek; Hanel, Jan; Popelková, Alena; Menclová, Petra; Tomášek, Václav; Šťastný, Karel

    2015-01-01

    In altricial birds, energy supply during growth is a major predictor of the physical condition and survival prospects of fledglings. A number of experimental studies have shown that nestling body mass and wing length can vary with particular extrinsic factors, but between-year observational data on this topic are scarce. Based on a seven-year observational study in a central European Tengmalm's owl population we examine the effect of year, brood size, hatching order, and sex on nestling body mass and wing length, as well as the effect of prey abundance on parameters of growth curve. We found that nestling body mass varied among years, and parameters of growth curve, i.e. growth rate and inflection point in particular, increased with increasing abundance of the owl's main prey (Apodemus mice, Microtus voles), and pooled prey abundance (Apodemus mice, Microtus voles, and Sorex shrews). Furthermore, nestling body mass varied with hatching order and between sexes being larger for females and for the first-hatched brood mates. Brood size had no effect on nestling body mass. Simultaneously, we found no effect of year, brood size, hatching order, or sex on the wing length of nestlings. Our findings suggest that in this temperate owl population, nestling body mass is more sensitive to prey abundance than is wing length. The latter is probably more limited by the physiology of the species.

  19. Thermal and maternal environments shape the value of early hatching in a natural population of a strongly cannibalistic freshwater fish.

    PubMed

    Pagel, Thilo; Bekkevold, Dorte; Pohlmeier, Stefan; Wolter, Christian; Arlinghaus, Robert

    2015-08-01

    Hatching early in the season is often assumed to elevate fitness, particularly in cannibalistic fish in which size-dependent predation mortality is a major selective force. While the importance of the thermal environment for the growth of fish is undisputed, the relevance of maternal effects for offspring growth in the wild is largely unknown. Otoliths of 366 age-0 pike (Esox lucius L.) were sampled in a natural lake over three seasons. All offspring were assigned to more than 330 potential mothers using 16 informative microsatellites. We found temperature and past maternal environment (as represented by juvenile growth rate), but not female total length, to jointly contribute to explain within- and among-season size variation in juvenile pike. While there was no statistical evidence for maternal effects on offspring growth rate, fast female juvenile growth positively correlated with the offspring length in early summer. One mechanism could be related to fast-growing females spawning somewhat earlier in the season. However, the more likely mechanism emerging in our study was that fast-growing females could have been in better condition prior to spawning, in turn possibly producing higher numbers of high-quality eggs. Our study is among the few to reveal carry-over effects related to past maternal environments on offspring performance in a naturally reproducing fish stock. At the same time, our study underscores recent arguments that size-dependent maternal effects may not be expressed in the wild and that early hatching does not generally produce size advantages in light of stochastically varying temperature conditions.

  20. Solutions of the coagulation equation with time-dependent coagulation rates. [For stellar formation mass functions

    SciTech Connect

    Lejeune, C.; Bastien, P.

    1986-10-01

    In attempting to reproduce the initial stellar mass function, the authors solved analytically the coagulation equation with an explicit time dependence in the coagulation rate in order to simulate the gravitational collapse of the fragments upon themselves as they move within the progenitor cloud. Two separate cases have been studied, with and without a mass dependence in the coagulation rate. The solutions show that: (1) inclusion of self-gravitation can change the results to the point of preventing coalescence to work altogether, depending on the values of the two free parameters; (2) the precise form of the mass dependence of the coagulation rate is not of prime importance in most situations of astrophysical interest; (3) coagulation alone is not sufficient to yield a realistic mass spectrum, and fragmentation must also be taken into account. 30 references.

  1. Time-series analysis of foreign exchange rates using time-dependent pattern entropy

    NASA Astrophysics Data System (ADS)

    Ishizaki, Ryuji; Inoue, Masayoshi

    2013-08-01

    Time-dependent pattern entropy is a method that reduces variations to binary symbolic dynamics and considers the pattern of symbols in a sliding temporal window. We use this method to analyze the instability of daily variations in foreign exchange rates, in particular, the dollar-yen rate. The time-dependent pattern entropy of the dollar-yen rate was found to be high in the following periods: before and after the turning points of the yen from strong to weak or from weak to strong, and the period after the Lehman shock.

  2. Reaction rate and composition dependence of the stability of thermonuclear burning on accreting neutron stars

    SciTech Connect

    Keek, L.; Cyburt, R. H.; Heger, A.

    2014-06-01

    The stability of thermonuclear burning of hydrogen and helium accreted onto neutron stars is strongly dependent on the mass accretion rate. The burning behavior is observed to change from Type I X-ray bursts to stable burning, with oscillatory burning occurring at the transition. Simulations predict the transition at a 10 times higher mass accretion rate than observed. Using numerical models we investigate how the transition depends on the hydrogen, helium, and CNO mass fractions of the accreted material, as well as on the nuclear reaction rates of 3α and the hot-CNO breakout reactions {sup 15}O(α, γ){sup 19}Ne and {sup 18}Ne(α, p){sup 21}Na. For a lower hydrogen content the transition is at higher accretion rates. Furthermore, most experimentally allowed reaction rate variations change the transition accretion rate by at most 10%. A factor 10 decrease of the {sup 15}O(α, γ){sup 19}Ne rate, however, produces an increase of the transition accretion rate of 35%. None of our models reproduce the transition at the observed rate, and depending on the true {sup 15}O(α, γ){sup 19}Ne reaction rate, the actual discrepancy may be substantially larger. We find that the width of the interval of accretion rates with marginally stable burning depends strongly on both composition and reaction rates. Furthermore, close to the stability transition, our models predict that X-ray bursts have extended tails where freshly accreted fuel prolongs nuclear burning.

  3. On the Firing Rate Dependency of the Phase Response Curve of Rat Purkinje Neurons In Vitro

    PubMed Central

    Couto, João; Linaro, Daniele; De Schutter, E; Giugliano, Michele

    2015-01-01

    Synchronous spiking during cerebellar tasks has been observed across Purkinje cells: however, little is known about the intrinsic cellular mechanisms responsible for its initiation, cessation and stability. The Phase Response Curve (PRC), a simple input-output characterization of single cells, can provide insights into individual and collective properties of neurons and networks, by quantifying the impact of an infinitesimal depolarizing current pulse on the time of occurrence of subsequent action potentials, while a neuron is firing tonically. Recently, the PRC theory applied to cerebellar Purkinje cells revealed that these behave as phase-independent integrators at low firing rates, and switch to a phase-dependent mode at high rates. Given the implications for computation and information processing in the cerebellum and the possible role of synchrony in the communication with its post-synaptic targets, we further explored the firing rate dependency of the PRC in Purkinje cells. We isolated key factors for the experimental estimation of the PRC and developed a closed-loop approach to reliably compute the PRC across diverse firing rates in the same cell. Our results show unambiguously that the PRC of individual Purkinje cells is firing rate dependent and that it smoothly transitions from phase independent integrator to a phase dependent mode. Using computational models we show that neither channel noise nor a realistic cell morphology are responsible for the rate dependent shift in the phase response curve. PMID:25775448

  4. Cryopreservation of sperm in common carp Cyprinus carpio: sperm motility and hatching success of embryos.

    PubMed

    Linhart, O; Rodina, M; Cosson, J

    2000-11-01

    In this study, fish sperm cryopreservation methods were elaborated upon for ex situ conservation of nine strains of Bohemian common carp. Common carp sperm were diluted in Kurokura medium and chilled to 4 degrees C and dimethyl sulfoxide was added. Cryotubes of sperm with media were then cooled from +4 to -9 degrees C at a rate of 4 degrees C min(-1) and then from -9 to -80 degrees C at a rate of 11 degrees C min(-1), held for 6 min at -80 degrees C, and finally transferred into liquid N(2). The spermatozoa were thawed in a water bath at 35 degrees C for 110 s and checked for fertilization yield, hatching yield of embryos, and larval malformations. Fresh and frozen/thawed sperm were evaluated for the percentage and for the velocity of motile sperm from video frames using image analysis. The percentage and velocity of sperm motility at 15 s after activation of frozen/thawed sperm was significantly lower than that of fresh sperm (nine males). ANOVA showed a significant influence of fresh vs frozen/thawed sperm on fertilization rate (P < 0.0001), but differences in hatching rate and in larval malformation (0-6.8%) were not significant, and different males had a significant influence on fertilization and hatching rate (P < 0.003 and P < 0.007, respectively). Multiple range analysis (LSD) showed significant differences between fresh and frozen/thawed sperm regarding fertilization rate (68 +/- 11 and 56 +/- 10%, respectively) and insignificant differences between fresh and frozen/thawed sperm on the hatching rate (50 +/- 18 and 52 +/- 9%, respectively). The percentage and velocity of fresh sperm motility were correlated, respectively, with the fertilization yield of frozen/thawed sperm at the levels r = 0.51 and r = 0.54.

  5. Physical mechanisms underlying the strain-rate-dependent mechanical behavior of kangaroo shoulder cartilage

    NASA Astrophysics Data System (ADS)

    Thibbotuwawa, Namal; Oloyede, Adekunle; Li, Tong; Singh, Sanjleena; Senadeera, Wijitha; Gu, YuanTong

    2015-09-01

    Due to anatomical and biomechanical similarities to human shoulder, kangaroo was chosen as a model to study shoulder cartilage. Comprehensive enzymatic degradation and indentation tests were applied on kangaroo shoulder cartilage to study mechanisms underlying its strain-rate-dependent mechanical behavior. We report that superficial collagen plays a more significant role than proteoglycans in facilitating strain-rate-dependent behavior of the kangaroo shoulder cartilage. By comparing the mechanical properties of degraded and normal cartilages, it was noted that proteoglycan and collagen degradation significantly compromised strain-rate-dependent mechanical behavior of the cartilage. Superficial collagen contributed equally to the tissue behavior at all strain-rates. This is different to the studies reported on knee cartilage and confirms the importance of superficial collagen on shoulder cartilage mechanical behavior. A porohyperelastic numerical model also indicated that collagen disruption would lead to faster damage of the shoulder cartilage than when proteoglycans are depleted.

  6. Effect of microstructure on anomalous strain-rate-dependent behaviour of bacterial cellulose hydrogel.

    PubMed

    Gao, Xing; Shi, Zhijun; Lau, Andrew; Liu, Changqin; Yang, Guang; Silberschmidt, Vadim V

    2016-05-01

    This study is focused on anomalous strain-rate-dependent behaviour of bacterial cellulose (BC) hydrogel that can be strain-rate insensitive, hardening, softening, or strain-rate insensitive in various ranges of strain rate. BC hydrogel consists of randomly distributed nanofibres and a large content of free water; thanks to its ideal biocompatibility, it is suitable for biomedical applications. Motivated by its potential applications in complex loading conditions of body environment, its time-dependent behaviour was studied by means of in-aqua uniaxial tension tests at constant temperature of 37 °C at various strain rates ranging from 0.000 1s(-1) to 0.3s(-1). Experimental results reflect anomalous strain-rate-dependent behaviour that was not documented before. Micro-morphological observations allowed identification of deformation mechanisms at low and high strain rates in relation to microstructural changes. Unlike strain-rate softening behaviours in other materials, reorientation of nanofibres and kinematics of free-water flow dominate the softening behaviour of BC hydrogel at high strain rates. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Effects of Mycoplasma anatis and cold stress on hatching success and growth of mallard ducklings

    USGS Publications Warehouse

    Samuel, M.D.; Goldberg, D.R.; Thomas, C.B.; Sharp, P.

    1995-01-01

    We inoculated game-farm mallard (Anas platyrhynchos) eggs and 1-day-old birds with Mycoplasma anatis to determine its effect on hatching success and growth rates of ducklings. Inoculations of eggs reduced hatching success, hatchling size, and duckling growth rates, compared to controls. Intratracheal inoculations of 1-day-old birds did not affect growth rates. Hatchlings and 1-day-old ducklings grew much slower for the first 7 to 10 days when raised at 17 to 19 C, compared to controls raised at 30 to 35 C. The effect of cold stress on growth was greater than the effect of M. anatis infection; we found no synergistic effects between cold stress and M. anatis infection.

  8. Oxygen consumption in the foraging honeybee depends on the reward rate at the food source.

    PubMed

    Moffatt, L; Núñez, J A

    1997-01-01

    Oxygen consumption of the honeybee Apis mellifera ligustica was measured as a function of the flow rate supply of sucrose solution at an automatic feeder located inside a respirometric chamber. Trained bees freely entered the respirometric chamber and collected the sucrose solution supplied. The mean value of the O2 consumption rate per visit increased with the sucrose flow rate, and for a given flow rate, with increasing locomotor activity. However, when no locomotor activity was displayed, O2 consumption also increased with increasing nectar flow rate. Crop load attained at the end of the visit showed a positive relationship with the nectar flow rate; however, for a given flow rate, O2 consumption showed either no correlation or a negative one with the final crop load attained. It is concluded that the energy expenditure of the foraging bee is controlled by a motivational drive whose intensity depends on the reward rate at the food source.

  9. Pairing context determines condition-dependence of song rate in a monogamous passerine bird

    PubMed Central

    David, Morgan; Auclair, Yannick; Dall, Sasha R. X.; Cézilly, Frank

    2013-01-01

    Condition-dependence of male ornaments is thought to provide honest signals on which females can base their sexual choice for genetic quality. Recent studies show that condition-dependence patterns can vary within populations. Although long-term association is thought to promote honest signalling, no study has explored the influence of pairing context on the condition-dependence of male ornaments. In this study, we assessed the influence of natural variation in body condition on song rate in zebra finches (Taeniopygia guttata) in three different situations: during short and long encounters with an unfamiliar female, and within heterosexual mated pairs. We found consistent individual differences in male directed and undirected song rate. Moreover, body condition had a positive effect on song rate in paired males. However, male song rate was not influenced by body condition during short or long encounters with unfamiliar females. Song rate appears to be an unreliable signal of condition to prospective females as even poor-condition birds can cheat and sing at a high rate. By contrast, paired females can reliably use song rate to assess their mate's body condition, and possibly the genetic quality. We propose that species' characteristics, such as mating system, should be systematically taken into account to generate relevant hypotheses about the evolution of condition-dependent male ornaments. PMID:23256191

  10. Place dependent stimulation rates improve pitch perception in cochlear implantees with single-sided deafness.

    PubMed

    Rader, Tobias; Döge, Julia; Adel, Youssef; Weissgerber, Tobias; Baumann, Uwe

    2016-09-01

    In normal hearing, the pitch of an acoustic tone can theoretically be encoded by either the place of stimulation in the cochlea or the corresponding rate of vibration. Thus spectral attributes and temporal fine structure of an acoustic signal are naturally correlated. Cochlear implants (CIs), neural prosthetic devices that restore hearing in the profoundly hearing impaired, currently disregard this mechanism; electrical stimulation is provided at fixed electrode positions with default place independent stimulation rate assignments. This does not account for individual cochlear encoding depending on electrode array placement, variations in insertion depth, and the proximity to nerve fibers. Encoding pitch in such manner delivers limited tonal information. Consequently, music appraisal in CI users is often rated cacophonic while speech perception in quiet is close to normal in top performers. We hypothesize that this limitation in electric stimulation is at least partially due to the mismatch between frequency and place encoding in CIs. In the present study, we determined individual electrode locations by analysis of cochlear radiographic images obtained after surgery and calculated place dependent stimulation rates according to models of the normal tonotopic function. Pitch matching in CI users with single-sided deafness shows that place dependent stimulation rates allow thus far unparalleled restoration of tonotopic pitch perception. Collapsed data of matched pitch frequencies as a function of calculated electrical stimulation rate were well fitted by linear regression (R(2) = 0.878). Sound processing strategies incorporating place dependent stimulation rates are expected to improve pitch perception in CI users.

  11. Microstructural heterogeneity in rate-dependent plasticity of multiphase titanium alloys

    NASA Astrophysics Data System (ADS)

    Zhang, Zhen; Dunne, Fionn P. E.

    2017-06-01

    Polycrystalline rate-dependent plasticity is found to originate from heterogeneous slip system/phase rate response. Micro-mechanism under low stress and low temperature (T < 0.3Tm) has been shown to be different from conventional rate sensitivity expectations. Hence the constitutive framework developed is dependent on the crystallographic orientation, properly capturing micro-scale anisotropic rate behaviour. The intrinsic rate anisotropy of the HCP α prism and basal and BCC β phase slip systems in Ti-6242, recently determined from micro-pillar and crystal plasticity modelling, have been utilised to investigate the structural strain rate sensitivities of colonies, polycrystals, bimodal and basket weave microstructures. The rate sensitivity of colony structures is dominated by the HCP α phase behaviour, at least for alloys containing up to ∼20% volume fraction β phase, and is largely independent of β-lath orientation. The apparent anisotropy of a1, a2 and a3 basal resolved shear stresses in Ti-6242 colonies is shown to originate from the local crystal stress states established as opposed to the α-β interfaces. Texture and α-β morphology are shown to affect rate dependence and to corroborate that the basal rate sensitivity is stronger than that for prism slip in Ti-6242. Morphological effects are shown to affect rate dependence but not strongly, but the number of HCP α phase variants in basketweave structures is found to have a significant effect with higher numbers of variants leading to lower strain rate sensitivities. This is potentially important in designing alloys to resist cold dwell fatigue.

  12. Scale-Dependent Rates of Uranyl Surface Complexation Reaction in Sediments

    SciTech Connect

    Liu, Chongxuan; Shang, Jianying; Kerisit, Sebastien N.; Zachara, John M.; Zhu, Weihuang

    2013-03-15

    Scale-dependency of uranyl[U(VI)] surface complexation rates was investigated in stirred flow-cell and column systems using a U(VI)-contaminated sediment from the US Department of Energy, Hanford site, WA. The experimental results were used to estimate the apparent rate of U(VI) surface complexation at the grain-scale and in porous media. Numerical simulations using molecular, pore-scale, and continuum models were performed to provide insights into and to estimate the rate constants of U(VI) surface complexation at the different scales. The results showed that the grain-scale rate constant of U(VI) surface complexation was over 3 to 10 orders of magnitude smaller, dependent on the temporal scale, than the rate constant calculated using the molecular simulations. The grain-scale rate was faster initially and slower with time, showing the temporal scale-dependency. The largest rate constant at the grain-scale decreased additional 2 orders of magnitude when the rate was scaled to the porous media in the column. The scaling effect from the grain-scale to the porous media became less important for the slower sorption sites. Pore-scale simulations revealed the importance of coupled mass transport and reactions in both intragranular and inter-granular domains, which caused both spatial and temporal dependence of U(VI) surface complexation rates in the sediment. Pore-scale simulations also revealed a new rate-limiting mechanism in the intragranular porous domains that the rate of coupled diffusion and surface complexation reaction was slower than either process alone. The results provided important implications for developing models to scale geochemical/biogeochemical reactions.

  13. A novel report of hatching plasticity in the phylum Echinodermata.

    PubMed

    Armstrong, A Frances; Blackburn, Holly N; Allen, Jonathan D

    2013-02-01

    Hatching plasticity occurs in response to a wide range of stimuli across many animal taxa, including annelids, arthropods, mollusks, and chordates. Despite the prominence of echinoderms in developmental biology and more than 100 years of detailed examination of their development under a variety of conditions, environmentally cued hatching plasticity has never been reported in the phylum Echinodermata. Here we report plasticity in the timing and stage of hatching of embryos of the sand dollar Echinarachnius parma in response to reductions in salinity. Embryos of E. parma increased their time to hatching more than twofold in response to ecologically relevant salinity reductions, while maintaining an otherwise normal developmental schedule. Embryos that experienced the greatest delay in hatching time emerged from the fertilization envelope as four-arm pluteus larvae rather than hatching as blastulae or early gastrulae. Salinity manipulations across multiple male-female pairs indicated high variability in hatching time both within and among clutches, suggesting significant intraspecific variation in developmental responses to salinity.

  14. Can-out hatch assembly and positioning system

    DOEpatents

    Basnar, P.J.; Frank, R.C.; Hoh, J.C.

    1985-07-03

    A can-out hatch assembly is adapted to engage in a sealed manner the upper end of a covered sealed container around an aperture in a sealed chamber and to remove the cover from the container permitting a contaminant to be transferred between the container and the chamber while isolating internal portions of the container and chamber from the surrounding environment. A swing bracket is coupled at a first end thereof to the inner, lower wall of the sealed container adjacent to the aperture therein. To a second end of the swing bracket is mounted a hatch cover which may be positioned in sealed engagement about the chamber's aperture by rotating the hatch cover in a first direction when the swing bracket is in the full down position. Rotation of the hatch cover in a second direction release it from sealed engagement with the chamber's aperture. A lid support rod also coupled to the second end of the swing bracket and inserted through an aperture in the center of the hatch cover may be rotated for theadably engaging the container's cover whereupon the cover may be removed from the container and the hatch cover displaced from the aperture by pivoting displacement of the swing bracket. The contaminant may then be either removed from the container and placed within the sealed chamber, or vice versa, followed by positioning of the cover upon the container and the hatch cover over the aperture in a sealed manner.

  15. Can-out hatch assembly with magnetic retention means

    DOEpatents

    Frank, R.C.; Hoh, J.C.

    1985-07-03

    A can-out hatch assembly may be positioned in sealed engagement about aperture within a chamber and is adapted to engage a cover on a container positioned over the aperture to allow the transfer of a contaminant from the chamber to the container while maintaining the contaminant as well as internal portions of the chamber and container isolated from the surrounding environment. With the container's cover engaged by the can-out hatch assembly, the hatch assembly as well as the cover may be pivotally displaced from the aperture with the cover maintaining the exterior portion of the hatch assembly isolated from the contaminant. After the contaminant is transferred from the chamber to the container, the hatch assembly and cover are again positioned in sealed engagement about the aperture. The hatch assembly then positions the cover upon the open end of the container in a sealed manner allowing the container to be removed while maintaining the chamber sealed relative to the surrounding environment. The can-out hatch assembly is particularly adapted for operation by remote control means within the sealed chamber.

  16. Can-out hatch assembly and positioning system

    DOEpatents

    Basnar, Paul J.; Frank, Robert C.; Hoh, Joseph C.

    1986-01-07

    A can-out hatch assembly is adapted to engage in a sealed manner the upper end of a covered sealed container around an aperture in a sealed chamber and to remove the cover from the container permitting a contaminant to be transferred between the container and the chamber while isolating internal portions of the container and chamber from the surrounding environment. A swing bracket is coupled at a first end thereof to the inner, lower wall of the sealed container adjacent to the aperture therein. To a second end of the swing bracket is mounted a hatch cover which may be positioned in sealed engagement about the chamber's aperture by rotating the hatch cover in a first direction when the swing bracket is in the full down position. Rotation of the hatch cover in a second direction releases it from sealed engagement with the chamber's aperture. A lid support rod also coupled to the second end of the swing bracket and inserted through an aperture in the center of the hatch cover may be rotated for threadably engaging the container's cover whereupon the cover may be removed from the container and the hatch cover displaced from the aperture by pivoting displacement of the swing bracket. The contaminant may then be either removed from the container and placed within the sealed chamber, or vice versa, followed by positioning of the cover upon the container and the hatch cover over the aperture in a sealed manner.

  17. Can-out hatch assembly with magnetic retention means

    DOEpatents

    Frank, Robert C.; Hoh, Joseph C.

    1986-01-01

    A can-out hatch assembly may be positioned in sealed engagement about an aperture within a chamber and is adapted to engage a cover on a container positioned over the aperture to allow the transfer of a contaminant from the chamber to the container while maintaining the contaminant as well as internal portions of the chamber and container isolated from the surrounding environment. With the container's cover engaged by the can-out hatch assembly, the hatch assembly as well as the cover may be pivotally displaced from the aperture with the cover maintaining the exterior portion of the hatch assembly isolated from the contaminant. After the contaminant is transferred from the chamber to the container, the hatch assembly and cover are again positioned in sealed engagement about the aperture. The hatch assembly then positions the cover upon the open end of the container in a sealed manner allowing the container to be removed while maintaining the chamber sealed relative to the surrounding environment. The can-out hatch assembly is particularly adapted for operation by remote control means within the sealed chamber.

  18. Can-out hatch assembly with magnetic retention means

    DOEpatents

    Frank, Robert C.; Hoh, Joseph C.

    1986-01-07

    A can-out hatch assembly may be positioned in sealed engagement about an aperture within a chamber and is adapted to engage a cover on a container positioned over the aperture to allow the transfer of a contaminant from the chamber to the container while maintaining the contaminant as well as internal portions of the chamber and container isolated from the surrounding environment. With the container's cover engaged by the can-out hatch assembly, the hatch assembly as well as the cover may be pivotally displaced from the aperture with the cover maintaining the exterior portion of the hatch assembly isolated from the contaminant. After the contaminant is transferred from the chamber to the container, the hatch assembly and cover are again positioned in sealed engagement about the aperture. The hatch assembly then positions the cover upon the open end of the container in a sealed manner allowing the container to be removed while maintaining the chamber sealed relative to the surrounding environment. The can-out hatch assembly is particularly adapted for operation by remote control means within the sealed chamber.

  19. Can-out hatch assembly and positioning system

    DOEpatents

    Basnar, Paul J.; Frank, Robert C.; Hoh, Joseph C.

    1986-01-01

    A can-out hatch assembly is adapted to engage in a sealed manner the upper end of a covered sealed container around an aperture in a sealed chamber and to remove the cover from the container permitting a contaminant to be transferred between the container and the chamber while isolating internal portions of the container and chamber from the surrounding environment. A swing bracket is coupled at a first end thereof to the inner, lower wall of the sealed container adjacent to the aperture therein. To a second end of the swing bracket is mounted a hatch cover which may be positioned in sealed engagement about the chamber's aperture by rotating the hatch cover in a first direction when the swing bracket is in the full down position. Rotation of the hatch cover in a second direction releases it from sealed engagement with the chamber's aperture. A lid support rod also coupled to the second end of the swing bracket and inserted through an aperture in the center of the hatch cover may be rotated for threadably engaging the container's cover whereupon the cover may be removed from the container and the hatch cover displaced from the aperture by pivoting displacement of the swing bracket. The contaminant may then be either removed from the container and placed within the sealed chamber, or vice versa, followed by positioning of the cover upon the container and the hatch cover over the aperture in a sealed manner.

  20. Age-related degeneration of the egg-laying system promotes matricidal hatching in Caenorhabditis elegans.

    PubMed

    Pickett, Christopher L; Kornfeld, Kerry

    2013-08-01

    The identification and characterization of age-related degenerative changes is a critical goal because it can elucidate mechanisms of aging biology and contribute to understanding interventions that promote longevity. Here, we document a novel, age-related degenerative change in C. elegans hermaphrodites, an important model system for the genetic analysis of longevity. Matricidal hatching--intra-uterine hatching of progeny that causes maternal death--displayed an age-related increase in frequency and affected ~70% of mated, wild-type hermaphrodites. The timing and incidence of matricidal hatching were largely independent of the levels of early and total progeny production and the duration of male exposure. Thus, matricidal hatching appears to reflect intrinsic age-related degeneration of the egg-laying system rather than use-dependent damage accumulation. Consistent with this model, mutations that extend longevity by causing dietary restriction significantly delayed matricidal hatching, indicating age-related degeneration of the egg-laying system is controlled by nutrient availability. To identify the underlying tissue defect, we analyzed serotonin signaling that triggers vulval muscle contractions. Mated hermaphrodites displayed an age-related decline in the ability to lay eggs in response to exogenous serotonin, indicating that vulval muscles and/or a further downstream function that is necessary for egg laying degenerate in an age-related manner. By characterizing a new, age-related degenerative event displayed by C. elegans hermaphrodites, these studies contribute to understanding a frequent cause of death in mated hermaphrodites and establish a model of age-related reproductive complications that may be relevant to the birthing process in other animals such as humans.

  1. Characterization of shock-dependent reaction rates in an aluminum/perfluoropolyether pyrolant

    NASA Astrophysics Data System (ADS)

    Wilson, Dennis; Granier, John; Johnson, Richard; Littrell, Donald

    2017-01-01

    Energetic formulations of perfluoropolyether (PFPE) and aluminum are highly non-ideal. They release energy via a fast self-oxidized combustion wave rather than a true self-sustaining detonation. Unlike high explosives, the reactions are shock dependent and can be overdriven to control energy release rate. Reaction rate experiments show that the velocity can vary from 1.25 to 3 km/s. This paper examines the effect of the initial shock conditions upon the reaction rate of the explosive. The following conditions were varied in a series of reaction rate experiments: the high explosive booster mass and geometry; shock attenuation; confinement; and rate stick diameter and length. Several experiments designed to isolate and quantify these dependencies are described and summarized.

  2. Crossover from negative to positive shear rate dependence in granular friction

    NASA Astrophysics Data System (ADS)

    Kuwano, Osamu; Ando, Ryosuke; Hatano, Takahiro

    2013-04-01

    Abstract The frictional properties of granular matter are important for analyzing various phenomena in geosciences. Here, we conduct an experiment on the shear-<span class="hlt">rate</span> <span class="hlt">dependence</span> of the friction coefficient, which determines the stability of granular flow. By changing the shear <span class="hlt">rate</span> over four orders of magnitude, we find the characteristic <span class="hlt">rate</span> at which the least friction is realized associated with the crossover from negative to positive shear <span class="hlt">rate</span> <span class="hlt">dependence</span>. The least friction is explained in terms of the competition between two very different physical processes, namely frictional healing and anelasticity. We determine the expression of the characteristic shear <span class="hlt">rate</span>, which is proportional to the square root of the normal stress.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4801581','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4801581"><span>Modeling of <span class="hlt">Rate-Dependent</span> Hysteresis Using a GPO-Based Adaptive Filter</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhang, Zhen; Ma, Yaopeng</p> <p>2016-01-01</p> <p>A novel generalized play operator-based (GPO-based) nonlinear adaptive filter is proposed to model <span class="hlt">rate-dependent</span> hysteresis nonlinearity for smart actuators. In the proposed filter, the input signal vector consists of the output of a tapped delay line. GPOs with various thresholds are used to construct a nonlinear network and connected with the input signals. The output signal of the filter is composed of a linear combination of signals from the output of GPOs. The least-mean-square (LMS) algorithm is used to adjust the weights of the nonlinear filter. The modeling results of four adaptive filter methods are compared: GPO-based adaptive filter, Volterra filter, backlash filter and linear adaptive filter. Moreover, a phenomenological operator-based model, the <span class="hlt">rate-dependent</span> generalized Prandtl-Ishlinskii (RDGPI) model, is compared to the proposed adaptive filter. The various <span class="hlt">rate-dependent</span> modeling methods are applied to model the <span class="hlt">rate-dependent</span> hysteresis of a giant magnetostrictive actuator (GMA). It is shown from the modeling results that the GPO-based adaptive filter can describe the <span class="hlt">rate-dependent</span> hysteresis nonlinear of the GMA more accurately and effectively. PMID:26861349</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26861349','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26861349"><span>Modeling of <span class="hlt">Rate-Dependent</span> Hysteresis Using a GPO-Based Adaptive Filter.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Zhen; Ma, Yaopeng</p> <p>2016-02-06</p> <p>A novel generalized play operator-based (GPO-based) nonlinear adaptive filter is proposed to model <span class="hlt">rate-dependent</span> hysteresis nonlinearity for smart actuators. In the proposed filter, the input signal vector consists of the output of a tapped delay line. GPOs with various thresholds are used to construct a nonlinear network and connected with the input signals. The output signal of the filter is composed of a linear combination of signals from the output of GPOs. The least-mean-square (LMS) algorithm is used to adjust the weights of the nonlinear filter. The modeling results of four adaptive filter methods are compared: GPO-based adaptive filter, Volterra filter, backlash filter and linear adaptive filter. Moreover, a phenomenological operator-based model, the <span class="hlt">rate-dependent</span> generalized Prandtl-Ishlinskii (RDGPI) model, is compared to the proposed adaptive filter. The various <span class="hlt">rate-dependent</span> modeling methods are applied to model the <span class="hlt">rate-dependent</span> hysteresis of a giant magnetostrictive actuator (GMA). It is shown from the modeling results that the GPO-based adaptive filter can describe the <span class="hlt">rate-dependent</span> hysteresis nonlinear of the GMA more accurately and effectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25730160','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25730160"><span>Multi-item direct behavior <span class="hlt">ratings</span>: <span class="hlt">Dependability</span> of two levels of assessment specificity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Volpe, Robert J; Briesch, Amy M</p> <p>2015-09-01</p> <p>Direct Behavior <span class="hlt">Rating</span>-Multi-Item Scales (DBR-MIS) have been developed as formative measures of behavioral assessment for use in school-based problem-solving models. Initial research has examined the <span class="hlt">dependability</span> of composite scores generated by summing all items comprising the scales. However, it has been argued that DBR-MIS may offer assessment of 2 levels of behavioral specificity (i.e., item-level, global composite-level). Further, it has been argued that scales can be individualized for each student to improve efficiency without sacrificing technical characteristics. The current study examines the <span class="hlt">dependability</span> of 5 items comprising a DBR-MIS designed to measure classroom disruptive behavior. A series of generalizability theory and decision studies were conducted to examine the <span class="hlt">dependability</span> of each item (calls out, noisy, clowns around, talks to classmates and out of seat), as well as a 3-item composite that was individualized for each student. Seven graduate students <span class="hlt">rated</span> the behavior of 9 middle-school students on each item over 3 occasions. <span class="hlt">Ratings</span> were based on 10-min video clips of students during mathematics instruction. Separate generalizability and decision studies were conducted for each item and for a 3-item composite that was individualized for each student based on the highest <span class="hlt">rated</span> items on the first <span class="hlt">rating</span> occasion. Findings indicate favorable <span class="hlt">dependability</span> estimates for 3 of the 5 items and exceptional <span class="hlt">dependability</span> estimates for the individualized composite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://wildfowl.wwt.org.uk/index.php/wildfowl/article/view/954','USGSPUBS'); return false;" href="https://wildfowl.wwt.org.uk/index.php/wildfowl/article/view/954"><span>The adaptive significance of <span class="hlt">hatching</span> synchrony of waterfowl eggs</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Flint, Paul L.; Lindberg, Mark S.; MacCluskie, Margaret C.; Sedinger, James S.</p> <p>1994-01-01</p> <p>We estimated the amount of incubation time that first laid Black Brent eggs received before completion of the clutch. First laid eggs received up to 48 hours of incubation before the last egg was laid in Brent clutches. Waterfowl clutches usually <span class="hlt">hatch</span> within a period of 24 hours, suggesting that some mechanism reduces developmental asynchrony during incubation. The combination of incubation during laying and <span class="hlt">hatch</span> synchronization mechanisms should be adaptive because these traits reduce nest exposure, maintain egg viability, and result in an earlier <span class="hlt">hatch</span> date, all of which increase fitness in waterfowl.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810055584&hterms=hummel&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhummel','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810055584&hterms=hummel&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhummel"><span>Comparison of radiative-convective models with constant and pressure-<span class="hlt">dependent</span> lapse <span class="hlt">rates</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hummel, J. R.; Kuhn, W. R.</p> <p>1981-01-01</p> <p>One of the most commonly used models for studying climatic processes is the convective adjustment radiation model. In current radiation models, stable temperature profiles are maintained with a convective adjustment in which the temperature lapse <span class="hlt">rate</span> is set equal to a critical lapse <span class="hlt">rate</span> whenever the computed lapse <span class="hlt">rates</span> exceed the critical value. First introduced by Manabe and Strickler (1964), a variety of convective adjustment models are now in use. It is pointed out that on a global scale, moist adiabatic processes, and thus moist adiabatic lapse <span class="hlt">rates</span>, approximate the atmospheric temperature profile. Comparisons of profiles from a one-dimensional-radiative-convective model have been made using the conventional 6.5 K/km as the critical lapse <span class="hlt">rate</span> and the pressure-<span class="hlt">dependent</span> moist adiabatic lapse <span class="hlt">rates</span>. For a clear sky and a single effective cloud the surface temperatures are 1 to 3 K higher with the constant 6.5 K/km critical lapse <span class="hlt">rate</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/14572658','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/14572658"><span>Growth <span class="hlt">rate</span> regulation of lac operon expression in Escherichia coli is cyclic AMP <span class="hlt">dependent</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kuo, Jong-Tar; Chang, Yu-Jen; Tseng, Ching-Ping</p> <p>2003-10-23</p> <p>In contrast to the ribosomal RNA gene expression increasing with growth <span class="hlt">rate</span>, transcription of the lac operon is downregulated by cell growth <span class="hlt">rate</span>. In continuous culture, growth <span class="hlt">rate</span> regulation of lac promoter was independent of carbon substrate used and its location on the chromosome. Since the lac operon is activated by cyclic adenosine monophosphate (cAMP), which decreases with increasing cell growth <span class="hlt">rate</span>, expression of plac-lacZ reporter fusion was analyzed in cya mutant under various growth conditions. The results demonstrated that expression of plac-lacZ in cya mutant was both lower and growth <span class="hlt">rate</span> independent. In addition, ppGpp (guanosine tetraphosphate) was not involved in the mechanism of growth <span class="hlt">rate</span> regulation of the lac promoter. Thus, the results of this study indicate that cAMP mediates the growth <span class="hlt">rate-dependent</span> regulation of lac operon expression in Escherichia coli.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16122724','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16122724"><span>Cryopreservation of European catfish Silurus glanis sperm: sperm motility, viability, and <span class="hlt">hatching</span> success of embryos.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Linhart, Otomar; Rodina, Marek; Flajshans, Martin; Gela, David; Kocour, Martin</p> <p>2005-12-01</p> <p>The aim of this study was to elaborate cryopreservation methods for ex situ conservation of European catfish. The success of sperm cryopreservation was evaluated by post-thaw sperm motility and velocity, percentage of live spermatozoa and fertility (<span class="hlt">hatching</span> <span class="hlt">rates</span>) using frozen/thawed sperm. The best <span class="hlt">hatching</span> <span class="hlt">rates</span> of 82-86% were obtained with sperm stored for 5 h before freezing in immobilizing solution and frozen with Me2SO in concentrations of 8, 10, and 12%, or with a mixture of 5% Me2SO and 5% propandiole. These results did not significantly differ from the fresh sperm control sample. The percentage of live spermatozoa in frozen/thawed sperm did not correlate with <span class="hlt">hatching</span> <span class="hlt">rate</span> or motility of spermatozoa, but was negatively correlated with velocity of spermatozoa (r=-0.47, P=0.05). The percentage motility in frozen/thawed sperm ranged from 8 to 62%, when sperm was stored in immobilizing solution 5h before freezing. The average value in the fresh sperm (control) was 96%. The frozen/thawed sperm motility <span class="hlt">rate</span> significantly correlated with the <span class="hlt">hatching</span> <span class="hlt">rate</span> (r=0.76, P=0.0002), but not with the percentage of live spermatozoa (r=0.16, P=0.52) or the sperm velocity (r=0.07, P=0.79). The velocity of frozen/thawed spermatozoa ranged from 37 to 85 microm/s, whereby methanol concentrations of 7.5 and 10% resulted in highest velocities. Freezing sperm volumes of 1-4 ml did not affect the quality of frozen/thawed sperm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24730833','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24730833"><span>Strain-<span class="hlt">rate-dependent</span> model for the dynamic compression of elastoplastic spheres.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Burgoyne, Hayden A; Daraio, Chiara</p> <p>2014-03-01</p> <p>We present a force-displacement contact model for the compressive loading of elastoplastic spheres. This model builds from the well known Hertz contact law for elastic, quasistatic compression to incorporate a material's strain-<span class="hlt">rate-dependent</span> plasticity in order to describe collisions between particles. In the quasistatic regime, finite-element analysis is used to derive an empirical function of the material properties. A Johnson-Cook strain <span class="hlt">rate</span> <span class="hlt">dependence</span> is then included into the model to study dynamic effects. We validate the model using split Hopkinson bar experiments and show that the model can accurately simulate the force-displacement response of strain-<span class="hlt">rate-dependent</span> elastoplastic spheres during dynamic compression and unloading.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhRvE..89c2203B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhRvE..89c2203B"><span>Strain-<span class="hlt">rate-dependent</span> model for the dynamic compression of elastoplastic spheres</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burgoyne, Hayden A.; Daraio, Chiara</p> <p>2014-03-01</p> <p>We present a force-displacement contact model for the compressive loading of elastoplastic spheres. This model builds from the well known Hertz contact law for elastic, quasistatic compression to incorporate a material's strain-<span class="hlt">rate-dependent</span> plasticity in order to describe collisions between particles. In the quasistatic regime, finite-element analysis is used to derive an empirical function of the material properties. A Johnson-Cook strain <span class="hlt">rate</span> <span class="hlt">dependence</span> is then included into the model to study dynamic effects. We validate the model using split Hopkinson bar experiments and show that the model can accurately simulate the force-displacement response of strain-<span class="hlt">rate-dependent</span> elastoplastic spheres during dynamic compression and unloading.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010047399','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010047399"><span>Implementation of Fiber Substructuring Into Strain <span class="hlt">Rate</span> <span class="hlt">Dependent</span> Micromechanics Analysis of Polymer Matrix Composites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldberg, Robert K.</p> <p>2001-01-01</p> <p>A research program is in progress to develop strain <span class="hlt">rate</span> <span class="hlt">dependent</span> deformation and failure models for the analysis of polymer matrix composites subject to impact loads. Previously, strain <span class="hlt">rate</span> <span class="hlt">dependent</span> inelastic constitutive equations developed to model the polymer matrix were incorporated into a mechanics of materials based micromechanics method. In the current work, the micromechanics method is revised such that the composite unit cell is divided into a number of slices. Micromechanics equations are then developed for each slice, with laminate theory applied to determine the elastic properties, effective stresses and effective inelastic strains for the unit cell. Verification studies are conducted using two representative polymer matrix composites with a nonlinear, strain <span class="hlt">rate</span> <span class="hlt">dependent</span> deformation response. The computed results compare well to experimentally obtained values.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6336181','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6336181"><span>CHARADE: A characteristic code for calculating <span class="hlt">rate-dependent</span> shock-wave response</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Johnson, J.N.; Tonks, D.L.</p> <p>1991-01-01</p> <p>In this report we apply spatially one-dimensional methods and simple shock-tracking techniques to the solution of <span class="hlt">rate-dependent</span> material response under flat-plate-impact conditions. This method of solution eliminates potential confusion of material dissipation with artificial dissipative effects inherent in finite-difference codes, and thus lends itself to accurate calculation of elastic-plastic deformation, shock-to-detonation transition in solid explosives, and shock-induced structural phase transformation. Equations are presented for <span class="hlt">rate-dependent</span> thermoelastic-plastic deformation for (100) planar shock-wave propagation in materials of cubic symmetry (or higher). Specific numerical calculations are presented for polycrystalline copper using the mechanical threshold stress model of Follansbee and Kocks with transition to dislocation drag. A listing of the CHARADE (for characteristic <span class="hlt">rate</span> <span class="hlt">dependence</span>) code and sample input deck are given. 26 refs., 11 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006APS..MARV30008S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006APS..MARV30008S"><span><span class="hlt">Rate-dependent</span> Mechanical Deformation Behavior of POSS-filled and Plasticized Poly(vinyl chloride).</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Soong, Sharon; Cohen, Robert; Boyce, Mary</p> <p>2006-03-01</p> <p>In different temperatures or strain-<span class="hlt">rate</span> regimes, the <span class="hlt">rate</span> sensitivities of polymers change as various primary and secondary molecular mobility mechanisms are accessed. Incorporating nanoparticles into the polymer matrix can potentially alter the molecular level structure and offers an opportunity to tailor the <span class="hlt">rate-dependent</span> mechanical deformation behavior of the polymer. In this study, methacryl-POSS (C56H88O28Si8) and dioctyl phthalate (DOP) were incorporated into poly(vinyl chloride) (PVC) through melt blending. Dynamic Mechanical Analysis revealed that the incorporation of POSS in PVC plasticizes PVC and reduces both the alpha and beta transition temperatures. As for the PVC/DOP blends, while the alpha-transition temperatures were reduced, beta-motions vanishes with high DOP contents. The <span class="hlt">rate</span> <span class="hlt">dependent</span> yield behavior is characterized in compression testing. Zwick Mechine is used for low to moderate strain <span class="hlt">rate</span> (0.0001 to 0.1/s) and Split Hopkinson Bar is used for high strain <span class="hlt">rate</span> (500 to 2000/s). It was found that PVC with POSS shows a delay in yield strength <span class="hlt">rate</span>-sensitivity transition. For PVC with higher DOP contents which show restricted beta-motions, the <span class="hlt">rate</span>-sensitivity transition in yield stress faded away. Constitutive model used was able to predict the <span class="hlt">rate</span>-sensitivity transitions in the compression yield behavior of PVC compounds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA409547','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA409547"><span>The Mitral Valve Prolapsus : Quantification of the Regurgitation Flow <span class="hlt">Rate</span> by Experimental Time-<span class="hlt">Dependant</span> PIV</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2007-11-02</p> <p>The Mitral Valve Prolapsus : Quantification of the Regurgitation Flow <span class="hlt">Rate</span> by Experimental Time-<span class="hlt">Dependant</span> PIV. F. Billy1, D. Coisne1,2, L. Sanchez1... mitral valve insufficiency), assumes that the velocity field in the convergent region have hemispheric shapes and introduce miscalculation specially...upstream a prolaps model of regurgitant orifice based on 2D time <span class="hlt">dependent</span> PIV reconstruction. Keywords- Mitral Valve , Prolapsus, Regurgitation Flow</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016RSPSA.47250877S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016RSPSA.47250877S"><span>Discrete dislocation plasticity analysis of loading <span class="hlt">rate-dependent</span> static friction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Song, H.; Deshpande, V. S.; Van der Giessen, E.</p> <p>2016-08-01</p> <p>From a microscopic point of view, the frictional force associated with the relative sliding of rough surfaces originates from deformation of the material in contact, by adhesion in the contact interface or both. We know that plastic deformation at the size scale of micrometres is not only <span class="hlt">dependent</span> on the size of the contact, but also on the <span class="hlt">rate</span> of deformation. Moreover, <span class="hlt">depending</span> on its physical origin, adhesion can also be size and <span class="hlt">rate</span> <span class="hlt">dependent</span>, albeit different from plasticity. We present a two-dimensional model that incorporates both discrete dislocation plasticity inside a face-centred cubic crystal and adhesion in the interface to understand the <span class="hlt">rate</span> <span class="hlt">dependence</span> of friction caused by micrometre-size asperities. The friction strength is the outcome of the competition between adhesion and discrete dislocation plasticity. As a function of contact size, the friction strength contains two plateaus: at small contact length (≲0.6 μ m), the onset of sliding is fully controlled by adhesion while for large contact length (≳10 μ m), the friction strength approaches the size-independent plastic shear yield strength. The transition regime at intermediate contact size is a result of partial de-cohesion and size-<span class="hlt">dependent</span> dislocation plasticity, and is determined by dislocation properties, interfacial properties as well as by the loading <span class="hlt">rate</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040112003&hterms=development+theory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Ddevelopment%2Btheory','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040112003&hterms=development+theory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Ddevelopment%2Btheory"><span>Implementation of Higher Order Laminate Theory Into Strain <span class="hlt">Rate</span> <span class="hlt">Dependent</span> Micromechanics Analysis of Polymer Matrix Composites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kim, Heung Soo; Zhu, Linfa; Chattopadhyay, Aditi; Goldberg, Robert K.</p> <p>2004-01-01</p> <p>A procedure has been developed to investigate the nonlinear response of composite plates under large strain and high strain <span class="hlt">rate</span> loading. A recently developed strain <span class="hlt">dependent</span> micromechanics model is extended to account for the shear effects during impact. Four different assumptions of shear deformation effects are investigated to improve the development strain <span class="hlt">rate</span> <span class="hlt">dependent</span> micromechanics model. A method to determine through the thickness strain and transverse Poisson's ratio is developed. The revised micromechanics model is implemented into higher order laminate theory. Parametric studies are conducted to investigate transverse shear effects during impact.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NIMPA.838...74B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NIMPA.838...74B"><span><span class="hlt">Rate</span> <span class="hlt">dependence</span>, polarization, and light sensitivity of neutron-irradiated scCVD diamond sensors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bentele, B.; Cumalat, J. P.; Schaeffer, D.; Wagner, S. R.; Riley, G.; Spanier, S.</p> <p>2016-12-01</p> <p>We study the <span class="hlt">dependence</span> of the charge-collection-efficiency, or CCE, on the <span class="hlt">rate</span> of charged particles impinging on neutron-irradiated single-crystal Chemical-Vapor-Deposition (scCVD) diamond sensors. These effects are not observed in un-irradiated high quality scCVD sensors. The <span class="hlt">rate</span> <span class="hlt">dependence</span> appears to be associated with the build-up of an electric field opposing the applied charge-collection field in the sensor. We find that exposure of the detector to red or near-IR light reverses this effect on the CCE during operation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28272384','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28272384"><span>[<span class="hlt">Dependency</span> <span class="hlt">Rate</span> among Spain's Non-Institutionalized Population and Criteria for Evaluating Severity].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alegre Escolano, Antonio; Ayuso Gutiérrez, Mercedes; Guillén Estany, Montserrat; Monteverde Verdenelli, Malena; Pociello García, Enrique Pociello García</p> <p>2005-06-01</p> <p>The criteria for evaluating the degree of severity of <span class="hlt">dependence</span> has an impact on estimating the costs of the longterm care services, especially among the population over 65 years of age. The sensitivity of the <span class="hlt">dependency</span> <span class="hlt">rate</span> must be analyzed in view of different definitions of seriousness, whether by the maximum severity observed in the disability in activities of daily living or by the number and severity of all these disabilities. The data from the Disability, Deficiency and HealthCondition Survey conducted by the Spanish National Institute ofStatistics in 1999 are used. A comparison is drawn between two criteriafor evaluating the severity of an individual's disabilities.Models are made with the logarithms of the prevalence <span class="hlt">rates</span> by age,for each sex, a comparison of the existence of significant differencesbetween these criteria being drawn based on 95% confidence intervals. The criterion based on the maximum severity (employed by the Spanish National Institute of Statistics) underestimates the degree of total <span class="hlt">dependency</span> measured by the alternative criterion by 10%-25%, overestimating the degrees of moderate <span class="hlt">dependency</span> as of age 65 by up to 25%. Among the male population, this same criterion gives rise the medium <span class="hlt">dependency</span> as of age 95 being underestimated by 10%. The maximum severity criterion employed by the Spanish National Institute of Statistics underestimates the most serious <span class="hlt">dependency</span> <span class="hlt">rate</span>, especially as of 80 years of age.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27689037','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27689037"><span>The effect of the site of laser zona opening on the complete <span class="hlt">hatching</span> of mouse blastocysts and their cell numbers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sanmee, Usanee; Piromlertamorn, Waraporn; Vutyavanich, Teraporn</p> <p>2016-09-01</p> <p>We studied the effect of the site of laser zona opening on the complete <span class="hlt">hatching</span> of mouse blastocysts and the cell numbers of the completely <span class="hlt">hatched</span> blastocysts. Mouse blastocysts were randomly allocated to the inner cell mass (ICM) group (zona opening performed at the site of the ICM, n=125), the trophectoderm (TE) group (zona opening performed opposite to the ICM, n=125) and the control group (no zona opening, n=125). The <span class="hlt">rate</span> of complete <span class="hlt">hatching</span> of the blastocysts was not significantly different in the ICM and the TE group (84.8% vs 80.8%, respectively; p=0.402), but was significantly lower in the control group (51.2%, p<0.001). The cell numbers in the completely <span class="hlt">hatched</span> blastocysts were comparable in the control group, the ICM group, and the TE group (69±19.3, 74±15.7, and 71±16.8, respectively; p=0.680). These findings indicate that the site of laser zona opening did not influence the <span class="hlt">rate</span> of complete <span class="hlt">hatching</span> of mouse blastocysts or their cell numbers.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5039307','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5039307"><span>The effect of the site of laser zona opening on the complete <span class="hlt">hatching</span> of mouse blastocysts and their cell numbers</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sanmee, Usanee; Piromlertamorn, Waraporn</p> <p>2016-01-01</p> <p>Objective We studied the effect of the site of laser zona opening on the complete <span class="hlt">hatching</span> of mouse blastocysts and the cell numbers of the completely <span class="hlt">hatched</span> blastocysts. Methods Mouse blastocysts were randomly allocated to the inner cell mass (ICM) group (zona opening performed at the site of the ICM, n=125), the trophectoderm (TE) group (zona opening performed opposite to the ICM, n=125) and the control group (no zona opening, n=125). Results The <span class="hlt">rate</span> of complete <span class="hlt">hatching</span> of the blastocysts was not significantly different in the ICM and the TE group (84.8% vs 80.8%, respectively; p=0.402), but was significantly lower in the control group (51.2%, p<0.001). The cell numbers in the completely <span class="hlt">hatched</span> blastocysts were comparable in the control group, the ICM group, and the TE group (69±19.3, 74±15.7, and 71±16.8, respectively; p=0.680). Conclusion These findings indicate that the site of laser zona opening did not influence the <span class="hlt">rate</span> of complete <span class="hlt">hatching</span> of mouse blastocysts or their cell numbers. PMID:27689037</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26477539','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26477539"><span>Inverse density <span class="hlt">dependence</span> of parity <span class="hlt">rates</span> in the onchocerciasis vector Simulium damnosum s.l.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cheke, R A; Young, S; Garms, R</p> <p>2016-03-01</p> <p>A correlation between parity <span class="hlt">rates</span> and an index of adult numbers of Simulium damnosum s.l. (Diptera: Simuliidae) indicates an association, but does not prove causality or show the direction of any causal relationship. The question of whether adult numbers affect parity <span class="hlt">rates</span> or vice versa is reminiscent of the age-old query of which of the chicken and the egg came first. A method for resolving such issues based on analyses of pairs of time series was proposed by Granger in 1969. When Granger's method was applied to monthly numbers of adult female S. damnosum s.l. caught attempting to bite humans at Asubende, Ghana, and their parity <span class="hlt">rates</span>, a significant relationship (P = 0.005) emerged, clearly showing that parity <span class="hlt">rates</span> were <span class="hlt">dependent</span> on adult numbers. Implications of this inverse density <span class="hlt">dependence</span> and the results of analyses of other similar time series are presented and discussed. © 2015 The Royal Entomological Society.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JAP...122k5102D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JAP...122k5102D"><span>A <span class="hlt">rate-dependent</span> hybrid phase field model for dynamic crack propagation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Doan, Duc Hong; Bui, Tinh Quoc; Van Do, Thom; Duc, Nguyen Dinh</p> <p>2017-09-01</p> <p>Several models of variational phase field for fracture have been introduced and analyzed to different degrees of applications, and the <span class="hlt">rate</span>-independent phase field approach has been shown to be a versatile one, but it is not able to accurately capture crack velocity and dissipated energy in dynamic crack propagation. In this paper, we introduce a novel <span class="hlt">rate-dependent</span> regularized phase field approach to study dynamic fracture behaviors of polymethylmethacrylate materials, in which the <span class="hlt">rate</span> coefficient is estimated through energy balance, i.e., dynamics release energy, cohesive energy and dissipated energy. The mode-I dynamics crack problem is considered, and its accuracy is validated with respect to experimental data [F. Zhou, Ph.D. dissertation (The University of Tokyo, Japan, 1996)] and other numerical methods, taking the same configuration, material property, crack location, and other relevant assumptions. The results shed light on the requirement and need for taking the <span class="hlt">rate-dependent</span> coefficient in dynamic fracture analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JMPSo..63..113N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JMPSo..63..113N"><span>A numerical basis for strain-gradient plasticity theory: <span class="hlt">Rate</span>-independent and <span class="hlt">rate-dependent</span> formulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nielsen, K. L.; Niordson, C. F.</p> <p>2014-02-01</p> <p>A numerical model formulation of the higher order flow theory (<span class="hlt">rate</span>-independent) by Fleck and Willis [2009. A mathematical basis for strain-gradient plasticity theory - part II: tensorial plastic multiplier. Journal of the Mechanics and Physics of Solids 57, 1045-1057.], that allows for elastic-plastic loading/unloading and the interaction of multiple plastic zones, is proposed. The predicted model response is compared to the corresponding <span class="hlt">rate-dependent</span> version of visco-plastic origin, and coinciding results are obtained in the limit of small strain-<span class="hlt">rate</span> sensitivity. First, (i) the evolution of a single plastic zone is analyzed to illustrate the agreement with earlier published results, whereafter examples of (ii) multiple plastic zone interaction, and (iii) elastic-plastic loading/unloading are presented. Here, the simple shear problem of an infinite slab constrained between rigid plates is considered, and the effect of strain gradients, strain hardening and <span class="hlt">rate</span> sensitivity is brought out. For clarity of results, a 1D model is constructed following a procedure suitable for generalization to 2D and 3D.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5320612','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5320612"><span>Behavioral Status Influences the <span class="hlt">Dependence</span> of Odorant-Induced Change in Firing on Prestimulus Firing <span class="hlt">Rate</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Doucette, Wilder T.</p> <p>2017-01-01</p> <p>The firing <span class="hlt">rate</span> of the mitral/tufted cells in the olfactory bulb is known to undergo significant trial-to-trial variability and is affected by anesthesia. Here we ask whether odorant-elicited changes in firing <span class="hlt">rate</span> <span class="hlt">depend</span> on the <span class="hlt">rate</span> before application of the stimulus in the awake and anesthetized mouse. We find that prestimulus firing <span class="hlt">rate</span> varies widely on a trial-to-trial basis and that the stimulus-induced change in firing <span class="hlt">rate</span> decreases with increasing prestimulus firing <span class="hlt">rate</span>. Interestingly, this prestimulus firing <span class="hlt">rate</span> <span class="hlt">dependence</span> was different when the behavioral task did not involve detecting the valence of the stimulus. Finally, when the animal was learning to associate the odor with reward, the prestimulus firing <span class="hlt">rate</span> was smaller for false alarms compared with correct rejections, suggesting that intrinsic activity reflects the anticipatory status of the animal. Thus, in this sensory modality, changes in behavioral status alter the intrinsic prestimulus activity, leading to a change in the responsiveness of the second-order neurons. We speculate that this trial-to-trial variability in odorant responses reflects sampling of the massive parallel input by subsets of mitral cells. SIGNIFICANCE STATEMENT The olfactory bulb must deal with processing massive parallel input from ∼1200 distinct olfactory receptors. In contrast, the visual system receives input from a small number of photoreceptors and achieves recognition of complex stimuli by allocating processing for distinct spatial locations to different brain areas. Here we find that the change in firing <span class="hlt">rate</span> elicited by the odorant in second-order mitral cells <span class="hlt">depends</span> on the intrinsic activity leading to a change of magnitude in the responsiveness of these neurons relative to this prestimulus activity. Further, we find that prestimulus firing <span class="hlt">rate</span> is influenced by behavioral status. This suggests that there is top-down modulation allowing downstream brain processing areas to perform dynamic readout of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21517842','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21517842"><span><span class="hlt">Rate</span> of egg maturation in marine turtles exhibits 'universal temperature <span class="hlt">dependence</span>'.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Weber, Sam B; Blount, Jonathan D; Godley, Brendan J; Witt, Matthew J; Broderick, Annette C</p> <p>2011-09-01</p> <p>1. The metabolic theory of ecology (MTE) predicts that, after correcting for body mass variation among organisms, the <span class="hlt">rates</span> of most biological processes will vary as a universal function of temperature. However, empirical support for 'universal temperature <span class="hlt">dependence</span>' (UTD) is currently equivocal and based on studies of a limited number of traits. 2. In many ectothermic animals, the <span class="hlt">rate</span> at which females produce mature eggs is temperature <span class="hlt">dependent</span> and may be an important factor in determining the costs of reproduction. 3. We tested whether the <span class="hlt">rate</span> of egg maturation in marine turtles varies with environmental temperature as predicted by MTE, using the time separating successive clutches of individual females to estimate the <span class="hlt">rate</span> at which eggs are formed. We also assessed the phenotypic contribution to this <span class="hlt">rate</span>, by using radio telemetry to make repeated measurements of interclutch intervals for individual green turtles (Chelonia mydas). 4. <span class="hlt">Rates</span> of egg maturation increased with seasonally increasing water temperatures in radio-tracked green turtles, but were not repeatable for individual females, and did not vary according to maternal body size or reproductive investment (number and size of eggs produced). 5. Using a collated data set from several different populations and species of marine turtles, we then show that a single relationship with water temperature explains most of the variation in egg maturation <span class="hlt">rates</span>, with a slope that is statistically indistinguishable from the UTD predicted by MTE. However, several alternative statistical models also described the relationship between temperature and egg maturation <span class="hlt">rates</span> equally parsimoniously. 6. Our results offer novel support for the MTE's predicted UTD of biological <span class="hlt">rates</span>, although the underlying mechanisms require further study. The strong temperature <span class="hlt">dependence</span> of egg maturation combined with the apparently weak phenotypic contribution to this <span class="hlt">rate</span> has interesting behavioural implications in ectothermic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=S66-54454&hterms=Gordon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DGordon','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=S66-54454&hterms=Gordon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DGordon"><span>Astronaut Richard Gordon returns to <span class="hlt">hatch</span> of spacecraft following EVA</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1966-01-01</p> <p>Astronaut Richard F. Gordon Jr., pilot for the Gemini 11 space flight, returns to the <span class="hlt">hatch</span> of the spacecraft following extravehicular activity (EVA). This picture was taken over the Atlantic Ocean at approximately 160 nautical miles above the earth's surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/ca3034.photos.382871p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/ca3034.photos.382871p/"><span>8. INTERIOR VIEW OF STATION PARLEY LOOKING THROUGH THE <span class="hlt">HATCH</span>, ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>8. INTERIOR VIEW OF STATION PARLEY LOOKING THROUGH THE <span class="hlt">HATCH</span>, SHOWING THE FLOOR AND THE INSTRUMENT PEDESTAL WITH HARDWARE. - White's Point Reservation, Base End Stations, B"6, Bounded by Voyager Circle & Mariner Drive, San Pedro, Los Angeles County, CA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/wa0757.photos.576944p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/wa0757.photos.576944p/"><span>Interior below decks in fish hold looking forward. Fish <span class="hlt">hatch</span> ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>Interior below decks in fish hold looking forward. Fish <span class="hlt">hatch</span> opening is at upper left, ceiling planks and knees at center and right. - Purse Seiner SHENANDOAH, Gig Harbor Peninsula Historical Society and Museum, Gig Harbor, Pierce County, WA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss002e6537.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss002e6537.html"><span>Voss moves Orlan suit in forward <span class="hlt">hatch</span> of Zvezda module</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2001-06-01</p> <p>ISS002-E-6537 (1 June 2001) --- Astronaut James S. Voss, Expedition Two flight engineer, moves an Orlan spacesuit through the forward <span class="hlt">hatch</span> of the Zvezda Service Module. The image was recorded with a digital still camera.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss002e6539.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss002e6539.html"><span>Usachev moves Orlan suit in forward <span class="hlt">hatch</span> of Zvezda module</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2001-06-01</p> <p>ISS002-E-6539 (1 June 2001) --- Cosmonaut Yury V. Usachev of Rosaviakosmos, Expedition Two mission commander, moves an Orlan spacesuit through the forward <span class="hlt">hatch</span> of the Zvezda Service Module. The image was recorded with a digital still camera.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/de0330.photos.384113p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/de0330.photos.384113p/"><span>9. Mispillion Lighthouse, Tower Lantern Floor <span class="hlt">Hatch</span> Mispillion Lighthouse, ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>9. Mispillion Lighthouse, Tower Lantern Floor <span class="hlt">Hatch</span> - Mispillion Lighthouse, South bank of Mispillion River at its confluence with Delaware River at northeast end of County Road 203, 7 miles east of Milford, Milford, Sussex County, DE</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/ca1493.photos.033466p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/ca1493.photos.033466p/"><span>52. Patent steering gear, <span class="hlt">hatch</span> and steering compass binnacle, view ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>52. Patent steering gear, <span class="hlt">hatch</span> and steering compass binnacle, view from starboard looking aft. Photograph by Jet Lowe, April 1988. - Ship BALCLUTHA, 2905 Hyde Street Pier, San Francisco, San Francisco County, CA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/nv0242.photos.380525p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/nv0242.photos.380525p/"><span>14. View inside Building 802, the "Escape <span class="hlt">Hatch</span>" at the ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>14. View inside Building 802, the "Escape <span class="hlt">Hatch</span>" at the rear of the "Sleeping Quarters", facing south. - Naval Air Station Fallon, 100-man Fallout Shelter, 800 Complex, off Carson Road near intersection of Pasture & Berney Roads, Fallon, Churchill County, NV</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss026e029722.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss026e029722.html"><span>Nespoli removes docking mechanism to the ATV <span class="hlt">Hatch</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-02-25</p> <p>ISS026-E-029722 (25 Feb. 2011) --- As part of inverse activities onboard the International Space Station, European Space Agency astronaut Paolo Nespoli, Expedition 26 flight engineer, removes the docking mechanism to gain access to the ATV <span class="hlt">hatch</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss026e029719.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss026e029719.html"><span>Nespoli removes docking mechanism to the ATV <span class="hlt">Hatch</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-02-25</p> <p>ISS026-E-029719 (25 Feb. 2011) --- As part of inverse activities onboard the International Space Station, European Space Agency astronaut Paolo Nespoli, Expedition 26 flight engineer, removes the docking mechanism to gain access to the ATV <span class="hlt">hatch</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss026e029718.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss026e029718.html"><span>Nespoli removes docking mechanism to the ATV <span class="hlt">Hatch</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-02-25</p> <p>ISS026-E-029718 (25 Feb. 2011) --- As part of inverse activities onboard the International Space Station, European Space Agency astronaut Paolo Nespoli, Expedition 26 flight engineer, removes the docking mechanism to gain access to the ATV <span class="hlt">hatch</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss026e029725.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss026e029725.html"><span>Nespoli removes docking mechanism to the ATV <span class="hlt">Hatch</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-02-25</p> <p>ISS026-E-029725 (25 Feb. 2011) --- As part of inverse activities onboard the International Space Station, European Space Agency astronaut Paolo Nespoli, Expedition 26 flight engineer, removes the docking mechanism to gain access to the ATV <span class="hlt">hatch</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/ca2573.photos.382438p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/ca2573.photos.382438p/"><span>SOUTHWEST REAR, SHOWING CLOSED ENTRY <span class="hlt">HATCH</span>, BUILDING 1934. Looking north ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>SOUTHWEST REAR, SHOWING CLOSED ENTRY <span class="hlt">HATCH</span>, BUILDING 1934. Looking north - Edwards Air Force Base, X-15 Engine Test Complex, Observation Bunker Types, Rogers Dry Lake, east of runway between North Base & South Base, Boron, Kern County, CA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/hi0361.photos.332795p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/hi0361.photos.332795p/"><span>BLDG 10, INTERIOR DETAIL OF WINDOW AND CEILING FEED <span class="hlt">HATCHES</span> ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>BLDG 10, INTERIOR DETAIL OF WINDOW AND CEILING FEED <span class="hlt">HATCHES</span> - Naval Magazine Lualualei, Headquarters Branch, Storage Building, Kolekole Road near Sixty-first Street intersection, Pearl City, Honolulu County, HI</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1981E%26PSL..56..429L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1981E%26PSL..56..429L"><span>Implications of a concentration-<span class="hlt">dependent</span> growth <span class="hlt">rate</span> on the boundary layer crystal-melt model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lasaga, Antonio C.</p> <p>1981-12-01</p> <p>The influence of a melt boundary layer on crystal growth is analyzed. The treatment extends the results of Burton, Prim and Slichter (1953) and incorporates composition-<span class="hlt">dependent</span> growth <span class="hlt">rates</span>. It is shown that in these general cases the growth <span class="hlt">rate</span> cannot be arbitrarily fixed but must satisfy a self-consistent equation. Self-consistency problems arise because the growth <span class="hlt">rate</span> determines the composition profile in the melt and, in turn, the composition profile determines the growth <span class="hlt">rate</span>. The self-consistent growth <span class="hlt">rate</span> is shown to vary markedly with the ratio δ/D, where δ is the thickness of the boundary layer and D is the appropriate diffusion coefficient in the melt. This self-consistency can be very important in the analysis of both field and laboratory growth <span class="hlt">rates</span> as well as in trace element partition kinetic models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19800039510&hterms=stress-strain&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dstress-strain','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19800039510&hterms=stress-strain&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dstress-strain"><span>Time <span class="hlt">dependent</span> deformation of a basalt at low differential stress. [strain <span class="hlt">rate</span> and moisture content effects</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brodsky, N.; Spetzler, H.</p> <p>1979-01-01</p> <p>A detailed study of linear elastic deformation in Ralston basalt during triaxial loading has been made as a function of strain <span class="hlt">rate</span> (8 x 10 to the -8th per sec to 5 x 10 to the -5th per sec) and moisture content under constant confining pressure (500 bars) and temperature (20 C). Young's modulus was found to be constant and independent of moisture content and strain <span class="hlt">rate</span>; however, Poisson's ratio decreased 5.7 plus or minus 1.6% and 6.7 plus or minus 1.6% per order of magnitude increase in strain <span class="hlt">rate</span> for two suites of dry samples and 1.4 plus or minus 1.2% per equivalent change in strain <span class="hlt">rate</span> for one suite of wet rocks. Lateral expansion in dry rocks is therefore a more sensitive function of strain <span class="hlt">rate</span> than it is in wet rocks. It is suggested that this strain-<span class="hlt">rate</span> <span class="hlt">dependence</span> is related to microcracking.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17676366','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17676366"><span>Estimation of DNA sequence context-<span class="hlt">dependent</span> mutation <span class="hlt">rates</span> using primate genomic sequences.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Wei; Bouffard, Gerard G; Wallace, Susan S; Bond, Jeffrey P</p> <p>2007-09-01</p> <p>It is understood that DNA and amino acid substitution <span class="hlt">rates</span> are highly sequence context-<span class="hlt">dependent</span>, e.g., C --> T substitutions in vertebrates may occur much more frequently at CpG sites and that cysteine substitution <span class="hlt">rates</span> may <span class="hlt">depend</span> on support of the context for participation in a disulfide bond. Furthermore, many applications rely on quantitative models of nucleotide or amino acid substitution, including phylogenetic inference and identification of amino acid sequence positions involved in functional specificity. We describe quantification of the context <span class="hlt">dependence</span> of nucleotide substitution <span class="hlt">rates</span> using baboon, chimpanzee, and human genomic sequence data generated by the NISC Comparative Sequencing Program. Relative mutation <span class="hlt">rates</span> are reported for the 96 classes of mutations of the form 5' alphabetagamma 3' --> 5' alphadeltagamma 3', where alpha, beta, gamma, and delta are nucleotides and beta not equal delta, based on maximum likelihood calculations. Our results confirm that C --> T substitutions are enhanced at CpG sites compared with other transitions, relatively independent of the identity of the preceding nucleotide. While, as expected, transitions generally occur more frequently than transversions, we find that the most frequent transversions involve the C at CpG sites (CpG transversions) and that their <span class="hlt">rate</span> is comparable to the <span class="hlt">rate</span> of transitions at non-CpG sites. A four-class model of the <span class="hlt">rates</span> of context-<span class="hlt">dependent</span> evolution of primate DNA sequences, CpG transitions > non-CpG transitions approximately CpG transversions > non-CpG transversions, captures qualitative features of the mutation spectrum. We find that despite qualitative similarity of mutation <span class="hlt">rates</span> among different genomic regions, there are statistically significant differences.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28616189','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28616189"><span>The combined effects of reactant kinetics and enzyme stability explain the temperature <span class="hlt">dependence</span> of metabolic <span class="hlt">rates</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>DeLong, J P; Gibert, J P; Luhring, T M; Bachman, G; Reed, B; Neyer, A; Montooth, K L</p> <p>2017-06-01</p> <p>A mechanistic understanding of the response of metabolic <span class="hlt">rate</span> to temperature is essential for understanding thermal ecology and metabolic adaptation. Although the Arrhenius equation has been used to describe the effects of temperature on reaction <span class="hlt">rates</span> and metabolic traits, it does not adequately describe two aspects of the thermal performance curve (TPC) for metabolic <span class="hlt">rate</span>-that metabolic <span class="hlt">rate</span> is a unimodal function of temperature often with maximal values in the biologically relevant temperature range and that activation energies are temperature <span class="hlt">dependent</span>. We show that the temperature <span class="hlt">dependence</span> of metabolic <span class="hlt">rate</span> in ectotherms is well described by an enzyme-assisted Arrhenius (EAAR) model that accounts for the temperature-<span class="hlt">dependent</span> contribution of enzymes to decreasing the activation energy required for reactions to occur. The model is mechanistically derived using the thermodynamic rules that govern protein stability. We contrast our model with other unimodal functions that also can be used to describe the temperature <span class="hlt">dependence</span> of metabolic <span class="hlt">rate</span> to show how the EAAR model provides an important advance over previous work. We fit the EAAR model to metabolic <span class="hlt">rate</span> data for a variety of taxa to demonstrate the model's utility in describing metabolic <span class="hlt">rate</span> TPCs while revealing significant differences in thermodynamic properties across species and acclimation temperatures. Our model advances our ability to understand the metabolic and ecological consequences of increases in the mean and variance of temperature associated with global climate change. In addition, the model suggests avenues by which organisms can acclimate and adapt to changing thermal environments. Furthermore, the parameters in the EAAR model generate links between organismal level performance and underlying molecular processes that can be tested for in future work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/2137838','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/2137838"><span>Preload <span class="hlt">dependence</span> of fiber shortening <span class="hlt">rate</span> in conscious dogs with left ventricular hypertrophy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mirsky, I; Aoyagi, T; Crocker, V M; Fujii, A M</p> <p>1990-03-15</p> <p>Employing the new concept of systolic myocardial stiffness, this study addresses the questions of linearity of the end-systolic stress-strain relations in left ventricular hypertrophy and the preload <span class="hlt">dependence</span> of fiber shortening <span class="hlt">rate</span>. Pressure overload hypertrophy was induced in six puppies by banding the ascending aorta. Ultrasonic crystals were implanted for measurement of short axis and wall thickness in the six dogs with hypertrophy and in five control dogs. A pressure catheter was inserted through the apex for left ventricular pressure measurement. Load was altered by graded infusions of phenylephrine in the setting of beta-adrenergic blockade. Linearity of the end-systolic stress-strain relations was observed in all cases, and preload-corrected shortening <span class="hlt">rate</span>-afterload relations were derived from these stress-strain relations. Without preload correction, mid wall and endocardial shortening <span class="hlt">rate</span> were depressed (p less than 0.05 and p less than 0.005, respectively) in the hypertrophy group. However, with preload correction at 35 g/cm2, there was no significant difference in shortening <span class="hlt">rate</span> between the control and hypertrophy groups at afterloads of 150, 200 and 250 g/cm2. Endocardial shortening <span class="hlt">rate</span> at a preload of 25 versus 35 g/cm2 demonstrated a preload <span class="hlt">dependence</span> in both the control (p less than 0.04) and the hypertrophy group (p less than 0.01). Mid wall shortening <span class="hlt">rate</span> displayed a preload <span class="hlt">dependence</span> only in the hypertrophy group (p less than 0.05). It is concluded that end-systolic stress-strain relations are linear in control conditions and in hypertrophy, fiber shortening <span class="hlt">rate</span> is preload-<span class="hlt">dependent</span> and, thus, shortening <span class="hlt">rate</span>-afterload relations currently used to assess myocardial contractility need to be modified to account for these preload effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120013479','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120013479"><span>Does the <span class="hlt">Rate</span> of Collisionless Magnetic Reconnection <span class="hlt">Depend</span> on the Dissipation Mechanism?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Aunai, Nicolas; Hesse, Michael; Black, Carrie; Evans, Rebekah; Kuznetsova, Maria</p> <p>2012-01-01</p> <p>The importance of the electron dissipation effect on the reconnection <span class="hlt">rate</span> is investigated in the general case of asymmetric collisionless magnetic reconnection. Contrary to the standard collisionless reconnection model, it is found that the reconnection <span class="hlt">rate</span>, and the macroscopic evolution of the reconnecting system, crucially <span class="hlt">depend</span> on the nature of the dissipation mechanism and that the Hall effect alone is not able to sustain fast reconnection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120009901','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120009901"><span>Does the <span class="hlt">Rate</span> of Collisionless Reconnection <span class="hlt">Depend</span> on the Dissipation Mechanism?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Aunai, Nicolas; Hesse, Michael; Black, Carrie; Evans, Rebekah; Kuznetsova, maria</p> <p>2012-01-01</p> <p>The importance of the electron dissipation effect on the reconnection <span class="hlt">rate</span> is investigated in the general case of asymmetric collisionless magnetic reconnection. Contrary to the standard collisionless reconnection model, it is found that the reconnection <span class="hlt">rate</span>, and them acroscopic evolution of the reconnecting system, crucially <span class="hlt">depend</span> on the nature of the dissipation mechanism and that the Hall effect alone is not able to sustain fast reconnection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1398378-strain-rate-dependence-ramp-wave-evolution-strength-tantalum','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1398378-strain-rate-dependence-ramp-wave-evolution-strength-tantalum"><span>Strain-<span class="hlt">rate</span> <span class="hlt">dependence</span> of ramp-wave evolution and strength in tantalum</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Lane, J. Matthew D.; Foiles, Stephen M.; Lim, Hojun; ...</p> <p>2016-08-25</p> <p>We have conducted molecular dynamics (MD) simulations of quasi-isentropic ramp-wave compression to very high pressures over a range of strain <span class="hlt">rates</span> from 1011 down to 108 1/s. Using scaling methods, we collapse wave profiles from various strain <span class="hlt">rates</span> to a master profile curve, which shows deviations when material response is strain-<span class="hlt">rate</span> <span class="hlt">dependent</span>. Thus, we can show with precision where, and how, strain-<span class="hlt">rate</span> <span class="hlt">dependence</span> affects the ramp wave. We find that strain <span class="hlt">rate</span> affects the stress-strain material response most dramatically at strains below 20%, and that above 30% strain the material response is largely independent of strain <span class="hlt">rate</span>. We show goodmore » overall agreement with experimental stress-strain curves up to approximately 30% strain, above which simulated response is somewhat too stiff. We postulate that this could be due to our interatomic potential or to differences in grain structure and/or size between simulation and experiment. Strength is directly measured from per-atom stress tensor and shows significantly enhanced elastic response at the highest strain <span class="hlt">rates</span>. As a result, this enhanced elastic response is less pronounced at higher pressures and at lower strain <span class="hlt">rates</span>.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1398378','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1398378"><span>Strain-<span class="hlt">rate</span> <span class="hlt">dependence</span> of ramp-wave evolution and strength in tantalum</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lane, J. Matthew D.; Foiles, Stephen M.; Lim, Hojun; Brown, Justin L.</p> <p>2016-08-25</p> <p>We have conducted molecular dynamics (MD) simulations of quasi-isentropic ramp-wave compression to very high pressures over a range of strain <span class="hlt">rates</span> from 10<sup>11</sup> down to 10<sup>8</sup> 1/s. Using scaling methods, we collapse wave profiles from various strain <span class="hlt">rates</span> to a master profile curve, which shows deviations when material response is strain-<span class="hlt">rate</span> <span class="hlt">dependent</span>. Thus, we can show with precision where, and how, strain-<span class="hlt">rate</span> <span class="hlt">dependence</span> affects the ramp wave. We find that strain <span class="hlt">rate</span> affects the stress-strain material response most dramatically at strains below 20%, and that above 30% strain the material response is largely independent of strain <span class="hlt">rate</span>. We show good overall agreement with experimental stress-strain curves up to approximately 30% strain, above which simulated response is somewhat too stiff. We postulate that this could be due to our interatomic potential or to differences in grain structure and/or size between simulation and experiment. Strength is directly measured from per-atom stress tensor and shows significantly enhanced elastic response at the highest strain <span class="hlt">rates</span>. As a result, this enhanced elastic response is less pronounced at higher pressures and at lower strain <span class="hlt">rates</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1116483','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1116483"><span>Mapping Strain-<span class="hlt">rate</span> <span class="hlt">Dependent</span> Dislocation-Defect Interactions by Atomistic Simulations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fan, Yue; Osetskiy, Yury N; Yip, Sidney; Yildiz-Botterud, Bilge</p> <p>2013-01-01</p> <p>Probing the mechanisms of defect-defect interactions at strain <span class="hlt">rates</span> lower than 106 s-1 is an unresolved challenge to date to molecular dynamics (MD) techniques. Here we propose a novel atomistic approach based on transition state theory and the concept of a strain-<span class="hlt">dependent</span> effective activation barrier that is capable of simulating the kinetics of dislocation-defect interactions at virtually any strain <span class="hlt">rate</span>, exemplified within 10-7 to 107 s-1. We apply this approach to the problem of an edge dislocation colliding with a cluster of self-interstitial atoms (SIA) under shear deformation. Using an activation-relaxation algorithm (1), we uncover a unique strain-<span class="hlt">rate</span> <span class="hlt">dependent</span> trigger mechanism that allows the SIA cluster to be absorbed during the process leading to dislocation climb. Guided by this finding, we determine the activation barrier of the trigger mechanism as a function of shear strain, and use that in a coarse-graining <span class="hlt">rate</span> equation formulation for constructing a mechanism map in the phase space of strain-<span class="hlt">rate</span> and temperature. Our predictions of a crossover from a defect recovery at the low strain <span class="hlt">rate</span> regime to defect absorption behavior in the high strain-<span class="hlt">rate</span> regime are validated against our own independent, direct MD simulations at 105 to 107 s-1. Implications of the present approach for probing molecular-level mechanisms in strain-<span class="hlt">rate</span> regimes previously considered inaccessible to atomistic simulations are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27911094','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27911094"><span>Production traits of artificially and naturally <span class="hlt">hatched</span> geese in intensive and free-range systems: I. Growth traits.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Boz, M A; Sarica, M; Yamak, U S</p> <p>2017-04-01</p> <p>1. This study investigated the effect of incubation type and production system on geese growth traits. 2. A total of 216 geese were either naturally (114) or artificially (102) <span class="hlt">hatched</span> and reared in intensive or free-range production systems (4 replicates each) until 18 weeks of age. 3. Weights of naturally <span class="hlt">hatched</span> goslings (NHG) were significantly higher than artificially <span class="hlt">hatched</span> goslings (AHG) at 2 weeks (644 vs. 536 g); however, weights of AHG were significantly higher than NHG at both 6 weeks (3245 vs. 3010 g) and 18 weeks (5212 vs. 4353 g). 4. AHG had better feed conversion ratios (FCRs) than NHG (6.21 vs. 6.46 at 18 weeks). Feed consumption of naturally <span class="hlt">hatched</span> geese was found higher in first 4 weeks when compared to artificially <span class="hlt">hatched</span> geese and artificially <span class="hlt">hatched</span> geese consumed more feed than naturally <span class="hlt">hatched</span> geese after 8 weeks. 5. Production system had insignificant effects on feed consumption, FCRs, viability and mutilation <span class="hlt">rates</span>. 6. Slipped wings were more frequent in NHG than AHG (8.32% vs. 1.68% at 6 weeks; 23.84% vs. 5.12% between 7 and 18 weeks) and in free-range production when compared to intensive production (17.88% vs. 11.08% over the course of the production period). 7. The study results indicate that both artificially and NHG can be reared in free-range production systems without any loss in performance and in deference to animal welfare.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JPhCS.847a2041X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JPhCS.847a2041X"><span>Leuco-crystal-violet micelle gel dosimeters: Component effects on dose-<span class="hlt">rate</span> <span class="hlt">dependence</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xie, J. C.; Katz, E. A. B.; Alexander, K. M.; Schreiner, L. J.; McAuley, K. B.</p> <p>2017-05-01</p> <p>Designed experiments were performed to produce empirical models for the dose sensitivity, initial absorbance, and dose-<span class="hlt">rate</span> <span class="hlt">dependence</span> respectively for leucocrystal violet (LCV) micelle gel dosimeters containing cetyltrimethylammonium bromide (CTAB) and 2,2,2-trichloroethanol (TCE). Previous gels of this type showed dose-<span class="hlt">rate</span> <span class="hlt">dependent</span> behaviour, producing an ∼18% increase in dose sensitivity between dose <span class="hlt">rates</span> of 100 and 600 cGy min-1. Our models predict that the dose <span class="hlt">rate</span> <span class="hlt">dependence</span> can be reduced by increasing the concentration of TCE, CTAB and LCV. Increasing concentrations of LCV and CTAB produces a significant increase in dose sensitivity with a corresponding increase in initial absorbance. An optimization procedure was used to determine a nearly dose-<span class="hlt">rate</span> independent gel which maintained high sensitivity and low initial absorbance. This gel which contains 33 mM CTAB, 1.25 mM LCV, and 96 mM TCE in 25 mM trichloroacetic acid and 4 wt% gelatin showed an increase in dose sensitivity of only 4% between dose <span class="hlt">rates</span> of 100 and 600 cGy min-1, and provides an 80% greater dose sensitivity compared to Jordan’s standard gels with similar initial absorbance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24015933','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24015933"><span>Change in heat capacity for enzyme catalysis determines temperature <span class="hlt">dependence</span> of enzyme catalyzed <span class="hlt">rates</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hobbs, Joanne K; Jiao, Wanting; Easter, Ashley D; Parker, Emily J; Schipper, Louis A; Arcus, Vickery L</p> <p>2013-11-15</p> <p>The increase in enzymatic <span class="hlt">rates</span> with temperature up to an optimum temperature (Topt) is widely attributed to classical Arrhenius behavior, with the decrease in enzymatic <span class="hlt">rates</span> above Topt ascribed to protein denaturation and/or aggregation. This account persists despite many investigators noting that denaturation is insufficient to explain the decline in enzymatic <span class="hlt">rates</span> above Topt. Here we show that it is the change in heat capacity associated with enzyme catalysis (ΔC(‡)p) and its effect on the temperature <span class="hlt">dependence</span> of ΔG(‡) that determines the temperature <span class="hlt">dependence</span> of enzyme activity. Through mutagenesis, we demonstrate that the Topt of an enzyme is correlated with ΔC(‡)p and that changes to ΔC(‡)p are sufficient to change Topt without affecting the catalytic <span class="hlt">rate</span>. Furthermore, using X-ray crystallography and molecular dynamics simulations we reveal the molecular details underpinning these changes in ΔC(‡)p. The influence of ΔC(‡)p on enzymatic <span class="hlt">rates</span> has implications for the temperature <span class="hlt">dependence</span> of biological <span class="hlt">rates</span> from enzymes to ecosystems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/hi0893.photos.576851p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/hi0893.photos.576851p/"><span>DETAIL OF OPEN <span class="hlt">HATCH</span> SHOWING INTERIOR OF MISSILE TUBE AND ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>DETAIL OF OPEN <span class="hlt">HATCH</span> SHOWING INTERIOR OF MISSILE TUBE AND OPEN <span class="hlt">HATCH</span> AND DOOR ON OPPOSITE SIDE OF TUBE (AT THIRD LEVEL OF MISSILE LAB). VIEW FACING WEST - U.S. Naval Base, Pearl Harbor, Ford Island Polaris Missile Lab & U.S. Fleet Ballistic Missile Submarine Training Center, Between Lexington Boulvevard and the sea plane ramps on the southwest side of Ford Island, Pearl City, Honolulu County, HI</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ChPhC..33...47Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ChPhC..33...47Z"><span>DETECTORS AND EXPERIMENTAL METHODS: ELDRS and dose-<span class="hlt">rate</span> <span class="hlt">dependence</span> of vertical NPN transistor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zheng, Yu-Zhan; Lu, Wu; Ren, Di-Yuan; Wang, Gai-Li; Yu, Xue-Feng; Guo, Qi</p> <p>2009-01-01</p> <p>The enhanced low-dose-<span class="hlt">rate</span> sensitivity (ELDRS) and dose-<span class="hlt">rate</span> <span class="hlt">dependence</span> of vertical NPN transistors are investigated in this article. The results show that the vertical NPN transistors exhibit more degradation at low dose <span class="hlt">rate</span>, and that this degradation is attributed to the increase on base current. The oxide trapped positive charge near the SiO2-Si interface and interface traps at the interface can contribute to the increase on base current and the two-stage hydrogen mechanism associated with space charge effect can well explain the experimental results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/14641961','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/14641961"><span>Early post-<span class="hlt">hatching</span> starvation delays p70 S6 kinase activation in the muscle of neonatal chicks.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bigot, Karine; Taouis, Mohammed; Picard, Michel; Tesseraud, Sophie</p> <p>2003-12-01</p> <p>Chicken muscle ribosomal protein S6 kinase (S6K1) has been recently characterised and its enzymic activity is regulated by the nutritional and hormonal (insulin) status in vivo. The regulation of S6K1 is still unknown in neonatal chicks. The present study aimed to compare the activation of S6K1 in early-feeding (EF) and 48 h-delayed-feeding (DF) chicks from <span class="hlt">hatching</span> to 4 d of age. During post-<span class="hlt">hatching</span> starvation, S6K1 activity remained at the basal level measured in the control-<span class="hlt">hatched</span> chicks. The maximum S6K1 activity was recorded on the first day of feeding with an increase of about 2.5-fold in the EF and DF chicks (P<0.01). S6K1 activity was correlated with plasma insulin level, suggesting a probable insulin-<span class="hlt">dependent</span> S6K1 activation. The feeding-induced increase in S6K1 activity was related to its Thr389 residue phosphorylation. A similar pattern for protein kinase B phosphorylation was observed, upstream from S6K1. The S6K1 pathway was stimulated to the same extent in the EF and DF chicks, which indicates that post-<span class="hlt">hatching</span> starvation did not increase S6K1 activation. It is concluded that muscle S6K1 is activated as soon as food is available without improvement in the response of the S6K1 pathway after post-<span class="hlt">hatching</span> starvation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=alternate+AND+universe&id=EJ898763','ERIC'); return false;" href="https://eric.ed.gov/?q=alternate+AND+universe&id=EJ898763"><span>Direct Behavior <span class="hlt">Rating</span> (DBR): Generalizability and <span class="hlt">Dependability</span> across Raters and Observations</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Christ, Theodore J.; Riley-Tillman, T. Chris; Chafouleas, Sandra M.; Boice, Christina H.</p> <p>2010-01-01</p> <p>Generalizability theory was used to examine the generalizability and <span class="hlt">dependability</span> of outcomes from two single-item Direct Behavior <span class="hlt">Rating</span> (DBR) scales: DBR of actively manipulating and DBR of visually distracted. DBR is a behavioral assessment tool with specific instrumentation and procedures that can be used by a variety of service delivery…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26863256','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26863256"><span>Cooling <span class="hlt">Rate</span> <span class="hlt">Dependent</span> Ellipsometry Measurements to Determine the Dynamics of Thin Glassy Films.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Glor, Ethan C; Fakhraai, Zahra</p> <p>2016-01-26</p> <p>This report aims to fully describe the experimental technique of using ellipsometry for cooling <span class="hlt">rate</span> <span class="hlt">dependent</span> Tg (CR-Tg) experiments. These measurements are simple high-throughput characterization experiments, which can determine the glass transition temperature (Tg), average dynamics, fragility and the expansion coefficient of the super-cooled liquid and glassy states for a variety of glassy materials. This technique allows for these parameters to be measured in a single experiment, while other methods must combine a variety of different techniques to investigate all of these properties. Measurements of dynamics close to Tg are particularly challenging. The advantage of cooling <span class="hlt">rate</span> <span class="hlt">dependent</span> Tg measurements over other methods which directly probe bulk and surface relaxation dynamics is that they are relatively quick and simple experiments, which do not utilize fluorophores or other complicated experimental techniques. Furthermore, this technique probes the average dynamics of technologically relevant thin films in temperature and relaxation time (τα) regimes relevant to the glass transition (τα > 100 sec). The limitation to using ellipsometry for cooling <span class="hlt">rate</span> <span class="hlt">dependent</span> Tg experiments is that it cannot probe relaxation times relevant to measurements of viscosity (τα < 1 sec). Other cooling <span class="hlt">rate</span> <span class="hlt">dependent</span> Tg measurement techniques, however, can extend the CR-Tg method to faster relaxation times. Furthermore, this technique can be used for any glassy system so long as the integrity of the film remains throughout the experiment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27193784','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27193784"><span>Translation elicits a growth <span class="hlt">rate-dependent</span>, genome-wide, differential protein production in Bacillus subtilis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Borkowski, Olivier; Goelzer, Anne; Schaffer, Marc; Calabre, Magali; Mäder, Ulrike; Aymerich, Stéphane; Jules, Matthieu; Fromion, Vincent</p> <p>2016-05-17</p> <p>Complex regulatory programs control cell adaptation to environmental changes by setting condition-specific proteomes. In balanced growth, bacterial protein abundances <span class="hlt">depend</span> on the dilution <span class="hlt">rate</span>, transcript abundances and transcript-specific translation efficiencies. We revisited the current theory claiming the invariance of bacterial translation efficiency. By integrating genome-wide transcriptome datasets and datasets from a library of synthetic gfp-reporter fusions, we demonstrated that translation efficiencies in Bacillus subtilis decreased up to fourfold from slow to fast growth. The translation initiation regions elicited a growth <span class="hlt">rate-dependent</span>, differential production of proteins without regulators, hence revealing a unique, hard-coded, growth <span class="hlt">rate-dependent</span> mode of regulation. We combined model-based data analyses of transcript and protein abundances genome-wide and revealed that this global regulation is extensively used in B. subtilis We eventually developed a knowledge-based, three-step translation initiation model, experimentally challenged the model predictions and proposed that a growth <span class="hlt">rate-dependent</span> drop in free ribosome abundance accounted for the differential protein production. © 2016 The Authors. Published under the terms of the CC BY 4.0 license.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5185876','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5185876"><span>Time <span class="hlt">dependent</span> parallel viscosity and relaxation <span class="hlt">rate</span> of poloidal rotation in the banana regime</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hsu, C.T.; Shaing, K.C.; Gormley, R. )</p> <p>1994-01-01</p> <p>Time <span class="hlt">dependent</span> ion parallel viscous force in the banana regime with arbitrary inverse aspect ratio [epsilon] is calculated using the eigenfunction approach. The flux surface averaged viscosity is then used to study the relaxation process of the poloidal rotation which leads to oscillatory relaxation behavior. The relaxation <span class="hlt">rate</span> [nu][sub [ital p</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996IJMPC...7..731B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996IJMPC...7..731B"><span>Age-Of <span class="hlt">Dependent</span> Mutation <span class="hlt">Rate</span> and Weak Children in the Penna Model in Biological Ageing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berntsen, K. Nikolaj</p> <p></p> <p>We investigate the effect of an age-<span class="hlt">dependent</span> mutation <span class="hlt">rate</span> in the Penna model of ageing and then we observe that the high mortality for human babies can be reproduced by the model if one assumes babies to be weaker than adults.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22413241','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22413241"><span>The vibrational <span class="hlt">dependence</span> of dissociative recombination: <span class="hlt">Rate</span> constants for N{sub 2}{sup +}</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Guberman, Steven L.</p> <p>2014-11-28</p> <p>Dissociative recombination <span class="hlt">rate</span> constants are reported with electron temperature <span class="hlt">dependent</span> uncertainties for the lowest 5 vibrational levels of the N{sub 2}{sup +} ground state. The <span class="hlt">rate</span> constants are determined from ab initio calculations of potential curves, electronic widths, quantum defects, and cross sections. At 100 K electron temperature, the <span class="hlt">rate</span> constants overlap with the exception of the third vibrational level. At and above 300 K, the <span class="hlt">rate</span> constants for excited vibrational levels are significantly smaller than that for the ground level. It is shown that any experimentally determined total <span class="hlt">rate</span> constant at 300 K electron temperature that is smaller than 2.0 × 10{sup −7} cm{sup 3}/s is likely to be for ions that have a substantially excited vibrational population. Using the vibrational level specific <span class="hlt">rate</span> constants, the total <span class="hlt">rate</span> constant is in very good agreement with that for an excited vibrational distribution found in a storage ring experiment. It is also shown that a prior analysis of a laser induced fluorescence experiment is quantitatively flawed due to the need to account for reactions with unknown <span class="hlt">rate</span> constants. Two prior calculations of the dissociative recombination <span class="hlt">rate</span> constant are shown to be inconsistent with the cross sections upon which they are based. The <span class="hlt">rate</span> constants calculated here contribute to the resolution of a 30 year old disagreement between modeled and observed N{sub 2}{sup +} ionospheric densities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23013947','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23013947"><span>Level of <span class="hlt">dependence</span> in patients on haemodialysis in Catalonia and evolution of mortality <span class="hlt">rates</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Andreu-Periz, Lola; Puig-Llobet, Montserrat; Cases-Amenós, Aleix</p> <p>2012-01-01</p> <p>Age and the comorbidities associated with ESRD impair the functional autonomy of patients on haemodialysis (HD). Our objectives were to assess the level of <span class="hlt">dependence</span> in patients on HD and their mortality <span class="hlt">rates</span> after three years of treatment. To do so, we followed the criteria established by the "Ley de Promoción de la Autonomía Personal y Atención a las Personas en situación de dependencia", the Spanish Law of <span class="hlt">Dependence</span> (LD). We carried out a cross-sectional descriptive study between October 2007 and January 2008. From 3702 patients in 40 dialysis units in Catalonia, 806 were selected as potential <span class="hlt">dependent</span> individuals according to the criteria of their healthcare providers. Variables studied included: level of <span class="hlt">dependence</span> according to the LD criteria, age, time on HD, associated pathology, treatment characteristics, family circumstances, and survival from 2009 to 2011. According to the LD, 137 were not <span class="hlt">dependent</span>, 350 had a grade 1 <span class="hlt">dependence</span> level, 237 grade 2, and 82 grade 3. In addition, 121 were living in an institution. The mean age was 74.9 ± 18.2 years and the median time on HD was 36 months. The prevalence of common pathologies was: diabetes (35.7%) and cardiovascular disease (29.1%). Musculoskeletal alterations (87%) and neurological disorders (38%) were the main causes of <span class="hlt">dependence</span>. 64.2% of patients had a catheter as a vascular access. 34.9% of patients survived after three years, and these had a lower level of <span class="hlt">dependence</span> when compared to those patients who had died, with no statistically significant differences within those three years. According to the LD, the prevalence of <span class="hlt">dependent</span> patients in Catalonia is substantial (18.07%). These patients have a high mortality <span class="hlt">rate</span> after three years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2045058','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2045058"><span>Barbiturates increase the <span class="hlt">rate</span> of voltage-<span class="hlt">dependent</span> inactivation of the calcium current in snail neurones.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Nishi, K.; Oyama, Y.</p> <p>1983-01-01</p> <p>Effects of barbiturates (thiopentone, pentobarbitone, phenobarbitone and barbitone) on the calcium current (ICa) in identified Helix neurones were studied, using a conventional suction pipette technique. Barbiturates depressed the maximal peak amplitudes (MPA) of ICa in a dose-<span class="hlt">dependent</span> manner without shifting the current-voltage relationships along the voltage axis. Barbiturates accelerated the decay phase of ICa at high concentrations (1 X 10(-4) to 3 X 10(-3) M), at which concentrations double-pulse experiments showed the increased <span class="hlt">rate</span> of a voltage-<span class="hlt">dependent</span> inactivation of ICa. It is concluded that the acceleration of the decay phase of ICa by barbiturates may be due to the increased <span class="hlt">rate</span> of the voltage-<span class="hlt">dependent</span> inactivation of ICa. PMID:6100847</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3816434','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3816434"><span>Mapping strain <span class="hlt">rate</span> <span class="hlt">dependence</span> of dislocation-defect interactions by atomistic simulations</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fan, Yue; Osetskiy, Yuri N.; Yip, Sidney; Yildiz, Bilge</p> <p>2013-01-01</p> <p>Probing the mechanisms of defect–defect interactions at strain <span class="hlt">rates</span> lower than 106 s−1 is an unresolved challenge to date to molecular dynamics (MD) techniques. Here we propose an original atomistic approach based on transition state theory and the concept of a strain-<span class="hlt">dependent</span> effective activation barrier that is capable of simulating the kinetics of dislocation–defect interactions at virtually any strain <span class="hlt">rate</span>, exemplified within 10−7 to 107 s−1. We apply this approach to the problem of an edge dislocation colliding with a cluster of self-interstitial atoms (SIAs) under shear deformation. Using an activation–relaxation algorithm [Kushima A, et al. (2009) J Chem Phys 130:224504], we uncover a unique strain-rate–<span class="hlt">dependent</span> trigger mechanism that allows the SIA cluster to be absorbed during the process, leading to dislocation climb. Guided by this finding, we determine the activation barrier of the trigger mechanism as a function of shear strain, and use that in a coarse-graining <span class="hlt">rate</span> equation formulation for constructing a mechanism map in the phase space of strain <span class="hlt">rate</span> and temperature. Our predictions of a crossover from a defect recovery at the low strain-<span class="hlt">rate</span> regime to defect absorption behavior in the high strain-<span class="hlt">rate</span> regime are validated against our own independent, direct MD simulations at 105 to 107 s−1. Implications of the present approach for probing molecular-level mechanisms in strain-<span class="hlt">rate</span> regimes previously considered inaccessible to atomistic simulations are discussed. PMID:24114271</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3160282','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3160282"><span>Dose- and <span class="hlt">Rate-Dependent</span> Effects of Cocaine on Striatal Firing Related to Licking</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tang, Chengke; Mittler, Taliah; Duke, Dawn C.; Zhu, Yun; Pawlak, Anthony P.; West, Mark O.</p> <p>2011-01-01</p> <p>To examine the role of striatal mechanisms in cocaine-induced stereotyped licking, we investigated the acute effects of cocaine on striatal neurons in awake, freely moving rats before and after cocaine administration (0, 5, 10, or 20 mg/kg). Stereotyped licking was induced only by the high dose. Relative to control (saline), cocaine reduced lick duration and concurrently increased interlick interval, particularly at the high dose, but it did not affect licking rhythm. Firing <span class="hlt">rates</span> of striatal neurons phasically related to licking movements were compared between matched licks before and after injection, minimizing any influence of sensorimotor variables on changes in firing. Both increases and decreases in average firing <span class="hlt">rate</span> of striatal neurons were observed after cocaine injection, and these changes exhibited a dose-<span class="hlt">dependent</span> pattern that strongly <span class="hlt">depended</span> on predrug firing <span class="hlt">rate</span>. At the middle and high doses relative to the saline group, the average firing <span class="hlt">rates</span> of slow firing neurons were increased by cocaine, resulting from a general elevation of movement-related firing <span class="hlt">rates</span>. In contrast, fast firing neurons showed decreased average firing <span class="hlt">rates</span> only in the high-dose group, with reduced firing <span class="hlt">rates</span> across the entire range for these neurons. Our findings suggest that at the high dose, increased phasic activity of slow firing striatal neurons and simultaneously reduced phasic activity of fast firing striatal neurons may contribute, respectively, to the continual initiation of stereotypic movements and the absence of longer movements. PMID:17991811</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22098839','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22098839"><span>Dose <span class="hlt">rate</span> <span class="hlt">dependence</span> for different dosimeters and detectors: TLD, OSL, EBT films, and diamond detectors</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Karsch, L.; Beyreuther, E.; Burris-Mog, T.; Kraft, S.; Richter, C.; Zeil, K.; Pawelke, J.</p> <p>2012-05-15</p> <p>Purpose: The use of laser accelerators in radiation therapy can perhaps increase the low number of proton and ion therapy facilities in some years due to the low investment costs and small size. The laser-based acceleration technology leads to a very high peak dose <span class="hlt">rate</span> of about 10{sup 11} Gy/s. A first dosimetric task is the evaluation of dose <span class="hlt">rate</span> <span class="hlt">dependence</span> of clinical dosimeters and other detectors. Methods: The measurements were done at ELBE, a superconductive linear electron accelerator which generates electron pulses with 5 ps length at 20 MeV. The different dose <span class="hlt">rates</span> are reached by adjusting the number of electrons in one beam pulse. Three clinical dosimeters (TLD, OSL, and EBT radiochromic films) were irradiated with four different dose <span class="hlt">rates</span> and nearly the same dose. A faraday cup, an integrating current transformer, and an ionization chamber were used to control the particle flux on the dosimeters. Furthermore two diamond detectors were tested. Results: The dosimeters are dose <span class="hlt">rate</span> independent up to 410{sup 9} Gy/s within 2% (OSL and TLD) and up to 1510{sup 9} Gy/s within 5% (EBT films). The diamond detectors show strong dose <span class="hlt">rate</span> <span class="hlt">dependence</span>. Conclusions: TLD, OSL dosimeters, and EBT films are suitable for pulsed beams with a very high pulse dose <span class="hlt">rate</span> like laser accelerated particle beams.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21539421','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21539421"><span>Does lighting manipulation during incubation affect <span class="hlt">hatching</span> rhythms and early development of sole?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Blanco-Vives, B; Aliaga-Guerrero, M; Cañavate, J P; Muñoz-Cueto, J A; Sánchez-Vázquez, F J</p> <p>2011-05-01</p> <p>Light plays a key role in the development of biological rhythms in fish. Previous research on Senegal sole has revealed that both spawning rhythms and larval development are strongly influenced by lighting conditions. However, <span class="hlt">hatching</span> rhythms and the effect of light during incubation are as yet unexplored. Therefore, the aim of this study was to investigate the impact of the light spectrum and photoperiod on Solea senegalensis eggs and larvae until day 7 post <span class="hlt">hatching</span> (dph). To this end, eggs were collected immediately after spawning during the night and exposed to continuous light (LL), continuous darkness (DD), or light-dark (LD) 12L:12D cycles of white light (LD(W)), blue light (LD(B); λ(peak) = 463 nm), or red light (LD(R); λ(peak) = 685 nm). Eggs exposed to LD(B) had the highest <span class="hlt">hatching</span> <span class="hlt">rate</span> (94.5% ± 1.9%), whereas LD(R) and DD showed the lowest <span class="hlt">hatching</span> <span class="hlt">rate</span> (54.4% ± 3.9% and 48.4% ± 4.2%, respectively). Under LD conditions, the <span class="hlt">hatching</span> rhythm peaked by the end of the dark phase, but was advanced in LD(B) (zeitgeber time 8 [ZT8]; ZT0 representing the onset of darkness) in relation to LD(W) and LD(R) (ZT11). Under DD conditions, the same rhythm persisted, although with lower amplitude, whereas under LL the <span class="hlt">hatching</span> rhythm split into two peaks (ZT8 and ZT13). From dph 4 onwards, larvae under LD(B) showed the best growth and quickest development (advanced eye pigmentation, mouth opening, and pectoral fins), whereas larvae under LD(R) and DD had the poorest performance. These results reveal that developmental rhythms at the egg stage are tightly controlled by light characteristics, underlining the importance of reproducing their natural underwater photoenvironment (LD cycles of blue wavelengths) during incubation and early larvae development of fish.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.9650D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.9650D"><span>The systematic study of the stability of forecasts in the <span class="hlt">rate</span>- and state-<span class="hlt">dependent</span> model.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>De Gaetano, D.; McCloskey, J.; Nalbant, S.</p> <p>2012-04-01</p> <p>Numerous observations have shown a general spatial correlation between positive Coulomb failure stress changes due to an earthquake and the locations of aftershocks. However this correlation does not give any indication of the <span class="hlt">rate</span> from which we can infer the magnitude using the Gutenberg-Richter law. Dieterich's <span class="hlt">rate</span>- and state-<span class="hlt">dependent</span> model can be used to obtain a forecast of the observed aftershock <span class="hlt">rate</span> for the space and time evolution of seismicity caused by stress changes applied to an infinite population of nucleating patches. The seismicity <span class="hlt">rate</span> changes on this model <span class="hlt">depend</span> on eight parameters: the stressing <span class="hlt">rate</span>, the amplitude of the stress perturbation, the physical constitutive properties of faults, the spatial parameters (location and radii of the cells), the start and duration of each of the temporal windows as well as the background seismicity <span class="hlt">rate</span>. The background seismicity is obtained from the epidemic type aftershock sequence model. We use the 1992 Landers earthquake as a case study, using the Southern California Earthquake Data Centre (SCEDC) catalogue, to examine if Dieterich's <span class="hlt">rate</span>- and state-<span class="hlt">dependent</span> model can forecast the aftershock seismicity <span class="hlt">rate</span>. A systematic study is performed on a range of values on all the parameters to test the forecasting ability of this model. The results obtained suggest variable success in forecasting, when varying the values for the parameters, with the spatial and temporal parameters being the most sensitive. Dieterich's <span class="hlt">rate</span>- and state-<span class="hlt">dependent</span> model is compared with a well studied null hypothesis, the Omori-Utsu law. This law describes the aftershock <span class="hlt">rate</span> as a power law in time following the main shock and <span class="hlt">depends</span> on only three parameters: the aftershock productivity, the elapsed time since the main shock and the constant time shift, all of which can be estimated in the early part of the aftershock sequence and then extrapolated to give a long term <span class="hlt">rate</span> forecast. All parameters are estimated using maximum</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SMaS...25f5017J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SMaS...25f5017J"><span>Nonlinear modeling on <span class="hlt">rate</span> <span class="hlt">dependent</span> ferroelectric and ferroelastic response of 1-3 piezocomposites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jayendiran, R.; Arockiarajan, A.</p> <p>2016-06-01</p> <p>The effect of loading <span class="hlt">rate</span> on ferroelectric and ferroelastic behavior of 1-3 piezocomposites is presented in this work. Experiments are conducted for various loading <span class="hlt">rates</span> under different loading conditions such as electrical and electromechanical to measure the <span class="hlt">rate</span> <span class="hlt">dependent</span> response of 1-3 piezocomposite compared with bulk piezoceramics. A thermodynamic based <span class="hlt">rate</span> <span class="hlt">dependent</span> domain switching criteria has been proposed to predict the ferroelectric and ferroelastic behavior of homogenized 1-3 piezocomposites. In this model, volume fraction of six distinct uni-axial variants are used as internal variables to describe the microscopic state of the material. Plasticity based kinematic hardening parameter is introduced as a function of internal variables to describe the grain boundary effects. Homogenization of 1-3 piezocomposite material properties are obtained by finite element (FE) resonator models using commercially available FE tool Abaqus. To evaluate the possible modes of vibration of 1-3 piezocomposite four different configuration of FE resonators are modeled. The FE resonator model is validated with the impedance spectra obtained experimentally for length extensional and thickness extensional resonator models. The predicted effective properties using the resonance based technique are incorporated in the proposed <span class="hlt">rate</span> <span class="hlt">dependent</span> macromechanical model to study the behavior of 1-3 piezocomposites. The simulated results are compared with the experimental observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3137753','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3137753"><span>Point process analyses of variations in smoking <span class="hlt">rate</span> by setting, mood, gender, and <span class="hlt">dependence</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Shiffman, Saul; Rathbun, Stephen L.</p> <p>2010-01-01</p> <p>The immediate emotional and situational antecedents of ad libitum smoking are still not well understood. We re-analyzed data from Ecological Momentary Assessment using novel point-process analyses, to assess how craving, mood, and social setting influence smoking <span class="hlt">rate</span>, as well as assessing the moderating effects of gender and nicotine <span class="hlt">dependence</span>. 304 smokers recorded craving, mood, and social setting using electronic diaries when smoking and at random nonsmoking times over 16 days of smoking. Point-process analysis, which makes use of the known random sampling scheme for momentary variables, examined main effects of setting and interactions with gender and <span class="hlt">dependence</span>. Increased craving was associated with higher <span class="hlt">rates</span> of smoking, particularly among women. Negative affect was not associated with smoking <span class="hlt">rate</span>, even in interaction with arousal, but restlessness was associated with substantially higher smoking <span class="hlt">rates</span>. Women's smoking tended to be less affected by negative affect. Nicotine <span class="hlt">dependence</span> had little moderating effect on situational influences. Smoking <span class="hlt">rates</span> were higher when smokers were alone or with others smoking, and smoking restrictions reduced smoking <span class="hlt">rates</span>. However, the presence of others smoking undermined the effects of restrictions. The more sensitive point-process analyses confirmed earlier findings, including the surprising conclusion that negative affect by itself was not related to smoking <span class="hlt">rates</span>. Contrary to hypothesis, men's and not women's smoking was influenced by negative affect. Both smoking restrictions and the presence of others who are not smoking suppress smoking, but others’ smoking undermines the effects of restrictions. Point-process analyses of EMA data can bring out even small influences on smoking <span class="hlt">rate</span>. PMID:21480683</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhRvE..87a2710M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhRvE..87a2710M"><span>Unwinding and rewinding the nucleosome inner turn: Force <span class="hlt">dependence</span> of the kinetic <span class="hlt">rate</span> constants</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mochrie, S. G. J.; Mack, A. H.; Schlingman, D. J.; Collins, R.; Kamenetska, M.; Regan, L.</p> <p>2013-01-01</p> <p>A simple model for the force-<span class="hlt">dependent</span> unwinding and rewinding <span class="hlt">rates</span> of the nucleosome inner turn is constructed and quantitatively compared to the results of recent measurements [A. H. Mack , J. Mol. Biol.JMOBAK0022-283610.1016/j.jmb.2012.08.021 423, 687 (2012)]. First, a coarse-grained model for the histone-DNA free-energy landscape that incorporates both an elastic free-energy barrier and specific histone-DNA bonds is developed. Next, a theoretical expression for the <span class="hlt">rate</span> of transitions across a piecewise linear free-energy landscape with multiple minima and maxima is presented. Then, the model free-energy landscape, approximated as a piecewise linear function, and the theoretical expression for the transition <span class="hlt">rates</span> are combined to construct a model for the force-<span class="hlt">dependent</span> unwinding and rewinding <span class="hlt">rates</span> of the nucleosome inner turn. Least-mean-squares fitting of the model <span class="hlt">rates</span> to the <span class="hlt">rates</span> observed in recent experiments <span class="hlt">rates</span> demonstrates that this model is able to well describe the force-<span class="hlt">dependent</span> unwinding and rewinding <span class="hlt">rates</span> of the nucleosome inner turn, observed in the recent experiments, except at the highest forces studied, where an additional ad hoc term is required to describe the data, which may be interpreted as an indication of an alternate high-force nucleosome disassembly pathway, that bypasses simple unwinding. The good agreement between the measurements and the model at lower forces demonstrates that both specific histone-DNA contacts and an elastic free-energy barrier play essential roles for nucleosome winding and unwinding, and quantifies their relative contributions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23410362','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23410362"><span>Unwinding and rewinding the nucleosome inner turn: force <span class="hlt">dependence</span> of the kinetic <span class="hlt">rate</span> constants.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mochrie, S G J; Mack, A H; Schlingman, D J; Collins, R; Kamenetska, M; Regan, L</p> <p>2013-01-01</p> <p>A simple model for the force-<span class="hlt">dependent</span> unwinding and rewinding <span class="hlt">rates</span> of the nucleosome inner turn is constructed and quantitatively compared to the results of recent measurements [A. H. Mack et al., J. Mol. Biol. 423, 687 (2012)]. First, a coarse-grained model for the histone-DNA free-energy landscape that incorporates both an elastic free-energy barrier and specific histone-DNA bonds is developed. Next, a theoretical expression for the <span class="hlt">rate</span> of transitions across a piecewise linear free-energy landscape with multiple minima and maxima is presented. Then, the model free-energy landscape, approximated as a piecewise linear function, and the theoretical expression for the transition <span class="hlt">rates</span> are combined to construct a model for the force-<span class="hlt">dependent</span> unwinding and rewinding <span class="hlt">rates</span> of the nucleosome inner turn. Least-mean-squares fitting of the model <span class="hlt">rates</span> to the <span class="hlt">rates</span> observed in recent experiments <span class="hlt">rates</span> demonstrates that this model is able to well describe the force-<span class="hlt">dependent</span> unwinding and rewinding <span class="hlt">rates</span> of the nucleosome inner turn, observed in the recent experiments, except at the highest forces studied, where an additional ad hoc term is required to describe the data, which may be interpreted as an indication of an alternate high-force nucleosome disassembly pathway, that bypasses simple unwinding. The good agreement between the measurements and the model at lower forces demonstrates that both specific histone-DNA contacts and an elastic free-energy barrier play essential roles for nucleosome winding and unwinding, and quantifies their relative contributions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22493481','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22493481"><span>Simulation of biochemical reactions with time-<span class="hlt">dependent</span> <span class="hlt">rates</span> by the rejection-based algorithm</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Thanh, Vo Hong; Priami, Corrado</p> <p>2015-08-07</p> <p>We address the problem of simulating biochemical reaction networks with time-<span class="hlt">dependent</span> <span class="hlt">rates</span> and propose a new algorithm based on our rejection-based stochastic simulation algorithm (RSSA) [Thanh et al., J. Chem. Phys. 141(13), 134116 (2014)]. The computation for selecting next reaction firings by our time-<span class="hlt">dependent</span> RSSA (tRSSA) is computationally efficient. Furthermore, the generated trajectory is exact by exploiting the rejection-based mechanism. We benchmark tRSSA on different biological systems with varying forms of reaction <span class="hlt">rates</span> to demonstrate its applicability and efficiency. We reveal that for nontrivial cases, the selection of reaction firings in existing algorithms introduces approximations because the integration of reaction <span class="hlt">rates</span> is very computationally demanding and simplifying assumptions are introduced. The selection of the next reaction firing by our approach is easier while preserving the exactness.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000121259','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000121259"><span>Implementation of Laminate Theory Into Strain <span class="hlt">Rate</span> <span class="hlt">Dependent</span> Micromechanics Analysis of Polymer Matrix Composites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldberg, Robert K.</p> <p>2000-01-01</p> <p>A research program is in progress to develop strain <span class="hlt">rate</span> <span class="hlt">dependent</span> deformation and failure models for the analysis of polymer matrix composites subject to impact loads. Previously, strain <span class="hlt">rate</span> <span class="hlt">dependent</span> inelastic constitutive equations developed to model the polymer matrix were implemented into a mechanics of materials based micromechanics method. In the current work, the computation of the effective inelastic strain in the micromechanics model was modified to fully incorporate the Poisson effect. The micromechanics equations were also combined with classical laminate theory to enable the analysis of symmetric multilayered laminates subject to in-plane loading. A quasi-incremental trapezoidal integration method was implemented to integrate the constitutive equations within the laminate theory. Verification studies were conducted using an AS4/PEEK composite using a variety of laminate configurations and strain <span class="hlt">rates</span>. The predicted results compared well with experimentally obtained values.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhRvE..77e6102P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhRvE..77e6102P"><span>Size-<span class="hlt">dependent</span> standard deviation for growth <span class="hlt">rates</span>: Empirical results and theoretical modeling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Podobnik, Boris; Horvatic, Davor; Pammolli, Fabio; Wang, Fengzhong; Stanley, H. Eugene; Grosse, I.</p> <p>2008-05-01</p> <p>We study annual logarithmic growth <span class="hlt">rates</span> R of various economic variables such as exports, imports, and foreign debt. For each of these variables we find that the distributions of R can be approximated by double exponential (Laplace) distributions in the central parts and power-law distributions in the tails. For each of these variables we further find a power-law <span class="hlt">dependence</span> of the standard deviation σ(R) on the average size of the economic variable with a scaling exponent surprisingly close to that found for the gross domestic product (GDP) [Phys. Rev. Lett. 81, 3275 (1998)]. By analyzing annual logarithmic growth <span class="hlt">rates</span> R of wages of 161 different occupations, we find a power-law <span class="hlt">dependence</span> of the standard deviation σ(R) on the average value of the wages with a scaling exponent β≈0.14 close to those found for the growth of exports, imports, debt, and the growth of the GDP. In contrast to these findings, we observe for payroll data collected from 50 states of the USA that the standard deviation σ(R) of the annual logarithmic growth <span class="hlt">rate</span> R increases monotonically with the average value of payroll. However, also in this case we observe a power-law <span class="hlt">dependence</span> of σ(R) on the average payroll with a scaling exponent β≈-0.08 . Based on these observations we propose a stochastic process for multiple cross-correlated variables where for each variable (i) the distribution of logarithmic growth <span class="hlt">rates</span> decays exponentially in the central part, (ii) the distribution of the logarithmic growth <span class="hlt">rate</span> decays algebraically in the far tails, and (iii) the standard deviation of the logarithmic growth <span class="hlt">rate</span> <span class="hlt">depends</span> algebraically on the average size of the stochastic variable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21915323','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21915323"><span>Bacteria stimulate <span class="hlt">hatching</span> of yellow fever mosquito eggs.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ponnusamy, Loganathan; Böröczky, Katalin; Wesson, Dawn M; Schal, Coby; Apperson, Charles S</p> <p>2011-01-01</p> <p>Aedes aegypti Linnaeus is a peridomestic mosquito that lays desiccation-resistant eggs in water-filled human-made containers. Previous investigations connected egg <span class="hlt">hatching</span> with declining dissolved oxygen (DO) that is associated with bacterial growth. However, past studies failed to uncouple DO from other potential stimulatory factors and they contained little quantitative information about the microbial community; consequently, a direct role for bacteria or compounds associated with bacteria in stimulating egg <span class="hlt">hatching</span> cannot be dismissed. Environmental factors stimulating <span class="hlt">hatch</span> of Ae. aegypti eggs were investigated using non-sterile and sterile white oak leaf (WOL) infusions and a bacterial culture composed of a mix of 14 species originally isolated from bamboo leaf infusion. In WOL infusion with active microbes, 92.4% of eggs <span class="hlt">hatched</span> in 2-h at an average DO concentration of 2.4 ppm. A 24-h old bacterial culture with a DO concentration of 0.73 ppm also stimulated 95.2% of eggs <span class="hlt">hatch</span> within 1-h. In contrast, only 4.0% of eggs <span class="hlt">hatched</span> in sterile infusion, whose DO averaged 7.4 ppm. Effects of bacteria were uncoupled from DO by exposing eggs to bacterial cells suspended in NaCl solution. Over a 4-h exposure period, 93.8% of eggs <span class="hlt">hatched</span> while DO concentration changed minimally from 7.62 to 7.50 ppm. Removal of bacteria by ultra-filtration and cell-free filtrate resulted in only 52.0% of eggs <span class="hlt">hatching</span> after 4-h at an average DO concentration of 5.5 ppm. Collectively, the results provide compelling evidence that bacteria or water-soluble compounds secreted by bacteria, not just low DO concentration, stimulate <span class="hlt">hatching</span> of Ae. aegypti eggs. However, the specific cues involved remain to be identified. These research findings contribute new insight into an important aspect of the oviposition biology of Ae. aegypti, a virus vector of global importance, providing the basis for a new paradigm of environmental factors involved in egg <span class="hlt">hatching</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3167859','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3167859"><span>Bacteria Stimulate <span class="hlt">Hatching</span> of Yellow Fever Mosquito Eggs</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ponnusamy, Loganathan; Böröczky, Katalin; Wesson, Dawn M.; Schal, Coby; Apperson, Charles S.</p> <p>2011-01-01</p> <p>Background Aedes aegypti Linnaeus is a peridomestic mosquito that lays desiccation-resistant eggs in water-filled human-made containers. Previous investigations connected egg <span class="hlt">hatching</span> with declining dissolved oxygen (DO) that is associated with bacterial growth. However, past studies failed to uncouple DO from other potential stimulatory factors and they contained little quantitative information about the microbial community; consequently, a direct role for bacteria or compounds associated with bacteria in stimulating egg <span class="hlt">hatching</span> cannot be dismissed. Methodology/Principal Findings Environmental factors stimulating <span class="hlt">hatch</span> of Ae. aegypti eggs were investigated using non-sterile and sterile white oak leaf (WOL) infusions and a bacterial culture composed of a mix of 14 species originally isolated from bamboo leaf infusion. In WOL infusion with active microbes, 92.4% of eggs <span class="hlt">hatched</span> in 2-h at an average DO concentration of 2.4 ppm. A 24-h old bacterial culture with a DO concentration of 0.73 ppm also stimulated 95.2% of eggs <span class="hlt">hatch</span> within 1-h. In contrast, only 4.0% of eggs <span class="hlt">hatched</span> in sterile infusion, whose DO averaged 7.4 ppm. Effects of bacteria were uncoupled from DO by exposing eggs to bacterial cells suspended in NaCl solution. Over a 4-h exposure period, 93.8% of eggs <span class="hlt">hatched</span> while DO concentration changed minimally from 7.62 to 7.50 ppm. Removal of bacteria by ultra-filtration and cell-free filtrate resulted in only 52.0% of eggs <span class="hlt">hatching</span> after 4-h at an average DO concentration of 5.5 ppm. Conclusions/Significance Collectively, the results provide compelling evidence that bacteria or water-soluble compounds secreted by bacteria, not just low DO concentration, stimulate <span class="hlt">hatching</span> of Ae. aegypti eggs. However, the specific cues involved remain to be identified. These research findings contribute new insight into an important aspect of the oviposition biology of Ae. aegypti, a virus vector of global importance, providing the basis for a new paradigm of environmental</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28119633','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28119633"><span>Energetic Effects of Pre-<span class="hlt">hatch</span> Albumen Removal on Embryonic Development and Early Ontogeny in Gallus gallus.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Peña-Villalobos, Isaac; Piriz, Gabriela; Palma, Verónica; Sabat, Pablo</p> <p>2016-01-01</p> <p>Studies on the yolk and albumen content in bird eggs, and the effects of variations in their relative loads in the phenotype of the birds, have revealed multiple consequences at different levels of biological organization, from biochemical traits to behavior. However, little is known about the effect of albumen variation on energetics performance during development and early ontogeny, despite the fact that variation in energy expenditure may have consequences in terms of fitness for both feral and domestic species. In this work, we evaluated experimentally whether variations in the content of albumen of Gallus gallus eggs could generate differences in metabolic <span class="hlt">rates</span> during embryonic development. Additionally, we assessed changes in the activity of mitochondrial enzymes (cytochrome c oxidase and citrate synthase) in skeletal muscles and liver. Finally, we evaluated the success of <span class="hlt">hatching</span> of these embryos and their metabolic <span class="hlt">rates</span> (MR) post-<span class="hlt">hatching</span>. The results revealed a significant reduction in MR in the last fifth of embryonic life, and reduced catabolic activities in the skeletal muscle of chicks <span class="hlt">hatched</span> from albumen-removed eggs. However, the same group demonstrated an increase in catabolic activity in the liver, suggesting the existence of changes in energy allocation between tissues. Besides, we found a decrease in <span class="hlt">hatching</span> success in the albumen-removed group, suggesting a negative effect of the lower albumen content on eggs, possibly due to lower catabolic activities in skeletal muscle. We also found a compensatory phenomenon in the first week after <span class="hlt">hatching</span>, i.e., birds from albumen-removed eggs did not show a decrease in MR either at thermoneutral temperatures or at 10°C, compared to the control group. Collectively, our data suggest that a reduction in albumen may generate a trade-off between tissue metabolic activities, and may explain the differences in metabolic <span class="hlt">rates</span> and <span class="hlt">hatching</span> success, supporting the immediate adaptive response (IAR) hypothesis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5222843','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5222843"><span>Energetic Effects of Pre-<span class="hlt">hatch</span> Albumen Removal on Embryonic Development and Early Ontogeny in Gallus gallus</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Peña-Villalobos, Isaac; Piriz, Gabriela; Palma, Verónica; Sabat, Pablo</p> <p>2017-01-01</p> <p>Studies on the yolk and albumen content in bird eggs, and the effects of variations in their relative loads in the phenotype of the birds, have revealed multiple consequences at different levels of biological organization, from biochemical traits to behavior. However, little is known about the effect of albumen variation on energetics performance during development and early ontogeny, despite the fact that variation in energy expenditure may have consequences in terms of fitness for both feral and domestic species. In this work, we evaluated experimentally whether variations in the content of albumen of Gallus gallus eggs could generate differences in metabolic <span class="hlt">rates</span> during embryonic development. Additionally, we assessed changes in the activity of mitochondrial enzymes (cytochrome c oxidase and citrate synthase) in skeletal muscles and liver. Finally, we evaluated the success of <span class="hlt">hatching</span> of these embryos and their metabolic <span class="hlt">rates</span> (MR) post-<span class="hlt">hatching</span>. The results revealed a significant reduction in MR in the last fifth of embryonic life, and reduced catabolic activities in the skeletal muscle of chicks <span class="hlt">hatched</span> from albumen-removed eggs. However, the same group demonstrated an increase in catabolic activity in the liver, suggesting the existence of changes in energy allocation between tissues. Besides, we found a decrease in <span class="hlt">hatching</span> success in the albumen-removed group, suggesting a negative effect of the lower albumen content on eggs, possibly due to lower catabolic activities in skeletal muscle. We also found a compensatory phenomenon in the first week after <span class="hlt">hatching</span>, i.e., birds from albumen-removed eggs did not show a decrease in MR either at thermoneutral temperatures or at 10°C, compared to the control group. Collectively, our data suggest that a reduction in albumen may generate a trade-off between tissue metabolic activities, and may explain the differences in metabolic <span class="hlt">rates</span> and <span class="hlt">hatching</span> success, supporting the immediate adaptive response (IAR) hypothesis</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4282296','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4282296"><span>Spawning Characteristics and Artificial <span class="hlt">Hatching</span> of Female Mottled Skate, Beringraja pulchra in the West Coast of Korea</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kang, Hee-Woong; Jo, Yeong-Rok; Kang, Duk-Yong; Jeong, Gyeong-Suk; Jo, Hyun-Su</p> <p>2013-01-01</p> <p>The gonadsomatic index (GSI) of mottled skate was the highest in April, GSI and HSI showed a reverse phase for its reproductive cycle. The fish had one pair of egg capsules, having 1 to 7 fertilized eggs, and spawned all the year round. When surveying the reproductive characteristics of females over 63 ㎝ in disc width, we found the spawning peak was between April to June, and the appearance ratio of egg capsules was the highest in May (32.1%). The eggs were <span class="hlt">hatched</span> at 8°C, 13°C, 18°C, water temperature (12.8 to 24.2°C), and the best <span class="hlt">hatching</span> temperature was 18°C. The number of fish <span class="hlt">hatched</span> was 4 to 5 fish/egg capsules, and the <span class="hlt">hatching</span> <span class="hlt">rate</span> was 100%. The sex ratios of <span class="hlt">hatching</span> larvae were 45.5% female and 54.5% male. Therefore this study will provide fundamental data and information for artificial reproduction of the mottled skate. PMID:25949140</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23661096','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23661096"><span>Pesticide exposure impacts not only <span class="hlt">hatching</span> of dormant eggs, but also hatchling survival and performance in the water flea Daphnia magna.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Navis, Sabine; Waterkeyn, Aline; Voet, Tom; De Meester, Luc; Brendonck, Luc</p> <p>2013-07-01</p> <p>Laboratory ecotoxicity tests and biomonitoring in aquatic systems are currently based on the active component of invertebrate communities. Even though dormant egg banks are crucial for the long term survival and community dynamics of many aquatic organisms, the effects of anthropogenic activities on dormant egg bank dynamics have rarely been studied. In this study we investigated the effects of two pesticides with a different mode of action (carbaryl and fenoxycarb) on <span class="hlt">hatching</span> of Daphnia magna dormant eggs (ephippia) as well as on survival, growth and reproduction of the <span class="hlt">hatched</span> neonates. Dormant eggs were exposed to the pesticides simultaneously to incubation under conditions that induce <span class="hlt">hatching</span> (long daylight and 20 °C). Carbaryl had no negative effects on embryonic development or <span class="hlt">hatching</span> <span class="hlt">rate</span> up to concentrations almost 1,000 times the median effect concentration (EC50) of neonate survival in acute tests. Fenoxycarb, however, had a significant dose-related effect by delaying or completely stopping the <span class="hlt">hatching</span> process and caused severe abnormalities in developing individuals. Both pesticides had significant negative effects on survival and reproduction of the hatchlings. These results indicate that, in addition to inducing mortality of active individuals, pesticides can affect zooplankton communities by altering <span class="hlt">hatching</span> dynamics and life history traits of <span class="hlt">hatched</span> individuals. We briefly discuss how such pollution induced changes in the benthic-pelagic coupling could translate into trans-generational effects impacting ecological and evolutionary dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24656375','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24656375"><span>Depth and <span class="hlt">rate</span> <span class="hlt">dependent</span> mechanical behaviors for articular cartilage: experiments and theoretical predictions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gao, Li-Lan; Zhang, Chun-Qiu; Gao, Hong; Liu, Zhi-Dong; Xiao, Peng-Peng</p> <p>2014-05-01</p> <p>An optimized digital image correlation (DIC) technique was applied to investigate the depth-<span class="hlt">dependent</span> mechanical properties of articular cartilage and simultaneously the depth-<span class="hlt">dependent</span> nonlinear viscoelastic constitutive model of cartilage was proposed and validated. The creep tests were performed with different stress levels and it is found that the initial strain and instantaneous strain increase; however the creep compliance decreases with the increase of compressive stress. The depth-<span class="hlt">dependent</span> creep strain of cartilage was obtained by analyzing the images acquired using the optimized DIC technique. Moreover the inhomogeneous creep compliance distributions within the tissues were determined at different creep time points. It is noted that both creep strain and creep compliance with different creep times decrease from cartilage surface to deep. The depth-<span class="hlt">dependent</span> creep compliance increases with creep time and the increasing amplitude of creep compliance decreases along cartilage depth. The depth-<span class="hlt">dependent</span> and stress <span class="hlt">rate</span> <span class="hlt">dependent</span> nonlinear stress and strain curves were obtained for articular cartilage through uniaxial compression tests. It is found that the Young's modulus of cartilage increases obviously along cartilage depth from superficial layer to deep layer and the Young's modulus of different layers for cartilage increases with the increase of stress <span class="hlt">rate</span>. The Poisson's ratio of cartilage increases along cartilage depth with given compressive strain and the Poisson's ratio of different layers decreases with the increase of compressive strain. The depth-<span class="hlt">dependent</span> nonlinear viscoelastic constitutive model was proposed and some creep data were applied to determine the parameters of the model. The depth-<span class="hlt">dependent</span> compressive behaviors of cartilage were predicted by the model and the results show that there are good agreements between the experimental data and predictions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title9-vol1/pdf/CFR-2011-title9-vol1-sec82-9.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title9-vol1/pdf/CFR-2011-title9-vol1-sec82-9.pdf"><span>9 CFR 82.9 - Interstate movement of <span class="hlt">hatching</span> eggs from a quarantined area.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-01-01</p> <p>... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Interstate movement of <span class="hlt">hatching</span> eggs... Interstate movement of <span class="hlt">hatching</span> eggs from a quarantined area. <span class="hlt">Hatching</span> eggs from birds or poultry not known...) The <span class="hlt">hatching</span> eggs are accompanied by a permit obtained in accordance with § 82.11; (b) Copies of...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title9-vol1/pdf/CFR-2010-title9-vol1-sec82-9.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title9-vol1/pdf/CFR-2010-title9-vol1-sec82-9.pdf"><span>9 CFR 82.9 - Interstate movement of <span class="hlt">hatching</span> eggs from a quarantined area.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-01-01</p> <p>... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Interstate movement of <span class="hlt">hatching</span> eggs... Interstate movement of <span class="hlt">hatching</span> eggs from a quarantined area. <span class="hlt">Hatching</span> eggs from birds or poultry not known...) The <span class="hlt">hatching</span> eggs are accompanied by a permit obtained in accordance with § 82.11; (b) Copies of...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title9-vol1/pdf/CFR-2013-title9-vol1-sec82-9.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title9-vol1/pdf/CFR-2013-title9-vol1-sec82-9.pdf"><span>9 CFR 82.9 - Interstate movement of <span class="hlt">hatching</span> eggs from a quarantined area.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-01-01</p> <p>... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Interstate movement of <span class="hlt">hatching</span> eggs... Interstate movement of <span class="hlt">hatching</span> eggs from a quarantined area. <span class="hlt">Hatching</span> eggs from birds or poultry not known...) The <span class="hlt">hatching</span> eggs are accompanied by a permit obtained in accordance with § 82.11; (b) Copies of...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title9-vol1/pdf/CFR-2012-title9-vol1-sec82-9.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title9-vol1/pdf/CFR-2012-title9-vol1-sec82-9.pdf"><span>9 CFR 82.9 - Interstate movement of <span class="hlt">hatching</span> eggs from a quarantined area.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-01-01</p> <p>... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Interstate movement of <span class="hlt">hatching</span> eggs... Interstate movement of <span class="hlt">hatching</span> eggs from a quarantined area. <span class="hlt">Hatching</span> eggs from birds or poultry not known...) The <span class="hlt">hatching</span> eggs are accompanied by a permit obtained in accordance with § 82.11; (b) Copies of...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1912324R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1912324R"><span>Strain <span class="hlt">rate</span> <span class="hlt">dependent</span> activation of slip systems in calcite marbles from Syros (Cyclades, Greece)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rogowitz, Anna; Grasemann, Bernhard; Morales, Luiz F. G.; Huet, Benjamin; White, Joseph C.</p> <p>2017-04-01</p> <p>The activation of certain slip systems in calcite has been experimentally proven to be highly temperature <span class="hlt">dependent</span>, but also the strain <span class="hlt">rate</span> plays an important role on the activation of the dominant slip system. In this study, observations from a flanking structure (i.e. shear zone) that developed under lower greenschist-facies conditions, in an almost pure calcite marble (Syros Island, Greece) are presented. The shear zone is characterized by a strain gradient from the slightly deformed tips (γ ˜ 50) to the highly strained centre (γ up to 1000) while the host rock is moderately deformed (γ ˜ 3). During the shear zone development, the strain gradient coincided with a strain <span class="hlt">rate</span> gradient with strain <span class="hlt">rate</span> varying from 10-13 to 10-9 s-1. The studied outcrop thus represents the final state of a natural experiment and gives us a great opportunity to get natural constraints on strain <span class="hlt">rate</span> <span class="hlt">dependent</span> mechanical behaviour in a calcite marble. Detailed microstructural analyses have been performed via optical microscopy, electron microscopy, electron backscatter diffraction mapping and transmission electron microscopy, on samples from the highly strained shear zone and the host rock. The analyses show that the calcite microfabric varies <span class="hlt">depending</span> on position within the shear zone, indicating activation of different deformation, recrystallization mechanisms and slip systems at different strain <span class="hlt">rates</span>. Up to strain <span class="hlt">rates</span> of ˜10-10 s-1 the marble deformed exclusively within the dislocation creep field, showing a change in recrystallization mechanism and dominant active slip system. While the marble preferentially recrystallized by grain boundary migration at relatively low strain <span class="hlt">rates</span> (˜10-13 s-1), subgrain rotation recrystallization seems to be the dominant mechanism at higher strain <span class="hlt">rates</span> (˜10-12 to 10-10 s-1). At higher strain <span class="hlt">rates</span> (˜10-9 s-1), the recrystallization mechanism is bulging, resulting in the development of an extremely fine grained ultramylonite</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.S31A2213D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.S31A2213D"><span>The systematic study of the stability of forecasts in the <span class="hlt">rate</span>- and state-<span class="hlt">dependent</span> model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>De Gaetano, D.; McCloskey, J.; Nalbant, S. S.</p> <p>2011-12-01</p> <p>Numerous observations have shown a general spatial correlation between positive Coulomb failure stress changes due to an earthquake and the locations of aftershocks. However this correlation does not give any indication of the <span class="hlt">rate</span> from which we can infer the magnitude using the Gutenberg-Richter law. Dieterich's <span class="hlt">rate</span>- and state-<span class="hlt">dependent</span> model can be used to obtain a forecast of the observed aftershock <span class="hlt">rate</span> for the space and time evolution of seismicity caused by stress changes applied to an infinite population of nucleating patches. The seismicity <span class="hlt">rate</span> changes on this model <span class="hlt">depend</span> on eight parameters: the stressing <span class="hlt">rate</span>, the amplitude of the stress perturbation, the physical constitutive properties of faults, the spatial parameters (location and radii of the cells), the start and duration of each of the temporal windows as well as the background seismicity <span class="hlt">rate</span>. The background seismicity is declustered using the epidemic type aftershock sequence model. We use the 1992 Landers earthquake as a case study, using the Southern California Earthquake Data Centre (SCEDC) catalogue, to examine if Dieterich's <span class="hlt">rate</span>- and state-<span class="hlt">dependent</span> model can forecast the aftershock seismicity <span class="hlt">rate</span>. We perform a systematic study on a range of values on all the parameters to test the forecasting ability of this model. The results obtained suggest variable success in forecasting, when varying the values for the parameters, with the spatial and temporal parameters being the most sensitive. The Omori-Utsu law describes the aftershock <span class="hlt">rate</span> as a power law in time following the main shock and <span class="hlt">depends</span> on only three parameters: the aftershock productivity, the elapsed time since the main shock and the constant time shift, all of which can be estimated in the early part of the aftershock sequence and then extrapolated to give a long term <span class="hlt">rate</span> forecast. All parameters are estimated using maximum likelihood methods. We compare the Dieterich and the Omori-Utsu forecasts using the Akaike information</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21463315','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21463315"><span>The effects of temperature change on the <span class="hlt">hatching</span> success and larval survival of largemouth bass Micropterus salmoides and smallmouth bass Micropterus dolomieu.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Landsman, S J; Gingerich, A J; Philipp, D P; Suski, C D</p> <p>2011-04-01</p> <p>In this study, the effects of abrupt temperature change on the <span class="hlt">hatching</span> success and larval survival of eggs, yolk-sac larvae (YSL) and larvae above nest (LAN), for both largemouth bass Micropterus salmoides and smallmouth bass Micropterus dolomieu were quantified. Temperature had a significant effect on <span class="hlt">hatching</span> success and time to 50% mortality, with large heat shocks causing accelerated mortality. The temperature changes shown to influence survival of all life stages, however, were beyond what is typically experienced in the wild. Micropterus salmoides had greater egg <span class="hlt">hatching</span> success <span class="hlt">rates</span> and increased survival <span class="hlt">rates</span> at YSL and LAN stages, relative to M. dolomieu. Additionally, egg <span class="hlt">hatching</span> success and survival of LAN varied across nests within the study. These findings suggest that temperature alone may not account for variations in year-class strength and may emphasize the need for protection of the nest-guarding male Micropterus spp. to ensure recruitment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/9390609','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/9390609"><span>Time-<span class="hlt">dependent</span> changes in heart <span class="hlt">rate</span> and pupil size during desflurane or sevoflurane anesthesia.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tayefeh, F; Larson, M D; Sessler, D I; Eger, E I; Bowland, T</p> <p>1997-12-01</p> <p>To better characterize alterations in autonomic function associated with prolonged anesthesia, we tested the hypothesis that the time-<span class="hlt">dependent</span> effects of sevoflurane and desflurane differ. We studied seven male volunteers, each anesthetized for 8 h with 1.25 minimum alveolar anesthetic concentration desflurane on one study day and with 8 h sevoflurane on another. These volunteers did not undergo surgery and were minimally stimulated during the study. Measurements included blood pressure, heart <span class="hlt">rate</span>, pupillary size and light reactivity, concentrations of serum catecholamines, and carbon dioxide production. Over time, heart <span class="hlt">rate</span> and pupil size increased significantly. During 6 of the 14 anesthetics (45%), heart <span class="hlt">rate</span> at some point exceeded 95 bpm; similarly, pupil size at some time exceeded 5 mm during 8 anesthetics (57%). In contrast, plasma catecholamine concentrations and carbon dioxide production remained unchanged, and blood pressure remained nearly constant. There are thus substantial time-<span class="hlt">dependent</span> changes in autonomic functions during prolonged anesthesia, even in unstimulated, nonsurgical volunteers, but we could not detect a difference in these changes during desflurane compared with sevoflurane anesthesia. Pupil size and heart <span class="hlt">rate</span> changes are used to guide the delivery of anesthesia. In volunteers, pupil size and heart <span class="hlt">rate</span> increased with increasing duration of constant desflurane or sevoflurane anesthesia. Thus, anesthetic duration alters heart <span class="hlt">rate</span> and pupil size independent of surgery and changes in anesthetic delivery.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2620346','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2620346"><span>Influence of Temperature on Multiplication and Egg <span class="hlt">Hatching</span> of Longidorus africanus</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ploeg, Antoon T.</p> <p>1999-01-01</p> <p>Longidorus africanus multiplication on tomato was highest at 29 °C. Few nematodes were recovered after 6 weeks at soil temperatures of 35 °C or below 23 °C. The time to egg <span class="hlt">hatching</span> was shortest and the percentage of eggs <span class="hlt">hatching</span> was highest at 29 °C. The minimum temperature and the heat sum above this temperature required for egg development were calculated to be 14.3 °C and 94.08 degree-days, respectively. The thermal times required for egg development by L. africanus and L. elongatus were nearly identical. For both species the product of the base temperature and the heat sum was near constant, and at a temperature of 22.3 °C the <span class="hlt">rates</span> of egg development were equal. PMID:19270878</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27899034','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27899034"><span>Ionizing radiation sensitivity of the ocular lens and its dose <span class="hlt">rate</span> <span class="hlt">dependence</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hamada, Nobuyuki</p> <p>2017-10-01</p> <p>In 2011, the International Commission on Radiological Protection reduced the threshold for the lens effects of low linear energy transfer (LET) radiation. On one hand, the revised threshold of 0.5 Gy is much lower than previously recommended thresholds, but mechanisms behind high radiosensitivity remain incompletely understood. On the other hand, such a threshold is independent of dose <span class="hlt">rate</span>, in contrast to previously recommended separate thresholds each for single and fractionated/protracted exposures. Such a change was made predicated on epidemiological evidence suggesting that a threshold for fractionated/protracted exposures is not higher than an acute threshold, and that a chronic threshold is uncertain. Thus, the dose <span class="hlt">rate</span> <span class="hlt">dependence</span> is still unclear. This paper therefore reviews the current knowledge on the radiosensitivity of the lens and the dose <span class="hlt">rate</span> <span class="hlt">dependence</span> of radiation cataractogenesis, and discusses its mechanisms. Mounting biological evidence indicates that the lens cells are not necessarily radiosensitive to cell killing, and the high radiosensitivity of the lens thus appears to be attributable to other mechanisms (e.g., excessive proliferation, abnormal differentiation, a slow repair of DNA double-strand breaks, telomere, senescence, crystallin changes, non-targeted effects and inflammation). Both biological and epidemiological evidence generally supports the lack of dose <span class="hlt">rate</span> effects. However, there is also biological evidence for the tissue sparing dose <span class="hlt">rate</span> (or fractionation) effect of low-LET radiation and an enhancing inverse dose fractionation effect of high-LET radiation at a limited range of LET. Emerging epidemiological evidence in chronically exposed individuals implies the inverse dose <span class="hlt">rate</span> effect. Further biological and epidemiological studies are warranted to gain deeper knowledge on the radiosensitivity of the lens and dose <span class="hlt">rate</span> <span class="hlt">dependence</span> of radiation cataractogenesis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25774028','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25774028"><span>Effect of nesting environment on incubation temperature and <span class="hlt">hatching</span> success of Morelet's crocodile (Crocodylus moreletii) in an urban lake of Southeastern Mexico.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>López-Luna, Marco A; Hidalgo-Mihart, Mircea G; Aguirre-León, Gustavo; González-Ramón, Mariana Del C; Rangel-Mendoza, Judith A</p> <p>2015-01-01</p> <p>Incubation temperature is an important aspect in terms of biological performance among crocodiles, and several controlled experiments have demonstrated a significant relationship between incubation temperature, success in <span class="hlt">hatching</span> and survival of hatchlings. However, a few studies have tested these relationships in the wild. The objective of this study was to determine the relationship of nest characteristics and environment (<span class="hlt">hatch</span> year, nest basal area and height, clutch size, distance to shore line, and vegetation cover), to incubation temperature and <span class="hlt">hatching</span> success among Morelet's crocodile (Crocodylus moreletii). The study was carried out during the nesting seasons of Morelet's crocodile, from 2007 to 2009 in the Laguna de Las Ilusiones, an urban lake located in Villahermosa, Tabasco, Mexico. We physically characterized 18 nests and inserted a temperature data logger in each nest chamber. At the end of the nesting season and prior to <span class="hlt">hatching</span>, we recovered the crocodile eggs and data loggers and calculated <span class="hlt">hatching</span> success, under laboratory conditions. We related the environmental variables of the nest with the mean and fluctuation (standard deviation) of nest temperature, using linear models. We also related the environmental variables affecting the nest, to mean nest temperature and fluctuation in incubation temperature and to <span class="hlt">hatching</span> success, using linear models. Although we found differences in incubation temperature between nests, mean incubation temperature did not differ between years, but there were differences in nest thermal fluctuation between years. The mean incubation temperature for 11 nests (61.1%) was lower than the suggested Female-Male pivotal temperature (producing 50% of each sex) for this species, and all hatchlings obtained were males. There were no differences in clutch size between years, but <span class="hlt">hatching</span> success varied. Our study indicates that <span class="hlt">hatching</span> success <span class="hlt">depends</span> on certain environmental variables and nest conditions to which the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1150291','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1150291"><span>Density-<span class="hlt">Dependent</span> Demographic Variation Determines Extinction <span class="hlt">Rate</span> of Experimental Populations</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2005-01-01</p> <p>Understanding population extinctions is a chief goal of ecological theory. While stochastic theories of population growth are commonly used to forecast extinction, models used for prediction have not been adequately tested with experimental data. In a previously published experiment, variation in available food was experimentally manipulated in 281 laboratory populations of Daphnia magna to test hypothesized effects of environmental variation on population persistence. Here, half of those data were used to select and fit a stochastic model of population growth to predict extinctions of populations in the other half. When density-<span class="hlt">dependent</span> demographic stochasticity was detected and incorporated in simple stochastic models, <span class="hlt">rates</span> of population extinction were accurately predicted or only slightly biased. However, when density-<span class="hlt">dependent</span> demographic stochasticity was not accounted for, as is usual when forecasting extinction of threatened and endangered species, predicted extinction <span class="hlt">rates</span> were severely biased. Thus, an experimental demonstration shows that reliable estimates of extinction risk may be obtained for populations in variable environments if high-quality data are available for model selection and if density-<span class="hlt">dependent</span> demographic stochasticity is accounted for. These results suggest that further consideration of density-<span class="hlt">dependent</span> demographic stochasticity is required if predicted extinction <span class="hlt">rates</span> are to be relied upon for conservation planning. PMID:15934788</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SMaS...26d5001L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SMaS...26d5001L"><span>On <span class="hlt">rate-dependent</span> mechanical model for adaptive magnetorheological elastomer base isolator</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Yancheng; Li, Jianchun</p> <p>2017-04-01</p> <p>This paper presents research on the phenomenological model of an adaptive base isolator. The adaptive base isolator is made of field-<span class="hlt">dependent</span> magnetorheological elastomer (MRE) which can alter its physical property under application of magnetic field. Experimental testing demonstrated that the developed MRE base isolator possesses an amazing ability to vary its stiffness under applied magnetic field. However, several challenges have been encountered when it comes modeling such novel device. For example, under a large deformation, the MRE base isolator exhibits a clear strain stiffening effect and this behavior escalates with the increasing of applied current. In addition, the MRE base isolator has also shown typical <span class="hlt">rate-dependent</span> behavior. Following a review on mechanical models for viscos-elastic rubber devices, a novel <span class="hlt">rate-dependent</span> model is proposed in this paper to capture the behavior of the new MRE base isolator. To develop a generalized model, the proposed model was evaluated using its performance under random displacement input and a seismic input. It shows that the proposed <span class="hlt">rate-dependent</span> model can successfully describe the complex behavior of the device.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26135219','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26135219"><span>Viscosity <span class="hlt">Dependence</span> of Some Protein and Enzyme Reaction <span class="hlt">Rates</span>: Seventy-Five Years after Kramers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sashi, Pulikallu; Bhuyan, Abani K</p> <p>2015-07-28</p> <p>Kramers <span class="hlt">rate</span> theory is a milestone in chemical reaction research, but concerns regarding the basic understanding of condensed phase reaction <span class="hlt">rates</span> of large molecules in viscous milieu persist. Experimental studies of Kramers theory rely on scaling reaction <span class="hlt">rates</span> with inverse solvent viscosity, which is often equated with the bulk friction coefficient based on simple hydrodynamic relations. Apart from the difficulty of abstraction of the prefactor details from experimental data, it is not clear why the linearity of <span class="hlt">rate</span> versus inverse viscosity, k ∝ η(-1), deviates widely for many reactions studied. In most cases, the deviation simulates a power law k ∝ η(-n), where the exponent n assumes fractional values. In <span class="hlt">rate</span>-viscosity studies presented here, results for two reactions, unfolding of cytochrome c and cysteine protease activity of human ribosomal protein S4, show an exceedingly overdamped <span class="hlt">rate</span> over a wide viscosity range, registering n values up to 2.4. Although the origin of this extraordinary reaction friction is not known at present, the results indicate that the viscosity exponent need not be bound by the 0-1 limit as generally suggested. For the third reaction studied here, thermal dissociation of CO from nativelike cytochrome c, the <span class="hlt">rate</span>-viscosity behavior can be explained using Grote-Hynes theory of time-<span class="hlt">dependent</span> friction in conjunction with correlated motions intrinsic to the protein. Analysis of the glycerol viscosity-<span class="hlt">dependent</span> <span class="hlt">rate</span> for the CO dissociation reaction in the presence of urea as the second variable shows that the protein stabilizing effect of subdenaturing amounts of urea is not affected by the bulk viscosity. It appears that a myriad of factors as diverse as parameter uncertainty due to the difficulty of knowing the exact reaction friction and both mode and consequences of protein-solvent interaction work in a complex manner to convey as though Kramers <span class="hlt">rate</span> equation is not absolute.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013NatCC...3..244V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013NatCC...3..244V"><span>Evolutionary response of the egg <span class="hlt">hatching</span> date of a herbivorous insect under climate change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van Asch, Margriet; Salis, Lucia; Holleman, Leonard J. M.; van Lith, Bart; Visser, Marcel E.</p> <p>2013-03-01</p> <p>Under changing climatic conditions, species need to adapt to their new environment. Genetic adaptation is crucial to prevent population extinction but examples where climate change leads to genetic changes in wild populations have been few. The synchronization between the timing of egg <span class="hlt">hatching</span> of a herbivorous insect, the winter moth (Operophtera brumata), and the seasonal bud burst of its food plant, oak (Quercus robur), has been disrupted by climate change and a quantitative genetic model predicts that selection will delay the egg <span class="hlt">hatching</span> date. Here we show, using both long-term observational data and experiments, that the egg <span class="hlt">hatching</span> date has changed genetically, resulting in closer synchrony with oak bud burst. The observed <span class="hlt">rate</span> of change matches the predicted <span class="hlt">rate</span> of change of one day per year. Hence, altered selection pressures, caused by environmental change, result in a rapid adaptive response in insect phenology. These genetic changes in a key life-history trait in this herbivorous insect therefore seem to be fast enough to match the climate-change-induced advancement of their host phenology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28086752','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28086752"><span>Single genome retrieval of context-<span class="hlt">dependent</span> variability in mutation <span class="hlt">rates</span> for human germline.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sahakyan, Aleksandr B; Balasubramanian, Shankar</p> <p>2017-01-13</p> <p>Accurate knowledge of the core components of substitution <span class="hlt">rates</span> is of vital importance to understand genome evolution and dynamics. By performing a single-genome and direct analysis of 39,894 retrotransposon remnants, we reveal sequence context-<span class="hlt">dependent</span> germline nucleotide substitution <span class="hlt">rates</span> for the human genome. The <span class="hlt">rates</span> are characterised through <span class="hlt">rate</span> constants in a time-domain, and are made available through a dedicated program (Trek) and a stand-alone database. Due to the nature of the method design and the imposed stringency criteria, we expect our <span class="hlt">rate</span> constants to be good estimates for the <span class="hlt">rates</span> of spontaneous mutations. Benefiting from such data, we study the short-range nucleotide (up to 7-mer) organisation and the germline basal substitution propensity (BSP) profile of the human genome; characterise novel, CpG-independent, substitution prone and resistant motifs; confirm a decreased tendency of moieties with low BSP to undergo somatic mutations in a number of cancer types; and, produce a Trek-based estimate of the overall mutation <span class="hlt">rate</span> in human. The extended set of <span class="hlt">rate</span> constants we report may enrich our resources and help advance our understanding of genome dynamics and evolution, with possible implications for the role of spontaneous mutations in the emergence of pathological genotypes and neutral evolution of proteomes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.1997W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.1997W"><span><span class="hlt">Rate</span>- and state-<span class="hlt">dependent</span> seismicity during fluid injection in rocks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wenzel, Friedemann</p> <p>2015-04-01</p> <p>Dieterich (1994) developed a theoretical frame of seismicity evolution due to stress changes in a medium based on <span class="hlt">rate</span>- and state-theory of frictional fault motion. The theory assumes a volume density of seismic faults with a specific initial slip velocity distribution upon which the stress changes act. Each fault then follows the <span class="hlt">rate</span>- and state-<span class="hlt">dependent</span> frictional law where instabilities develop not as Coulomb failure. The evolution is expressed in the form of a differential equation, which can be used for aftershock generation after a shear stress change caused by a main shock but equally well for normal stress changes on faults caused by fluid pressure changes resulting from injection. For a constant injection <span class="hlt">rate</span> the seismic activity increases at a given distance from the injection point once the pressure exceeds a threshold value. If the pressure <span class="hlt">rate</span> is high enough the seismic activity becomes proportional to the local pressure <span class="hlt">rate</span> in accordance with criticality theory of Shapiro (2002). Once the <span class="hlt">rate</span> drops the seismicity reduced to lower levels. Shut off and variable injection <span class="hlt">rates</span> must be evaluated numerically but lead to results comparable to the criticality theory. The presentation outlines the physical concept of the <span class="hlt">rate</span>- and state-approach in comparison to the criticality approach and shows the main analytic and numerical results.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3897126','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3897126"><span>A numerical investigation of oxygen concentration <span class="hlt">dependence</span> on biodegradation <span class="hlt">rate</span> laws in vapor intrusion</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yao, Yijun; Shen, Rui; Pennel, Kelly G.; Suuberg, Eric M.</p> <p>2013-01-01</p> <p>In subsurface vapor intrusion, aerobic biodegradation has been considered as a major environmental factor that determines the soil gas concentration attenuation factors for contaminants such as petroleum hydrocarbons. The site investigation showed that oxygen could play an important role in this biodegradation <span class="hlt">rate</span>, and this paper explores the influence of oxygen concentration in biodegradation reactions included in vapor intrusion (VI) models. Two different three dimensional (3-D) numerical models of vapor intrusion were explored for their sensitivity to the form of the biodegradation <span class="hlt">rate</span> law. A second order biodegradation <span class="hlt">rate</span> law, explicitly including oxygen concentration <span class="hlt">dependence</span>, was introduced into one model. The results indicate that the aerobic/anoxic interface depth is determined by the ratio of contaminant source vapor to atmospheric oxygen concentration, and that the contaminant concentration profile in the aerobic zone was significantly influenced by the choice of <span class="hlt">rate</span> law. PMID:24197079</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AIPC..780..545T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AIPC..780..545T"><span>Sleep Stage <span class="hlt">Dependence</span> of Invariance Characteristics in Fluctuations of Healthy Human Heart <span class="hlt">Rate</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Togo, Fumiharu; Kiyono, Ken; Struzik, Zbigniew R.; Yamamoto, Yoshiharu</p> <p>2005-08-01</p> <p>The outstanding feature of healthy human heart <span class="hlt">rate</span> is the robust scale invariance in the non-Gaussian probability density function (PDF), which is preserved not only in a quiescent condition, but also in a dynamic state during waking hours [K. Kiyono et al. Phys. Rev. Lett. 93 (2004)]. Together with 1/f like scaling, this characteristic is a strong indication of far-from-equilibrium, critical-like dynamics of heart <span class="hlt">rate</span> regulation. Our results suggest that healthy human heart <span class="hlt">rate</span> departs from a critical state-like operation during sleeping hours, at a <span class="hlt">rate</span> which is heterogeneous with respect to sleep stages annotated according to traditional techniques. We study specific contributions of sleep stages to the relative departure from criticality through the analysis of sleep stage <span class="hlt">dependence</span> of the root mean square of multiscale local energy and the multiscale PDF. There is a possibility that the involvement of cortical activity may be important for a critical state-like operation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003ApPhL..82..188M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003ApPhL..82..188M"><span><span class="hlt">Rate-dependent</span> indentation hardness of a power-law creep solder alloy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ma, Xin; Yoshida, Fusahito</p> <p>2003-01-01</p> <p>Berkovich depth-sensing indentation tests with different loading <span class="hlt">rates</span> have been performed on a creep material, Sn-3.5Ag-0.75Cu solder alloy. The resulting indentation load-depth curves are <span class="hlt">rate</span> <span class="hlt">dependent</span> and have varying creep penetration depths during the same hold time. Creep indentation hardness H, defined from the concept of "work of indentation," varies with the volume strain occurring during the creep hold time, which is a measure of creep strain <span class="hlt">rate</span> ɛ˙cr. Thus, <span class="hlt">rate</span> sensitivity m of the indented material can be determined from the ln H vs ln ɛ˙cr curve. The derived value of m is consistent with the results from conventional uniaxial tensile and compression experiments of bulk solder alloy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24197079','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24197079"><span>A numerical investigation of oxygen concentration <span class="hlt">dependence</span> on biodegradation <span class="hlt">rate</span> laws in vapor intrusion.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yao, Yijun; Shen, Rui; Pennel, Kelly G; Suuberg, Eric M</p> <p>2013-12-01</p> <p>In subsurface vapor intrusion, aerobic biodegradation has been considered as a major environmental factor that determines the soil gas concentration attenuation factors for contaminants such as petroleum hydrocarbons. The site investigation has shown that oxygen can play an important role in this biodegradation <span class="hlt">rate</span>, and this paper explores the influence of oxygen concentration on biodegradation reactions included in vapor intrusion (VI) models. Two different three dimensional (3-D) numerical models of vapor intrusion were explored for their sensitivity to the form of the biodegradation <span class="hlt">rate</span> law. A second order biodegradation <span class="hlt">rate</span> law, explicitly including oxygen concentration <span class="hlt">dependence</span>, was introduced into one model. The results indicate that the aerobic/anoxic interface depth is determined by the ratio of contaminant source vapor to atmospheric oxygen concentration, and that the contaminant concentration profile in the aerobic zone was significantly influenced by the choice of <span class="hlt">rate</span> law.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24213614','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24213614"><span>Integrated <span class="hlt">rate-dependent</span> and dual pathway AV nodal functions: principles and assessment framework.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Billette, Jacques; Tadros, Rafik</p> <p>2014-01-15</p> <p>The atrioventricular (AV) node conducts slowly and has a long refractory period. These features sustain the filtering of atrial impulses and hence are often modulated to optimize ventricular <span class="hlt">rate</span> during supraventricular tachyarrhythmias. The AV node is also the site of a clinically common reentrant arrhythmia. Its function is assessed for a variety of purposes from its responses to a premature protocol (S1S2, test beats introduced at different cycle lengths) repeatedly performed at different basic <span class="hlt">rates</span> and/or to an incremental pacing protocol (increasingly faster <span class="hlt">rates</span>). Puzzlingly, resulting data and interpretation differ with protocols as well as with chosen recovery and refractory indexes, and are further complicated by the presence of built-in fast and slow pathways. This problem applies to endocavitary investigations of arrhythmias as well as to many experimental functional studies. This review supports an integrated framework of <span class="hlt">rate-dependent</span> and dual pathway AV nodal function that can account for these puzzling characteristics. The framework was established from AV nodal responses to S1S2S3 protocols that, compared with standard S1S2 protocols, allow for an orderly quantitative dissociation of the different factors involved in changes in AV nodal conduction and refractory indexes under <span class="hlt">rate-dependent</span> and dual pathway function. Although largely based on data from experimental studies, the proposed framework may well apply to the human AV node. In conclusion, the <span class="hlt">rate-dependent</span> and dual pathway properties of the AV node can be integrated within a common functional framework the contribution of which to individual responses can be quantitatively determined with properly designed protocols and analytic tools.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhyA..463..270S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhyA..463..270S"><span>An accurate analytic representation of the temperature <span class="hlt">dependence</span> of nonresonant nuclear reaction <span class="hlt">rate</span> coefficients</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shizgal, Bernie D.</p> <p>2016-12-01</p> <p>There has been intense interest for several decades by different research groups to accurately model the temperature <span class="hlt">dependence</span> of a large number of nuclear reaction <span class="hlt">rate</span> coefficients for both light and heavy nuclides. The <span class="hlt">rate</span> coefficient, k(T) , is given by the Maxwellian average of the reactive cross section expressed in terms of the astrophysical factor, S(E) , which for nonresonant reactions is generally written as a power series in the relative energy E. A computationally efficient algorithm for the temperature <span class="hlt">dependence</span> of nuclear reaction <span class="hlt">rate</span> coefficients is required for fusion reactor research and for models of nucleosynthesis and stellar evolution. In this paper, an accurate analytical expression for the temperature <span class="hlt">dependence</span> of nuclear reaction <span class="hlt">rate</span> coefficients is provided in terms of τ = 3(b / 2) 2/3 or equivalently, T - 1/3 , where b = B /√{kB T }, B is the Gamow factor and kB is the Boltzmann constant. The methodology is appropriate for all nonresonant nuclear reactions for which S(E) can be represented as a power series in E. The explicit expression for the <span class="hlt">rate</span> coefficient versus temperature is derived with the asymptotic expansions of the moments of w(E) = exp(- E /kB T - B /√{ E }) in terms of τ. The zeroth order moment is the familiar Gaussian approximation to the <span class="hlt">rate</span> coefficient. Results are reported for the representative reactions D(d, p)T, D(d, n)3He and 7Li(p, α) α and compared with several different fitting procedures reported in the literature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=208142','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=208142"><span>Genetic and physical analyses of the growth <span class="hlt">rate-dependent</span> regulation of Escherichia coli zwf expression.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rowley, D L; Pease, A J; Wolf, R E</p> <p>1991-01-01</p> <p>Growth <span class="hlt">rate-dependent</span> regulation of the level of Escherichia coli glucose 6-phosphate dehydrogenase, encoded by zwf, and 6-phosphogluconate dehydrogenase, encoded by gnd, is similar during steady-state growth and after nutritional upshifts. To determine whether the mechanism regulating zwf expression is like that of gnd, which involves a site of posttranscriptional control located within the structural gene, we prepared and analyzed a set of zwf-lacZ protein fusions in which the fusion joints are distributed across the glucose 6-phosphate dehydrogenase coding sequence. Expression of beta-galactosidase from the protein fusions was as growth <span class="hlt">rate</span> <span class="hlt">dependent</span> as that of glucose 6-phosphate dehydrogenase itself, indicating that regulation does not involve an internal regulatory region. The level of beta-galactosidase in zwf-lac operon fusion strains and the level of zwf mRNA from a wild-type strain increased with increasing growth <span class="hlt">rate</span>, which suggests that growth <span class="hlt">rate</span> control is exerted on the mRNA level. The half-life of the zwf mRNA mass was 3.0 min during growth on glucose and 3.4 min during growth on acetate. Thus, zwf transcription appears to be the target for growth <span class="hlt">rate</span> control of the glucose 6-phosphate dehydrogenase level. Images PMID:1906868</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JChPh.142x4508S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JChPh.142x4508S"><span>Cooling-<span class="hlt">rate</span> <span class="hlt">dependence</span> of kinetic and mechanical stabilities of simulated glasses</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Staley, Hannah; Flenner, Elijah; Szamel, Grzegorz</p> <p>2015-06-01</p> <p>Glasses created through vapor deposition on a substrate maintained at a proper temperature possess higher kinetic and mechanical stabilities than glasses created by cooling at a constant <span class="hlt">rate</span>. Molecular dynamics simulations are being increasingly used to understand why vapor deposition improves glasses' stability. There are, however, few detailed molecular dynamics studies of the <span class="hlt">dependence</span> of the properties of glasses cooled at a constant <span class="hlt">rate</span> on the <span class="hlt">rate</span> of cooling. Thus, there is no clear benchmark for comparing ultrastable simulated glasses to simulated glasses prepared through cooling at a constant <span class="hlt">rate</span>. Here, we examine the <span class="hlt">dependence</span> of the properties of simulated glasses on the cooling <span class="hlt">rate</span> used in their preparation. We examine the kinetic stability by measuring the time it takes for a glass to transform back to a liquid upon heating and heterogeneous dynamics during heating. We also examine properties of the energy landscape, and we evaluate mechanical stability by calculating the shear modulus of the glass. The methods outlined here can be used to assess kinetic and mechanical stabilities of simulated glasses generated using specialized algorithms and provide a benchmark for those algorithms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5098729','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5098729"><span>The <span class="hlt">rate</span> <span class="hlt">dependence</span> of the saturation flow stress of Cu and 1100 Al</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Preston, D.L.; Tonks, D.L.; Wallace, D.C.</p> <p>1991-01-01</p> <p>The strain-<span class="hlt">rate</span> <span class="hlt">dependence</span> of the saturation flow stress of OFHC Cu and 1100 Al from 10{sup {minus}3}s{sup {minus}1} to nearly to 10{sup 12}s{sup {minus}1} is examined. The flow stress above 10{sup 9}s{sup {minus}1} is estimated using Wallace's theory of overdriven shocks in metals. A transition to the power-law behavior {Psi} {approximately} {tau}{sub s}{sup 5} occurs at a strain <span class="hlt">rate</span> of order 10{sup 5}s{sup {minus}1}. 10 refs., 2 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22257147','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22257147"><span>Monitoring of ultraviolet pulse <span class="hlt">rate</span> <span class="hlt">dependent</span> photomechanical actuation in carbon nanotubes using fiber Bragg gratings</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shivananju, B. N.; Suri, Ashish; Asokan, S.; Misra, Abha</p> <p>2014-01-06</p> <p>In this Letter, we present a non-contact method of controlling and monitoring photomechanical actuation in carbon nanotubes (CNT) by exposing it to ultra-violet radiation at different pulse <span class="hlt">rates</span> (10 to 200 Hz). This is accomplished by imparting a reversible photo induced strain (5–330 με) on CNT coated fibre Bragg gratings; CNT undergoes an internal reversible structural change due to cyclic photon absorption that leads to the development of mechanical strain, which in turn allows reversible switching of the Bragg wavelength. The results also reveal an interesting pulse <span class="hlt">rate</span> <span class="hlt">dependent</span> rise and fall times of photomechanical actuation in CNT.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3586365','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3586365"><span>Should we maintain baby <span class="hlt">hatches</span> in our society?</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2013-01-01</p> <p>Background A baby <span class="hlt">hatch</span> called the “Stork’s Cradle” has been in place at Jikei Hospital in Kumamoto City, Japan, since May 10, 2007. Babyklappes were first established in Germany in 2000, and there are currently more than 90 locations. Attitudes regarding baby <span class="hlt">hatches</span> are divided in Japan and neither opinions for nor against baby <span class="hlt">hatches</span> have thus far been overwhelming. To consider the appropriateness of baby <span class="hlt">hatches</span>, we present and examine the validity of each major objection to establishing baby <span class="hlt">hatches</span>. Discussion There are various objections to baby <span class="hlt">hatches</span> as follows: It violates a child’s right to know the identity of his or her biological parents by allowing anonymous birth; it neglects fulfillment of the biological parents’ basic obligation to raise their child and its very availability induces abandonment of infants; some people abuse it for very selfish reasons; it cannot save babies’ lives; the rights of one parent can be ignored if the other surrenders a child without his or her consent; it puts a baby in medical jeopardy; and it has no clear legal basis. The authors would argue that there are many plausible refutations for each objection mainly based on priority of child’s right to life, pregnant women’s vulnerability and necessity of anonymity, social responsibility to protect and raise children, differences between dropping a child off at a baby <span class="hlt">hatch</span> and child neglect, limited function of social childcare center, inevitability of abuse by a minority of people, necessary distinction between outcomes that occur only because baby <span class="hlt">hatches</span> exist and those that occur regardless of their existence, important local direct and upmost measures for women in trouble, and difference between ambiguous legality and illegality. Summary We argue that a certain number of baby <span class="hlt">hatches</span> should continue to be established as a last resort, in a form that can maintain anonymity if the parent dropping the child off so desires. It should be supported if it is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3361291','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3361291"><span>Striatal Input- and <span class="hlt">Rate-Dependent</span> Effects of Muscarinic Receptors on Pallidal Firing</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Querejeta, Enrique; Alatorre, Alberto; Ríos, Alain; Barrientos, Rafael; Oviedo-Chávez, Aldo; Bobadilla-Lugo, Rosa Amalia; Delgado, Alfonso</p> <p>2012-01-01</p> <p>The globus pallidus (GP) plays a key role in the overall basal ganglia (BG) activity. Despite evidence of cholinergic inputs to GP, their role in the spiking activity of GP neurons has not received attention. We examine the effect of local activation and blockade of muscarinic receptors (MRs) in the spontaneous firing of GP neurons both in normal and ipsilateral striatum-lesioned rats. We found that activation of MRs produces heterogeneous responses in both normal and ipsilateral striatum-lesioned rats: in normal rats the response evoked by MRs <span class="hlt">depends</span> on the predrug basal firing <span class="hlt">rate</span>; the inhibition evoked by MRs is higher in normal rats than in striatum-lesioned rats; the number of neurons that undergo inhibition is lower in striatum-lesioned rats than in normal rats. Our data suggest that modulation of MRs in the GP <span class="hlt">depends</span> on the firing <span class="hlt">rate</span> before their activation and on the integrity of the striato-pallidal pathway. PMID:22654627</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24521661','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24521661"><span>Invasion <span class="hlt">rate</span> of deer ked <span class="hlt">depends</span> on spatiotemporal variation in host density.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Meier, C M; Bonte, D; Kaitala, A; Ovaskainen, O</p> <p>2014-06-01</p> <p>Invasive parasites are of great global concern. Understanding the factors influencing the spread of invading pest species is a first step in developing effective countermeasures. Growing empirical evidence suggests that spread <span class="hlt">rates</span> are essentially influenced by spatiotemporal dynamics of host-parasite interactions, yet approaches modelling spread <span class="hlt">rate</span> have typically assumed static environmental conditions. We analysed invasion history of the deer ked (Lipoptena cervi) in Finland with a diffusion-reaction model, which assumed either the movement <span class="hlt">rate</span>, the population growth <span class="hlt">rate</span>, or both <span class="hlt">rates</span> may <span class="hlt">depend</span> on spatial and temporal distribution of moose (Alces alces), the main host of deer ked. We fitted the model to the data in a Bayesian framework, and used the Bayesian information criterion to show that accounting for the variation in local moose density improved the model's ability to describe the pattern of the invasion. The highest ranked model predicted higher movement <span class="hlt">rate</span> and growth <span class="hlt">rate</span> of deer ked with increasing moose density. Our results suggest that the historic increase in host density has facilitated the spread of the deer ked. Our approach illustrates how information about the ecology of an invasive species can be extracted from the spatial pattern of spread even with rather limited data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA527680','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA527680"><span>Strain-<span class="hlt">Rate</span> <span class="hlt">Dependency</span> of Strength of Soft Marine Deposits of the Gulf of Mexico</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2010-06-01</p> <p>abstract number: 090612-057 Strain-<span class="hlt">rate</span> <span class="hlt">dependency</span> of strength of soft marine deposits of the Gulf of Mexico Andrei Abelev and Philip Valent...from the Gulf of Mexico . The vane test may not always be the most accurate method of describing the undrained shear strength, mainly because it...deposits of the Gulf of Mexico 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21308713','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21308713"><span>Improved model for the angular <span class="hlt">dependence</span> of excimer laser ablation <span class="hlt">rates</span> in polymer materials</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pedder, J. E. A.; Holmes, A. S.; Dyer, P. E.</p> <p>2009-10-26</p> <p>Measurements of the angle-<span class="hlt">dependent</span> ablation <span class="hlt">rates</span> of polymers that have applications in microdevice fabrication are reported. A simple model based on Beer's law, including plume absorption, is shown to give good agreement with the experimental findings for polycarbonate and SU8, ablated using the 193 and 248 nm excimer lasers, respectively. The modeling forms a useful tool for designing masks needed to fabricate complex surface relief by ablation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22092057','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22092057"><span>Optimal Control of Markov Processes with Age-<span class="hlt">Dependent</span> Transition <span class="hlt">Rates</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ghosh, Mrinal K. Saha, Subhamay</p> <p>2012-10-15</p> <p>We study optimal control of Markov processes with age-<span class="hlt">dependent</span> transition <span class="hlt">rates</span>. The control policy is chosen continuously over time based on the state of the process and its age. We study infinite horizon discounted cost and infinite horizon average cost problems. Our approach is via the construction of an equivalent semi-Markov decision process. We characterise the value function and optimal controls for both discounted and average cost cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=384798','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=384798"><span>Temperature <span class="hlt">dependence</span> of metabolic <span class="hlt">rates</span> for microbial growth, maintenance, and survival</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Price, P. Buford; Sowers, Todd</p> <p>2004-01-01</p> <p>Our work was motivated by discoveries of prokaryotic communities that survive with little nutrient in ice and permafrost, with implications for past or present microbial life in Martian permafrost and Europan ice. We compared the temperature <span class="hlt">dependence</span> of metabolic <span class="hlt">rates</span> of microbial communities in permafrost, ice, snow, clouds, oceans, lakes, marine and freshwater sediments, and subsurface aquifer sediments. Metabolic <span class="hlt">rates</span> per cell fall into three groupings: (i) a <span class="hlt">rate</span>, μg(T), for growth, measured in the laboratory at in situ temperatures with minimal disturbance of the medium; (ii) a <span class="hlt">rate</span>, μm(T), sufficient for maintenance of functions but for a nutrient level too low for growth; and (iii) a <span class="hlt">rate</span>, μs(T), for survival of communities imprisoned in deep glacial ice, subsurface sediment, or ocean sediment, in which they can repair macromolecular damage but are probably largely dormant. The three groups have metabolic <span class="hlt">rates</span> consistent with a single activation energy of ≈110 kJ and that scale as μg(T):μm(T):μs(T) ≈ 106:103:1. There is no evidence of a minimum temperature for metabolism. The <span class="hlt">rate</span> at -40°C in ice corresponds to ≈10 turnovers of cellular carbon per billion years. Microbes in ice and permafrost have metabolic <span class="hlt">rates</span> similar to those in water, soil, and sediment at the same temperature. This finding supports the view that, far below the freezing point, liquid water inside ice and permafrost is available for metabolism. The <span class="hlt">rate</span> μs(T) for repairing molecular damage by means of DNA-repair enzymes and protein-repair enzymes such as methyltransferase is found to be comparable to the <span class="hlt">rate</span> of spontaneous molecular damage. PMID:15070769</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24664208','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24664208"><span>Hybridization alters spontaneous mutation <span class="hlt">rates</span> in a parent-of-origin-<span class="hlt">dependent</span> fashion in Arabidopsis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bashir, Tufail; Sailer, Christian; Gerber, Florian; Loganathan, Nitin; Bhoopalan, Hemadev; Eichenberger, Christof; Grossniklaus, Ueli; Baskar, Ramamurthy</p> <p>2014-05-01</p> <p>Over 70 years ago, increased spontaneous mutation <span class="hlt">rates</span> were observed in Drosophila spp. hybrids, but the genetic basis of this phenomenon is not well understood. The model plant Arabidopsis (Arabidopsis thaliana) offers unique opportunities to study the types of mutations induced upon hybridization and the frequency of their occurrence. Understanding the mutational effects of hybridization is important, as many crop plants are grown as hybrids. Besides, hybridization is important for speciation and its effects on genome integrity could be critical, as chromosomal rearrangements can lead to reproductive isolation. We examined the <span class="hlt">rates</span> of hybridization-induced point and frameshift mutations as well as homologous recombination events in intraspecific Arabidopsis hybrids using a set of transgenic mutation detector lines that carry mutated or truncated versions of a reporter gene. We found that hybridization alters the frequency of different kinds of mutations. In general, Columbia (Col)×Cape Verde Islands and Col×C24 hybrid progeny had decreased T→G and T→A transversion <span class="hlt">rates</span> but an increased C→T transition <span class="hlt">rate</span>. Significant changes in frameshift mutation <span class="hlt">rates</span> were also observed in some hybrids. In Col×C24 hybrids, there is a trend for increased homologous recombination <span class="hlt">rates</span>, except for the hybrids from one line, while in Col×Cape Verde Islands hybrids, this <span class="hlt">rate</span> is decreased. The overall genetic distance of the parents had no influence on mutation <span class="hlt">rates</span> in the progeny, as closely related accessions on occasion displayed higher mutation <span class="hlt">rates</span> than accessions that are separated farther apart. However, reciprocal hybrids had significantly different mutation <span class="hlt">rates</span>, suggesting parent-of-origin-<span class="hlt">dependent</span> effects on the mutation frequency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006PhyA..371..513V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006PhyA..371..513V"><span>Valuation of stochastic interest <span class="hlt">rate</span> securities with time-<span class="hlt">dependent</span> variance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Villarroel, Javier</p> <p>2006-11-01</p> <p>We consider the problem of how to prize general securities whose payoff at maturity only <span class="hlt">depends</span> on the interest <span class="hlt">rate</span> rT at the time of exercise, where rt is supposed to be a stochastic Feller process. We show how to generalize the results of Cox et al. [Econometrica 53 (2) (1985) 385] regarding bond valuation to a situation where the stochastic evolution of rt under the martingale probability involves time-<span class="hlt">dependent</span> coefficients and the payoff is arbitrary. The solution to this problem is given in terms of the propagator for the heat operator with a potential. This propagator is constructed in terms of a classical harmonic oscillator with time-<span class="hlt">dependent</span> frequency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4614441','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4614441"><span>On <span class="hlt">rate-dependent</span> polycrystal deformation: the temperature sensitivity of cold dwell fatigue</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhang, Zhen; Cuddihy, M. A.; Dunne, F. P. E.</p> <p>2015-01-01</p> <p>A temperature and <span class="hlt">rate-dependent</span> crystal plasticity framework has been used to examine the temperature sensitivity of stress relaxation, creep and load shedding in model Ti-6Al polycrystal behaviour under dwell fatigue conditions. A temperature close to 120°C is found to lead to the strongest stress redistribution and load shedding, resulting from the coupling between crystallographic slip <span class="hlt">rate</span> and slip system dislocation hardening. For temperatures in excess of about 230°C, grain-level load shedding from soft to hard grains diminishes because of the more rapid stress relaxation, leading ultimately to the diminution of the load shedding and hence, it is argued, the elimination of the dwell debit. Under conditions of cyclic stress dwell, at temperatures between 20°C and 230°C for which load shedding occurs, the <span class="hlt">rate-dependent</span> accumulation of local slip by ratcheting is shown to lead to the progressive cycle-by-cycle redistribution of stress from soft to hard grains. This phenomenon is termed cyclic load shedding since it also <span class="hlt">depends</span> on the material's creep response, but develops over and above the well-known dwell load shedding, thus providing an additional rationale for the incubation of facet nucleation. PMID:26528078</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5555227','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5555227"><span>Somatostatin analogue, octreotide, reduces increased glomerular filtration <span class="hlt">rate</span> and kidney size in insulin-<span class="hlt">dependent</span> diabetes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Serri, O.; Beauregard, H.; Brazeau, P.; Abribat, T.; Lambert, J.; Harris, A.; Vachon, L. Sandoz Canada Inc., Dorval, Quebec )</p> <p>1991-02-20</p> <p>To determine whether treatment with a somatostatin analogue can reduce kidney hyperfiltration and hypertrophy in insulin-<span class="hlt">dependent</span> diabetes mellitus, the authors studied 11 patients with insulin-<span class="hlt">dependent</span> diabetes mellitus and glomerular hyperfiltration. The patients were assigned randomly to receive continuous subcutaneous infusion of either octreotide, 300 {mu}g/24 h (five patients) or placebo (six patients) for 12 weeks. At baseline, mean glomerular filtration <span class="hlt">rate</span> and mean total kidney volume were not significantly different in the two groups. However, after 12 weeks of treatment, the mean glomerular filtration <span class="hlt">rate</span> was significantly lower in the octreotide group than in the placebo group. Furthermore, the mean total kidney volume was significantly lower after treatment in the octreotide group than in the placebo group. Glycemic control did not change significantly in either group. They conclude that subcutaneous infusion of octreotide for 12 weeks reduces increased glomerular filtration <span class="hlt">rate</span> and kidney size in patients with insulin-<span class="hlt">dependent</span> diabetes mellitus despite the fact that glycemic control remains unchanged.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010084978','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010084978"><span>State-<span class="hlt">Dependent</span> Pseudo-Linear Filter for Spacecraft Attitude and <span class="hlt">Rate</span> Estimation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bar-Itzhack, Itzhack Y.; Harman, Richard R.</p> <p>2001-01-01</p> <p>This paper presents the development and performance of a special algorithm for estimating the attitude and angular <span class="hlt">rate</span> of a spacecraft. The algorithm is a pseudo-linear Kalman filter, which is an ordinary linear Kalman filter that operates on a linear model whose matrices are current state estimate <span class="hlt">dependent</span>. The nonlinear rotational dynamics equation of the spacecraft is presented in the state space as a state-<span class="hlt">dependent</span> linear system. Two types of measurements are considered. One type is a measurement of the quaternion of rotation, which is obtained from a newly introduced star tracker based apparatus. The other type of measurement is that of vectors, which permits the use of a variety of vector measuring sensors like sun sensors and magnetometers. While quaternion measurements are related linearly to the state vector, vector measurements constitute a nonlinear function of the state vector. Therefore, in this paper, a state-<span class="hlt">dependent</span> linear measurement equation is developed for the vector measurement case. The state-<span class="hlt">dependent</span> pseudo linear filter is applied to simulated spacecraft rotations and adequate estimates of the spacecraft attitude and <span class="hlt">rate</span> are obtained for the case of quaternion measurements as well as of vector measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17132674','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17132674"><span>Dose-<span class="hlt">rate</span> <span class="hlt">dependent</span> effects of ionizing radiation on vascular reactivity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Suvorava, T; Luksha, L; Bulanova, K Ya; Lobanok, L M</p> <p>2006-01-01</p> <p>This study was designed to investigate the dose-<span class="hlt">rate</span> <span class="hlt">dependent</span> effects of ionising radiation on endothelium- and NO-mediated reactivity of aorta and coronary vessels. Rats were exposed to acute ((137)Cs, 9 x 10(-4) Gy s(-1), 18 min) and chronic ((137)Cs, 2.8 x 10(-7) Gy s(-1), 41 days) radiation in 1 Gy dose. Acute irradiation transiently increased coronary flow in eNOS-activity-<span class="hlt">dependent</span> manner on day 3 after exposure. In striking contrast, chronic irradiation caused a significant depression of coronary flow even on day 90 after irradiation and abolished the effects of NO-synthase inhibitor N-nitro-L-arginine methyl ester (10 micromol l(-1)). Furthermore, low intensity radiation strongly diminished the vasodilator properties of NO-donor sodium nitroprusside (5 micromol l(-1)). A similar pattern was observed in aortic rings. Endothelium-<span class="hlt">dependent</span> vasodilation was increased on days 3 and 10 after acute irradiation, but strongly inhibited following chronic exposure for the entire post-radiation period. This was accompanied by a diminished vasodilator response to NO-donor on days 3, 10 and 30 of post-radiation but not on day 90. The data suggest that ionising radiation in 1 Gy induces changes of aortic and coronary vessels reactivity <span class="hlt">depending</span> on the dose-<span class="hlt">rate</span> and the interval after exposure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title50-vol13/pdf/CFR-2013-title50-vol13-part660-subpartI-app1.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title50-vol13/pdf/CFR-2013-title50-vol13-part660-subpartI-app1.pdf"><span>50 CFR Figure 1 to Subpart I of... - Existing California Area Closures (<span class="hlt">hatched</span> areas extend to 3 miles offshore; cross-<span class="hlt">hatched</span> areas...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Existing California Area Closures (<span class="hlt">hatched</span> areas extend to 3 miles offshore; cross-<span class="hlt">hatched</span> areas extend beyond 3 miles offshore) and Optional.... I, Fig. 1 Figure 1 to Subpart I of Part 660—Existing California Area Closures (<span class="hlt">hatched</span> areas...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title50-vol13/pdf/CFR-2012-title50-vol13-part660-subpartI-app1.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title50-vol13/pdf/CFR-2012-title50-vol13-part660-subpartI-app1.pdf"><span>50 CFR Figure 1 to Subpart I of... - Existing California Area Closures (<span class="hlt">hatched</span> areas extend to 3 miles offshore; cross-<span class="hlt">hatched</span> areas...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Existing California Area Closures (<span class="hlt">hatched</span> areas extend to 3 miles offshore; cross-<span class="hlt">hatched</span> areas extend beyond 3 miles offshore) and Optional.... I, Fig. 1 Figure 1 to Subpart I of Part 660—Existing California Area Closures (<span class="hlt">hatched</span> areas...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title50-vol13/pdf/CFR-2014-title50-vol13-part660-subpartI-app1.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title50-vol13/pdf/CFR-2014-title50-vol13-part660-subpartI-app1.pdf"><span>50 CFR Figure 1 to Subpart I of... - Existing California Area Closures (<span class="hlt">hatched</span> areas extend to 3 miles offshore; cross-<span class="hlt">hatched</span> areas...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Existing California Area Closures (<span class="hlt">hatched</span> areas extend to 3 miles offshore; cross-<span class="hlt">hatched</span> areas extend beyond 3 miles offshore) and Optional.... I, Fig. 1 Figure 1 to Subpart I of Part 660—Existing California Area Closures (<span class="hlt">hatched</span> areas...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22127032','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22127032"><span>ANALYTICAL THEORY FOR THE INITIAL MASS FUNCTION. III. TIME <span class="hlt">DEPENDENCE</span> AND STAR FORMATION <span class="hlt">RATE</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hennebelle, Patrick</p> <p>2013-06-20</p> <p>The present paper extends our previous theory of the stellar initial mass function (IMF) by including time <span class="hlt">dependence</span> and by including the impact of the magnetic field. The predicted mass spectra are similar to the time-independent ones with slightly shallower slopes at large masses and peak locations shifted toward smaller masses by a factor of a few. Assuming that star-forming clumps follow Larson-type relations, we obtain core mass functions in good agreement with the observationally derived IMF, in particular, when taking into account the thermodynamics of the gas. The time-<span class="hlt">dependent</span> theory directly yields an analytical expression for the star formation <span class="hlt">rate</span> (SFR) at cloud scales. The SFR values agree well with the observational determinations of various Galactic molecular clouds. Furthermore, we show that the SFR does not simply <span class="hlt">depend</span> linearly on density, as is sometimes claimed in the literature, but also <span class="hlt">depends</span> strongly on the clump mass/size, which yields the observed scatter. We stress, however, that any SFR theory <span class="hlt">depends</span>, explicitly or implicitly, on very uncertain assumptions like clump boundaries or the mass of the most massive stars that can form in a given clump, making the final determinations uncertain by a factor of a few. Finally, we derive a fully time <span class="hlt">dependent</span> model for the IMF by considering a clump, or a distribution of clumps accreting at a constant <span class="hlt">rate</span> and thus whose physical properties evolve with time. In spite of its simplicity, this model reproduces reasonably well various features observed in numerical simulations of converging flows. Based on this general theory, we present a paradigm for star formation and the IMF.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28067517','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28067517"><span>Temperature-<span class="hlt">Dependent</span> <span class="hlt">Rate</span> Coefficients for the Reaction of CH2OO with Hydrogen Sulfide.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Smith, Mica C; Chao, Wen; Kumar, Manoj; Francisco, Joseph S; Takahashi, Kaito; Lin, Jim Jr-Min</p> <p>2017-02-09</p> <p>The reaction of the simplest Criegee intermediate CH2OO with hydrogen sulfide was measured with transient UV absorption spectroscopy in a temperature-controlled flow reactor, and bimolecular <span class="hlt">rate</span> coefficients were obtained from 278 to 318 K and from 100 to 500 Torr. The average <span class="hlt">rate</span> coefficient at 298 K and 100 Torr was (1.7 ± 0.2) × 10(-13) cm(3) s(-1). The reaction was found to be independent of pressure and exhibited a weak negative temperature <span class="hlt">dependence</span>. Ab initio quantum chemistry calculations of the temperature-<span class="hlt">dependent</span> reaction <span class="hlt">rate</span> coefficient at the QCISD(T)/CBS level are in reasonable agreement with the experiment. The reaction of CH2OO with H2S is 2-3 orders of magnitude faster than the reaction with H2O monomer. Though <span class="hlt">rates</span> of CH2OO scavenging by water vapor under atmospheric conditions are primarily controlled by the reaction with water dimer, the H2S loss pathway will be dominated by the reaction with monomer. The agreement between experiment and theory for the CH2OO + H2S reaction lends credence to theoretical descriptions of other Criegee intermediate reactions that cannot easily be probed experimentally.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050192390','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050192390"><span>Nonlinearity and Strain-<span class="hlt">Rate</span> <span class="hlt">Dependence</span> in the Deformation Response of Polymer Matrix Composites Modeled</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldberg, Robert K.</p> <p>2000-01-01</p> <p>There has been no accurate procedure for modeling the high-speed impact of composite materials, but such an analytical capability will be required in designing reliable lightweight engine-containment systems. The majority of the models in use assume a linear elastic material response that does not vary with strain <span class="hlt">rate</span>. However, for containment systems, polymer matrix composites incorporating ductile polymers are likely to be used. For such a material, the deformation response is likely to be nonlinear and to vary with strain <span class="hlt">rate</span>. An analytical model has been developed at the NASA Glenn Research Center at Lewis Field that incorporates both of these features. A set of constitutive equations that was originally developed to analyze the viscoplastic deformation of metals (Ramaswamy-Stouffer equations) was modified to simulate the nonlinear, <span class="hlt">rate-dependent</span> deformation of polymers. Specifically, the effects of hydrostatic stresses on the inelastic response, which can be significant in polymers, were accounted for by a modification of the definition of the effective stress. The constitutive equations were then incorporated into a composite micromechanics model based on the mechanics of materials theory. This theory predicts the deformation response of a composite material from the properties and behavior of the individual constituents. In this manner, the nonlinear, <span class="hlt">rate-dependent</span> deformation response of a polymer matrix composite can be predicted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3935878','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3935878"><span>Automatic Detection of Key Innovations, <span class="hlt">Rate</span> Shifts, and Diversity-<span class="hlt">Dependence</span> on Phylogenetic Trees</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rabosky, Daniel L.</p> <p>2014-01-01</p> <p>A number of methods have been developed to infer differential <span class="hlt">rates</span> of species diversification through time and among clades using time-calibrated phylogenetic trees. However, we lack a general framework that can delineate and quantify heterogeneous mixtures of dynamic processes within single phylogenies. I developed a method that can identify arbitrary numbers of time-varying diversification processes on phylogenies without specifying their locations in advance. The method uses reversible-jump Markov Chain Monte Carlo to move between model subspaces that vary in the number of distinct diversification regimes. The model assumes that changes in evolutionary regimes occur across the branches of phylogenetic trees under a compound Poisson process and explicitly accounts for <span class="hlt">rate</span> variation through time and among lineages. Using simulated datasets, I demonstrate that the method can be used to quantify complex mixtures of time-<span class="hlt">dependent</span>, diversity-<span class="hlt">dependent</span>, and constant-<span class="hlt">rate</span> diversification processes. I compared the performance of the method to the MEDUSA model of <span class="hlt">rate</span> variation among lineages. As an empirical example, I analyzed the history of speciation and extinction during the radiation of modern whales. The method described here will greatly facilitate the exploration of macroevolutionary dynamics across large phylogenetic trees, which may have been shaped by heterogeneous mixtures of distinct evolutionary processes. PMID:24586858</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2620551','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2620551"><span>Factors Affecting Egg <span class="hlt">Hatch</span> of Heterodera mediterranea and Differential Responses of Olive Cultivars to Infestation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Castillo, P.; Vovlas, N.</p> <p>2002-01-01</p> <p>The influence of temperature and olive root exudates on Heterodera mediterranea egg <span class="hlt">hatch</span> and the effects of H. mediterranea on the growth of two olive cultivars (Arbequina and Picual) were investigated. Egg <span class="hlt">hatch</span> occurred over a temperature range of 10 to 30°C and was optimal at 20 to 25°C. There were no differences in egg <span class="hlt">hatch</span> between sterile deionized distilled water or root exudate dilutions (undiluted, diluted 1:1, and 1:2) of Arbequina and Picual at 20°C. Heterodera mediterranea reproduced on both olive cultivars in growth chambers at 25°C. Soil and root final nematode populations, as well as total number of cysts per plant and reproduction <span class="hlt">rate</span>, were significantly higher in Arbequina than in Picual. Shoot dry and root fresh weights as well as increases of shoot height, trunk diameter, and numbers of nodes were significantly suppressed by infection with 10,000 eggs + second-stage juveniles/pot in Arbequina but not in Picual. PMID:19265924</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACPD...1513109A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACPD...1513109A"><span>Analysis of isothermal and cooling <span class="hlt">rate</span> <span class="hlt">dependent</span> immersion freezing by a unifying stochastic ice nucleation model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alpert, P. A.; Knopf, D. A.</p> <p>2015-05-01</p> <p>Immersion freezing is an important ice nucleation pathway involved in the formation of cirrus and mixed-phase clouds. Laboratory immersion freezing experiments are necessary to determine the range in temperature (T) and relative humidity (RH) at which ice nucleation occurs and to quantify the associated nucleation kinetics. Typically, isothermal (applying a constant temperature) and cooling <span class="hlt">rate</span> <span class="hlt">dependent</span> immersion freezing experiments are conducted. In these experiments it is usually assumed that the droplets containing ice nuclei (IN) all have the same IN surface area (ISA), however the validity of this assumption or the impact it may have on analysis and interpretation of the experimental data is rarely questioned. A stochastic immersion freezing model based on first principles of statistics is presented, which accounts for variable ISA per droplet and uses physically observable parameters including the total number of droplets (Ntot) and the heterogeneous ice nucleation <span class="hlt">rate</span> coefficient, Jhet(T). This model is applied to address if (i) a time and ISA <span class="hlt">dependent</span> stochastic immersion freezing process can explain laboratory immersion freezing data for different experimental methods and (ii) the assumption that all droplets contain identical ISA is a valid conjecture with subsequent consequences for analysis and interpretation of immersion freezing. The simple stochastic model can reproduce the observed time and surface area <span class="hlt">dependence</span> in immersion freezing experiments for a variety of methods such as: droplets on a cold-stage exposed to air or surrounded by an oil matrix, wind and acoustically levitated droplets, droplets in a continuous flow diffusion chamber (CFDC), the Leipzig aerosol cloud interaction simulator (LACIS), and the aerosol interaction and dynamics in the atmosphere (AIDA) cloud chamber. Observed time <span class="hlt">dependent</span> isothermal frozen fractions exhibiting non-exponential behavior with time can be readily explained by this model considering varying ISA. An</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhDT........62A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhDT........62A"><span>Computational microstructure modeling of asphalt mixtures subjected to <span class="hlt">rate-dependent</span> fracture</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aragao, Francisco Thiago Sacramento</p> <p>2011-12-01</p> <p>Computational microstructure models have been actively pursued by the pavement mechanics community as a promising and advantageous alternative to limited analytical and semi-empirical modeling approaches. The primary goal of this research is to develop a computational microstructure modeling framework that will eventually allow researchers and practitioners of the pavement mechanics community to evaluate the effects of constituents and mix design characteristics (some of the key factors directly affecting the quality of the pavement structures) on the mechanical responses of asphalt mixtures. To that end, the mixtures are modeled as heterogeneous materials with inelastic mechanical behavior. To account for the complex geometric characteristics of the heterogeneous mixtures, an image treatment process is used to generate finite element meshes that closely reproduce the geometric characteristics of aggregate particles (size, shape, and volume fraction) that are distributed within a fine aggregate asphaltic matrix (FAM). These two mixture components, i.e., aggregate particles and FAM, are modeled, respectively, as isotropic linear elastic and isotropic linear viscoelastic materials and the material properties required as inputs for the computational model are obtained from simple and expedited laboratory tests. In addition to the consideration of the complex geometric characteristics and inelastic behavior of the mixtures, this study uses the cohesive zone model to simulate fracture as a gradual and <span class="hlt">rate-dependent</span> phenomenon in which the initiation and propagation of discrete cracks take place in different locations of the mixture microstructure. <span class="hlt">Rate-dependent</span> cohesive zone fracture properties are obtained using a procedure that combines laboratory tests of semi-circular bending specimens of the FAM and their numerical simulations. To address the <span class="hlt">rate-dependent</span> fracture characteristics of the FAM phase, a <span class="hlt">rate-dependent</span> cohesive zone model is developed and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16484299','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16484299"><span><span class="hlt">Rate</span> <span class="hlt">dependency</span> of beta-adrenergic modulation of repolarizing currents in the guinea-pig ventricle.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rocchetti, M; Freli, V; Perego, V; Altomare, C; Mostacciuolo, G; Zaza, A</p> <p>2006-07-01</p> <p>Beta-adrenergic stimulation modulates ventricular currents and sinus cycle length (CL). We investigated how changes in CL affect the current induced by isoprenaline (Iso) during the action potential (AP) of guinea-pig ventricular myocytes. Action-potential clamp was applied at CLs of 250 and 1000 ms to measure: (1) the net current induced by 0.1 microm Iso (I(Iso)); (2) the L-type Ca2+ current I(CaL) and slow delayed rectifier current I(Ks) components of I(Iso) (I(IsoCa) and I(IsoK)), identified as the Iso-induced current sensitive to nifedipine and HMR1556, respectively; and (3) I(Iso) persisting after inhibition of both I(Ca) and I(Ks) (I(isoR)). The pause <span class="hlt">dependency</span> of I(Ks) and its modulation were evaluated in voltage-clamp experiments. The <span class="hlt">rate</span> <span class="hlt">dependency</span> of the duration of the action potential at 90% repolarization (APD90) and its modulation by isoprenaline were tested in current-clamp experiments. At a CL of 250 ms I(Iso) was inward during initial repolarization and reversed at 59% of APD90. At a CL of 1000 ms I(Iso) became mostly inward in all cells. Switching to shorter CL did not change I(IsoCa) and I(IsoK) amplitudes, but moved their peak amplitudes to earlier repolarization; I(IsoR) was independent of CL. Acceleration of I(IsoK) at shorter CL was based on faster pause <span class="hlt">dependency</span> of I(Ks) activation <span class="hlt">rate</span>. The 'restitution' of activation <span class="hlt">rates</span> was modulated by isoprenaline. The APD90-CL relation was rotated anticlockwise by isoprenaline and crossed the control curve at a CL of 150 ms (400 beats min(-1)). We conclude that: (1) isoprenaline induced markedly different current profiles according to pacing <span class="hlt">rate</span>, involving CL-<span class="hlt">dependent</span> I(Ca) and I(Ks) modulation; (2) the effect of isoprenaline on APD90 was CL <span class="hlt">dependent</span>, and negligible during tachycardia; and (3) during sympathetic activation, repolarization stability may involve matched modulation of sinus <span class="hlt">rate</span> and repolarizing currents.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6842141','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6842141"><span>pH <span class="hlt">dependence</span> of the <span class="hlt">rate</span> and quantum yield of the retinal photoisomerization in bacteriorhodopsin</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Logunov, S.L.; Song, L.; El-Sayed, M.A. )</p> <p>1994-10-20</p> <p>The quantum yield of the retinal photoisomerization, the primary step in the bacteriorhodopsin (bR) photosynthesis, is determined from the picosecond bleach recovery of the absorption at 560 nm in the pH range 6.8-11.3. From this and the <span class="hlt">dependence</span> of the observed retinal excited state decay on pH, the effects of pH on both the photoisomerization and internal conversion <span class="hlt">rates</span> are also determined. The results show that while the quantum yield of photoisomerization is independent of pH, each of the <span class="hlt">rate</span> constants decreased by more than a factor of 2 at elevated pH. This suggests that the perturbation resulting from the pH changes affects both <span class="hlt">rate</span> constants similarly. This observation is discussed in terms of the theoretically proposed potential energy surfaces of the ground and excited states of retinal in bR. 16 refs., 3 figs., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhyA..433...42H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyA..433...42H"><span>The virus variation model by considering the degree-<span class="hlt">dependent</span> spreading <span class="hlt">rate</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Han, Dun; Sun, Mei; Li, Dandan</p> <p>2015-09-01</p> <p>Considering the difference of different individuals' physical quality and antibody, this paper investigates the epidemic spreading model with the virus mutation. By using the mean-field theory, the epidemic threshold with degree-<span class="hlt">dependent</span> spreading <span class="hlt">rate</span> can be theoretical drawn. According to the numerical simulations, we can obtain that the average infected virus version in the BA network is less than the ER network. In addition, if the effective spreading <span class="hlt">rate</span> is either small or large enough, the average virus version of the whole infected individuals will reduce. However, when the spreading <span class="hlt">rate</span> takes some proper values, the average infected virus version can greatly increase. Finally, we study how the different initial infected nodes influence the average virus version of the whole infected individuals. The numerical results show that the greater of the initial infected degree, the smaller of the average virus version of the whole infected individuals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22047643','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22047643"><span>MAGNETIC BRAKING FORMULATION FOR SUN-LIKE STARS: <span class="hlt">DEPENDENCE</span> ON DIPOLE FIELD STRENGTH AND ROTATION <span class="hlt">RATE</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Matt, Sean P.; Pinsonneault, Marc H.; Greene, Thomas P. E-mail: kmac@ucar.edu E-mail: thomas.p.greene@nasa.gov</p> <p>2012-08-01</p> <p>We use two-dimensional axisymmetric magnetohydrodynamic simulations to compute steady-state solutions for solar-like stellar winds from rotating stars with dipolar magnetic fields. Our parameter study includes 50 simulations covering a wide range of relative magnetic field strengths and rotation <span class="hlt">rates</span>, extending from the slow- and approaching the fast-magnetic-rotator regimes. Using the simulations to compute the angular momentum loss, we derive a semi-analytic formulation for the external torque on the star that fits all of the simulations to a precision of a few percent. This formula provides a simple method for computing the magnetic braking of Sun-like stars due to magnetized stellar winds, which properly includes the <span class="hlt">dependence</span> on the strength of the magnetic field, mass loss <span class="hlt">rate</span>, stellar radius, surface gravity, and spin <span class="hlt">rate</span>, and which is valid for both slow and fast rotators.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28364019','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28364019"><span>Arterial viscoelasticity: role in the <span class="hlt">dependency</span> of pulse wave velocity on heart <span class="hlt">rate</span> in conduit arteries.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xiao, Hanguang; Tan, Isabella; Butlin, Mark; Li, Decai; Avolio, Alberto P</p> <p>2017-06-01</p> <p>Experimental investigations have established that the stiffness of large arteries has a <span class="hlt">dependency</span> on acute heart <span class="hlt">rate</span> (HR) changes. However, the possible underlying mechanisms inherent in this HR <span class="hlt">dependency</span> have not been well established. This study aimed to explore a plausible viscoelastic mechanism by which HR exerts an influence on arterial stiffness. A multisegment transmission line model of the human arterial tree incorporating fractional viscoelastic components in each segment was used to investigate the effect of varying fractional order parameter (α) of viscoelasticity on the <span class="hlt">dependence</span> of aortic arch to femoral artery pulse wave velocity (afPWV) on HR. HR was varied from 60 to 100 beats/min at a fixed mean flow of 100 ml/s. PWV was calculated by intersecting tangent method (afPWVTan) and by phase velocity from the transfer function (afPWVTF) in the time and frequency domain, respectively. PWV was significantly and positively associated with HR for α ≥ 0.6; for α = 0.6, 0.8, and 1, HR-<span class="hlt">dependent</span> changes in afPWVTan were 0.01 ± 0.02, 0.07 ± 0.04, and 0.22 ± 0.09 m/s per 5 beats/min; HR-<span class="hlt">dependent</span> changes in afPWVTF were 0.02 ± 0.01, 0.12 ± 0.00, and 0.34 ± 0.01 m/s per 5 beats/min, respectively. This crosses the range of previous physiological studies where the <span class="hlt">dependence</span> of PWV on HR was found to be between 0.08 and 0.10 m/s per 5 beats/min. Therefore, viscoelasticity of the arterial wall could contribute to mechanisms through which large artery stiffness changes with changing HR. Physiological studies are required to confirm this mechanism.NEW & NOTEWORTHY This study used a transmission line model to elucidate the role of arterial viscoelasticity in the <span class="hlt">dependency</span> of pulse wave velocity on heart <span class="hlt">rate</span>. The model uses fractional viscoelasticity concepts, which provided novel insights into arterial hemodynamics. This study also provides a means of assessing the clinical manifestation of the association of pulse wave velocity and heart <span class="hlt">rate</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25530994','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25530994"><span><span class="hlt">Rate</span> sensitive continuum damage models and mesh <span class="hlt">dependence</span> in finite element analyses.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ljustina, Goran; Fagerström, Martin; Larsson, Ragnar</p> <p>2014-01-01</p> <p>The experiences from orthogonal machining simulations show that the Johnson-Cook (JC) dynamic failure model exhibits significant element size <span class="hlt">dependence</span>. Such mesh <span class="hlt">dependence</span> is a direct consequence of the utilization of local damage models. The current contribution is an investigation of the extent of the possible pathological mesh <span class="hlt">dependence</span>. A comparison of the resulting JC model behavior combined with two types of damage evolution is considered. The first damage model is the JC dynamic failure model, where the development of the "damage" does not affect the response until the critical state is reached. The second one is a continuum damage model, where the damage variable is affecting the material response continuously during the deformation. Both the plasticity and the damage models are <span class="hlt">rate</span> <span class="hlt">dependent</span>, and the damage evolutions for both models are defined as a postprocessing of the effective stress response. The investigation is conducted for a series of 2D shear tests utilizing different FE representations of the plane strain plate with pearlite material properties. The results show for both damage models, using realistic pearlite material parameters, that similar extent of the mesh <span class="hlt">dependence</span> is obtained and that the possible viscous regularization effects are absent in the current investigation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.8205B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.8205B"><span>A novel optical freezing array for the examination of cooling <span class="hlt">rate</span> <span class="hlt">dependence</span> in heterogeneous ice nucleation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Budke, Carsten; Dreischmeier, Katharina; Koop, Thomas</p> <p>2014-05-01</p> <p>Homogeneous ice nucleation is a stochastic process, implying that it is not only temperature but also time <span class="hlt">dependent</span>. For heterogeneous ice nucleation it is still under debate whether there is a significant time <span class="hlt">dependence</span> or not. In case of minor time <span class="hlt">dependence</span> it is probably sufficient to use a singular or slightly modified singular approach, which mainly supposes temperature <span class="hlt">dependence</span> and just small stochastic variations. We contribute to this discussion using a novel optical freezing array termed BINARY (Bielefeld Ice Nucleation ARraY). The setup consists of an array of microliter-sized droplets on a Peltier cooling stage. The droplets are separated from each other with a polydimethylsiloxane (PDMS) spacer to prevent a Bergeron-Findeisen process, in which the first freezing droplets grow at the expense of the remaining liquid ones due to their vapor pressure differences. An automatic detection of nucleation events is realized optically by the change in brightness during freezing. Different types of ice nucleating agents were tested with the presented setup, e. g. pollen and clay mineral dust. Exemplarily, cooling <span class="hlt">rate</span> <span class="hlt">dependent</span> measurements are shown for the heterogeneous ice nucleation induced by Snomax®. The authors gratefully acknowledge funding by the German Research Foundation (DFG) through the project BIOCLOUDS (KO 2944/1-1) and through the research unit INUIT (FOR 1525) under KO 2944/2-1. We particularly thank our INUIT partners for fruitful collaboration and sharing of ideas and IN samples.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20505994','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20505994"><span>The influence of strain <span class="hlt">rate</span> <span class="hlt">dependency</span> on the structure-property relations of porcine brain.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Begonia, Mark T; Prabhu, Raj; Liao, Jun; Horstemeyer, Mark F; Williams, Lakiesha N</p> <p>2010-10-01</p> <p>This study examines the internal microstructure evolution of porcine brain during mechanical deformation. Strain <span class="hlt">rate</span> <span class="hlt">dependency</span> of porcine brain was investigated under quasi-static compression for strain <span class="hlt">rates</span> of 0.00625, 0.025, and 0.10 s(-1). Confocal microscopy was employed at 15, 30, and 40% strain to quantify microstructural changes, and image analysis was implemented to calculate the area fraction of neurons and glial cells. The nonlinear stress-strain behavior exhibited a viscoelastic response from the strain <span class="hlt">rate</span> sensitivity observed, and image analysis revealed that the mean area fraction of neurons and glial cells increased according to the applied strain level and strain <span class="hlt">rate</span>. The area fraction for the undamaged state was 7.85 ± 0.07%, but at 40% strain the values were 11.55 ± 0.35%, 13.30 ± 0.28%, and 19.50 ± 0.14% for respective strain <span class="hlt">rates</span> of 0.00625, 0.025, and 0.10 s(-1). The increased area fractions were a function of the applied strain <span class="hlt">rate</span> and were attributed to the compaction of neural constituents and the stiffening tissue response. The microstructural variations in the tissue were linked to mechanical properties at progressive levels of compression in order to generate structure-property relationships useful for refining current FE material models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22365847','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22365847"><span>STRONG <span class="hlt">DEPENDENCE</span> OF THE INNER EDGE OF THE HABITABLE ZONE ON PLANETARY ROTATION <span class="hlt">RATE</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yang, Jun; Abbot, Dorian S.; Boué, Gwenaël; Fabrycky, Daniel C.</p> <p>2014-05-20</p> <p>Planetary rotation <span class="hlt">rate</span> is a key parameter in determining atmospheric circulation and hence the spatial pattern of clouds. Since clouds can exert a dominant control on planetary radiation balance, rotation <span class="hlt">rate</span> could be critical for determining the mean planetary climate. Here we investigate this idea using a three-dimensional general circulation model with a sophisticated cloud scheme. We find that slowly rotating planets (like Venus) can maintain an Earth-like climate at nearly twice the stellar flux as rapidly rotating planets (like Earth). This suggests that many exoplanets previously believed to be too hot may actually be habitable, <span class="hlt">depending</span> on their rotation <span class="hlt">rate</span>. The explanation for this behavior is that slowly rotating planets have a weak Coriolis force and long daytime illumination, which promotes strong convergence and convection in the substellar region. This produces a large area of optically thick clouds, which greatly increases the planetary albedo. In contrast, on rapidly rotating planets a much narrower belt of clouds form in the deep tropics, leading to a relatively low albedo. A particularly striking example of the importance of rotation <span class="hlt">rate</span> suggested by our simulations is that a planet with modern Earth's atmosphere, in Venus' orbit, and with modern Venus' (slow) rotation <span class="hlt">rate</span> would be habitable. This would imply that if Venus went through a runaway greenhouse, it had a higher rotation <span class="hlt">rate</span> at that time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21924432','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21924432"><span>Repolarization heterogeneity and <span class="hlt">rate</span> <span class="hlt">dependency</span> in a canine rapid pacing model of heart failure.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lux, Robert L; Gettes, Leonard S</p> <p>2011-01-01</p> <p>Repolarization heterogeneity and <span class="hlt">rate</span> <span class="hlt">dependency</span> have long been established as factors contributing to arrhythmogenic risk. However, there are conflicting observations regarding the nature and extent of ventricular repolarization heterogeneity that complicate understanding of arrhythmogenic mechanisms. To explore these disparate findings, we studied ventricular repolarization heterogeneity and <span class="hlt">rate</span> <span class="hlt">dependency</span> in a canine, rapid pacing model of heart failure. We studied ventricular repolarization heterogeneity and <span class="hlt">rate</span> <span class="hlt">dependency</span> in 10 canine hearts (5 normal and 5 after 1 month of rapid pacing at 240 beats per minute) by analyzing 64 body surface electrocardiograms, 64 epicardial, and 190 intramural plunge electrograms. We estimated mean ventricular depolarization and repolarization times from R- and T-wave peaks of the root-mean-square electrocardiogram (body surface) and local depolarization and repolarization times using activation-recovery interval (ARI) methods from recordings obtained during a range of fixed <span class="hlt">rate</span> pacing. In addition, we estimated local epicardial and transmural gradients of ARIs to assess cardiac locations of greatest spatial repolarization heterogeneity. We compared changes in repolarization at different <span class="hlt">rates</span> between normal and heart failure hearts. Findings documented prolongation of repolarization, repolarization <span class="hlt">rate</span> <span class="hlt">dependency</span>, and increased repolarization gradients in the heart failure hearts compared with control as observed from body surface, epicardial, and transmural measurements. Maximum local epicardial and intramural ARI gradients were comparable both in heart failure and control hearts. Intramural ARI distributions tended to be more irregular in the heart failure hearts compared with the systematic epicardium to endocardium ARI increase observed in control animals. This study documented prolongation of repolarization, increase in both epicardial and transmural repolarization gradients, and irregularity of transmural</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JMEP...21.1462B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JMEP...21.1462B"><span>Strain <span class="hlt">Rate</span> <span class="hlt">Dependency</span> of Bronze Metal Matrix Composite Mechanical Properties as a Function of Casting Technique</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brown, Lloyd; Joyce, Peter; Radice, Joshua; Gregorian, Dro; Gobble, Michael</p> <p>2012-07-01</p> <p>Strain <span class="hlt">rate</span> <span class="hlt">dependency</span> of mechanical properties of tungsten carbide (WC)-filled bronze castings fabricated by centrifugal and sedimentation-casting techniques are examined, in this study. Both casting techniques are an attempt to produce a functionally graded material with high wear resistance at a chosen surface. Potential applications of such materials include shaft bushings, electrical contact surfaces, and brake rotors. Knowledge of strain <span class="hlt">rate-dependent</span> mechanical properties is recommended for predicting component response due to dynamic loading or impact events. A brief overview of the casting techniques for the materials considered in this study is followed by an explanation of the test matrix and testing techniques. Hardness testing, density measurement, and determination of the volume fraction of WC particles are performed throughout the castings using both image analysis and optical microscopy. The effects of particle filling on mechanical properties are first evaluated through a microhardness survey of the castings. The volume fraction of WC particles is validated using a thorough density survey and a rule-of-mixtures model. Split Hopkinson Pressure Bar (SHPB) testing of various volume fraction specimens is conducted to determine strain <span class="hlt">dependence</span> of mechanical properties and to compare the process-property relationships between the two casting techniques. The baseline performances of C95400 bronze are provided for comparison. The results show that the addition of WC particles improves microhardness significantly for the centrifugally cast specimens, and, to a lesser extent, in the sedimentation-cast specimens, largely because the WC particles are more concentrated as a result of the centrifugal-casting process. Both metal matrix composites (MMCs) demonstrate strain <span class="hlt">rate</span> <span class="hlt">dependency</span>, with sedimentation casting having a greater, but variable, effects on material response. This difference is attributed to legacy effects from the casting process, namely</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5100830','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5100830"><span>Effects of freshwater petroleum contamination on amphibian <span class="hlt">hatching</span> and metamorphosis</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mahaney, P.A. . Dept. of Zoology)</p> <p>1994-02-01</p> <p>This study examined the effects of freshwater petroleum contamination on amphibian reproduction. The primary objectives were to assess the potential environmental and physiological impacts of runoff petroleum products on amphibians, using the green tree frog (Hyla cinerea) as a target species and engine crankcase oil as a contaminant. Egg <span class="hlt">hatching</span> success, tadpole growth, and successful metamorphosis were measured in four concentrations of oil. The effects of oil on food source was also studied. <span class="hlt">Hatching</span> success was not measurably influenced by the presence of oil. Tadpole and alga growth were negatively associated with the presence of oil. No tadpoles from the high concentration of oil treatments successfully metamorphosed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28025784','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28025784"><span>Multi-scale detection of <span class="hlt">rate</span> changes in spike trains with weak <span class="hlt">dependencies</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Messer, Michael; Costa, Kauê M; Roeper, Jochen; Schneider, Gaby</p> <p>2017-04-01</p> <p>The statistical analysis of neuronal spike trains by models of point processes often relies on the assumption of constant process parameters. However, it is a well-known problem that the parameters of empirical spike trains can be highly variable, such as for example the firing <span class="hlt">rate</span>. In order to test the null hypothesis of a constant <span class="hlt">rate</span> and to estimate the change points, a Multiple Filter Test (MFT) and a corresponding algorithm (MFA) have been proposed that can be applied under the assumption of independent inter spike intervals (ISIs). As empirical spike trains often show weak <span class="hlt">dependencies</span> in the correlation structure of ISIs, we extend the MFT here to point processes associated with short range <span class="hlt">dependencies</span>. By specifically estimating serial <span class="hlt">dependencies</span> in the test statistic, we show that the new MFT can be applied to a variety of empirical firing patterns, including positive and negative serial correlations as well as tonic and bursty firing. The new MFT is applied to a data set of empirical spike trains with serial correlations, and simulations show improved performance against methods that assume independence. In case of positive correlations, our new MFT is necessary to reduce the number of false positives, which can be highly enhanced when falsely assuming independence. For the frequent case of negative correlations, the new MFT shows an improved detection probability of change points and thus, also a higher potential of signal extraction from noisy spike trains.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16927234','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16927234"><span>Mass and temperature <span class="hlt">dependence</span> of metabolic <span class="hlt">rate</span> in litter and soil invertebrates.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Meehan, Timothy D</p> <p>2006-01-01</p> <p>Metabolic scaling theory provides a framework for modeling the combined mass and temperature <span class="hlt">dependence</span> of metabolic <span class="hlt">rate</span>. The theory predicts that whole-organism metabolic <span class="hlt">rate</span> should scale with body mass raised to the 3/4 power as a consequence of the physical characteristics of internal distribution networks. Metabolic <span class="hlt">rate</span> is predicted to vary with absolute body temperature, T, according to the Boltzmann factor, e(-E/kT), where E is the apparent activation energy of biochemical reactions, 0.2-1.2 eV, and k is Boltzmann's constant. I evaluated those predictions, using a compilation of published data on the metabolic <span class="hlt">rates</span> of litter- and soil-dwelling earthworms, isopods, oribatid mites, springtails, and spiders. Earthworms, oribatid mites, springtails, and spiders had mass-scaling exponents that were statistically indistinguishable from the expected value of 0.75. The scaling exponent for terrestrial isopods, 0.91, was significantly greater than expected. All taxa had apparent activation energies within the predicted range of 0.2-1.2 eV. Activation energies for isopods, oribatid mites, springtails, and spiders were not significantly different from the average expected value of 0.6 eV, while the activation energy for earthworms, 0.25 eV, was significantly lower than 0.6 eV. Updated equations for estimating metabolic <span class="hlt">rate</span> from body mass and environmental temperature are given for investigations into the ecological energetics of litter and soil animals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005APS..SHK.F7042M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005APS..SHK.F7042M"><span>A <span class="hlt">Rate-Dependent</span> Viscoelastic Damage Model for Simulation of Solid Propellant Impacts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matheson, Erik</p> <p>2005-07-01</p> <p>A viscoelastic deformation and damage model (VED) for solid rocket propellants has been developed based on an extensive set of mechanical properties experiments. Monotonic tensile tests performed at several strain <span class="hlt">rates</span> showed <span class="hlt">rate</span> and dilatation effects. During cyclic tensile tests, hysteresis and a <span class="hlt">rate-dependent</span> shear modulus were observed. A tensile relaxation experiment showed significant stress decay in the sample. Taylor impact tests exhibited large dilatations without significant crack growth. Extensive modifications to a viscoelastic-viscoplastic model (VEP) necessary to capture these experimental results have led to development of the VED model. In particular, plasticity has been eliminated in the model, and the multiple Maxwell viscoelastic formulation has been replaced with a time-<span class="hlt">dependent</span> shear modulus. Furthermore, the loading and unloading behaviors of the material are modeled independently. To characterize the damage and dilatation behavior, the Tensile Damage and Distention (TDD) model is run in conjunction with VED. The VED model is connected to a single-cell driver as well as to the CTH shock physics code. Simulations of tests show good comparisons with tensile tests and some aspects of the Taylor tests.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AIPC..845..913M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AIPC..845..913M"><span>A <span class="hlt">Rate-Dependent</span> Viscoelastic Damage Model for Simulation of Solid Propellant Impacts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matheson, E. R.; Nguyen, D. Q.</p> <p>2006-07-01</p> <p>A viscoelastic deformation and damage model (VED) for solid rocket propellants has been developed based on an extensive set of mechanical properties experiments. Monotonic tensile tests performed at several strain <span class="hlt">rates</span> showed <span class="hlt">rate</span> and dilatation effects. During cyclic tensile tests, hysteresis and a <span class="hlt">rate-dependent</span> shear modulus were observed. A tensile relaxation experiment showed significant stress decay in the sample. Taylor impact tests exhibited large dilatations without significant crack growth. Extensive modifications to a viscoelastic-viscoplastic model (VEP) necessary to capture these experimental results have led to development of the VED model. In particular, plasticity has been eliminated in the model, and the multiple Maxwell viscoelastic formulation has been replaced with a time-<span class="hlt">dependent</span> shear modulus. Furthermore, the loading and unloading behaviors of the material are modeled independently. To characterize the damage and dilatation behavior, the Tensile Damage and Distention (TDD) model is run in conjunction with VED. The VED model is connected to a single-cell driver as well as to the CTH shock physics code. Simulations of tests show good comparisons with tensile tests and some aspects of the Taylor tests.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26834855','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26834855"><span>Strain-<span class="hlt">rate</span> <span class="hlt">Dependence</span> of Elastic Modulus Reveals Silver Nanoparticle Induced Cytotoxicity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Caporizzo, Matthew Alexander; Roco, Charles M; Ferrer, Maria Carme Coll; Grady, Martha E; Parrish, Emmabeth; Eckmann, David M; Composto, Russell John</p> <p></p> <p>Force-displacement measurements are taken at different <span class="hlt">rates</span> with an atomic force microscope to assess the correlation between cell health and cell viscoelasticity in THP-1 cells that have been treated with a novel drug carrier. A variable indentation-<span class="hlt">rate</span> viscoelastic analysis, VIVA, is employed to identify the relaxation time of the cells that are known to exhibit a frequency <span class="hlt">dependent</span> stiffness. The VIVA agrees with a fluorescent viability assay. This indicates that dextran-lysozyme drug carriers are biocompatible and deliver concentrated toxic material (rhodamine or silver nanoparticles) to the cytoplasm of THP-1 cells. By modelling the frequency <span class="hlt">dependence</span> of the elastic modulus, the VIVA provides three metrics of cytoplasmic viscoelasticity: a low frequency modulus, a high frequency modulus and viscosity. The signature of cytotoxicity by rhodamine or silver exposure is a frequency independent twofold increase in the elastic modulus and cytoplasmic viscosity, while the cytoskeletal relaxation time remains unchanged. This is consistent with the known toxic mechanism of silver nanoparticles, where metabolic stress causes an increase in the rigidity of the cytoplasm. A variable indentation-<span class="hlt">rate</span> viscoelastic analysis is presented as a straightforward method to promote the self-consistent comparison between cells. This is paramount to the development of early diagnosis and treatment of disease.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003SPIE.4952..125K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003SPIE.4952..125K"><span>Repetition <span class="hlt">rate-dependent</span> oxygen consumption modifies cytotoxicity in photodynamic therapy using pulsed light</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kawauchi, Satoko; Morimoto, Yuji; Asanuma, Hiroshi; Sato, Hiroyuki; Arai, Tsunenori; Sato, Shunichi; Sakata, Isao; Takemura, Takeshi; Nakajima, Susumu; Kikuchi, Makoto</p> <p>2003-06-01</p> <p>We studied the repetition-<span class="hlt">rate</span> <span class="hlt">dependence</span> of PDT cytotoxicity and relation between PDT cytotoxicity and both oxygen consumption and photobleaching during PDT in vitro. Mice renal carcinoma cells were incubated wtih second-generation photosensitizier, PAD-S31, and were irradiated with 670-nm nanoseconds pulsed light from YAG-OPO system. Four repetition <span class="hlt">rates</span> of 30, 15, 5 and 3 Hz were investigated, provided that the incident peak intensity and the total light dose adjusted to 1.2 MW/cm2 and 40 J/cm2, respectively. We found limited cytotoxicity about 40% at 30 and 15 Hz and sufficient cytotoxicity about 80% at 5 and 3 Hz. The oxygen measurement during irradiation revealed that the 5- and 30Hz irradiation caused slow oxygen consumption, while rapid oxygen consumption followed by a rapid recovery of oxygenation at 30 and 15 Hz. Interestingly, the fluorescence measurement during irradiation also demonstrated that photobleaching discontinued in the same period of oxygen recovery at 30 and 15 Hz. These discontinued oxygen consumption and photobleaching at 30 and 15 Hz might have limited effective total fluence and resulted in suppressed cytotoxicity. These results suggest that the PDT efficacy using a pulsed laser significantly <span class="hlt">depends</span> on the pulse repetition <span class="hlt">rate</span> probably due to different oxygen consumption process during PDT.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvP...6b4008V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvP...6b4008V"><span>Notch Fracture Toughness of Glasses: <span class="hlt">Dependence</span> on <span class="hlt">Rate</span>, Age, and Geometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vasoya, Manish; Rycroft, Chris H.; Bouchbinder, Eran</p> <p>2016-08-01</p> <p>Understanding the fracture toughness (resistance) of glasses is a fundamental problem of prime theoretical and practical importance. Here we theoretically study its <span class="hlt">dependence</span> on the loading <span class="hlt">rate</span>, the age (history) of the glass, and the notch radius ρ . Reduced-dimensionality analysis suggests that the notch fracture toughness results from a competition between the initial, age- and history-<span class="hlt">dependent</span>, plastic relaxation time scale τ0pl and an effective loading time scale τext(K˙ I,ρ ) , where K˙ I is the tensile stress-intensity-factor <span class="hlt">rate</span>. The toughness is predicted to scale with √{ρ } independently of ξ ≡τext/τ0pl for ξ ≪1 , to scale as T √{ρ }log (ξ ) for ξ ≫1 (related to thermal activation, where T is the temperature), and to feature a nonmonotonic behavior in the crossover region ξ ˜O (1 ) (related to plastic yielding dynamics). These predictions are verified using 2D computations, providing a unified picture of the notch fracture toughness of glasses. The theory highlights the importance of time-scale competition and far-from-steady-state elasto-viscoplastic dynamics for understanding the toughness and shows that the latter varies quite significantly with the glass age (history) and applied loading <span class="hlt">rate</span>. Experimental support for bulk metallic glasses is presented, and possible implications for applications are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25607231','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25607231"><span>Distance <span class="hlt">dependence</span> of the energy transfer <span class="hlt">rate</span> from a single semiconductor nanostructure to graphene.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Federspiel, François; Froehlicher, Guillaume; Nasilowski, Michel; Pedetti, Silvia; Mahmood, Ather; Doudin, Bernard; Park, Serin; Lee, Jeong-O; Halley, David; Dubertret, Benoît; Gilliot, Pierre; Berciaud, Stéphane</p> <p>2015-02-11</p> <p>The near-field Coulomb interaction between a nanoemitter and a graphene monolayer results in strong Förster-type resonant energy transfer and subsequent fluorescence quenching. Here, we investigate the distance <span class="hlt">dependence</span> of the energy transfer <span class="hlt">rate</span> from individual, (i) zero-dimensional CdSe/CdS nanocrystals and (ii) two-dimensional CdSe/CdS/ZnS nanoplatelets to a graphene monolayer. For increasing distances d, the energy transfer <span class="hlt">rate</span> from individual nanocrystals to graphene decays as 1/d(4). In contrast, the distance <span class="hlt">dependence</span> of the energy transfer <span class="hlt">rate</span> from a two-dimensional nanoplatelet to graphene deviates from a simple power law but is well described by a theoretical model, which considers a thermal distribution of free excitons in a two-dimensional quantum well. Our results show that accurate distance measurements can be performed at the single particle level using graphene-based molecular rulers and that energy transfer allows probing dimensionality effects at the nanoscale.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23343285','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23343285"><span><span class="hlt">Dependence</span> of the width of the glass transition interval on cooling and heating <span class="hlt">rates</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schmelzer, Jürn W P; Tropin, Timur V</p> <p>2013-01-21</p> <p>In a preceding paper [J. W. P. Schmelzer, J. Chem. Phys. 136, 074512 (2012)], a general kinetic criterion of glass formation has been advanced allowing one to determine theoretically the <span class="hlt">dependence</span> of the glass transition temperature on cooling and heating <span class="hlt">rates</span> (or similarly on the <span class="hlt">rate</span> of change of any appropriate control parameter determining the transition of a stable or metastable equilibrium system into a frozen-in, non-equilibrium state of the system, a glass). In the present paper, this criterion is employed in order to develop analytical expressions for the <span class="hlt">dependence</span> of the upper and lower boundaries and of the width of the glass transition interval on the <span class="hlt">rate</span> of change of the external control parameters. It is shown, in addition, that the width of the glass transition range is strongly correlated with the entropy production at the glass transition temperature. The analytical results are supplemented by numerical computations. Analytical results and numerical computations as well as existing experimental data are shown to be in good agreement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JChPh.138c4507S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JChPh.138c4507S"><span><span class="hlt">Dependence</span> of the width of the glass transition interval on cooling and heating <span class="hlt">rates</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schmelzer, Jürn W. P.; Tropin, Timur V.</p> <p>2013-01-01</p> <p>In a preceding paper [J. W. P. Schmelzer, J. Chem. Phys. 136, 074512 (2012), 10.1063/1.3685510], a general kinetic criterion of glass formation has been advanced allowing one to determine theoretically the <span class="hlt">dependence</span> of the glass transition temperature on cooling and heating <span class="hlt">rates</span> (or similarly on the <span class="hlt">rate</span> of change of any appropriate control parameter determining the transition of a stable or metastable equilibrium system into a frozen-in, non-equilibrium state of the system, a glass). In the present paper, this criterion is employed in order to develop analytical expressions for the <span class="hlt">dependence</span> of the upper and lower boundaries and of the width of the glass transition interval on the <span class="hlt">rate</span> of change of the external control parameters. It is shown, in addition, that the width of the glass transition range is strongly correlated with the entropy production at the glass transition temperature. The analytical results are supplemented by numerical computations. Analytical results and numerical computations as well as existing experimental data are shown to be in good agreement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25966880','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25966880"><span>Pre-<span class="hlt">hatching</span> fluoxetine-induced neurochemical, neurodevelopmental, and immunological changes in newly <span class="hlt">hatched</span> cuttlefish.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bidel, Flavie; Di Poi, Carole; Imarazene, Boudjema; Koueta, Noussithé; Budzinski, Hélène; Van Delft, Pierre; Bellanger, Cécile; Jozet-Alves, Christelle</p> <p>2016-03-01</p> <p>Embryonic and early postembryonic development of the cuttlefish Sepia officinalis (a cephalopod mollusk) occurs in coastal waters, an environment subject to considerable pressure from xenobiotic pollutants such as pharmaceutical residues. Given the role of serotonin in brain development and its interaction with neurodevelopmental functions, this study focused on fluoxetine (FLX), a selective serotonin reuptake inhibitor (SSRI, antidepressant). The goal was to determine the effects of subchronic waterborne FLX exposure (1 and 10 μg L(-1)) during the last 15 days of embryonic development on neurochemical, neurodevelopmental, behavioral, and immunological endpoints at <span class="hlt">hatching</span>. Our results showed for the first time that organic contaminants, such as FLX, could pass through the eggshell during embryonic development, leading to a substantial accumulation of this molecule in hatchlings. We also found that FLX embryonic exposure (1 and 10 μg L(-1)) (1) modulated dopaminergic but not serotonergic neurotransmission, (2) decreased cell proliferation in key brain structures for cognitive and visual processing, (3) did not induce a conspicuous change in camouflage quality, and (4) decreased lysozyme activity. In the long term, these alterations observed during a critical period of development may impair complex behaviors of the juvenile cuttlefish and thus lead to a decrease in their survival. Finally, we suggest a different mode of action by FLX between vertebrate and non-vertebrate species and raise questions regarding the vulnerability of early life stages of cuttlefish to the pharmaceutical contamination found in coastal waters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4331261','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4331261"><span>Stimulus intensity determines experience-<span class="hlt">dependent</span> modifications in neocortical neuron firing <span class="hlt">rates</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Glazewski, Stanislaw; Barth, Alison L</p> <p>2015-01-01</p> <p>Although subthreshold inputs of neocortical sensory neurons are broadly tuned, the spiking output is more restricted. These subthreshold inputs provide a substrate for stimulus intensity-<span class="hlt">dependent</span> changes their spiking output, as well as for experience-<span class="hlt">dependent</span> plasticity to alter firing properties. Here we investigated how different stimulus intensities modified the firing output of individual neurons in layer 2/3 of the mouse barrel cortex. Decreasing stimulus intensity over a 30-fold range lowered the firing <span class="hlt">rates</span> evoked by principal whisker stimulation and reduced the overall size of the responding ensemble in whisker-undeprived animals. We then examined how these responses were changed after single-whisker experience (SWE). After 7 days of SWE, the mean magnitude of response to spared whisker stimulation at the highest stimulus intensity was not altered. However, lower-intensity whisker stimulation revealed a more than 10-fold increase in mean firing output compared with control animals. Also, under control conditions, only ∽15% of neurons showed any firing at low stimulus intensity, compared with more than 70% of neurons after SWE. However, response changes measured in the immediately surrounding representations were detected only for the highest stimulus intensity. Overall, these data showed that the measurement of experience-<span class="hlt">dependent</span> changes in the spike output of neocortical neurons was highly <span class="hlt">dependent</span> upon stimulus intensity. PMID:25546174</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1984JGR....89.4185S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984JGR....89.4185S"><span><span class="hlt">Rate-dependent</span> extensional deformation resulting from crack growth in rock</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Segall, Paul</p> <p>1984-06-01</p> <p>Quasi-static propagation and dilation of macroscopic mode I cracks is considered as a source of inelastic strain in crustal rocks undergoing extensional deformations. The approach here is to first characterize the propagation of a single dilating crack and then to consider how a large two-dimensional array of similar, parallel cracks accomodates an applied deformation. The driving force for propagation of each crack, Gi, is found as a function of the applied strain and the instantaneous crack lengths ci. The <span class="hlt">rate</span> of crack propagation is taken to be a function of the instantaneous crack extension force ċi = ċ (Gi). A specific propagation <span class="hlt">rate</span> extension force relation is developed that both fits the available experimental data and has vanishing propagation <span class="hlt">rate</span> at a finite value of G. From these results a specific internal state variable constitutive law is derived relating uniaxial stress to the instantaneous uniaxial strain and crack density. For strains less than those necessary to cause crack propagation, the rock is predicted to behave like a linear elastic solid. Following the onset of propagation, the average stress may continue to increase if the strain <span class="hlt">rate</span> accommodated by crack growth is slow in comparison to the applied strain <span class="hlt">rate</span>. For constant strain <span class="hlt">rate</span> boundary conditions the solutions exhibit strain softening, leading to peak stress and then a stress decrease. The peak stress increases nearly logarithmically with increasing applied strain <span class="hlt">rate</span>. The response to unloading <span class="hlt">depends</span> strongly on whether or not cracks heal. Unloading that follows sealing of the cracks with mineral precipitates causes the rock to undergo a permanent nonrecoverable strain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6838276','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6838276"><span>Corrections to charge exchange spectroscopic measurements in TFTR due to energy-<span class="hlt">dependent</span> excitation <span class="hlt">rates</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Howell, R.B.; Fonck, R.J.; Knize, R.J.; Jaehnig, K.P.</p> <p>1988-08-01</p> <p>The use of charge exchange spectrocopy to determine plasma rotation speeds and ion temperature is complicated by the energy <span class="hlt">dependence</span> of the excitation cross sections. The Doppler-broadened spectral line shape is distorted by the relative velocity between the neutral hydrogen atoms of the injected beam and impurity ions. The asymmetric nature of the energy <span class="hlt">dependence</span> of this cross section causes a non-motional shift of the line center and a non-thermal change in the line width. These effects vary with the angles between the beam direction, rotation velocity direction, and direction of the viewing sightline. When viewing two neutral beams at different angles on TFTR, the two measurements of v/sub phi/(r) show discrepancies about 20 to 30% with each other. The calculation of the spectral intensity profiles, using the excitation <span class="hlt">rates</span> available, overcorrects these discrepancies and indicates the need for better excitation coefficients. 10 refs., 5 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5622085','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5622085"><span>Negative ion formation by Rydberg electron transfer: Isotope-<span class="hlt">dependent</span> <span class="hlt">rate</span> constants</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Carman, H.S. Jr.; Klots, C.E.; Compton, R.N.</p> <p>1991-01-01</p> <p>The formation of negative ions during collisions of rubidium atoms in selected ns and nd Rydberg states with carbon disulfide molecules has been studied for a range of effective principal quantum numbers (10 {le} n* {le} 25). For a narrow range of n* near n* = 17, <span class="hlt">rate</span> constants for CS{sub 2}{sup {minus}} formation are found to <span class="hlt">depend</span> upon the isotopic composition of the molecule, producing a negative ion isotope ratio (mass 78 to mass 76, amu) up to 10.5 times larger than the natural abundance ratio of CS{sub 2} isotopes in the reagent. The isotope ratio is found to <span class="hlt">depend</span> strongly upon the initial quantum state of the Rydberg atom and perhaps upon the collision energy and CS{sub 2} temperature. 32 refs., 5 figs., 1 tab.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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