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Sample records for nonhormonal estrus synchronization

  1. Synchronization of estrus and fertility in zebu beef heifers treated with three estrus synchronization protocols.

    PubMed

    Corbet, N J; Miller, R G; Bindon, B M; Burrow, H M; D'Occhio, M J; Entwistle, K W; Fitzpatrick, L A; Wilkins, J F; Kinder, J E

    1999-02-01

    The effects on estrus and fertility of 3 estrus synchronization protocols were studied in Brahman beef heifers. In Treatment 1 (PGF protocol; n=234), heifers received 7.5 mg, i.m. prostianol on Day 0 and were inseminated after observed estrus until Day 5. Treatment 2 (10-d NOR protocol; n = 220) consisted of norgestomet (NOR; 3 mg, s.c. implant and 3 mg, i.m.) and estradiol valerate (5 mg, i.m.) treatment on Day -10, NOR implant removal and 400 IU, i.m. PMSG on Day 0, and AI after observed estrus through to Day 5. Treatment 3 (14-d NOR+PGF protocol; n = 168) constituted a NOR implant (3 mg, sc) on Day -14, NOR implant removal on Day 0, PGF on Day 16, and AI after observed estrus through to Day 21. All heifers were examined for return to estrus at the next cycle and inseminated after observed estrus. The heifers were then exposed to bulls for at least 21 d. During the period of estrus observation (5 d) after treatment, those heifers treated with the PGF protocol had a lower (P<0.01) rate of estrual response (58%) than heifers treated with the 10-d NOR (87%) or 14-d NOR+PGF (88%) protocol. Heifers treated with the 10-d NOR protocol displayed estrus earlier and had a closer synchrony of estrus than heifers treated with either the PGF or the 14-d NOR+PGF protocol. Heifers treated with the 14-d NOR+PGF protocol had higher (P<0.05) conception and calving rates (51 and 46%) to AI at the induced estrus than heifers treated with the PGF (45 and 27%) or the 10-d NOR (38 and 33%) protocol. Calving rate to 2 rounds of AI was greater (P<0.05) for heifers treated with the 14-d NOR-PGF (50%) protocol than heifers treated with the 10-d NOR (38%) but not the PGF (43%) protocol. Breeding season calving rates were similar among the 3 protocols. The results show that the 14-d NOR+PGF estrus synchronization protocol induced a high incidence of estrus with comparatively high fertility in Brahman heifers. PMID:10729049

  2. Resynchronization of estrus in beef cattle: Ovarian function, estrus and fertility following progestin treatment and treatments to synchronize ovarian follicular development and estrus

    PubMed Central

    Colazo, Marcos G.; Kastelic, John P.; Small, Julie A.; Wilde, Randy E.; Ward, Douglas R.; Mapletoft, Reuben J.

    2007-01-01

    The objective was to optimize rebreeding of nonpregnant, previously inseminated beef cattle. In Experiment 1, 43 cows received a used intravaginal progesterone-releasing insert (IVPRI; Days 0–7) 12.3 d after ovulation and received concurrently no treatment, 100 μg gonadotropin releasing hormone (GnRH), 1 mg estradiol cypionate (ECP), or 150 mg progesterone. Emergence of a new ovarian follicular wave was most synchronous (P < 0.0001) in the GnRH group. In Experiment 2, 675 heifers were given GnRH or no treatment on Day 0, fed melengestrol acetate (MGA; 0.5 mg/head/d) from Days 0–5 (Day 0 = 13–14 d after timed insemination; TAI), given 0.5 mg ECP or nothing on Day 7, and reinseminated 6–12 h after onset of estrus. Estrus was more synchronous (P < 0.05) in heifers given GnRH versus no treatment on Day 0. In Experiment 3, 317 TAI heifers were resynchronized with either MGA or a used IVPRI with or without ECP on Day 7; estrus was more synchronous (P < 0.05) and pregnancy rates were higher (54.1% versus 39.2%, P < 0.05) in heifers given a used IVPRI than those fed MGA. For resynchronization of heifers, pregnancy rates were not significantly improved with GnRH treatment, but were higher with a used IVPRI than with MGA. PMID:17310622

  3. Synchronization of estrus and fertility in beef cattle with two injections of buserelin and prostaglandin.

    PubMed

    Twagiramungu, H; Guilbault, L A; Proulx, J; Dufour, J J

    1992-12-01

    Postpartum beef cows and heifers in Group 1 received 8 mug of buserelin on Day 0 (the beginning of the experiment) and 500 microg of cloprostenol (PGF) on Day 6 (GnRH I, n=54). In Group 2 (GnRH II, n=54), the females were injected with buserelin on Day 0 (8 microg) and Day 3 (4 microg), and PGF on Day 6 and Day 9 for females not detected in estrus previously. Animals were bred by AI 12 hours after the onset of estrus. Blood samples were collected on Day -11 and Day 0 to assess cyclicity and on Day 3 and Days 6 to 12 to examine luteal activity. Progesterone levels did not differ between the 2 groups between Days 0 to 9. In both groups, the proportion of spontaneous estruses from Days 0 to 6 was reduced. Precision of estrus was higher (P<0.005) in the GnRH II group than in the GnRH I group of cows that were detected in estrus between Days 6 and 9. The synchronization rate, interval to estrus, pregnancy and conception rates were similar in GnRH I and GnRH II groups. The conception rate and interval to estrus were similar in cyclic and acyclic cows. Increasing the number of buserelin injections enhanced the precision of estrus, but not the conception rate, without any detrimental effect on luteal activity and induced more estruses in postpartum acyclic beef cattle. PMID:16727210

  4. Efficacy of four synchronization protocols on the estrus behavior and conception in native Korean cattle (Hanwoo).

    PubMed

    Lee, Myeung-Sik; Rahman, Md Saidur; Kwon, Woo-Sung; Chung, Hak-Jae; Yang, Boh-Suk; Pang, Myung-Geol

    2013-11-01

    Ineffective estrus detection is the foremost limiting factor in the fertility of farmed cattle worldwide. Failure to detect estrus or erroneous diagnosis of estrus results in great economic losses in Korea each year. This study was carried out in order to comprehensively describe the estrus behaviors and conception rates of different estrus synchronization protocols applied to 40 cycling native Korean cattle (Hanwoo). The cows were grouped into four (n = 10) and treated with the following protocols: (1) Day -15: controlled intravaginal drug-releasing device (CIDR) for 12 days; Day -5: prostaglandin F2α (PGF2α), (2) ovulation synchronization (OVS): Day -15: GnRH; Day -6: PGF2α; Day -4: GnRH, (3) Day -15: progesterone-releasing intravaginal device for 12 days; Day -5: PGF2α; and (4) Day -15: PGF2α; Day -4: PGF2α. Artificial insemination was performed 12 hours after the detection of estrus using frozen-thawed semen. Estrus signs were compared using a charge-coupled device camera (CCDC) and a control method (direct visual observation). The pregnancy of the cows was determined by transrectal ultrasonography at Days 25 to 30 postinsemination. The results indicated that the day of estrus return was significantly earlier using the CCDC method compared with direct visualization (P < 0.05). Mounting of other cows was the most predominant sign of estrus among the flock (P < 0.05), as analyzed using the CCDC. In the OVS group, a lower rate of mounting was observed than in the other three groups. Moreover, significantly fewer estrus behaviors were noticed in the OVS protocol group (P < 0.05). Both first service conception and overall conception rates were significantly higher (P < 0.05) in the CIDR and OVS treatment groups. In conclusion, the CIDR and OVS protocols appear to be the best practice for the synchronization of estrus for reproductive competence through the CCDC in Hanwoo cows. However, CIDR has a practical advantage over OVS with respect to estrus detection

  5. Effects of timed artificial insemination following estrus synchronization in postpartum beef cattle

    PubMed Central

    Malik, A.; Wahid, H.; Rosnina, Y.; Kasim, A.; Sabri, M.

    2012-01-01

    The objectives of this study were to evaluate estrus response and pregnancy rates resulting from timed artificial insemination (AI) following estrus synchronization using CIDR in postpartum beef cattle. A total of 100 cows were randomly divided into three groups. Groups 1, 2 and 3 were artificially inseminated at 48-50 h (n=30), 53-55 h (n=30) and 58-60 h (n=40) after CIDR removal, respectively. Estrus synchronization was carried out using a CIDR containing 1.38 mg progesterone. All cows were given 2 mg estradiol benzoate, intramuscularly on the day of CIDR insertion (D 0). The CIDR was removed after 8 days and 125 μg of prostaglandin F2α (PGF2α) was injected intramuscularly. One day after CIDR removal all cows were given 1 mg of estradiol benzoate intramuscularly (D 9). Cows were observed visually for estrus after removal of CIDR. Between 30 and 32 days after timed AI, pregnancy was determined using transrectal ultrasonography. The first estrus observation which is approximately 32 h after CIDR removal showed no significant difference (P>0.05) among the three groups. The onset response of estrus after 32 h removal of CIDR was less than 10% in all three groups 6.6% (G1), 6.8% (G2) and 7.3% (G3). Furthermore, percentages of estrus response (D 10) following CIDR removal were 76.6%, 75.0% and 77.5%. The difference between on D 9 and D 10 estrus response were statistically significant (P<0.05). The pregnancy rates were 23.3% (G1), 26.6% (G2) and 37.5% (G3), which were not significant (P>0.05). PMID:26623282

  6. Comparison of timed AI after synchronized ovulation to AI at estrus: reproductive and economic considerations.

    PubMed

    Tenhagen, B A; Drillich, M; Surholt, R; Heuwieser, W

    2004-01-01

    A timed artificial insemination (TAI) protocol using OvSynch was compared to artificial insemination (AI) at detected estrus in 2 large dairy herds differing in reproductive management. Cows were synchronized for TAI starting at 62 and 42 d in milk in herds 1 and 2, respectively. The OvSynch regimen included: GnRH (buserelin) at 0.02 mg (i.m.) on d 0; PGF2alpha (tiaprost) at 0.75 mg (i.m.) on d 7; buserelin at 0.02 mg (i.m.) on d 9; and TAI 16 to 20 h later. After TAI, cows seen in estrus received AI, whereas cows diagnosed not pregnant were resynchronized for TAI. Control cows received AI based on detected estrus after voluntary waiting periods of 72 d in herd 1 and 50 d in herd 2. An economic analysis included costs associated with days open, culling, AI, synchrony products, treatment, and examinations. A sensitivity analysis of those variables determined effects on total costs per pregnancy. Use of OvSynch reduced intervals to first AI and days open in both herds and reduced culling for infertility in herd 2. Conception rates for first AI at detected estrus were significantly higher compared to TAI in both herds and for overall AI at estrus in herd 2. For groups assigned to AI at estrus, mean 21-d submission rates over 200 d for AI were higher in herd 1 than in herd 2 (55.6 vs. 28.6%). Days open and culling were the major cost factors. Although OvSynch improved reproduction in both herds, AI based on detected estrus was economically superior in herd 1, whereas OvSynch was superior in herd 2. This was consistent across ranges of cost factors evaluated. Evaluation of synchrony protocols should include reproductive performance along with appropriate costs associated with treatments. Such costs may offset benefits to reproduction in herds with good estrous detection rates. PMID:14765814

  7. Supplementation with rumen-protected L-arginine-HCl increased fertility in sheep with synchronized estrus.

    PubMed

    de Chávez, Julio Agustín Ruiz; Guzmán, Adrian; Zamora-Gutiérrez, Diana; Mendoza, Germán David; Melgoza, Luz María; Montes, Sergio; Rosales-Torres, Ana María

    2015-08-01

    The aim of the present study was to evaluate the effects of L-arginine-HCl supplementation on ovulation rate, fertility, prolificacy, and serum VEGF concentrations in ewes with synchronized oestrus. Thirty Suffolk ewes with a mean body weight of 45 ± 3 kg and a mean body condition score (BCS) of 2.4 ± 0.28 were synchronized for estrus presentation with a progestin-containing sponge (20 mg Chronogest® CR) for 9 days plus PGF2-α (Lutalyse; Pfizer, USA) on day 7 after the insertion of the sponge. The ewes were divided into two groups; i.e., a control group (n = 15) that was fed on the native pasture (basal diet) and an L-arginine-HCl group (n = 15) that received 7.8 g of rumen-protected L-arginine-HCl from day 5 of the sponge insertion until day 25 after mating plus the basal diet. The L-arginine-HCl was administered daily via an esophageal probe between days 5 and 9 of the synchronization protocol and every third day subsequently. Blood samples were drawn from the jugular vein every 6 days throughout the entire experimental period. The results revealed that the L-arginine-HCl supplementation increased fertility during the synchronized estrus (P = 0.05). However, no effects were observed on the final BCS (P = 0.78), estrus presentation (P = 0.33), multiple ovulations (P = 0.24), prolificacy (P = 0.63), or serum VEGF concentration. In conclusion, L-arginine-HCl supplementation during the period used in this study increased fertility in sheep with synchronized estrus possibly due to improved embryo-fetal survival during early pregnancy. PMID:25991464

  8. Comparison of long-term progestin-based estrus synchronization protocols in beef heifers.

    PubMed

    Mallory, D A; Wilson, D J; Busch, D C; Ellersieck, M R; Smith, M F; Patterson, D J

    2010-11-01

    Two experiments evaluated long-term progestin-based estrus-synchronization programs on the basis of potential for use in facilitating fixed-time AI in estrous cycling and prepubertal beef heifers. In Exp. 1, heifers were assigned to 1 of 2 treatments by age, BW, and estrous cyclicity status. Heifers assigned to the melengestrol acetate-PGF(2α) protocol (MGA-PG; n = 50) received MGA (0.5 mg·animal(-1)·d(-1)) in a 1.0-kg carrier from d 0 to 13 and were administered PGF(2α) (25 mg, intramuscularly) 19 d after MGA withdrawal (d 32). Heifers assigned to the Show-Me-Synch protocol (n = 49) received a controlled internal drug release (CIDR) insert (1.38 g of progesterone) from d 2 to 16 followed by PGF(2α) administration 16 d after CIDR removal (d 32). All heifers were fitted with HeatWatch estrus-detection transmitters at the time of progestin removal for continuous estrus detection through the synchronized period after PGF(2α). In Exp. 2, heifers (n = 396) were assigned to the same 2 treatments described in Exp. 1 by age, BW, and reproductive tract score. Heifers in Exp. 2, however, were fitted with HeatWatch estrus-detection transmitters at PGF(2α) to characterize estrus-distribution patterns during the synchronized period after PGF(2α). Heifers in both experiments were inseminated approximately 12 h after the onset of estrus. In Exp. 1, estrous response after PGF(2α) and mean interval to estrus after PGF(2α) did not differ between MGA-PG and Show-Me-Synch treatments (P = 0.97). The variance for interval to estrus after PGF(2α) tended (P = 0.06) to be reduced among MGA-PG-treated heifers compared with Show-Me-Synch-treated heifers. Conception to AI, AI pregnancy, and final pregnancy rates did not differ (P > 0.1) between treatments. In Exp. 2, estrous response after PGF(2α) was greater (P = 0.01) among Show-Me-Synch-treated heifers (92%) compared with MGA-PG-treated heifers (85%); however, mean interval to estrus after PGF(2α) did not differ (P = 0

  9. An evaluation of estrus synchronization programs in reproductive management of dairy herds.

    PubMed

    Ryan, D P; Snijders, S; Yaakub, H; O'Farrell, K J

    1995-12-01

    The objectives of this experiment were to evaluate the effect of various estrus synchronization programs on estrus detection rate (EDR) and pregnancy rate (PR) in lactating cows. Spring-calving, lactating dairy cows (n = 3,096) were allocated to one of six treatments: 1) PG (n = 514), estrus detection for 10 d before the onset of the breeding season (BS), cows detected in estrus received PGF2 alpha (PGF) 8 d after estrus, and all cows to be bred by d 11 of BS; 2) PG+EBZ (n = 510), as in PG plus cows treated with PGF received 1 mg of estradiol benzoate 48 h later; 3) C (n = 522), progestogen (controlled intravaginal drug release; CIDR) inserted per vaginum 10 d before BS for 8 d, PGF treatment on the day before CIDR removal, and AI within 6 d after CIDR withdrawal; 4) C+EBZ (n = 520), as in C, plus 10 mg of estradiol benzoate 10 d before BS; 5) C+BUS (n = 517), as in C plus 10 micrograms of buserelin on the day of CIDR insertion; or 6) CON (n = 513), no treatment, and a 32-d period of AI. Relative to other CIDR-treated groups, estradiol benzoate at the time of CIDR insertion reduced (P < .05) the EDR (C, 85.0%;C+EBZ, 75.9%; C+BUS, 88.5%). The PR to first AI was reduced (P < .05) by C compared with other treatments (PG, 60.9%; PG+EBZ, 57.2%; C, 46.6%; C+EBZ, 60.5%; C+BUS, 57.9%; CON, 60.1%). The interval from the onset of BS to AI and pregnancy was reduced (P < .05) by up to 9 d by estrus synchronization relative to controls (PG, 5.5 +/- .2 d; PG+EBZ, 5.2 +/- .2 d; C 1.7 +/- .1 d; C+EBZ, 2.3 +/- .1 d; C+BUS, 106 +/- .04d, CON, 10.4 +/- .3 d). In conclusion an 8-d progestogen-buserelin-PGF treatment resulted in the best overall estrus detection and pregnancy rates, which would be beneficial to a compact calving program. PMID:8655445

  10. Estrus synchronization of lactating dairy cows with GnRH, progesterone, and prostaglandin F2 alpha.

    PubMed

    Xu, Z Z; Burton, L J

    2000-03-01

    The reproductive performance of synchronized cows was compared with that of nonsynchronized cows. In trial 1, cyclic cows in five seasonal herds were randomly divided into two groups. Cows in one group (n = 515) were treated with a GnRH agonist and an intravaginal progesterone device, followed in 7 d by a PGF2 alpha injection, and the device was removed 1 d after PGF2 alpha. Cows in the other group (n = 512) did not receive any treatment and acted as control. In trial 2, the treatments were similar to those used in trial 1 except that the progesterone device was removed at the time of PGF2 alpha injection (synchronized: n = 516; control: n = 512). The estrus synchronization rate was 92.8% in trial 1 and 92.2% in trial 2. Conception rate to first artificial insemination (AI) was lower for synchronized cows than for control cows in trial 1 (56.5 vs. 62.7%), but similar in trial 2 (64.6 vs. 63.3%). Across both trials, the pregnancy rate during the AI breeding period was greater for the synchronized cows (85.6%) than for the control cows (81.2%). The synchronization treatment reduced the interval from start of the breeding season to conception for cows conceiving by AI (8.9 vs. 14.8 d) or by AI or natural mating (14.1 vs. 21.6 d). The synchronization protocol used in trial 2 achieved better conception rate than that used in trial 1, but the precision of estrus was less in trial 2 than in trial 1. PMID:10750104

  11. Influence of an agonist of gonadotropin-releasing hormone (buserelin) on estrus synchronization and fertility in beef cows.

    PubMed

    Twagiramungu, H; Guilbault, L A; Proulx, J; Villeneuve, P; Dufour, J J

    1992-06-01

    The objective of this experiment was to determine the effect of sequential treatment with buserelin (a GnRH agonist) and cloprostenol (a prostaglandin F2 alpha analog) on estrous response and fertility in beef cattle with different ovarian conditions. On d 0 (1st d of treatment), the control group (n = 52, 10 heifers and 42 cows) and the GnRH group (n = 48, 10 heifers and 38 cows) received 2 mL of saline or 2 mL of Receptal (8 micrograms of buserelin), respectively. On d 6, all cows that had not exhibited spontaneous estrus were given i.m. 500 micrograms of cloprostenol (PGF). Ultrasonography on d 0 and assays of progesterone in blood on d -11, 0, and 6 were used to identify follicular and luteal status of animals. Cattle were observed for estrus from d 0 to 10. Cows showing estrus were bred artificially 12 h after onset of estrus. Over the 10-d period, the number of cows detected in estrus and pregnancy and conception rates were identical for the two groups. However, between d 0 and 6, the proportion of cows exhibiting estrus was lower (P less than .01) in the GnRH group than in the control group. Between d 6 and 10, the synchronization rate and precision of estrus were greater (P less than .01) in the buserelin-treated group than in the control group. Conception rate and interval from PGF injection to onset of estrus were not different between the two treatment groups. Presence of a large (greater than 10 mm) follicle on d 0 enhanced synchronization rate and precision of estrus.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1634414

  12. Efficacy of Heatsynch protocol for induction of estrus, synchronization of ovulation and timed artificial insemination in yaks (Poephagus grunniens L.).

    PubMed

    Sarkar, M; Sengupta, D H; Bora, B Dutta; Rajkhoa, J; Bora, S; Bandopadhaya, S; Ghosh, M; Ahmed, F A; Saikia, P; Mohan, Krishna; Prakash, B S

    2008-03-01

    The objective of this study was to test the efficacy of induction of estrus, synchronization of ovulation and timed artificial insemination in anestrous yaks using the Heatsynch protocol. In Experiment 1, 10 anestrous yaks were administered an analogue of gonadotropin releasing hormone (GnRH) followed by prostaglandin (PG)F2alpha 7 days later and then estradiol cyponate (ECP) 24 h after that. Ovulation was detected by rectal palpation at 2h intervals beginning at the initial signs of estrus. Blood samples were collected at 2h intervals beginning at the time of ECP injection up to 2h after the occurrence of ovulation for the determination of LH and progesterone. All the animals responded to the Heatsynch protocol with expression of estrus and synchronization of ovulation. The mean time interval from the ECP injection to ovulation was 59.4+/-2.62 h (range 50-72 h). The interval from the LH peak to ovulation was 30.2+/-2.3 h. The high degree of synchrony in ovulation could be attributed to the synchrony in the timing of LH peaks. In Experiment 2, 10 anestrous yaks were treated with the Heatsynch protocol (as in Experiment 1) and TAI was performed at 48 and 60 h after the ECP treatment. Concurrently, 16 cycling yaks were inseminated approximately 12 h after detection of spontaneous estrus. Pregnancy rates were similar in both groups, 40% for TAI and 43.75% for yaks inseminated following spontaneous estrus (p>0.05). From this study, two conclusions can be drawn. First, the Heatsynch protocol can be successfully used to induce and synchronize estrus in anestrous yaks and, second, ovulation following the Heatsynch protocol is synchronized adequately to permit the use of fixed time AI in this species. PMID:17383122

  13. Estrus response and follicular development in Boer does synchronized with flugestone acetate and PGF2α or their combination with eCG or FSH.

    PubMed

    Bukar, Muhammad Modu; Yusoff, Rosnina; Haron, Abd Wahid; Dhaliwal, Gurmeet Kaur; Khan, Mohd Azam Goriman; Omar, Mohammed Ariff

    2012-10-01

    The effects of different estrus synchronization techniques on follicular development and estrus response were studied in 81 nulliparous Boer does. The does were divided into nine groups. Eight of the nine groups were synchronized with prostaglandin F2-alpha (PGF(2α)) or flugestone acetate (FGA) or their combinations, and the ninth group was a control group. In addition to the above combinations, four of the eight synchronized groups were given 5 mg follicle-stimulating hormone (FSH) and the remaining four groups were administered 300 IU equine chorionic gonadotrophin (eCG). Posttreatment follicular development was monitored until ovulation occurred using a real-time B-mode ultrasound scanner (Aloka, 500 SSD, Japan), with a 7.5-MHz transrectal linear probe. All the does from the synchronized groups that were given eCG exhibited oestrus while only 88.9% of the does synchronized with FSH showed estrus. The estrus response was observed to be the least among the does synchronized with PGF(2α) + FSH (33.3%) combination followed closely by the FGA + FSH (42.9%) combinations. It was observed that the combinations of FGA + PGF(2α) + FSH resulted in increased percentage of estrus response, duration of estrus, and ovulation. The number of follicles was higher (P < 0.05) in FSH-synchronized groups than the eCG-synchronized groups. It was concluded that the best estrus synchronization protocol in goats is the FGA + eCG with or without PGF(2α). However, the PGF(2α) + FGA + FSH method of estrus synchronization is the most promising combination for further development as a better alternative to estrus synchronization with eCG in does. PMID:22461200

  14. Comparative efficacy of different estrus synchronization protocols on estrus induction response, fertility and plasma progesterone and biochemical profile in crossbred anestrus cows

    PubMed Central

    Dhami, A. J.; Nakrani, B. B.; Hadiya, K. K.; Patel, J. A.; Shah, R. G.

    2015-01-01

    Aim: To evaluate estrus induction response and fertility including plasma progesterone and biochemical profile following use of three standard hormonal protocols in anestrus crossbred cows. Materials and Methods: The study was carried out on 40 true anestrus and 10 normal cyclic cows. 10 anestrus cows each were treated with standard intravaginal controlled internal drug release (CIDR) device, Ovsynch (GPG) protocol, and Norgestomet ear implant with fixed-time artificial insemination (FTAI). 10 anestrus cows were kept as untreated control while 10 cows exhibiting the first estrus within 90 days postpartum without any treatment served as normal cyclic control. Blood samples were obtained from treated cows on day 0, 7, 9 (AI) of treatment and day 21 post-AI, and from control groups on the day of AI and day 21 post-AI for estimation of plasma progesterone, protein, cholesterol, calcium, and inorganic phosphorus profile. Results: The use of CIDR, Ovsynch, and Norgestomet ear implant protocols resulted in 100% estrus induction with conception rates at induced estrus of 60%, 50%, and 50%, and the overall of three cycles as 80%, 80%, and 70%. In untreated anestrus control (n=10), only three cows exhibited spontaneous estrus within 90 days of follow-up and conceived giving the first service and overall conception rates of 66.66% and 30.00%, respectively. In normal cyclic control (n=10), the conception rates at first and overall of three cycles were 50% and 80%. The overall mean plasma progesterone (P4) concentrations in anestrus cows studied on day 0 (initiation), 7 (prostaglandin injection and/or removal of implant), 9 (FTAI) of treatment and on day 21 post-AI revealed that the values on day 7 and 21 were significantly (p<0.01) higher than other two periods in all three groups. The concentrations were significantly (p<0.05) higher in conceived than non-conceived group on day 21 post-AI in CIDR (4.36±0.12 vs. 1.65±0.82 ng/ml) and Ovsynch (4.85±0.62 vs. 1.59±0.34 ng

  15. Use of intravaginal progesterone-releasing inserts in a synchronization protocol before timed AI and for synchronizing return to estrus in Holstein heifers.

    PubMed

    Rivera, H; Lopez, H; Fricke, P M

    2005-03-01

    Holstein heifers (n = 189) were submitted to a 42-d artificial insemination (AI) period in which they underwent AI after once-daily evaluation of rubbed tail chalk. At the onset of the AI period (d 0), heifers were assigned randomly to receive synchronization of ovulation and timed AI (TAI; d 0: 100 mug of GnRH; d 6: 25 mg of PGF(2alpha); d 8: 100 mug of GnRH + TAI) either without (GPG; n = 95), or with inclusion of a CIDR insert (CIDR; n = 94) from d 0 to 6. No CIDR heifers received AI before d 8 compared with 24% of GPG heifers, and pregnancy rate per AI (PR/AI) at 30 d after TAI did not differ between treatments. To synchronize return to estrus for heifers failing to conceive after TAI, heifers (n = 166) receiving TAI to first service were randomly assigned to receive no further treatment (control; n = 85) or receive a new CIDR insert between 14 and 20 d after TAI (Resynch; n = 81). No Resynch heifers received AI during CIDR treatment compared with 35% of control heifers, and the proportion of heifers receiving AI within 72 h after the day of CIDR removal was 78 vs. 50% for Resynch vs. control heifers, respectively. No treatment x inseminator interaction was detected at first or second AI; however, overall PR/AI was modest for heifers throughout the experiment due to poor performance of 2 of the 3 herd inseminators (14, 6, and 58% PR/AI, respectively). Inclusion of CIDR inserts suppressed estrus during the TAI protocol with no reduction in PR/ AI. Resynchronization of estrus using CIDR inserts resulted in tighter synchrony of estrus among nonpregnant heifers compared with untreated controls. PMID:15738230

  16. Estrus synchronization in microminipig using estradiol dipropionate and prostaglandin F2α

    PubMed Central

    NOGUCHI, Michiko; IKEDO, Tomonobu; KAWAGUCHI, Hiroaki; TANIMOTO, Akihide

    2016-01-01

    The induction of pseudopregnancy by the exogenous administration of estradiol dipropionate (EDP) was investigated in cyclic Microminipigs (MMpigs) and the effects of exogenous administration of prostaglandin (PG) F2α on estrus exhibition were assessed in pseudopregnant MMpigs. In experiment 1, ovariectomized MMpigs were given a single intramuscular injection of 0.5, 1.5, or 2.5 mg of EDP. The estradiol-17β level at each of these doses was significantly higher 1 to 3 days after EDP administration than on the day of the injection. In experiment 2, animals were given 1.5 mg of EDP once at 9 to 12 days after the end of estrus (D0) and then no (1.5 mg × 1 group), one (D0 and D4; 1.5 mg × 2 group), or two (D0, D4 and D7; 1.5 mg × 3 group) additional treatments. The pseudopregnancy rate was significantly higher in the 1.5 mg × 3 than in the 1.5 mg × 1 group. In experiment 3, PGF2α was administered twice between 26 and 28 days after EDP treatment to five pseudopregnant gilts with a 24-h interval between the two injections. Estrus after PGF2α treatment and LH surge were observed in 100% and 80% pseudopregnant MMpigs, respectively. The interval from the day of the first PGF2α treatment to the onset of estrus was 6.5 ± 0.2 days. These results indicate that multiple EDP treatments are required for induction of pseudopregnancy in MMpigs and estrus exhibition can be controlled in MMpigs by treatment with EDP and PGF2α. PMID:27151362

  17. Estrus synchronization in microminipig using estradiol dipropionate and prostaglandin F2α.

    PubMed

    Noguchi, Michiko; Ikedo, Tomonobu; Kawaguchi, Hiroaki; Tanimoto, Akihide

    2016-08-25

    The induction of pseudopregnancy by the exogenous administration of estradiol dipropionate (EDP) was investigated in cyclic Microminipigs (MMpigs) and the effects of exogenous administration of prostaglandin (PG) F2α on estrus exhibition were assessed in pseudopregnant MMpigs. In experiment 1, ovariectomized MMpigs were given a single intramuscular injection of 0.5, 1.5, or 2.5 mg of EDP. The estradiol-17β level at each of these doses was significantly higher 1 to 3 days after EDP administration than on the day of the injection. In experiment 2, animals were given 1.5 mg of EDP once at 9 to 12 days after the end of estrus (D0) and then no (1.5 mg × 1 group), one (D0 and D4; 1.5 mg × 2 group), or two (D0, D4 and D7; 1.5 mg × 3 group) additional treatments. The pseudopregnancy rate was significantly higher in the 1.5 mg × 3 than in the 1.5 mg × 1 group. In experiment 3, PGF2α was administered twice between 26 and 28 days after EDP treatment to five pseudopregnant gilts with a 24-h interval between the two injections. Estrus after PGF2α treatment and LH surge were observed in 100% and 80% pseudopregnant MMpigs, respectively. The interval from the day of the first PGF2α treatment to the onset of estrus was 6.5 ± 0.2 days. These results indicate that multiple EDP treatments are required for induction of pseudopregnancy in MMpigs and estrus exhibition can be controlled in MMpigs by treatment with EDP and PGF2α. PMID:27151362

  18. Evaluation of protocols to synchronize estrus and ovulation in seasonal calving pasture-based dairy production systems.

    PubMed

    Herlihy, M M; Berry, D P; Crowe, M A; Diskin, M G; Butler, S T

    2011-09-01

    Lactating dairy cows (n=1,538) were enrolled in a randomized complete block design study to evaluate protocols to synchronize estrus and ovulation. Within each herd (n=8), cows were divided into 3 calving groups: early, mid, and late, based on days in milk (DIM) at mating start date (MSD). Early calving cows (n=1,244) were ≥42 DIM at MSD, mid-calving cows (n=179) were 21 to 41 DIM at MSD, and late-calving cows (n=115) were 0 to 20 DIM at MSD. Cows in the early, mid-, and late-calving groups were synchronized to facilitate estrus or timed AI (TAI) at MSD (planned breeding 1; PB1), 21 d (PB2), and 42 d (PB3) after MSD, respectively. For each PB, cows in the relevant calving group were stratified by parity and calving date and randomly assigned to 1 of 4 experimental groups: (1) d -10 GnRH (10 μg of i.m. buserelin) and controlled internal drug release insert (CIDR; 1.38 g of progesterone); d -3 PGF(2α) (25 mg of i.m. dinoprost); and d -2 CIDR out and AI at observed estrus (CIDR_OBS); (2) same as CIDR_OBS, but GnRH 36 h after CIDR out and TAI 18 h later (CIDR_TAI); (3) same as CIDR_TAI, but no CIDR (Ovsynch); or (4) untreated controls (CTRL). The CIDR_OBS, CIDR_TAI, and Ovsynch had shorter mean intervals from calving to first service compared with the CTRL (69.2, 63.4, and 63.7 vs. 73.7 d, respectively). Both CIDR_OBS (predicted probability; PP of pregnancy=0.59) and CIDR_TAI (PP of pregnancy=0.54) had increased odds of conceiving at first service compared with Ovsynch [PP of pregnancy=0.45; odds ratio (OR)=1.81 and OR=1.46, respectively], and Ovsynch had decreased likelihood of conceiving at first service (OR=0.70) compared with CTRL (PP of pregnancy=0.53). Both CIDR_TAI hazard ratio; HR [95% confidence interval=1.21 (1.04, 1.41)] and Ovsynch [HR (95% confidence interval)=1.23 (1.05, 1.44)] were associated with an increased likelihood of earlier conception compared with the CTRL. A greater proportion of cows on the CIDR_TAI treatment successfully established

  19. Seasonality, estrous cycle characterization, estrus synchronization, semen cryopreservation, and artificial insemination in the Pacific white-sided dolphin (Lagenorhynchus obliquidens).

    PubMed

    Robeck, T R; Steinman, K J; Greenwell, M; Ramirez, K; Van Bonn, W; Yoshioka, M; Katsumata, E; Dalton, L; Osborn, S; O'Brien, J K

    2009-08-01

    The reproductive physiology of the Pacific white-sided dolphin, Lagenorhynchus obliquidens, was characterized to facilitate the development of artificial insemination (AI) using cryopreserved spermatozoa. Specific objectives were to: 1) describe reproductive seasonality of the Pacific white sided dolphins; 2) describe urinary LH and ovarian steroid metabolites during the estrous cycle; 3) correlate LH and ovarian steroidal metabolite patterns to ultrasound-monitored follicular growth and ovulation; and 4) assess the efficacy of synchronizing estrus, sperm collection/cryopreservation, and intrauterine insemination. Ovulations (64%, n=37) and conceptions (83%, n=18) occurred from August to October. Peak mean serum testosterone (24 ng/ml), cross-sectional testicular area (41.6 cm(2)), and sperm concentration (144.3 x 10(7) sperm/ml) occurred in July, August, and September respectively. Spermatozoa were only found in ejaculates from July to October. Estrous cycles (n=22) were 31 d long and were comprised of a 10 d follicular and 21 d luteal phase. Ovulation occurred 31.2 h after the onset of the LH surge and 19.3 h after the LH peak. Follicular diameter and circumference within 12 h of ovulation were 1.52 and 4.66 cm respectively. Estrus synchronization attempts with altrenogest resulted in 17 (22%) ovulatory cycles with ovulation occurring 21 d post-altrenogest. Ten AI attempts using cryopreserved semen resulted in five pregnancies (50%). The mean gestation length was 356 days (range 348-367). These data provide new information on the Pacific white-sided dolphin's reproductive physiology and collectively enabled the first application of AI in this species. PMID:19494046

  20. Short communication: Drug residues in goat milk after prophylactic use of antibiotics in intravaginal sponges for estrus synchronization.

    PubMed

    Romero, T; Balado, J; Althaus, R L; Beltrán, M C; Molina, M P

    2016-01-01

    The aim of this study was to determine whether the prophylactic use of antibiotics in intravaginal sponges used for estrus synchronization in goats may result in the presence of inhibitors in milk and, therefore, of positive results by microbial screening tests. Ninety-eight Murciano-Granadina goats were used, divided into 7 groups of 14 animals. Intravaginal sponges were placed in 6 groups using 2 concentrations of 3 different antibiotics: doxycycline, oxytetracycline, and sulfathiazole-framycetin. The sponges of the control group were placed without antibiotics. Milk samples were collected daily until 7 d posttreatment and analyzed using 3 microbial tests. Positive samples were retested by specific receptor-binding assays to confirm the positive results. Vaginal status was evaluated by visual assessment of the external aspect of the sponges after removal. The microbial test response was not affected by either day posttreatment or dose of antibiotic used, except for oxytetracycline at the higher concentration. Moreover, no positive results were obtained using receptor-binding assays, suggesting that residues, if present in milk, did not exceed the regulatory (safety) levels established for these drugs. The occurrence of soiled sponges was higher in the control group. With respect to the dose of antibiotics used, no significant differences were found for the lower dose administered. However, a significant increase in the percentage of clean sponges was observed for the higher dose of doxycycline. We conclude that the prophylactic use of low doses of doxycycline, oxytetracycline, or sulfathiazole in intravaginal sponges used for synchronization of estrus helps to reduce clinical vaginitis in dairy goats and does not seem to be the cause of positive results in microbial inhibitor tests used to detect antibiotics in goat milk. PMID:26585470

  1. Synchronization of ovarian follicular waves with a gonadotropin-releasing hormone agonist to increase the precision of estrus in cattle: a review.

    PubMed

    Twagiramungu, H; Guilbault, L A; Dufour, J J

    1995-10-01

    Treatment with GnRH and PGF2 alpha is a practical method for controlling ovarian follicular and luteal functions and increasing the precision of estrus synchronization in cyclic and acyclic postpartum cows and heifers. This method reduces considerably the period of time needed for estrus detection; it synchronizes the estrous cycle of 70 to 80% of the cyclic cows to within a 4-d interval without any detrimental effect on the fertility rate (65 to 85%). Moreover, resumption of ovarian activity and normal fertility in acyclic cows in favored. Administration of GnRH eliminates the large follicles by ovulation or atresia and induces emergence of a new follicular wave within 3 to 4 d after treatment at any stage of the estrous cycle, but it limits further growth of these emerging follicles by increasing atresia. The precision of estrus and the unaltered fertility rate is due to the synchronized selection of a new larger growing follicle, which becomes the ovulatory follicle after PGF(2 alpha)-induced luteolysis 6 d after GnRH treatment. Also, fixed-time AI programs without the need for estrus detection may be possible using a second injection of GnRH in a GnRH-PGF(2 alpha)-GnRH protocol to ovulate the selected follicle at a precise time. We describe a physiological model to explain how the precision of estrus is improved following PGF(2 alpha)-induced luteolysis, via the effect of pretreatment with GnRH on follicular development and luteal functions in cattle. Application of this model to the development of reliable methods of fixed-time insemination is also explored. PMID:8617687

  2. Photoperiod length and the estrus synchronization protocol used before AI affect the twin pregnancy rate in dairy cattle.

    PubMed

    Andreu-Vázquez, C; Garcia-Ispierto, I; López-Gatius, F

    2012-10-01

    This study addresses potential management risk factors affecting the incidence of twin pregnancies in high-producing dairy cows. Special attention was paid to the estrus synchronization protocol used before the AI resulting in pregnancy. Possible factors affecting the twin pregnancy rate were analyzed through binary logistic regression procedures on 2015 pregnant cows from July 2010 to July 2011. Twin pregnancy was recorded in 361 of the 2015 pregnancy diagnoses made (17.9%). Twin pregnancy rates differed among herds (P < 0.001) and ranged from 12.4% to 23.9%. Based on the odds ratios, the risk of twin pregnancy was reduced by factors of 0.65 or 0.71 when AI was performed during the warm season or an increasing photoperiod, respectively and increased by a factor of 1.11 for each unit increase in lactation number; by factors of 4.57 or 6.33 in cows that received a progesterone-releasing intravaginal device (PRID) plus 500 or 750 IU of equine chorionic gonadotropin (eCG) 28 days before the pregnancy AI, respectively; by a factor of 2.39 in cows with an ovarian cyst diagnosed in the 14 days prior to AI and treated with prostaglandins (PG); by factors of 1.94 or 3.91 in cows that received two PG doses during the 14 days prior to AI or cows that following failed PRID treatment had received PG started over the 28 days prior to AI, respectively; and by a factor of 2.58 in cows that had previously delivered twins compared to cows delivering singletons. Our results indicate that cow factors, such as lactation number and previous twining, as well as environmental factors, such as photoperiod and season and management related to synchronization protocols affect significantly the incidence of twin pregnancies. PMID:22898015

  3. Use of fluorogestone acetate sponges or controlled internal drug release for estrus synchronization in ewes: Effects of hormonal profiles and reproductive performance.

    PubMed

    Swelum, Ayman Abdel-Aziz; Alowaimer, Abdullah Nasser; Abouheif, Mohamed Ahmed

    2015-09-01

    This study was carried out using 300 multiparous Najdi ewes during breeding season to compare the effects of fluorogestone acetate (FGA) sponges and controlled internal drug release (CIDR) dispensers to synchronize estrus on reproductive performance and hormonal profiles. Ewes were equally and randomly allotted into group A (FGA) and group B (CIDR); intravaginal progestagen was administered for 14-day period with intramuscular administration of 600-IU eCG at withdrawal time. Estrus was detected using a vasectomized ram starting 12 hours after progestagen withdrawal and repeated every 12 hours up to 84 hours. Blood samples were collected at the time of progestagen withdrawal (0 hour), 24 hours, and 48 hours. Follicle-stimulating hormone, LH, estradiol, and progesterone serum concentrations were measured using commercial ELISA kits and microtitrimetric plates. Timed laparoscopic insemination was performed 48 hours after progestagen withdrawal. Pregnancy and the number of fetuses were diagnosed by ultrasonography on Day 23 after insemination and confirmed on Days 35 and 60. The results revealed that the retention, vaginal discharge, and drawstring breakage rates after progestagen removal were significantly (P ≤ 0.05) higher in the FGA group (94.00, 98.58, and 9.22, respectively) than those in the CIDR group. On the other hand, pregnancy, fertility, twinning rates, and fecundity were significantly (P ≤ 0.05) higher in the CIDR group (77.86, 75.57, 34.34, and 1.02, respectively) than in the FGA group. Estrus responses in FGA and CIDR groups increased gradually to attain their significantly (P ≤ 0.05) higher percentages after 48 hours of progestagen withdrawal (91.49 and 92.37, respectively); thereafter, they decreased. The overall estrus responses and prolificacy did not differ between the FGA and CIDR groups. Follicle-stimulating hormone was significantly higher in the FGA group at 24 and 48 hours after progestagen withdrawal, whereas LH was significantly higher

  4. Progesterone status, parity, body condition, and days postpartum before estrus or ovulation synchronization in suckled beef cattle influence artificial insemination pregnancy outcomes.

    PubMed

    Stevenson, J S; Hill, S L; Bridges, G A; Larson, J E; Lamb, G C

    2015-05-01

    Our objective was to assess the effects of progesterone before initiating an estrus- or ovulation-synchronization program in addition to the influence of parity, BCS, and days postpartum on resulting pregnancy rates per AI. Experimental data were combined from 73 herd-year studies consisting of more than 8,500 suckled beef cows exposed to variants of the CO-Synch program. Blood was harvested from samples collected at 10 and 0 d before the onset of CO-Synch, and progesterone concentrations of the samples were determined. The progesterone environment preceding synchronization was assessed in 3 ways on the basis of progesterone concentrations measured in the 2 defined blood samples. All binomial logistic regression models used procedure GLIMMIX in SAS and included the fixed effects of program duration, inclusion of progesterone via an intravaginal insert, parity, days postpartum at AI, BCS, and appropriate interactions. In addition, model 1 included 3 categories of progesterone concentrations (low [<1 ng/mL], medium [1.00 to 3.99 ng/mL], and high [≥4.00 ng/mL] concentrations) at 10 and 0 d before synchronization and their interaction. Model 2 included 4 categories defining the stage of the estrous cycle (late diestrus, early diestrus, and proestrus-estrus-metestrus) or anestrus, at which cows started the synchronization program. Model 3 defined cows as cycling or noncycling at the onset of the program. Significant effects of progesterone supplementation, which hormone was used to initiate the timed AI program, parity, BCS, days postpartum, and progesterone status assessed in 3 ways were consistent in nearly all models. Progesterone status at the onset of synchronization was not important to pregnancy outcomes in multiparous cows, whereas pregnancy rate per AI was suppressed in primiparous cows that began in a low-progesterone environment (proestrus, estrus, metestrus, or anestrus). A significant 3-way interaction of parity, BCS, and days postpartum in 2 models

  5. Estrus synchronization and fertility in post-partum dairy cattle after administration of human chorionic gonadotrophin (HCG) and prostaglandin F2 alpha analog.

    PubMed

    De Rensis, F; Allegri, M; Seidel, G E

    1999-07-15

    Human chorionic gonadotrophin (hCG) plus PGF2 alpha was compared with GnRH plus PGF2 alpha for estrus synchronization of dairy cows. There were 3 treatments: GnRH analog (Buserelin, 12.6 micrograms) plus PGF2 alpha analog (Cloprostenol, 150 micrograms) 6 d later (GnRH + PGF[Day 6]); hCG (2000 IU) plus PGF2 alpha 9 d later (hCG + PGF[Day 9]); and hCG plus PGF2 alpha 6 d later (hCG + PGF[Day 6]). Treatment occurred either Days 55 to 90 or Days 91 to 135 post partum. For responses during the first 10 d after PGF2 alpha administration, estrus synchronization (P = 0.24), efficacy (percentage of treated pregnant; P = 0.20) and conception (percentage of inseminated pregnant; P = 0.23) rates were not different among the 3 treatments. Cows treated between Days 55 and 90 had a higher rate (P < 0.05) of detected estrus during this period (69% for GnRH + PG [Day 6], 70% for hCG + PGF[Day 9] and 72% for hCG + PGF[Day 6]) compared with cows treated between Days 91 and 135 (52% for GnRH + PGF[Day 6], 50% for hCG + PGF[Day 9] and 57% for hCG + PGF[Day 6]). Efficacy of treatment was higher (P < 0.05) in animals treated between Days 55 and 90 (54% for GnRH + PGF[Day 6], 56% for hCG + PGF[Day 9] and 63% for hCG + PGF [Day 6]) compared to animals treated between Days 91 and 135 (36% for GnRH + PGF[Day 6], 35% for hCG + PGF[Day 9] and 47% for hCG + PGF[Day 6]). There were no significant differences in conception between Days 51 and 90 and Days 91 and 135. The interval between parturition-first AI with conception was significantly (P < 0.001) shorter in GnRH + PGF (Day 6; 106 d), hCG + PGF (Day 9; 109 d) and hCG + PGF (Day 6; 103 d) treated cattle than in 106 untreated animals (136 d). Thus, GnRH plus PGF2 alpha or hCG plus PGF2 alpha treatments elicited similar effects in estrus synchronization, treatment efficacy, and conception rate in post-partum dairy cows. PMID:10734393

  6. Factors associated with fertility outcomes in cows treated with protocols to synchronize estrus and ovulation in seasonal-calving, pasture-based dairy production systems.

    PubMed

    Herlihy, M M; Crowe, M A; Berry, D P; Diskin, M G; Butler, S T

    2013-03-01

    Logistic regression was used to identify factors associated with fertility outcomes in cows treated with protocols to synchronize estrus and ovulation. Lactating dairy cows (n=1,538) were enrolled in a completely randomized block design study to evaluate synchronization treatments. Within each herd (n=8), cows were divided into 3 calving groups: early [≥ 42 d in milk (DIM) at mating start date (MSD); n=1,244], mid (21 to 41 DIM at MSD; n=179), and late (0 to 20 DIM at MSD; n=115), based on DIM at MSD. Cows in the early-, mid-, and late-calving groups were synchronized to facilitate estrus or timed artificial insemination (TAI) at MSD (planned breeding 1; PB1), 21 d (PB2), and 42 d (PB3) after MSD, respectively. For each PB, cows in the relevant calving group were stratified by parity and calving date and randomly assigned to (1) d -10 GnRH (10 μg i.m. of buserelin) and CIDR [controlled internal drug release insert, 1.38 g of progesterone (P4)]; d -3 PGF(2α) (25mg i.m. of dinoprost); d -2 CIDR out and AI at observed estrus (CIDR_OBS); (2) same as CIDR_OBS, but GnRH 36 h after CIDR out and TAI 18 h later (CIDR_TAI); (3) same as CIDR_TAI, but no CIDR (i.e., Ovsynch); or (4) untreated controls (CTRL). Use of a CIDR-based ovulation synchronization protocol (i.e., CIDR_TAI) increased synchronization rates in anovular cows. Both CIDR_OBS and CIDR_TAI animals without a corpus luteum (CL) had increased likelihood of conception at first service compared with Ovsynch animals without a CL. Animals with low body condition score (BCS) treated with CIDR_OBS had an increased likelihood of conceiving at first service compared with low-BCS animals treated with CIDR_TAI, Ovsynch, or CTRL. Animals <60 d in milk (DIM) treated with CIDR_OBS and CIDR_TAI had increased likelihood of conceiving at first service compared with animals treated with Ovsynch. Treatment with CIDR_TAI increased synchronization rate in cows categorized as low BCS, anovulatory, and <60 DIM compared with both

  7. Expression of cumulus-oocyte complex genes and embryonic development in goats subjected to progestogen-based estrus synchronization.

    PubMed

    Thammasiri, Jiratti; Navanukraw, Chainarong; Uriyapongson, Suthipong; Khanthusaeng, Vilaivan; Kamollirt, Chuchat

    2016-07-15

    The objective was to investigate the effect of short-term (7 days) and long-term (14 days) progesterone-based estrus synchronization on number of follicles, progesterone concentrations, cumulus-oocyte complex (COC) gene expression, and embryonic development in goats. Nulliparous Thai-native goats (n = 45) were randomly assigned to one of two estrus synchronization treatments. Goats were treated with intravaginal sponges containing 60-mg medroxyprogesterone acetate (MAP; Synchrogest esponjas, Spain) during 7 or 14 days (short-term or long-term protocol, respectively). Multiple follicular development was induced by intramuscularly injections of 300-IU eCG in both groups (1 day before sponge withdrawal). An ovariectomy was performed at 24 hours after sponge removal to evaluate number of follicle and collect oocyte for IVF. Oocyte quality (healthy or nonhealthy) was determined by morphology of COCs before IVM. Recovery of COCs and total cellular RNA isolation were applied to determine apoptosis-related gene expression. After IVF, embryos were evaluated during the eight-day culture as numbers of cleaved oocyte, morula, and blastocyst embryo. Total numbers of follicles and oocytes were similar for both treatments. Plasma progesterone concentrations were not different during MAP insertion period (P > 0.05). However, goats that received the short-term protocol had a greater number of 4 to 6-mm follicle, healthy oocytes, cleaved oocytes, and morula embryos than goats that received the long-term protocol (P < 0.01). In addition, the expression of B-cell lymphoma 2 messenger RNA was greater (P < 0.05) in COCs derived from the 7 days MAP-treated when compared to the 14 days MAP-treated goats. These data highlight that the 7-day progestin-based treatment may contribute to quality of oocytes and embryonic development in goats. PMID:27056418

  8. ASAS centennial paper: Contributions in the Journal of Animal Science to the development of protocols for breeding management of cattle through synchronization of estrus and ovulation.

    PubMed

    Lauderdale, J W

    2009-02-01

    American Society of Animal Science members, publishing in Journal of Animal Science (JAS), completed research that resulted in understanding the estrous cycle of cattle, which led to the ability to inseminate cattle on a given day with pregnancy rates similar to those achieved by 21-d breeding by a fertile and sound bull. Research published in JAS led to understanding estrus, ovulation, the estrous cycle, and postpartum interval for cattle (1930s through 1960s) and hormonal factors affecting corpus luteum lifespan of cattle (1950s through 1980s). Research during the 1940s to 1960s, using gonadotropins and progesterone to manage the estrous cycle of cattle, established the concepts for estrous synchronization and stimulated commercial research directed at developing cost-effective progestogen estrous synchronization products, leading to commercially available products from 1967 through today (Repromix, melengestrol acetate, Syncro-Mate-B, controlled internal drug release). Prostaglandin F(2alpha) products were approved for estrous synchronization (1970s, 1980s), and GnRH products were approved for use in cattle to treat ovarian follicular cysts (1970s, 1980s). Research published in JAS was essential for understanding the biology of and potential value of both PGF(2alpha) and GnRH and contributed both to new knowledge and scientific bases for future Food and Drug Administration Center for Veterinary Medicine approval of those products. Research during the1980s through 2000s led to understanding ovarian follicular waves and described the timing of follicular recruitment, selection, dominance, and atresia; this research was essential for the ability to effectively manage follicles to achieve success with timed AI. The knowledge gained through research published in JAS resulted in development of the numerous estrous synchronization and breeding management protocols that are cost-effective and meet the breeding management needs of most beef and dairy enterprises. PMID

  9. Effect of PMSG dosage on the reproductive performance of adult ewes and ewe lambs bred at a progestagen-PMSG synchronized estrus.

    PubMed

    Ainsworth, L; Shrestha, J N

    1985-11-01

    The effect of dose of pregnant mares' serum gonadotropin (PMSG) on the reproductive performance of adult ewes and ewe lambs and lamb survival at birth after treatment with fluorogestone acetate (FGA)-impregnated intravaginal sponges and PMSG (250 IU or 500 IU) to synchronize estrus was evaluated. Ewes were exposed to rams for breeding at the synchronized and subsequent estrous cycles. The flock, comprised of three synthetic strains and two control breeds, was maintained in a controlled environment and exposed to an artificial light regimen which alternated at 4-mo intervals from 16h of light daily to 9h of light daily. Trials were conducted during January, May and September at the end of a 9-h daylength cycle. Adult ewes were bred in May and 8 mo later in January. Ewe lambs were bred in September at 6.5 to 7.5 mo of age. The overall reproductive performance of the adult ewes was similar at the two breedings: fertility approximately 90%, prolificacy approximately 2.7, fecundity approximately 240% and lambs born alive approximately 2.4. Dosage of PMSG had no effect. Reproductive performance of ewe lambs was lower and there was a strain x treatment interaction, suggesting greater variability in response. The results indicate there is no advantage to using a higher dose of PMSG in ewes with a natural relatively high fecundity. Moreover, the use of the artificial photoperiod appears to overcome the natural seasonal variation in reproductive performance. PMID:16726102

  10. Effect of estrus synchronization with norgestomet on the integrity of oocytes from persistent follicles in beef cattle.

    PubMed

    Borchert, K M; Farin, C E; Washburn, S P

    1999-10-01

    Our objective was to determine whether oocyte integrity is compromised when oocytes are recovered from progestogen-induced persistent follicles. Beef cows were presynchronized using PGF2alpha (PGF). Cows detected in estrus after PGF were assigned to either NOR (one 6-mg norgestomet implant for 10 d starting on d 16 of cycle; day 0 = estrus; n = 112) or CON (control, no implant [n = 128] and presynchronized 8 d later than NOR). All cows received 25 mg of PGF at the end of treatment (NOR, d 26; CON, d 18). Treatments produced persistent preovulatory follicles (NOR) or normal preovulatory-size follicles (CON), which were measured via ultrasonography 1 d before slaughter. Ovaries were collected from all animals (NOR, d 27; CON, d 19) along with random (RAN) ovaries from cattle slaughtered on the same days. Cumulus oocyte complexes (COC) were aspirated from the preovulatory follicles with recovery rates of 63% across treatments. Small follicles (2 to 7 mm diameter) from NOR, CON, and RAN cows were also aspirated to recover COC. Preovulatory follicles were larger (19.5+/-.9 vs. 13.6+/-.4 mm, P<.05), serum P4 was lower (.4+/-.1 vs. 3.9+/-.2 ng/mL, P<.05), and serum E2 was higher (28.7+/-1.6 vs. 7.6+/-.8 pg/mL, P<.05) in NOR than in CON cows. Cumulus oocyte complexes recovered from preovulatory follicles (62 NOR, 64 CON) were matured, fertilized, and cultured in vitro for comparison of embryonic development. A subset (24 NOR, 34 CON) of COC were assigned morphological quality grades. A separate set of recovered COC (10 NOR, 15 CON) was fixed within 1 h after recovery for assessment of the stage of meiosis. Treatments did not differ for oocyte quality grade or stage of meiosis. However, COC from NOR cows had more layers of cumulus cells (P<.05), and more of those COC had undergone cumulus expansion (29.2 vs. 5.9%, P<.05 for NOR vs. CON, respectively). Development of cleaved embryos to the morula and blastocyst stages from preovulatory follicles (22.6% NOR, 18.9% CON) or

  11. Control of estrus and ovulation in beef heifers.

    PubMed

    Patterson, David J; Thomas, Jordan M; Martin, Neal T; Nash, Justin M; Smith, Michael F

    2013-11-01

    Expanded use of artificial insemination (AI) and/or adoption of emerging reproductive technologies for beef heifers and cows require precise methods of estrous-cycle control. New protocols for inducing and synchronizing a fertile estrus in replacement beef heifers and postpartum beef cows in which progestins are used provide new opportunities for beef producers to synchronize estrus and ovulation and to facilitate fixed-time AI. This article reviews the various estrous synchronization protocols currently available for use in replacement beef heifers. New methods of inducing and synchronizing estrus now create the opportunity to significantly expand the use of AI in the United States cowherd. PMID:24182437

  12. Efficacy of nonhormonal vaginal contraceptives from a hydrogel delivery system.

    PubMed

    Saxena, B B; Singh, M; Gospin, R M; Chu, C C; Ledger, W J

    2004-09-01

    This investigation describes the synthesis of a biodegradable hydrogel composed of a core surrounded by four concentric sheaths containing dextran, copolymers of polylactide and epsilon-caprolactone. The hydrogel was impregnated with iron (II) d-gluconate dihydrate, which causes complete spermiostasis due to lipid peroxidation, ascorbic acid to increase the viscosity of the cervical mucus and mixtures of polyamino and polycarboxylic acids to sustain vaginal pH close to 4.5. The combined effects of the agents in the daily eluates of the hydrogel were efficacious up to 16 days, within 30 s, as shown by sperm penetration tests. For in vivo studies, rabbits were chosen as the experimental model because they are easy to handle and the female is always in estrus. The anterior vagina of estrous female rabbits was instilled with the hydrogel, and then inseminated with the semen from a fertile male. Postinsemination flush from the female rabbits showed that all of the sperm were dead. These observations demonstrate the potential for the development of a biocompatible, nonhormonal, intravaginal contraceptive device. PMID:15325890

  13. New frontiers in nonhormonal male contraception

    PubMed Central

    Cheng, C. Yan; Mruk, Dolores D.

    2015-01-01

    The world’s population is nearing 6.8 billion, and we are in need of a male contraceptive that is safe, effective, reversible and affordable. Hormonal approaches, which employ different formulations of testosterone administered in combination with other hormones, have shown considerable promise in clinical trials, and they are currently at the forefront of research and development. However, the long-term effects of using hormones throughout a male’s reproductive life for contraception are unknown, and it may take decades before this information becomes available. Because of this, many investigators are aiming to bring a nonhormonal male contraceptive to the consumer market. Indeed, there are several distinct but feasible avenues in which fertility can be regulated without affecting the hypothalamus-pituitary-testis axis. In this review, we discuss several approaches for fertility control involving the testis that one day may lead to the development of a nonhormonal male contraceptive. PMID:20933122

  14. Evaluation of reproductive and economic outcomes of dairy heifers inseminated at induced estrus or at fixed time after a 5-day or 7-day progesterone insert-based ovulation synchronization protocol.

    PubMed

    Lopes, G; Johnson, C R; Mendonça, L G D; Silva, P R B; Moraes, J G N; Ahmadzadeh, A; Dalton, J C; Chebel, R C

    2013-03-01

    The objectives of the current experiment were to evaluate the reproductive performance and economic outcome of 3 synchronization strategies for first artificial insemination (AI) of dairy heifers. Holstein heifers from 2 herds (site A, California, n=415; site B, Idaho, n=425) were assigned to 1 of 3 treatments. Heifers assigned to the AI on estrus (AIE) treatment received an injection of 25mg of PGF(2α) at enrollment (d 0) and every 11 d thereafter until AI occurred. Heifers assigned to the CIDR5 treatment received a controlled internal drug release insert (CIDR) containing 1.38 g of progesterone, which was removed 5 d later concomitantly with an injection of 25mg of PGF(2α), and received fixed-time AI (TAI) concomitantly with an injection of 100 μg of GnRH 53 to 60 h later. Heifers assigned to the CIDR7 treatment received a CIDR insert, which was removed 7 d later concomitantly with an injection of 25mg of PGF(2α), and received TAI concomitantly with an injection of 100 μg of GnRH 53 to 60 h later. Heifers were observed for estrus and inseminated up to 98 and 73 d after enrollment in sites A and B, respectively. Thereafter, heifers were moved to pens with bulls and considered failure to conceive to AI if still not pregnant at the end of the observation period. Economic outcomes were based on cost of synchronization protocol (CIDR treatment=$11, PGF(2α) or GnRH treatments=$2.5/treatment, estrous detection=$0.80/heifer per day), rearing cost ($2.75/heifer per day), and economic loss if a heifer did not conceive to first AI ($150). Input cost of the reproductive programs=synchronization protocol cost + semen cost + rearing cost + replacement cost. Pregnancy per AI (P/AI) 38 ± 3 d after first AI was greatest for AIE heifers (61.1%) followed by CIDR5 (44.8%) and CIDR7 (35.7%) heifers. Furthermore, P/AI 73 ± 7 d after first AI was greatest for AIE (58.8%) and tended to be greater for CIDR5 (42%) than for CIDR7 (34.1%) heifers. The percentage of heifers that had

  15. Synchronization

    NASA Astrophysics Data System (ADS)

    Pikovsky, Arkady; Rosenblum, Michael; Kurths, Jürgen

    2003-04-01

    Preface; 1. Introduction; Part I. Synchronization Without Formulae: 2. Basic notions: the self-sustained oscillator and its phase; 3. Synchronization of a periodic oscillator by external force; 4. Synchronization of two and many oscillators; 5. Synchronization of chaotic systems; 6. Detecting synchronization in experiments; Part II. Phase Locking and Frequency Entrainment: 7. Synchronization of periodic oscillators by periodic external action; 8. Mutual synchronization of two interacting periodic oscillators; 9. Synchronization in the presence of noise; 10. Phase synchronization of chaotic systems; 11. Synchronization in oscillatory media; 12. Populations of globally coupled oscillators; Part III. Synchronization of Chaotic Systems: 13. Complete synchronization I: basic concepts; 14. Complete synchronization II: generalizations and complex systems; 15. Synchronization of complex dynamics by external forces; Appendix 1. Discovery of synchronization by Christiaan Huygens; Appendix 2. Instantaneous phase and frequency of a signal; References; Index.

  16. The efficiency of vaginal temperature measurement for detection of estrus in Japanese Black cows

    PubMed Central

    SAKATANI, Miki; TAKAHASHI, Masashi; TAKENOUCHI, Naoki

    2016-01-01

    Recently, weak estrous behavior was assumed to be the cause of a decline in breeding efficiency in cattle. The present study investigated the effect of measuring the vaginal temperature on the detection of estrus in Japanese Black cows. First, the effect of hormone administration to cows with a functional corpus luteum on the vaginal temperature was evaluated by continuous measurement using a temperature data logger. After 24 h of cloprostenol (PG) treatment, the vaginal temperature was significantly lower than on day 7 after estrus, and the low values were maintained until the beginning of estrus (P < 0.05). The cows that received PG and exogenous progesterone (CIDR) did not show a temperature decrease until the CIDR was removed. This finding suggested that the vaginal temperature change reflected the progesterone concentration. The rate of detection of natural estrus was lower for a pedometer than for the vaginal temperature (P < 0.05); synchronization of estrus resulted in a high estrus detection rate regardless of the detection method. In a subsequent experiment, the effect of vaginal temperature measurement and the use of a pedometer on estrus detection was evaluated in the cool and hot seasons. The average activities during non-estrus and the activity increase ratio (estrus/non-estrus) changed according to season (P < 0.01, P < 0.05). However, the average vaginal temperatures during estrus and non-estrus were not affected by season. The estrus detection rate of the pedometer was lower in summer and lower than that obtained using the vaginal temperature. These results indicated that vaginal temperature measurement might be effective for detecting estrus regardless of estrous behavior. PMID:26853785

  17. Technical note: a novel approach to the detection of estrus in dairy cows using ultra-wideband technology.

    PubMed

    Homer, E M; Gao, Y; Meng, X; Dodson, A; Webb, R; Garnsworthy, P C

    2013-10-01

    Detection of estrus is a key determinant of profitability of dairy herds, but estrus is increasingly difficult to observe in the modern dairy cow with shorter duration and less-intense estrus. Concurrent with the unfavorable correlation between milk yield and fertility, estrus-detection rates have declined to less than 50%. We tested ultra-wideband (UWB) radio technology (Thales Research & Technology Ltd., Reading, UK) for proof of concept that estrus could be detected in dairy cows (two 1-wk-long trials; n=16 cows, 8 in each test). The 3-dimensional positions of 12 cows with synchronized estrous cycles and 4 pregnant control cows were monitored continuously using UWB mobile units operating within a network of 8 base units for a period of 7d. In the study, 10 cows exhibited estrus as confirmed by visual observation, activity monitoring, and milk progesterone concentrations. Automated software was developed for analysis of UWB data to detect cows in estrus and report the onset of estrus in real time. The UWB technology accurately detected 9 out of 10 cows in estrus. In addition, UWB technology accurately confirmed all 6 cows not in estrus. In conclusion, UWB technology can accurately detect estrus and hence we have demonstrated proof of concept for a novel technology that has significant potential to improve estrus-detection rates. PMID:23910546

  18. Nonpuberal estrus in beef heifers.

    PubMed

    Rutter, L M; Randel, R D

    1986-10-01

    The frequency of occurrence of behavioral estrus without subsequent development of functional luteal tissue (termed nonpuberal estrus, NPE), was determined in 43 Simmental X Hereford-Brahman heifers. Blood samples were collected weekly from the start of the study to first behavioral estrus and then daily from d 1 (d 0 = estrus) through d 14 following first and subsequently observed estrous behaviors. All blood samples were analyzed for serum progesterone (P4) concentrations by radioimmunoassay. More heifers (62.8%) exhibited NPE than had luteal development after their first behavioral estrus (37.2%). There was a tendency for fewer light-weight heifers (less than or equal to 240 kg at the start of the experiment) to exhibit a puberal first estrus compared with the heavy-weight (greater than 240 kg at the start of the experiment) heifers (31.2% vs 68.8%, respectively; P = .12). Heifers that had a puberal first estrus were older (376 +/- 12 d vs 334 +/- 9 d, P less than .05) compared with heifers that had NPE. Weight at first behavioral estrus was similar between heifers that had a puberal first estrus and those that had NPE (298 +/- 8 kg and 289 +/- 6 kg, respectively). More heifers that had a puberal first estrus also had an elevation in serum P4 concentrations before that first estrus (64.3% vs 20.0%, P less than .05), and the serum P4 elevation was greater (2.5 +/- .4 ng vs 1.2 +/- .1 ng, P less than .05) than heifers that had NPE. We have concluded from these results that NPE is a common occurrence in heifers approaching puberty.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3771388

  19. Expression of estrus improves fertility and decreases pregnancy losses in lactating dairy cows that receive artificial insemination or embryo transfer.

    PubMed

    Pereira, M H C; Wiltbank, M C; Vasconcelos, J L M

    2016-03-01

    The objective was to evaluate if expression of estrus by dairy cattle altered fertility in timed artificial insemination (AI; n=5,430) or timed embryo transfer (ET; n=2,003) programs that used estradiol and progesterone (P4) to synchronize ovulation. Ovarian ultrasonography was performed on d 0 (time of AI) and 7 to determine ovulatory follicle diameter and ovulation. Only cows with a visible corpus luteum on d 7 were used in this study. At the time of controlled internal drug release removal, all cows received a tail-head device for detection of estrus and were considered in estrus when the paint of the device was completely removed by d 0. Circulating P4 concentrations were evaluated on d 7. Pregnancies per AI (P/AI) or ET (P/ET) were determined by ultrasonography on d 32 and 60. At d-32 pregnancy diagnosis, cows with expression of estrus had increased P/AI [no estrus=25.5% (222/846) vs. estrus=38.9% (1,785/4,584)] and P/ET [no estrus=32.7% (193/606) vs. estrus=46.2% (645/1,397)]. Similarly, at d-60 pregnancy diagnosis, expression of estrus increased P/AI [no estrus=20.1% (179/846) vs. estrus=33.3% (1,530/4,584)] and P/ET [no estrus=25.1% (150/606) vs. estrus=37.5% (525/1,397)]. Pregnancy loss was lower in cows that expressed estrus in timed AI [TAI; no estrus=20.1% (43/222) vs. estrus 14.4% (255/1,785)] and timed ET [TET; no estrus=22.7% (43/193) vs. estrus=18.6% (120/645)] compared with cows with no estrus. Independent of expression of estrus cows ovulating either too small or too large of follicles had lower P/AI. No effect of ovulatory follicle diameter on P/ET was noted in cows that expressed estrus; although, cows that did not express estrus tended to have lower P/ET if they ovulated larger follicles. In cows that showed estrus, follicle diameter did not affect pregnancy loss, but cows that did not show estrus and ovulated larger follicles tended to have greater pregnancy loss after TAI and had greater pregnancy loss on TET. A positive effect of d-7 P4

  20. Effective and clinically meaningful non-hormonal hot flash therapies.

    PubMed

    Guttuso, Thomas

    2012-05-01

    Although many non-hormonal compounds have shown statistically significant benefit over placebo in hot flash randomized controlled trials (RCTs), these studies have varied considerably in basic methodology making it challenging to deduce which compounds have the greatest potential to provide clinically meaningful benefit. This review used evidence-based methodology closely mirroring the FDA and EMEA guidelines as a template to identify "well-designed" RCTs from which effective and clinically meaningful non-hormonal hot flash therapies could be identified. In addition, pertinent safety information was reviewed. Out of 3548 MEDLINE citations and abstracts, 51 well-designed hot flash RCTs were identified. From these trials, gabapentin, oxybutynin ER, desvenlafaxine, soy-derived isoflavones and black cohosh each showed a clinically meaningful treatment effect in at least 1 RCT. Among these 5 compounds, only gabapentin demonstrated consistent and statistically significant benefit over placebo in all of its well-designed RCTs. Desvenlafaxine, soy-derived isoflavones, and black cohosh demonstrated statistically significant benefit over placebo in 75%, 21%, and 17% of the well-designed RCTs for each compound, respectively. There was only 1 well-designed RCT using oxybutynin ER, which showed it to have a robust and clinically meaningful benefit. In terms of safety, there have been cardiovascular risks associated with desvenlafaxine use in postmenopausal women with hot flashes. The use of anticonvulsants, in general, has been associated with an absolute 0.21% increase in suicidal thoughts and behavior. Further research is needed with several of these nonhormonal compounds to replicate these findings and to also directly compare their efficacy and tolerability with those of hormone replacement therapy. PMID:22377187

  1. Follicular growth monitoring in the female cat during estrus.

    PubMed

    Malandain, E; Rault, D; Froment, E; Baudon, S; Desquilbet, L; Begon, D; Chastant-Maillard, S

    2011-10-15

    Follicular growth in the feline ovary is usually detected indirectly, through behavior observation, vaginal smears, or more invasively, by estradiol assay in blood. This study was designed to describe follicular dynamics by transabdominal ultrasonography. Secondly, the stage of follicular growth was associated to behavioral and vaginal changes. Ovarian ultrasonography was performed during nine anovulatory and 12 ovulatory cycles. Forty-eight follicles were followed during anovulatory cycles: on the first day of estrus behavior, 4.8 ± 0.2 follicles (2 to 7 per female) of 2.3 ± 0.01 mm mean diameter were present. Follicular growth continued at a rate of 0.2 ± 0.04 mm per day. At least one follicle in the cohort reached a diameter greater than 3.0 mm. Maximal follicular growth (when one follicle of the cohort reached the maximal diameter observed for the whole estrus) was reached 3.8 ± 0.3 days after the onset of estrus with the largest follicle reaching a diameter of 3.5 ± 0.04 mm. Growth of the various follicles within a cohort was not exactly synchronous. When no ovulation took place, the follicular diameter decreased by 0.1 ± 0.01 mm per day until the end of estrus. The first day after the end of behavioral estrus, the diameter of the largest follicle in each cohort was 2.7 ± 0.05 mm. No correlation was found between follicular development and either vaginal smear characteristics, or time elapsed since the onset of estrus. When ovulations were mechanically induced after one follicle had reached 3.0 mm in diameter, artificial insemination produced normal pregnancy rate and litter size: four pregnant females out of nine, and 2 to 4 kittens per litter. Ultrasonography proved thus to allow the monitoring of follicular growth in the female cat, with low correlation with behavior and vaginal smear modifications. Further studies are needed to evaluate the interest of an ultrasonographic ovarian follow-up to determine the optimal moment for ovulation induction

  2. Determining Proportion of Exfoliative Vaginal Cell during Various Stages of Estrus Cycle Using Vaginal Cytology Techniques in Aceh Cattle

    PubMed Central

    Siregar, Tongku N.; Melia, Juli; Rohaya; Thasmi, Cut Nila; Masyitha, Dian; Wahyuni, Sri; Rosa, Juliana; Nurhafni; Panjaitan, Budianto; Herrialfian

    2016-01-01

    The aim of this study was to investigate the period of estrus cycle in aceh cattle, Indonesia, based on vaginal cytology techniques. Four healthy females of aceh cattle with average weight of 250–300 kg, age of 5–7 years, and body condition score of 3-4 were used. All cattle were subjected to ultrasonography analysis for the occurrence of corpus luteum before being synchronized using intramuscular injections of PGF2 alpha 25 mg. A vaginal swab was collected from aceh cattle, stained with Giemsa 10%, and observed microscopically. Period of estrus cycle was predicted from day 1 to day 24 after estrus synchronization was confirmed using ultrasonography analysis at the same day. The result showed that parabasal, intermediary, and superficial epithelium were found in the vaginal swabs collected from proestrus, metestrus, and diestrus aceh cattle. Proportions of these cells in the particular period of estrus cycle were 36.22, 32.62, and 31.16 (proestrus); 21.33, 32.58, and 46.09 (estrus); 40.75, 37.58, and 21.67 (metestrus); and 41.07, 37.38, and 21.67 (diestrus), respectively. In conclusion, dominant proportion of superficial cell that occurred in estrus period might be used as the base for determining optimal time for insemination. PMID:26977335

  3. Expression and detection of estrus in dairy cows: the role of new technologies.

    PubMed

    Fricke, P M; Carvalho, P D; Giordano, J O; Valenza, A; Lopes, G; Amundson, M C

    2014-05-01

    Despite the widespread adoption of hormonal synchronization protocols that allow for timed artificial insemination (AI), detection of estrus plays an important role in the reproductive management program on most dairies in the United States. Increased physical activity is a secondary sign of estrus in dairy cattle, and a new generation of electronic systems that continuously monitor physical activity to predict timing of AI have been developed and marketed to the dairy industry. A variety of management and physiologic challenges inhibit detection of behavioral estrus on farms, but the prevalence of anouvular cows near the end of the voluntary waiting period is particularly problematic. Only 70% of lactating Holstein cows were detected in estrus when using an activity monitoring system, with the remaining 20% of cows classified as anovular and 10% ovulating without showing signs of activity. Mean time of AI in relation to ovulation based on the activity monitoring system was acceptable for most of the cows with increased activity, however, variability in the duration of estrus and timing of AI in relation to ovulation could result in poor pregnancy outcomes in some cows. Use of a Presynch-Ovsynch protocol for submission of cows for first AI has been widely adopted by dairies in the United States, and a combined approach in which AI based on activity is followed by submission of cows not detected with activity to timed AI after synchronization of ovulation may be an effective strategy for submission of cows to first AI. Based on a field trial on a large commercial dairy in the United States, the activity monitoring system detected 70% of cows with increased activity after the second PGF2α injection of a Presynch-Ovsynch protocol, however, cows inseminated to increased activity had fewer pregnancies per AI (P/AI) compared with cows with increased activity after the second PGF2α injection that received timed AI after completing the Presynch-Ovsynch protocol. Based on

  4. Non-Hormonal treatment of BPH/BOO

    PubMed Central

    Osman, Nadir I.; Mangera, Altaf; Chapple, Christopher R.

    2014-01-01

    Objectives: To review the use of non-hormonal pharmacotherapies in the treatment of lower urinary tract symptoms (LUTS) due to presumed benign prostatic hyperplasia (BPH). Materials and Methods: A search of the PUBMED database was conducted for the terms BPH, LUTS, bladder outlet obstruction, alpha-adrenoceptor blockers, anti-muscarinics, and phosphodiesterase-5-inhibitors. Results: Medical therapy has long been established as the accepted standard of care in the treatment of male LUTS. The aim of treatment is improvement in symptoms and quality of life whilst minimizing adverse effects. The agents most widely used as 1st line therapy are alpha-blockers (AB), as a standalone or in combination with 2 other classes of drug; 5-α reductase inhibitors and anti-muscarinics. AB have rapid efficacy, improving symptoms and flow rate in a matter of days, these effects are then maintained over time. AB do not impact on prostate size and do not prevent acute urinary retention or the need for surgery. Anti-mucarinics, alone or in combination with an AB are safe and efficacious in the treatment of bothersome storage symptoms associated with LUTS/BPH. Phosphodiesterase-5 inhibitors are an emerging treatment option that improve LUTS without improving flow rates. Conclusions: AB are the most well-established pharmacotherapy in the management of men with LUTS/BPH. The emergence of different classes of agent offers the opportunity to target underlying pathophysiologies driving symptoms and better individualize treatment. PMID:24744520

  5. Behavioral and physiological changes around estrus events identified using multiple automated monitoring technologies.

    PubMed

    Dolecheck, K A; Silvia, W J; Heersche, G; Chang, Y M; Ray, D L; Stone, A E; Wadsworth, B A; Bewley, J M

    2015-12-01

    This study included 2 objectives. The first objective was to describe estrus-related changes in parameters automatically recorded by the CowManager SensOor (Agis Automatisering, Harmelen, the Netherlands), DVM bolus (DVM Systems LLC, Greeley, CO), HR Tag (SCR Engineers Ltd., Netanya, Israel), IceQube (IceRobotics Ltd., Edinburgh, UK), and Track a Cow (Animart Inc., Beaver Dam, WI). This objective was accomplished using 35 cows in 3 groups between January and June 2013 at the University of Kentucky Coldstream Dairy. We used a modified Ovsynch with G7G protocol to partially synchronize ovulation, ending after the last PGF2α injection (d 0) to allow estrus expression. Visual observation for standing estrus was conducted for four 30-min periods at 0330, 1000, 1430, and 2200h on d 2, 3, 4, and 5. Eighteen of the 35 cows stood to be mounted at least once during the observation period. These cows were used to compare differences between the 6h before and after the first standing event (estrus) and the 2wk preceding that period (nonestrus) for all technology parameters. Differences between estrus and nonestrus were observed for CowManager SensOor minutes feeding per hour, minutes of high ear activity per hour, and minutes ruminating per hour; twice daily DVM bolus reticulorumen temperature; HR Tag neck activity per 2h and minutes ruminating per 2h; IceQube lying bouts per hour, minutes lying per hour, and number of steps per hour; and Track a Cow leg activity per hour and minutes lying per hour. No difference between estrus and nonestrus was observed for CowManager SensOor ear surface temperature per hour. The second objective of this study was to explore the estrus detection potential of machine-learning techniques using automatically collected data. Three machine-learning techniques (random forest, linear discriminant analysis, and neural network) were applied to automatically collected parameter data from the 18 cows observed in standing estrus. Machine learning

  6. A systematic review of non-hormonal treatments of vasomotor symptoms in climacteric and cancer patients.

    PubMed

    Drewe, Juergen; Bucher, Kathleen A; Zahner, Catherine

    2015-01-01

    The cardinal climacteric symptoms of hot flushes and night sweats affect 24-93% of all women during the physiological transition from reproductive to post-reproductive life. Though efficacious, hormonal therapy and partial oestrogenic compounds are linked to a significant increase in breast cancer. Non-hormonal treatments are thus greatly appreciated. This systematic review of published hormonal and non-hormonal treatments for climacteric, and breast and prostate cancer-associated hot flushes, examines clinical efficacy and therapy-related cancer risk modulation. A PubMed search included literature up to June 19, 2014 without limits for initial dates or language, with the search terms, (hot flush* OR hot flash*) AND (clinical trial* OR clinical stud*) AND (randomi* OR observational) NOT review). Retrieved references identified further papers. The focus was on hot flushes; other symptoms (night sweats, irritability, etc.) were not specifically screened. Included were some 610 clinical studies where a measured effect of the intervention, intensity and severity were documented, and where patients received treatment of pharmaceutical quality. Only 147 of these references described studies with alternative non-hormonal treatments in post-menopausal women and in breast and prostate cancer survivors; these results are presented in Additional file 1. The most effective hot flush treatment is oestrogenic hormones, or a combination of oestrogen and progestins, though benefits are partially outweighed by a significantly increased risk for breast cancer development. This review illustrates that certain non-hormonal treatments, including selective serotonin reuptake inhibitors, gabapentin/pregabalin, and Cimicifuga racemosa extracts, show a positive risk-benefit ratio. Key pointsSeveral non-hormonal alternatives to hormonal therapy have been established and registered for the treatment of vasomotor climacteric symptoms in peri- and post-menopausal women.There are indications

  7. Synchronization and Artificial Insemination Strategies in Beef Cattle.

    PubMed

    Lamb, Graham Clifford; Mercadante, Vitor R G

    2016-07-01

    Utilization of estrus or ovulation synchronization and fixed-timed artificial insemination (TAI) has facilitated the widespread utilization of artificial insemination (AI) and can greatly impact the economic viability of cow-calf systems by enhancing weaning weights. Implementation of TAI programs by beef producers results in limited frequency of handling cattle and elimination of the need to detect estrus. Continued use of intensive reproductive management tools such as estrus synchronization and AI will result positive changes to calving distribution, pregnancy rates, and subsequent calf value. PMID:27140297

  8. Efficiency of the OVATEC unit for estrus detection and calf sex control in beef cows.

    PubMed

    Wehner, G R; Wood, C; Tague, A; Barker, D; Hubert, H

    1997-03-01

    Seventy five spring calving Gelbvieh and Angus cows were utilized over a three year period to evaluate the usefulness of the OVATEC intravaginal probe for indicating the onset of estrus and providing the possibility to influence the sex of the offspring by choosing a breeding time in relation to critical changes in cervical mucus conductivity. Cows were randomly assigned by breed each year into one of four treatments: (1) probed and inseminated when impedance values declined, creating conditions expected to favor X-bearing sperm and with it an increase in the conception of females (PF); (2) probed and inseminated when impedance values were rebounding, expected to favor Y-bearing sperms and with it an increase in the conception of males (PB); (3) standing estrus (AI); or (4) natural service by bull (NS). Cows grazed or were fed hay from tall fescue-legume pastures. Lutalyse was used to synchronize estrus in a two injection scheme. Vaginal probe readings were taken at first injection, second injection and every 12 h thereafter for 6 days. Visual observations for estrus were obtained for PF, PB and AI every 12 h postsecond injection. Rectal palpations of ovaries were obtained at standing heat in all but NS treatments. In cycling cows, probe readings increased prediction of estrus onset (P < 0.10) compared to visual observations and were similar (P > 0.95) to rectal palpations in all probed cows. PF cows delivered heifer calves at greater rates (P < 0.025) than all other treatments whereas PB cows delivered bulls at greater rates (P < 0.05) than all other treatments. Heifer to bull ratios were not different (P > 0.95) for AI or NS treatments. The results of this study indicate that the potential exists for increasing female offspring conceptions utilizing cervical mucus conductivity as a gauge for insemination times. PMID:9231244

  9. Breeding laboratory cats during artificially induced estrus.

    PubMed

    Cline, E M; Jennings, L L; Sojka, N J

    1980-12-01

    Mature female cats of known reproductive history were randomly divided into groups for natural breeding or mating following hormonal induction of estrus. Treatment with a single injection of 100 international units of pregnant mares' serum followed in 7 days by 50 international units of human chorionic gonadotropin produced results comparable to natural breeding. Daily injections of pregnant mares' serum (300-500 international units total) resulted in fewer successful pregnancies and adversely affected the ability of kittens to survive to weaning. PMID:7464025

  10. Estrus response and fertility of Menz and crossbred ewes to single prostaglandin injection protocol.

    PubMed

    Mekuriaw, Zeleke; Assefa, Habtemariam; Tegegne, Azage; Muluneh, Dagne

    2016-01-01

    Natural lambing in sheep in Ethiopia occurs throughout the year in a scattered manner negatively affecting survival and growth rates of the lambs born during the unfavorable season of the year. Thus, controlling the time of mating artificially using exogenous source of hormones is considered as one of the ways to mitigated problems related to haphazard lambing. To this end, an experiment was conducted to evaluate efficacy of prostaglandin-based estrus synchronization protocol in local and crossbred ewes. A total of 160 ewes (80 local and 80 crossbreds) which lambed at least once and aged 3-5 years were used. Lutalyse® (dinoprost tromethamine sterile solution equivalent to 5 mg dinoprost per ml) and its analog, Synchromate® (cloprostenol sodium equivalent to 0.250 mg cloprostenol per ml), were tested at different doses. The treatments used were intramuscular injection of (1) 2.50 ml of Lutalyse® (12.5 mg dinoprost tromethamine), (2) 2 ml of Lutalyse® (10.0 mg dinoprost tromethamine), (3) 1 ml of Synchromate® (0.25 mg of cloprostenol Sodium), and (4) 0.8 ml of Synchromate® (0.20 mg of cloprostenol Sodium). Forty ewes (20 local and 20 crossbreds) were allocated per treatment. Following injection of the respective hormones, rams of known fertility were introduced into the flock for the duration of 96 h at the ratio of one ram to 10 ewes. All estrus synchronization protocols except treatment 4 (0.8 ml of Synchromate®) induced estrus (heat) in majority (55-65%) of local and crossbred ewes within 96 h post-hormone injection. The time interval from hormone administration to onset of estrus was also more or less similar for all treatment groups except for treatment group 4 which showed heat quicker. The highest lambing rate was recorded in local ewes (84.62% (11/13) treated with 2.5 ml of Lutalyse®, whereas the least was obtained in crossbreds (33.33% (3/9) treated with 0.8 ml Synchromate®. In conclusion, even though 2.5 ml and 2 ml of Lutalyse® or 1 ml of

  11. Non-hormonal male contraception: A review and development of an Eppin based contraceptive.

    PubMed

    O'Rand, Michael G; Silva, Erick J R; Hamil, Katherine G

    2016-01-01

    Developing a non-hormonal male contraceptive requires identifying and characterizing an appropriate target and demonstrating its essential role in reproduction. Here we review the development of male contraceptive targets and the current therapeutic agents under consideration. In addition, the development of EPPIN as a target for contraception is reviewed. EPPIN is a well characterized surface protein on human spermatozoa that has an essential function in primate reproduction. EPPIN is discussed as an example of target development, testing in non-human primates, and the search for small organic compounds that mimic contraceptive antibodies; binding EPPIN and blocking sperm motility. Although many hurdles remain before the success of a non-hormonal male contraceptive, continued persistence should yield a marketable product. PMID:26593445

  12. Nonhormonal Management of Hot Flashes for Women on Risk Reduction Therapy

    PubMed Central

    Sideras, Kostandinos; Loprinzi, Charles L.

    2014-01-01

    Hot flashes are very common in women in menopause and can have a detrimental effect on quality of life. Women on risk reduction therapy are particularly prone because treatments, such as tamoxifen, raloxifene, or oophorectomy, have the potential to exacerbate these symptoms. Hormonal treatments, despite the fact that they represent the most effective therapies, are not used for the treatment of hot flashes in these women because of concerns that they may increase the risk for breast cancer. As a result, several nonhormonal therapies have been tested in randomized placebo-controlled trials and shown to be effective, such as paroxetine, venlafaxine, desvenlafaxine, fluoxetine, citalopram, gabapentin, and pregabalin. In addition, several nonpharmacotogic therapies have been tested with various successes. An additional consideration is how some of those drugs, especially fluoxetine and paroxetine, interact with the metabolism of tamoxifen. This article discusses these issues, and provides some recommendations regarding use of nonhormonal therapies for treating hot flashes in women on risk reduction therapy, with an emphasis on pharmacogenomic considerations. PMID:20971841

  13. Characteristics of estrous cycles in gilts treated with gonadotropins after estrus or treatment with a progestogen.

    PubMed

    Estienne, Mark J; Crawford, Russell J

    2015-03-01

    A combination of eCG (400 IU) and hCG (200 IU) (P.G. 600; Merck Animal Health, Summit, NJ, USA) stimulates puberty in gilts, but variation in the estrual response exists among farms. We hypothesized that some of the variability is a consequence of gilts that have commenced cycling being inadvertently treated. The objective of experiment 1 was to determine the effect of intramuscular (im) P.G. 600 on estrous cycles in sexually mature gilts. Gilts in treatment 1 (n = 16) received P.G. 600 at the onset of daily boar exposure. Gilts in treatments 2 to 5 (n = 16 per treatment) were allowed to express a natural first estrus and were then treated with P.G. 600 during the first estrous cycle as follows: treatment 2 at Day 6, treatment 3 at Day 12, and treatment 4 at Day 18 of the estrous cycle. Treatment 5 gilts received no P.G. 600. The proportion of gilts displaying a normal estrous cycle (18-24 days) was greater (P < 0.05) for treatments 4 (100%) and 5 (100%) compared with treatments 1 (73.3%) and 3 (60%), with treatment 2 having a value (87.5%) that was not different from the other groups. For treatment 3, 33% of gilts displayed an increased interestrus interval that averaged 32.5 days. Concentrations of progesterone remained elevated 20 days after the onset of first estrus in treatment 3 gilts, which supports the concept that P.G. 600 administered at Day 12 of the estrous cycle induced follicular growth, ovulation, and formation of CL that functioned for approximately 15 days, increasing the length of the estrous cycle. It is common for swine producers to have groups of replacement gilts that include both cycling and prepubertal animals, or individuals, the cycling status of which is unknown. The objective of experiment 2 was to evaluate a system using a combination of a progestogen (Matrix; Merck Animal Health) and P.G. 600 to synchronize estrus in replacement gilts. Crossbred gilts, assumed to be a mix of cycling and prepubertal females, were allocated to

  14. Influence of lameness on follicular growth, ovulation, reproductive hormone concentrations and estrus behavior in dairy cows

    PubMed Central

    Morris, M.J.; Kaneko, K.; Walker, S.L.; Jones, D.N.; Routly, J.E.; Smith, R.F.; Dobson, H.

    2011-01-01

    The objective of this study was to examine the effect of a chronic stressor, lameness, on reproductive parameters. Seventy cows 30–80 days post-partum were scored for lameness and follicular phases synchronized with GnRH followed seven days later by prostaglandin (PG). Fifteen Lame animals did not respond to GnRH ovarian stimulation. Milk progesterone for 5 days prior to PG was lower in the remaining Lame cows than Healthy herdmates. Fewer Lame cows ovulated (26/37 versus 17/18; P = 0.04) and the interval from PG to ovulation was shorter in Lame cows. In Subset 1 (20 animals), the LH pulse frequency was similar in ovulating animals (Lame and Healthy) but lower in Lame non-ovulators. An LH surge always preceded ovulation but lameness did not affect the interval from PG to LH surge onset or LH surge concentrations. Before the LH surge, estradiol was lower in non-ovulating cows compared to those that ovulated and estradiol concentrations were positively correlated with LH pulse frequency. In Subset 2 (45 cows), Lame ovulating cows had a less intense estrus than Healthy cows, although Lame cows began estrus and stood-to-be-mounted earlier than Healthy cows. In conclusion, we have identified several parameters to explain poor fertility in some chronically stressed animals. From 30 to 80 days post-partum, there was a graded effect that ranged from 29% Lame cows with absence of ovarian activity, whereas another 21% Lame cows failed to express estrus or ovulate a low estrogenic follicle; in 50% cows, many reproductive parameters were unaffected by lameness. PMID:21601262

  15. Changes in Mouse Uterine Transcriptome in Estrus and Proestrus1

    PubMed Central

    Yip, Kerri Stanley; Suvorov, Alexander; Connerney, Jeannette; Lodato, Nicholas J.; Waxman, David J.

    2013-01-01

    ABSTRACT Changes in the CD-1 mouse uterine transcriptome during proestrus and estrus were investigated to help elucidate mechanisms of uterine tissue remodeling during the estrus cycle and their regulation by estrogen and progesterone in preparation of the uterus for pregnancy. Mice were staged beginning at 6 weeks of age, and uterine horns were harvested after monitoring two estrus cycles. Microarray analysis of whole uterine horn RNA identified 2428 genes differentially expressed in estrus compared to proestrus, indicating there is extensive remodeling of mouse uterus during the estrus cycle, affecting ∼10% of all protein-encoding genes. Many (∼50%) of these genes showed the same differential expression in independent analyses of isolated uterine lumenal epithelial cells. Changes in gene expression associated with structural alterations of the uterus included remodeling of the extracellular matrix, changes in cell keratins and adhesion molecules, activation of mitosis and changes in major histocompatibility complex class II (MHCII) presentation, complement and coagulation cascades, and cytochrome P450 expression. Signaling pathways regulated during the estrus cycle, involving ligand-gated channels, Wnt and hedgehog signaling, and transcription factors with poorly understood roles in reproductive tissues, included several genes and gene networks that have been implicated in pathological states. Many of the molecular pathways and biological functions represented by the genes differentially expressed from proestrus to estrus are also altered during the human menstrual cycle, although not necessarily at the corresponding phases of the cycle. These findings establish a baseline for further studies in the mouse model to dissect mechanisms involved in uterine tissue response to endocrine disruptors and the development of reproductive tract diseases. PMID:23740946

  16. Serum testosterone concentration, efficiency of estrus detection and libido expression in androgenized beef cows.

    PubMed

    Nix, J P; Spitzer, J C; Chenoweth, P J

    1998-04-15

    Twenty multiparous, cyclic, nonlactating beef cows were blocked by dominance rank and randomly and equally allotted to 1 of 4 treatment groups: an untreated control group, a synovex-treated group which received 8 Synovex-H implants with no additional hormones, a testosterone-treated group which received 500 mg, i.m. and 1500 mg, s.c. testosterone enanthate on Day 1 with additional 1000 mg, s.c. doses of testosterone enanthate every 14 d, and a synovex + testosterone-treated group which received 8 Synovex-H implants with 500 mg, i.m. and 1500 mg, s.c. testosterone enanthate on Day 1 only. Blood samples were collected via jugular venipuncture once a week beginning 3 wk prior to start of treatment. In addition, samples were collected just prior to treatment; once a day for 1 wk after initiation of treatment; and then twice a week until 225 d after treatment. Efficiency of estrus detection was assessed 22 d prior to start of treatment and every 14 d thereafter for 98 d, using estrus detection trials with synchronized females or modified libido tests. Scores for estrus detection trials included total mounts in 1 h and the percentage of estrous cows detected. Libido was scored on a scale of 0 through 6. All testosterone treatments raised plasma testosterone concentrations above control and pretreatment levels (testosterone and synovex + testosterone > synovex > control; all P < 0.05). Synovex-, testosterone- and synovex + testosterone-treated females performed more mounts in 1 h than the controls (18, 9, 6 and 1, respectively; all P < 0.05). All testosterone-treated cows mounted a higher number of estrous females than the controls (P < 0.05). Only synovex + testosterone- and testosterone-treated cows received libido scores above pretreatment and control values. However, libido of testosterone-treated cows decreased over time, while that of synovex + testosterone-treated females remained high until Day 98. Libido scores correlated positively with the number of mounts in 1

  17. Estrus cycle effect on muscle tyrosine kinase activity in bitches.

    PubMed

    Gomes Pöppl, Álan; Costa Valle, Sandra; Hilário Díaz González, Félix; de Castro Beck, Carlos Afonso; Kucharski, Luiz Carlos; Silveira Martins Da Silva, Roselis

    2012-03-01

    Estrus cycle is a well recognized cause of insulin resistance in bitches. The insulin receptor (IR) as well as the insulin-like growth factor-I receptor belong to the same subfamily of tyrosine kinase (TK) receptors. The objective of this study was to evaluate basal TK activity in muscle tissue of bitches during the estrus cycle. Twenty-four bitches were used in the study (7 in anestrus, 7 in estrus, and 10 in diestrus). Muscle samples, taken after spaying surgery to determine TK activity, were immediately frozen in liquid nitrogen and then stored at -80°C until the membranes were prepared by sequential centrifugation after being homogenized. TK activity was determined by Poly (Glu 4:Tyr 1) phosphorylation and expressed in cpm/μg of protein. TK activity was significantly lower (P < 0.001) in the animals in estrus (104.5 ± 11.9 cpm/μg of protein) and diestrus (94.5 ± 16.9 cpm/μg of protein) when compared with bitches in anestrus (183.2 ± 39.2 cpm/μg of protein). These results demonstrate, for the first time, lower basal TK activity in the muscle tissue of female dogs during estrus and diestrus, which may represent lower insulin signaling capacity, opening a new field of investigation into the molecular mechanisms of insulin resistance in dogs. PMID:22139063

  18. Estrous behavior and the estrus-to-ovulation interval in Nelore cattle (Bos indicus) with natural estrus or estrus induced with prostaglandin F2 alpha or norgestomet and estradiol valerate.

    PubMed

    Pinheiro, O L; Barros, C M; Figueiredo, R A; do Valle, E R; Encarnação, R O; Padovani, C R

    1998-02-01

    Estrous behavior and the estrus-to-ovulation interval are essential for estimating the best time to artificially inseminate cattle. Because these parameters are not well characterized in the Nelore breed (Bos indicus), the main purpose of the this study was to determine the estrus-to-ovulation interval in Nelore heifers and cows with natural estrus or with estrus induced by treatments with PGF2 alpha or norgestomet and estradiol valerate (NEV). The cows and heifers were observed continuously (24 h a day) to determine the onset of estrus and to study estrous behavior in the cows. Ten hours after the start of estrus the ovaries were scanned every 2 h by ultrasonography to monitor the dominant follicle until ovulation. Blood samples were collected periodically to determine progesterone levels by RIA. Administration of PGF2 alpha (2 injections, 11 days apart) did not induce estrus in most Nelore females in spite of the presence of functional CL, indicated by progesterone concentrations above 6.0 ng/ml in 25 of 28 animals. Treatment with NEV induced high sexual receptivity in cows (10/11), but only 66% ovulated. Cows with natural or induced estrus exhibited behavioral estrus of 10.9 +/- 1.4 h, and ovulation occurred 26.6 +/- 0.44 h (n = 26) after the onset of estrus. In most of the cows (53.8%) estrus began at night (between 1801 and 600 h), and 34.6% it started and finished during the night. It is concluded that in Nelore females ovulation occurs approximately 26 h after the onset of estrus. Additionally, estrous behavior is shorter than in European breeds, and there is a high incidence of estrus at night, which makes it difficult to detect and, consequently, impairs Al in Nelore cattle. The observation that a high percentage of Nelore females with an active CL did not respond to usual dosages of PGF2 alpha warrants further investigation. PMID:10732045

  19. Sexually active groups in cattle-a novel estrus sign.

    PubMed

    Sveberg, G; Refsdal, A O; Erhard, H W; Kommisrud, E; Aldrin, M; Tvete, I F; Buckley, F; Waldmann, A; Ropstad, E

    2013-07-01

    The current study presents a novel objective measure for characterizing sexually active groups (SAG 3-5) and relates this measure to other behaviors of lactating Holstein-Friesian cows. Cows in SAG 3-5 were required to participate in a minimum of 1 estrus behavior per 5min while staying within 3m (2 cow lengths) of its partner(s) for a minimum of 5min. Twenty Holstein-Friesian cows were video-monitored continuously through 1 complete estrous cycle (22d). Standing behavior, SAG 3-5, secondary estrus signs (SEC), and other social and agonistic behaviors were recorded continuously. The period of mounting estrus (MTE) was divided into the 3 parts: prestand, standing estrus (STE), and poststand. The mean durations of MTE, prestand, STE, and poststand period were 12.9±1.84, 4.0±1.93, 7.1±1.44, and 1.8±0.57h (n=13). The fractions of time spent in SAG 3-5 during MTE, prestand, STE, and poststand period were 13, 8, 19, and 1% (n=11). During MTE, cows participated, on average, in 5.8±1.24 SAG 3-5 and initiated 9.5±2.99 mounts, with mean durations of 0.25±0.03h and 4.00±0.36s, respectively. The novel measure SAG 3-5 was a sign of long duration not confined only to groups of STE cows. On one day when no cows were in estrus and during the periods 4 to 24h before and after MTE, no SAG 3-5 behaviors were observed. Luteal-phase cows participated in SAG 3-5 only when the partner was a single cow in estrus. The time spent in SAG 3-5 increased between 1 and 3h before MTE and the prestand period (3 vs. 8%) and reached a peak level during STE. From STE to poststand, time spent in SAG 3-5 decreased considerably (19 vs. 1%). The observed decrease in nonmutual agonistic behaviors 4 to 24h before MTE is suggested as an early sign of pre-estrus. Changes in SAG 3-5, agonistic behaviors, and SEC are suggested as indicators of the specific stages of MTE. Increased SEC initiated and SAG 3-5 were indicators of late pre-estrus and early estrus (prestand). Peak levels of SAG 3-5, SEC, and

  20. Synchronicity from synchronized chaos

    SciTech Connect

    Duane, Gregory

    2015-04-01

    The synchronization of loosely-coupled chaotic oscillators, a phenomenon investigated intensively for the last two decades, may realize the philosophical concept of “synchronicity”—the commonplace notion that related events mysteriously occur at the same time. When extended to continuous media and/or large discrete arrays, and when general (non-identical) correspondences are considered between states, intermittent synchronous relationships indeed become ubiquitous. Meaningful synchronicity follows naturally if meaningful events are identified with coherent structures, defined by internal synchronization between remote degrees of freedom; a condition that has been posited as necessary for synchronizability with an external system. The important case of synchronization between mind and matter is realized if mind is analogized to a computer model, synchronizing with a sporadically observed system, as in meteorological data assimilation. Evidence for the ubiquity of synchronization is reviewed along with recent proposals that: (1) synchronization of different models of the same objective process may be an expeditious route to improved computational modeling and may also describe the functioning of conscious brains; and (2) the nonlocality in quantum phenomena implied by Bell’s theorem may be explained in a variety of deterministic (hidden variable) interpretations if the quantum world resides on a generalized synchronization “manifold”.

  1. Synchronicity from synchronized chaos

    DOE PAGESBeta

    Duane, Gregory

    2015-04-01

    The synchronization of loosely-coupled chaotic oscillators, a phenomenon investigated intensively for the last two decades, may realize the philosophical concept of “synchronicity”—the commonplace notion that related events mysteriously occur at the same time. When extended to continuous media and/or large discrete arrays, and when general (non-identical) correspondences are considered between states, intermittent synchronous relationships indeed become ubiquitous. Meaningful synchronicity follows naturally if meaningful events are identified with coherent structures, defined by internal synchronization between remote degrees of freedom; a condition that has been posited as necessary for synchronizability with an external system. The important case of synchronization between mind andmore » matter is realized if mind is analogized to a computer model, synchronizing with a sporadically observed system, as in meteorological data assimilation. Evidence for the ubiquity of synchronization is reviewed along with recent proposals that: (1) synchronization of different models of the same objective process may be an expeditious route to improved computational modeling and may also describe the functioning of conscious brains; and (2) the nonlocality in quantum phenomena implied by Bell’s theorem may be explained in a variety of deterministic (hidden variable) interpretations if the quantum world resides on a generalized synchronization “manifold”.« less

  2. Hormonal and non-hormonal bases of maternal behavior: The role of experience and epigenetic mechanisms.

    PubMed

    Stolzenberg, Danielle S; Champagne, Frances A

    2016-01-01

    This article is part of a Special Issue "Parental Care". Though hormonal changes occurring throughout pregnancy and at the time of parturition have been demonstrated to prime the maternal brain and trigger the onset of mother-infant interactions, extended experience with neonates can induce similar behavioral interactions. Sensitization, a phenomenon in which rodents engage in parental responses to young following constant cohabitation with donor pups, was elegantly demonstrated by Rosenblatt (1967) to occur in females and males, independent of hormonal status. Study of the non-hormonal basis of maternal behavior has contributed significantly to our understanding of hormonal influences on the maternal brain and the cellular and molecular mechanisms that mediate maternal behavior. Here, we highlight our current understanding regarding both hormone-induced and experience-induced maternal responsivity and the mechanisms that may serve as a common pathway through which increases in maternal behavior are achieved. In particular, we describe the epigenetic changes that contribute to chromatin remodeling and how these molecular mechanisms may influence the neural substrates of the maternal brain. We also consider how individual differences in these systems emerge during development in response to maternal care. This research has broad implications for our understanding of the parental brain and the role of experience in the induction of neurobiological and behavior changes. PMID:26172856

  3. Non-hormonal interruption of incessant ovulation as a potential approach for ovarian cancer prevention.

    PubMed

    Fathalla, Mahmoud F

    2016-03-01

    Ovarian cancer is a silent killer. There is a need to intensify research efforts on prevention strategies. The causative role of incessant ovulation has been supported by the protective effect of oral hormonal contraceptives. The released follicular fluid in the process of ovulation bathes not only the surface of the ovary but also the fimbrial end of the fallopian tube. Evidence has been accumulating about a fimbrial tubal origin for ovarian high-grade serous carcinoma, and for the potential of opportunistic or elective salpingectomy as an intervention strategy. Alternatively, periodic suppression of ovulation could be beneficial among women who have no need or are not using oral hormonal contraceptives. Rupture of the ovarian follicle releasing the ovum and follicular fluid is a prostaglandin-mediated inflammatory process. It can be stopped by nonsteroidal anti-inflammatory drugs, leading to pharmacologic production of a luteinized unruptured follicle, simulating a normal non-conception cycle with unaltered steroid patterns/levels and cycle length. Non-hormonal periodic interruption of incessant ovulation could be recommended for women who are at high risk of ovarian cancer, but further research is needed to validate the potential of this approach. PMID:26876699

  4. Infrared technology for estrus detection and as a predictor of time of ovulation in dairy cows in a pasture-based system.

    PubMed

    Talukder, S; Kerrisk, K L; Ingenhoff, L; Thomson, P C; Garcia, S C; Celi, P

    2014-04-15

    The development and application of an algorithm to assess the ability of an infrared thermography (IRT) device to predict cows in estrus and about to ovulate was investigated. Twenty cows were synchronized using a controlled internal drug release and PGF2α. Vulval and muzzle temperatures were measured every 12 hours from controlled internal drug release insertion to 32 hours after PGF2α treatment and then every 4 hours until ovulation occurred or until 128 hours after PGF2α treatment (whichever occurred first). Thermal images obtained with a FLIR T620 series infrared camera were analyzed using ThermaCAM Researcher Professional 2.9 software. Cows were also monitored for behavioral signs of estrus and color changes of an Estrotect applied to the tail head of each cow 36 hours after PGF2α treatment. Algorithms were developed by adjusting body surface temperature of individual animals for ambient temperature and humidity during each observation period, and were expressed as a deviation from the baseline temperature. Of the 20 cows enrolled in this study, 12 (60%) ovulated. An IRT estrus alert was defined using different thresholds (D = 1 °C, 1.25 °C, and 1.5 °C). Sensitivity and specificity to predict estrus depended upon the chosen threshold level. At a threshold D = 1 °C, the highest sensitivity (92%; n = 11) and the lowest specificity (29%) and positive predictive value (64%) were observed. Conversely, D = 1.5 °C resulted in sensitivity of 75%, specificity of 57%, and positive predictive value of 69%. The mean ± standard deviation intervals between onset and the end of IRT estrus alert to ovulation were 30.7 ± 8.2 and 13.3 ± 7.7 hours, respectively. Ovulation occurred 24 to 47 hours after the onset of the IRT estrus alert for eight out of the 11 ovulated cows (73%). Although the sensitivity of the IRT alert was greater than visual observation (67%) and Estrotect activation (67%), the specificity and positive predictive value were lower than

  5. Lameness, Activity Time-Budgets, and Estrus Expression in Dairy Cattle

    PubMed Central

    Walker, S. L.; Smith, R. F.; Routly, J. E.; Jones, D. N.; Morris, M. J.; Dobson, H.

    2009-01-01

    The aim of the present study was to identify specific behavioral patterns that contribute to diminished estrus expression in lame cows. Behavioral scan and focal sampling were used to examine the effect of lameness on daily activity budgets, sexual behavior, feeding activities, and body condition score. A total of 59 milking cows (51.8 ± 1.4 d postpartum) were monitored on a commercial dairy farm for 5 d following estrus synchronization. Overall, lame cows (n = 39) spent proportionately less time elevated on their feet and more time lying down compared with nonlame cows (n = 20). This included lame cows spending less time walking or standing. Overall, the total proportion of scans in which an estrous behavior was observed was very small but tended to be smaller for lame compared with nonlame cows. Throughout a day, lame cows displayed a lower proportion of estrous behaviors in the early morning. Lameness did not affect durations of drinking, grazing, or ruminating, or how these behavioral states fluctuated throughout the day. Similarly, rumination chewing rates were the same for lame and nonlame cows, and there was no association between lameness and dominance/displacement while feeding at a feed-fence. Lame cows did, however, have a slower bite rate at pasture and had a lower body condition score. Lame cows were also nearer the rear of the herd, both as they left the field and when entering the milking parlor. In conclusion, lame cows have longer lying times and spend less time standing, walking, and expressing an estrous behavior. Lame cows also have a lower bite rate at pasture and are more likely to be of lower body condition score. PMID:19038930

  6. Persistent dominant follicle alters pattern of oviductal secretory proteins from cows at estrus.

    PubMed

    Binelli, M; Hampton, J; Buhi, W C; Thatcher, W W

    1999-07-01

    The experimental objective was to compare synthesis of oviductal secretory proteins of dairy cows bearing a persistent dominant follicle (PDF) versus a fresh dominant follicle (FDF) at estrus. On Day 7 after synchronized estrus (Day 0), cows received an intravaginal progesterone device and injection of prostaglandin F2alpha (PGF2alpha). On Day 9, cows received an injection of a GnRH agonist (FDF group; n = 3) or received no injection (PDF group, n = 3). On Day 16, all cows received PGF2alpha, and progesterone devices were removed. At slaughter on Day 18 or Day 19, oviducts ipsilateral and contralateral to the dominant follicle were divided into infundibulum, ampulla, and isthmus regions. Explants from oviductal regions were cultured in minimal essential medium supplemented with [3H]leucine for 24 h. Two-dimensional fluorographs of proteins in conditioned media were analyzed by densitometry. Rate of incorporation of [3H]leucine into macromolecules was greater in the infundibulum, ampulla, and isthmus of FDF cows (p < 0.01). Overall, intensities of radiolabeled secretory protein (P) 2 and P13 were greater for FDF than for PDF. In the ampulla, P14 was more intense for FDF while P7 was more intense for PDF. Abundance of P1 in the isthmus was greater for PDF cows. Across regions, P5, P6, P8, P9, and P11 were more intense for PDF than for FDF in the ipsilateral side. In the contralateral side, P19 was more intense for PDF than for FDF, whereas P6, P8, P9, and P11 were more intense for FDF. Differences in biosynthetic activity and in secreted oviductal proteins from cows bearing a PDF may contribute to the decrease in fertility associated with a PDF. PMID:10377040

  7. Mechanisms of nonhormonal activation of adenylate cyclase based on target analysis

    SciTech Connect

    Verkman, A.S.; Ausiello, D.A.; Jung, C.Y.; Skorecki, K.L.

    1986-08-12

    Radiation inactivation was used to examine the mechanism of activation of adenylate cyclase in the cultured renal epithelial cell line LLC-PK1 with hormonal (vasopressin) and nonhormonal (GTP, forskolin, fluoride, and chloride) activating ligands. Intact cells were frozen, irradiated at -70 degrees C (0-14 Mrad), thawed, and assayed for adenylate cyclase activity in the presence of activating ligands. The ln (adenylate cyclase activity) vs. radiation dose relation was linear (target size 162 kDa) for vasopressin- (2 microM) stimulated activity and concave downward for unstimulated (10 mM Mn/sup 2 +/), NaF- (10 mM) stimulated, and NaCl- (100 mM) stimulated activities. Addition of 2 microM vasopressin did not alter the ln activity vs. dose relation for NaF- (10 mM) stimulated activity. The dose-response relations for adenylate cyclase activation and for transition in the ln activity vs. dose curve shape were measured for vasopressin and NaF. On the basis of our model for adenylate cyclase subunit interactions reported previously (Verkman, A. S., Skorecki, K. L., and Ausiello, D. A. (1986) Am. J. Physiol. 260, C103-C123) and of new mathematical analyses, activation mechanisms for each ligand are proposed. In the unstimulated state, equilibrium between alpha beta and alpha + beta favors alpha beta; dissociated alpha binds to GTP (rate-limiting step), which then combines with the catalytic (C) subunit to form active enzyme. Vasopressin binding to receptor provides a rapid pathway for GTP binding to alpha. GTP and its analogues accelerate the rate of alpha GTP formation. Forskolin inhibits the spontaneous deactivation of activated C. Activation by fluoride may occur without alpha beta dissociation or GTP addition through activation of C by an alpha beta-F complex.

  8. A 67 kDa non-hormone binding estradiol receptor is present in human mammary cancers.

    PubMed

    Castoria, G; Migliaccio, A; Bilancio, A; Pagano, M; Abbondanza, C; Auricchio, F

    1996-03-01

    The presence of large amounts of a 67 kDa estradiol receptor that does not bind hormone was observed in 8 to 37 human mammary tumors (34 malignant and 3 benign). This form of receptor was detected by its conversion to hormone binding receptor by an endogenous tyrosine kinase in vitro. All 8 tumors were malignant. In these, the incubation of cytosol with ATP was seen to cause a 1- to 5-fold increase in estradiol-specific binding sites. These sites bound estradiol with physiological affinity, and their appearance was associated with tyrosine phosphorylation of estradiol receptor. The enzyme converting the non-hormone binding receptor into the hormone binding receptor is largely present in cytosol and scarce in membranes. It has been extensively purified. It is a 67 kDa protein under denaturating conditions, binds calmodulin-Sepharose in a Ca2+-dependent manner, is stimulated by Ca2+ and calmodulin, phosphorylates exogenous actin, is activated by the estradiol-receptor complex. The enzyme interacts with antibodies directed against the carboxy-terminal and catalytic domains of c-src. Therefore, it is a putative new member of the large c-src-related kinase family. Human mammary cancers with significant amounts of 67 kDa non-hormone binding receptor show relatively low levels of hormone binding estradiol receptor. The presence of non-hormone binding receptor that can be activated by in vitro tyrosine phosphorylation suggests that functional interaction of estradiol receptor with tyrosine kinases is altered in malignant tumors and has bearing on loss of hormone dependence and progression of the mammary cancer malignancy. PMID:8598306

  9. [Measuring the estrus cycle and its effect on superovulation in mice].

    PubMed

    Zhu, Na; Jia, Hong-Xiang; Liu, Xiao-Kun; Zhao, Xiao-E; Wei, Qiang; Ma, Bao-Hua

    2012-06-01

    This study compares superovulation efficiency during different stages of the estrus cycle in mice by investigating the pudendum appearance, vaginal epithelial cell type, and the follicular development dynamics, in relation to the estrus cycle. We determined the stages of the estrus cycle by observing the pudendum and making vaginal smears of the Kunming mouse, and ascertaining the follicular development by making paraffin sections. Based on the observation, mice in stages of proestrus, oestrus, metoestrus and dioestrus were superovulated respectively, and their follicular developments and embryo collection results were tracked to ascertain the appropriate estrus cycle stage for superovulation. Our data showed that pudendum appearance and vaginal smears could effectively distinguish different stages of the estrus cycle and that ovarian tissue observation showed that follicular development, corpus luteum formation and luteolysis were regular during the estrus cycle. Likewise, during the estrus cycle of the Kunming mouse, pudendum appearance, vaginal epithelial cell type and follicular development were relational to one another. Superovulating mice in different stages of the estrus cycle showed marked differences both in pregnancy rate and average number of embryos collected. Proestrus was significantly better than metoestrus and dioestrus (P<0.05), and better than oestrus, but the difference between them was not significant (P>0.05). We suggest that pudendum appearance and vaginal smears can be used to distinguish estrus cycle stages and that proestrus is the optimal stage of the estrus cycle for superovulation. PMID:22653855

  10. Selecting Female Mice in Estrus and Checking Plugs.

    PubMed

    Behringer, Richard; Gertsenstein, Marina; Nagy, Kristina Vintersten; Nagy, Andras

    2016-01-01

    The female mouse estrous cycle is divided into four phases: proestrus (development of ovarian follicles), estrus (ovulation), metestrus (formation of corpora lutea), and diestrus (beginning of follicle development for next ovulation and elimination of previous oocytes). The appearance of the epithelium of the external genitalia is used to identify the stage of the estrous cycle of a female mouse. This is usually easier to see in strains with either no or only light skin pigmentation. By examining the color, moistness, and degree of swelling of the vagina, females in estrus can readily be identified. To set up the matings, females are examined in the afternoon, and those in estrus are placed into the cages with males (one or two females in each cage with one male). Usually, 50% or more of the selected females will mate. The presence of a vaginal copulation plug next morning indicates that mating has occurred, but it does not mean that a pregnancy will result even if proven breeder fertile males were used. It is important to check vaginal plugs early in the morning because they fall out or are no longer detectable ~12 h after mating or sometimes earlier. PMID:27480722

  11. Fertility in Gyr Cows (Bos indicus) with Fixed Time Artificial Insemination and Visual Estrus Detection Using a Classification Table

    PubMed Central

    Ramírez-Iglesia, Lilido Nelson; Roman Bravo, Rafael María; Díaz de Ramirez, Adelina; Torres, Leandro J.

    2014-01-01

    The aim of this research was to compare two artificial insemination protocols (AIP): hormonal synchronization with fixed time artificial insemination (SC-FTAI) and the use of a table based on visual observation of estrus signs (VO) in order to identify cows in natural or spontaneous estrus being assigned to AI (NSE-IA). Two groups were formed: in the first group 109 cows were assigned to SC-FTAI, in which a commercial protocol is used; the second one included 108 randomly chosen cows, which were assigned to NSE-AI and in this group a modified table was used. Response variable was first service fertility rate (FSF), which was coded 1 for pregnant and 0 for empty. Predictor variables were AIP, postpartum anestrus, daily milk yield, body condition score at AI and calving number. Statistical analyses included association chi-square tests and logistic regression. Results showed an overall 41.94% FSF and a significant association was detected (P < 0.05) between FSF and daily milk yield; pregnancy rates were 42.20% and 41.67% for the SC-FTAI and NSE-IA groups, respectively (P > 0.05). The odds ratio for the effect of AIP was only 1.050, suggesting no differences in FSF between groups. The NSE-AI protocol can enhance both the technique of VO and reproductive efficiency. Further validation of the table is required. PMID:26464929

  12. Genetic merit for fertility traits in Holstein cows: II. Ovarian follicular and corpus luteum dynamics, reproductive hormones, and estrus behavior.

    PubMed

    Cummins, S B; Lonergan, P; Evans, A C O; Butler, S T

    2012-07-01

    The objective of this study was to characterize the estrous cycle of cows with similar proportions of Holstein genetics, similar genetic merit for milk production traits, but with good (Fert+) or poor (Fert-) genetic merit for fertility traits. In total, 37 lactating cows were enrolled on a protocol to synchronize estrus. Nineteen Fert+ and 12 Fert- cows that successfully ovulated a dominant follicle and established a corpus luteum underwent daily transrectal ultrasonography. Blood sampling was carried out at 8-h intervals from d 0 to 6 and from d 15 to ovulation, and once daily from d 7 to 15. Blood samples were analyzed for progesterone, estradiol, follicle stimulating hormone, and luteinizing hormone. Estrus behavior was recorded using neck activity collars and mounting pads. The Fert+ cows tended to have fewer follicular waves (2.2 vs. 2.7) and had a shorter estrous cycle (21.0 vs. 25.1 d) than Fert- cows. We observed no effect of genotype on day of first-wave emergence or day of first-wave dominant follicle peak diameter, but the peak diameter of the first-wave dominant follicle tended to be larger in Fert- cows. During the first 13 d of the cycle, Fert+ cows developed a corpus luteum that was 16% larger than that in Fert- cows. Circulating progesterone concentrations were 34% greater in Fert+ than in Fert- cows (5.15 vs. 3.84ng/mL, respectively) from d 5 to 13. During the final follicular wave, the interval from preovulatory follicle emergence to ovulation and the interval from preovulatory follicle dominance to ovulation were similar in both genotypes. Maximum preovulatory follicle diameter was larger in Fert+ than Fert- cows (17.9 vs. 16.8mm, respectively); however, circulating concentrations of estradiol were not different between genotypes. A greater proportion of Fert- cows ovulated to a silent heat than Fert+ cows (22 vs. 2%, respectively). Of cows that showed behavioral estrus, Fert+ cows had 41% greater mean activity count; however, no difference was

  13. Use of a domestic Korean black goat (Capra hircus coreanae) with its chest crayon-harnessed in detecting estrus of Himalayan tahrs (Hemitragus jemlahicus)

    PubMed Central

    Yong, Hwanyul

    2014-01-01

    The reliability of a Korean black goat (Capra hircus coreanae) to detect estrus in Himalayan tahrs (Hemitragus jemlahicus) for an artificial breeding program was investigated. Estrus in six female Himalayan tahrs was synchronized using fluorogestone acetate (FGA) sponges. Thirteen days later, 200 IU of PMSG and 100 IU of hCG were injected before removing the sponges and simultaneously injecting 5 mg of PGF2α the next day. Penetration of the cervical canal and the thickness and location of red crayon marks were examined 40~43 h later. Two females treated with sponges containing 60 or 45 mg of FGA had estrogen levels of 8.7 and 11.1 pg/mL, respectively. No red marks were found on the backs of these two tahrs. The remaining females had higher levels of estradiol, and the red crayon marks were clearly shown. The cervical folds of these tahrs were readily penetrated and the insemination gun was smoothly inserted into the uterine body. In conclusion, a Korean domestic goat with its chest crayon-harnessed was successfully used to detect estrus of Himalayan tahrs. This technique might be utilized as a part of breeding programs for wild goats and avoid the need for a vasectomy of conspecific males. PMID:24690603

  14. Factors affecting pregnancy rate to estrous synchronization and fixed-time artificial insemination in beef cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Application of AI in extensive beef cattle production is limited by the necessity to monitor estrus and handle animals twice daily for several weeks. Protocols that effectively synchronize ovarian follicular development and ovulation to enable fixed-time AI (TAI) would facilitate the use of AI. Obje...

  15. The relationship of plasma urea nitrogen with growth traits and age at first estrus in gilts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gilts that reach puberty at an earlier age with more backfat have greater lifetime productivity. Increased growth rates generally promote earlier age at first estrus; however, an association of age at first estrus with discrete measures of body fatness remains controversial. We tested the hypothesis...

  16. First deliveries after estrus induction using deslorelin and endoscopic transcervical insemination in the queen.

    PubMed

    Zambelli, Daniele; Bini, Costanza; Küster, Daniel Gerhard; Molari, Valeria; Cunto, Marco

    2015-09-15

    The present study consists of two distinct parts, experiment 1 and experiment 2. In experiment 1, 13 anestrous queens were treated with a 4.7-mg deslorelin subcutaneous implant to assess its effectiveness in inducing estrus in the domestic cat. Deslorelin is currently used for the reversible suppression of ovarian and testicular activity in dogs and cats and for estrus induction in the bitch. Estrus induction is also reported in the queen but never reported with a targeted study. All the queens showed a positive response to the induction protocol, and estrus was detected within an average of 5.0 ± 2.2 days after the implant placement in 13 out of 13 subjects (100%). Seven of 13 queens exhibited behavioral manifestations of estrus, and the mean number of follicles detected at ultrasound examination was 4.8 ± 1.6 per subject. In experiment 2, three of the queens previously treated with deslorelin for estrus induction were submitted to artificial insemination through endoscopic transcervical catheterization, a new nonsurgical technique for intrauterine sperm deposition. All of them (100%) were pregnant after insemination and they gave birth to healthy litters. The study, as a whole, proves the effectiveness of the 4.7-mg deslorelin subcutaneous implants in inducing estrus in the domestic cat and is, to our knowledge, the first study assessing fertility of the induced estruses. Moreover, it shows the effectiveness of endoscopic transcervical catheterization for artificial insemination in the queen. PMID:26092701

  17. QTL associations for weaning-to-estrus interval in a Landrace-Duroc-Yorkshire swine population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weaning-to-estrus interval (WEI) contributes to number of non-productive days of females within a breeding herd. Several reports have indicated females returning to estrus within seven days of weaning are more likely to settle on service thereby contributing to the overall economic potential of the...

  18. Spectral pattern of urinary water as a biomarker of estrus in the giant panda.

    PubMed

    Kinoshita, Kodzue; Miyazaki, Mari; Morita, Hiroyuki; Vassileva, Maria; Tang, Chunxiang; Li, Desheng; Ishikawa, Osamu; Kusunoki, Hiroshi; Tsenkova, Roumiana

    2012-01-01

    Near infrared spectroscopy (NIRS) has been successfully used for non-invasive diagnosis of diseases and abnormalities where water spectral patterns are found to play an important role. The present study investigates water absorbance patterns indicative of estrus in the female giant panda. NIR spectra of urine samples were acquired from the same animal on a daily basis over three consecutive putative estrus periods. Characteristic water absorbance patterns based on 12 specific water absorbance bands were discovered, which displayed high urine spectral variation, suggesting that hydrogen-bonded water structures increase with estrus. Regression analysis of urine spectra and spectra of estrone-3-glucuronide standard concentrations at these water bands showed high correlation with estrogen levels. Cluster analysis of urine spectra grouped together estrus samples from different years. These results open a new avenue for using water structure as a molecular mirror for fast estrus detection. PMID:23181188

  19. Spectral pattern of urinary water as a biomarker of estrus in the giant panda

    NASA Astrophysics Data System (ADS)

    Kinoshita, Kodzue; Miyazaki, Mari; Morita, Hiroyuki; Vassileva, Maria; Tang, Chunxiang; Li, Desheng; Ishikawa, Osamu; Kusunoki, Hiroshi; Tsenkova, Roumiana

    2012-11-01

    Near infrared spectroscopy (NIRS) has been successfully used for non-invasive diagnosis of diseases and abnormalities where water spectral patterns are found to play an important role. The present study investigates water absorbance patterns indicative of estrus in the female giant panda. NIR spectra of urine samples were acquired from the same animal on a daily basis over three consecutive putative estrus periods. Characteristic water absorbance patterns based on 12 specific water absorbance bands were discovered, which displayed high urine spectral variation, suggesting that hydrogen-bonded water structures increase with estrus. Regression analysis of urine spectra and spectra of estrone-3-glucuronide standard concentrations at these water bands showed high correlation with estrogen levels. Cluster analysis of urine spectra grouped together estrus samples from different years. These results open a new avenue for using water structure as a molecular mirror for fast estrus detection.

  20. Spectral pattern of urinary water as a biomarker of estrus in the giant panda

    PubMed Central

    Kinoshita, Kodzue; Miyazaki, Mari; Morita, Hiroyuki; Vassileva, Maria; Tang, Chunxiang; Li, Desheng; Ishikawa, Osamu; Kusunoki, Hiroshi; Tsenkova, Roumiana

    2012-01-01

    Near infrared spectroscopy (NIRS) has been successfully used for non-invasive diagnosis of diseases and abnormalities where water spectral patterns are found to play an important role. The present study investigates water absorbance patterns indicative of estrus in the female giant panda. NIR spectra of urine samples were acquired from the same animal on a daily basis over three consecutive putative estrus periods. Characteristic water absorbance patterns based on 12 specific water absorbance bands were discovered, which displayed high urine spectral variation, suggesting that hydrogen-bonded water structures increase with estrus. Regression analysis of urine spectra and spectra of estrone-3-glucuronide standard concentrations at these water bands showed high correlation with estrogen levels. Cluster analysis of urine spectra grouped together estrus samples from different years. These results open a new avenue for using water structure as a molecular mirror for fast estrus detection. PMID:23181188

  1. Effect of vaccination with a multivalent modified-live viral vaccine on reproductive performance in synchronized beef heifers.

    PubMed

    Walz, Paul H; Edmondson, Misty A; Riddell, Kay P; Braden, Timothy D; Gard, Julie A; Bayne, Jenna; Joiner, Kellye S; Galik, Patricia K; Zuidhof, Sjoert; Givens, M Daniel

    2015-03-15

    Prebreeding vaccination should provide fetal and abortive protection against bovine viral diarrhea virus (BVDV) and bovine herpesvirus 1 (BoHV-1) but not impede reproduction when administered to cattle before estrus synchronization and breeding. The objective was to assess reproductive performance when naive beef heifers were vaccinated with modified-live viral (MLV) vaccine 2 days after unsynchronized estrus, and then revaccinated with MLV vaccine at 10 or 31 days before synchronized natural breeding. Sixty beef heifers naive to BVDV and BoHV-1 were randomly assigned to one of four treatment groups. Groups A and B (n = 20 per group) were vaccinated with MLV vaccine containing BVDV and BoHV-1 at 2 days after initial detected estrus, and then revaccinated 30 days later, which corresponded to 10 days (group A) or 31 days (group B) before synchronized natural breeding. Groups C and D (n = 10 per group) served as controls and were vaccinated with an inactivated vaccine that did not contain BVDV or BoHV-1 at the same time points as groups A and B, respectively. Estrous behavior was assessed using radio frequency technology. Estrus synchronization was performed, with initiation occurring at revaccination (groups A and C) or 21 days after revaccination (groups B and D). After synchronization, heifers were submitted to a bull breeding pasture for 45 days. At the end of the breeding period, heifers were assessed for pregnancy using ultrasonography. Progesterone concentrations were evaluated at estrus and 10 days after unsynchronized and synchronized estrus, at initial pregnancy check, and at the end of the study. All pregnant heifers in groups A and B and five pregnant heifers in group C were euthanized between 44 and 62 days of gestation and ovarian and conceptus tissues were assayed for BVDV and BoHV-1. Vaccination with MLV vaccine did not result in significant negative reproductive impact based on the duration of interestrus intervals, proportion of heifers

  2. Litter loss triggers estrus in a nonsocial seasonal breeder

    PubMed Central

    Steyaert, Sam MJG; Swenson, Jon E; Zedrosser, Andreas

    2014-01-01

    Sexually selected infanticide (SSI) is often presumed to be rare among seasonal breeders, because it would require a near immediate return to estrus after the loss of an entire litter during the mating season. We evaluated changes in reproductive strategies and the reproductive fate of females that experienced litter loss during the mating season in a seasonal breeder with strong evidence for SSI, the brown bear. First, we used a long-term demographic dataset (1986–2011) to document that a large majority of females (>91%) that lose their entire litter during the mating season in fact do enter estrus, mate, and give birth during the subsequent birthing season. Second, we used high-resolution movement data (2005–2011) to evaluate how females changed reproductive strategies after losing their entire litter during the mating season. We hypothesized that females would shift from the sedentary lifestyle typical for females with cubs-of-the-year to a roam-to-mate behavior typical for receptive females in no more than a few (∼3) days after litter loss. We found that females with cubs-of-the-year moved at about 1/3 of the rate and in a less bimodal diurnal pattern than receptive females during the mating season. The probability of litter loss was positively related with movement rate, suggesting that being elusive and sedentary is a strategy to enhance cub survival rather than a relic of cub mobility itself. The movement patterns of receptive females and females after litter loss were indistinguishable within 1–2 days after the litter loss, and we illustrate that SSI can significantly reduce the female interbirth interval (50–85%). Our results suggest that SSI can also be advantageous for males in seasonally breeding mammals. We propose that infanticide as a male reproductive strategy is more prevalent among mammals with reproductive seasonality than observed or reported. PMID:24558586

  3. Saliva ferning, an unorthodox estrus detection method in water buffaloes (Bubalus bubalis).

    PubMed

    Ravinder, R; Kaipa, Onnureddy; Baddela, Vijay Simha; Singhal Sinha, Eshu; Singh, Prashant; Nayan, Varij; Velagala, Chandra Sekhar Naidu; Baithalu, Rubina Kumari; Onteru, Suneel Kumar; Singh, Dheer

    2016-09-15

    Estrus detection is a major problem in buffalo husbandry because of inconsistent expression of estrous signs at different seasons, and a high prevalence of the silent heat and postpartum anestrus in this species. Around 50% of the estrus events in buffaloes are currently undetected in the field conditions, resulting in a huge economic loss. Although the cervicovaginal fluid fern patterns confirm the estrus for a breeding decision, the fluid discharge is absent during the silent-heat condition. Therefore, the present study focused on the crystallization patterns of the saliva as an alternative method for estrus detection in buffaloes. Saliva is a body fluid available regularly, and its ferning ability before ovulation was established in women. In this study, eight female nonpregnant Murrah buffaloes (Bubalus bubalis) were considered during two experimental periods of 3 months each. One period was in summer with five animals, and another period was in rainy season with three animals. Estrus was determined by the estrus symptoms, ovarian ultrasonography, and salivary estradiol (E2) to progesterone (P4) ratio. A total of 450 saliva samples were collected from these animals on the daily basis. The salivary smear was prepared with 20 μL of the cell-free saliva on a clean glass slide, and its microscopic images were captured at a magnification of × 200. The images were used for fractal analysis as the salivary crystallization or fern patterns follow the fractal geometry. Saliva at estrus showed a typical symmetrical fern-like crystallization patterns with significantly (P < 0.05) lower fractal dimension values. Salivary estradiol levels and E2/P4 ratio were significantly (P < 0.05) higher at the estrus stage than those at the diestrus stage. An average period of an estrous cycle was 21.7 ± 2.7 days (n = 18 estrous cycles) in buffaloes on the basis of distinct salivary crystallization patterns. The proportion of estrus detection by the salivary fern patterns

  4. Non-hormonal treatment of vulvo-vaginal atrophy-related symptoms in post-menopausal women.

    PubMed

    Tersigni, C; Di Simone, N; Tempestilli, E; Cianfrini, F; Russo, R; Moruzzi, M C; Amar, I D; Fiorelli, A; Scambia, G; Villa, P

    2015-01-01

    In post-menopausal period vulvo-vaginal atrophy (VVA)-related symptoms may seriously affect women's quality of life. Hormonal replacement therapy effectively relieves these symptoms but it is not always safe or accepted, and a non-hormonal treatment is often needed instead. Over a period of 12 weeks, we tested the effect of a twice-a-week vulvo-vaginal application of a hyaluronic acid, AC collagen, isoflavones and vitamins-based cream (Perilei Pausa) on 35 women in post-menopausal period, reporting VVA-related symptoms. After 12 weeks of treatment with Perilei Pausa a significant improvement in vaginal dryness, vulvo-vaginal itching, dyspareunia (P < 0.001), dysuria (P = 0.02), nocturia (P = 0.009) and pollakiuria (P = 0.005) was reported by the women. Colposcopical score assessing the intensity of atrophic colpitis, cervico-vaginal paleness and petechiae was also reduced (P = 0.037, P = 0.016 and P = 0.032, respectively). No significant difference in terms of maturation value of cervico-vaginal epithelium was observed. In conclusion, Perilei Pausa may represent an effective and safe alternative treatment of symptomatic VVA in post-menopausal women. PMID:25968636

  5. Comparison of Holstein-Friesian and Norwegian Red dairy cattle for estrus length and estrous signs.

    PubMed

    Sveberg, G; Rogers, G W; Cooper, J; Refsdal, A O; Erhard, H W; Kommisrud, E; Buckley, F; Waldmann, A; Ropstad, E

    2015-04-01

    This study addressed the effect of breed on estrus length and estrous behavior by observing 20 Holstein-Friesian (HF) and 20 Norwegian Red (NRF) cows on an outdoor wood-chip pad through 1 estrous cycle (22d). Detailed behavioral data were collected by continuous (24 h) video monitoring of all cows. Accurate estimation of duration of estrous periods, behavioral signs (sum per period and counts per hour), and duration and number of sexually active groups were reported through all stages of mount estrus (prestand, standing estrus, and poststand). These dependent variables were analyzed with a basic statistical model that included fixed effects for breed and lactation group. Other independent variables (milk yield, body condition score, and number of cows in standing estrus) were added to the basic model one by one and included in an expanded model if they had an effect on the respective dependent variables. Estrus duration was considerably shorter in HF compared with NRF cows for all the major periods: mount estrus (11.2 ± 3.0 vs. 21.3 ± 2.7 h), standing estrus (7.1 ± 1.4 vs. 11.7 ± 1.3 h), mounting period (6.9 ± 2.7 vs. 18.2 ± 2.4 h), and mounted period (9.2 ± 2.8 vs. 17.5 ± 2.6 h). Additionally, the NRF cows spent more time in sexually active groups (36.1 ± 4.0 vs. 17.6 ± 4.8%) during standing estrus compared with HF cows. The NRF cows participated in a greater number of sexually active groups (9.6 ± 1.3 vs. 5.5 ± 1.3) with longer average duration (0.42 ± 0.04 vs. 0.20 ± 0.04 h) and continued to be more active in these groups through late stages of estrus (poststand) compared with the HF breed. Mounting activity differed between breeds as NRF mounted more times in total (46.3 ± 6.2 vs. 18.1 ± 6.3) and per hour (2.6 ± 0.4 vs. 1.5 ± 0.5) during mount estrus. In addition, NRF tended to express the primary estrous sign, standing when mounted, more often during standing estrus (32.4 ± 5.0 vs. 18.5 ± 5.2). The HF initiated more unsuccessful mounts (1

  6. Reproductive response of ewes synchronized with different lengths of MGA treatments in intrauterine insemination program.

    PubMed

    Emsen, E; Gimenez-Diaz, C; Kutluca, M; Koycegiz, F

    2011-06-01

    A total of 415 fat tailed ewes were randomly assigned to two groups to assess the effect of duration of melengestrol acetate (MGA) (9 versus 12d) administration on reproductive parameters associated with laparoscopic artificial insemination. At the end of MGA treatment, ewes in each group were subdivided and inseminated with one of two different insemination doses (10×10(7) or 20×10(7) sperm per 0.5 ml insemination dose) of fresh diluted semen. Inseminations were carried out 11-18 h after first detected estrus. Ewes were screened for their return to oestrus from 10 to 21 days post AI and inseminated at their returned oestrus. Pregnancy diagnosis was done from approximately 55 days after insemination in both synchronized and return estrus. For short (9-day) and long (12-day) term MGA treated groups, estrus rates were 62% versus 89% (P<0.0001), respectively. Ewes (n=115) that returned to estrus were inseminated (7-11h after estrus detection) with fresh diluted semen at different doses (20×10(7) or 40×10(7) or 60×10(7) sperm per 0.5 ml insemination dose). Pregnancy rates were 41% and 44% for short term and long term MGA treated ewes, respectively. Pregnancy rate of ewes which returned to oestrus was 53.4%. There was a significant (P<0.05) increase in pregnancy rates (38-52% for 11-16 h; 63% for 17-18 h) when insemination was held at 17-18 h after first detected estrus following MGA treatments. Pregnancy rates were found to be similar in ewes inseminated with 10×10(7) (36%) or 20×10(7) (47%) motile spermatozoa at first AI, and 20×10(7) (44%) or 40×10(7) (59%) or 60×10(7)(48%) at second AI. It was concluded that short term MGA treated ewes were recorded with lower estrus rates but was similar to pregnancy rates with long term MGA treatment. Acceptable pregnancy rates were achieved in MGA induced estrus when insemination is conducted at 17-18 h after estrus onset and with 20×10(7) sperm per insemination dose. PMID:21571456

  7. Uterine glycogen metabolism in mink during estrus, embryonic diapause and pregnancy.

    PubMed

    Dean, Matthew; Hunt, Jason; McDougall, Lisa; Rose, Jack

    2014-01-01

    We have determined uterine glycogen content, metabolizing enzyme expression and activity in the mink, a species that exhibits obligatory embryonic diapause, resulting in delayed implantation. Gross uterine glycogen concentrations were highest in estrus, decreased 50% by diapause and 90% in pregnancy (P ≤ 0.05). Endometrial glycogen deposits, which localized primarily to glandular and luminal epithelia, decreased 99% between estrus and diapause (P ≤ 0.05) and were nearly undetectable in pregnancy. Glycogen synthase and phosphorylase proteins were most abundant in the glandular epithelia. Glycogen phosphorylase activity (total) in uterine homogenates was higher during estrus and diapause, than pregnancy. While glycogen phosphorylase protein was detected during estrus and diapause, glycogen synthase was almost undetectable after estrus, which probably contributed to a higher glycogenolysis/glycogenesis ratio during diapause. Uterine glucose-6-phosphatase 3 gene expression was greater during diapause, when compared to estrus (P ≤ 0.05) and supports the hypothesis that glucose-6-phosphate resulting from phosphorylase activity was dephosphorylated in preparation for export into the uterine lumen. The relatively high amount of hexokinase-1 protein detected in the luminal epithelia during estrus and diapause may have contributed to glucose trapping after endometrial glycogen reserves were depleted. Collectively, our findings suggest to us that endometrial glycogen reserves may be an important source of energy, supporting uterine and conceptus metabolism up to the diapausing blastocyst stage. As a result, the size of uterine glycogen reserves accumulated prior to mating may in part, determine the number of embryos that survive to the blastocyst stage, and ultimately litter size. PMID:25225159

  8. Short communication: Ability of dogs to detect cows in estrus from sniffing saliva samples.

    PubMed

    Fischer-Tenhagen, C; Tenhagen, B-A; Heuwieser, W

    2013-02-01

    Efficient estrus detection in high-producing dairy cows is a permanent challenge for successful reproductive performance. In former studies, dogs have been trained to identify estrus-specific odor in vaginal fluid, milk, urine, and blood samples under laboratory conditions with an accuracy of more than 80%. For on-farm utilization of estrus-detection dogs it would be beneficial in terms of hygiene and safety if dogs could identify cows from the feed alley. The objective of this proof of concept study was to test if dogs can be trained to detect estrus-specific scent in saliva of cows. Saliva samples were collected from cows in estrus and diestrus. Thirteen dogs of various breeds and both sexes were trained in this study. Five dogs had no experience in scent detection, whereas 8 dogs had been formerly trained for detection of narcotics or cancer. In the training and test situation, dogs had to detect 1 positive out of 4 samples. Dog training was based on positive reinforcement and dogs were rewarded with a clicker and food for indicating saliva samples of cows in estrus. A false indication was ignored and documented in the test situation. Dogs with and without prior training were trained for 1 and 5 d, respectively. For determining the accuracy of detection, the position of the positive sample was unknown to the dog handler, to avoid hidden cues to the dog. The overall percentage of correct positive indications was 57.6% (175/304), with a range from 40 (1 dog) to 75% (3 dogs). To our knowledge, this is the first indication that dogs are able to detect estrus-specific scent in saliva of cows. PMID:23261382

  9. Analysis of non-hormonal nutritional supplements for anabolic-androgenic steroids - results of an international study.

    PubMed

    Geyer, H; Parr, M K; Mareck, U; Reinhart, U; Schrader, Y; Schänzer, W

    2004-02-01

    Several recent studies have shown evidence of some nutritional supplements containing prohibited anabolic androgenic steroids, so-called prohormones, which were not declared on the label. Therefore, a broad-based investigation of the international nutritional supplement market was initiated to clarify the extent of this problem. From October 2000 until November 2001, 634 non-hormonal nutritional supplements were purchased in 13 countries from 215 different suppliers. Most supplements were bought in shops in the respective countries (578 samples = 91.2 %) and on the internet (52 samples = 8.2 %). 289 supplements were from prohormone-selling companies and 345 supplements came from companies which do not offer prohormones. After isolation from the supplement matrix 11 different anabolic androgenic steroids, mainly prohormones of testosterone and nandrolone, were analysed by gas-chromatography/mass spectrometry. Out of the 634 samples analysed 94 (14.8 %) contained anabolic androgenic steroids not declared on the label ("positive supplements"). We could not obtain reliable data for 66 samples (10.4 %) due to matrix effects. In relation to the total number of products purchased per country, most of the positive supplements were bought in the Netherlands (25.8 %), in Austria (22.7 %), in the UK (18.8 %) and the USA (18.8 %). According to the label, all positive supplements were from companies located in only five countries: the USA, the Netherlands, the UK, Italy and Germany. 21.1 % of the nutritional supplements from prohormone-selling companies contained anabolic androgenic steroids, whereas 9.6 % of the supplements from companies not selling prohormones were positive. The positive supplements showed anabolic androgenic steroid concentrations of 0.01 micro g/g up to 190 micro g/g. The administration of supplements containing nandrolone prohormones adding up to a total uptake of more than 1 micro g resulted in positive doping results for norandrosterone for several

  10. Short communication: Comparison of estrus characteristics in Holstein heifers by 2 activity monitoring systems.

    PubMed

    Silper, B F; Madureira, A M L; Kaur, M; Burnett, T A; Cerri, R L A

    2015-05-01

    Two activity monitoring systems-Heatime (SCR Engineers Ltd., Netanya, Israel) and IceTag (IceRobotics Ltd., Edinburgh, UK)-were compared on their ability to detect and quantify estrus expression. Holstein heifers (n=57) were fitted with Heatime (HT) and IceTag (IT) sensors from 12 mo of age until confirmation of pregnancy. Upon detection of high activity by HT, ovaries were scanned by ultrasound, a blood sample was collected for analysis of plasma estradiol, and signs of estrus (clear vaginal mucus, uterine muscle tone, visual mounting activity, standing to be mounted, or rump showing signs of repeated acceptance of mounts) were recorded. Because only estrus episodes detected by HT (n=111) were further evaluated, only the positive predictive value was measured. Heifers were housed in groups of 24 in a freestall pen. Data were analyzed using Proc CORR and GLM of SAS (SAS Institute Inc., Cary, NC). The positive predictive value was 84.7% (94/111) for HT and 98.7% (74/75) for IT. Estrus duration was recorded by HT as 14.3±4.1h [mean ± standard deviation (SD)] and by IT as 15.0±4.0h; duration measurements were correlated (r=0.60). The mean duration difference was 0.74±3.52h. Recordings of onset and end of estrus by IT were 3.5±4.3h and 2.9±4.9h earlier than those by HT. The overlap in duration was 9h. Measurements of estrus intensity were correlated (r=0.63). Peak activity was 77.3±19.5 index value (approximately 7.7 SD from basal activity) on HT. The relative increase in activity measured by IT was 360±170% baseline value. Measurements of intensity and duration from HT were correlated (r=0.64) but those from IT were not (r=0.13). Plasma estradiol concentration (11.2±4.6pg/mL) was not correlated with preovulatory follicle diameter or with duration or intensity of estrus. Diameter of preovulatory follicle (15.7±2.6mm) had no correlation with duration of estrus and was only weakly correlated with intensity measured by either system. Baseline steps/hour was

  11. Control of estrus and ovulation: Fertility to timed insemination of gilts and sows.

    PubMed

    De Rensis, F; Kirkwood, R N

    2016-10-01

    It is possible to control follicular development in gilts and sows with the use of hormones including the progestogen altrenogest, GnRH, eCG, hCG, and porcine luteinizing hormone (pLH). These hormones can be used to develop protocols for control of estrus with artificial insemination (AI) timed to estrus detection (timed artificial insemination; TAI) or to control estrus and ovulation with insemination at a fixed time without the requirement of estrus detection (fixed-timed artificial insemination; FTAI). In cyclic gilts, double TAI after protocols based on altrenogest and eCG plus hCG administration can achieve a 70% of farrowing rate. Valuable results can be obtained in weaned sows by the utilization of protocols based on eCG administration at weaning and then GnRH or pLH at estrus onset followed by single or double TAI. In cyclic gilts, single or double FTAI regardless of estrus expression can be applied after protocols based on altrenogest administration followed by eCG and then GnRH, hCG, or pLH some hours later; farrowing rates are similar to control animals inseminated at estrus detection. With sows, a protocol based on eCG administration at weaning and hCG, GnRH, or pLH some hours later followed by single or double FTAI can give fertility rates comparable to control animal inseminated at estrus. Most recently, injection or vaginal deposition of GnRH 96 hours after weaning followed by a single FTAI 24 to 30 hours later is resulting in reproductive performance not different to animals subject to multiple inseminations after natural estrus. It is possible to apply FTAI in lactating sows. The protocols are based on eCG during lactation followed by hCG and FTAI. These protocols will induce ovulation during lactation, but pregnancy rates are reduced. However, in the future, a better knowledge on the effect of hormone administration on follicular dynamics during lactation may allow the development of more effective protocols. PMID:27287469

  12. Factors affecting expression of estrus measured by activity monitors and conception risk of lactating dairy cows.

    PubMed

    Madureira, A M L; Silper, B F; Burnett, T A; Polsky, L; Cruppe, L H; Veira, D M; Vasconcelos, J L M; Cerri, R L A

    2015-10-01

    The objective of this study was to determine risk-factors affecting increase in physical activity during estrus and pregnancy per artificial insemination (P/AI) in lactating dairy cows. Cows were monitored continuously by 2 automated activity monitors [a collar-mounted accelerometer (HT; Heatime, SCR Engineers, Netanya, Israel) and a leg-mounted pedometer (BO; Boumatic Heat-seeker-TX, Boumatic Dairy Equipment, Madison, WI)]. When an increase in activity was detected, body condition score (BCS) and blood samples were collected, ovaries were scanned by ultrasonography, and, if the cow was eligible for breeding, artificial insemination was performed. Milk production and health-related data were recorded throughout the experimental period. Pregnancy diagnosis was performed at 42 ± 7 d of gestation. Data were analyzed using Pearson correlation, ANOVA, and logistic regression. A total of 1,099 true events of estrus from 318 lactating Holstein cows were recorded, averaging 3.46 ± 1.1 events per cow. Positive predictive value for estrus episodes detected by the HT and BO systems were 89.6 and 85.5%, respectively. Mean peak activity at estrus (PA) recorded by the HT system was 71.6 ± 20.7 index-value, and 334.3 ± 155.7% relative increase by the BO system. Compared with primiparous, multiparous cows expressed estrus with lower PA (69.3 ± 0.8 vs. 75.9 ± 1.1 index for HT; 323.9 ± 6.0 vs. 354.8 ± 8.48% for BO) and shorter duration (DU; 10.7 ± 0.2 vs. 12.0 ± 0.3 h); DU was measured by HT only. Lower BCS was associated with decreased PA measured by both systems, estrus DU, and P/AI. Peak activity was weakly correlated with milk production on the day of artificial insemination (r = -0.20); however, when categorized into quartiles, the highest-yield cows had lower PA and DU. Follicle diameter was not correlated with PA or DU, but cows with greater concentrations of estradiol had higher PA. Cows with greater PA in both systems had greater P/AI than those with lower PA (36

  13. Synchronous demodulator

    NASA Technical Reports Server (NTRS)

    Sutton, John F. (Inventor)

    1991-01-01

    A synchronous demodulator includes a switch which is operated in synchronism with an incoming periodic signal and both divides and applies that signal to two signal channels. The two channels each include a network for computing and holding, for a predetermined length of time, the average signal value on that channel and applies those valves, in the form of two other signals, to the inputs of a differential amplifier. The networks may be R-C networks. The output of the differential amplifier may or may not form the output of the synchronous detector and may or may not be filtered. The output will not include a periodic signal due to the presence of a dc offset. Additionally, the output will not contain any substantial ripple due to periodic components in the input signal. In a somewhat more complex version, containing twice the structural components of the above synchronous demodulator with a more complex switching mechanism, essentially all ripple due to periodic components in the input signal are eliminated.

  14. Synchronizing Fireflies

    ERIC Educational Resources Information Center

    Zhou, Ying; Gall, Walter; Nabb, Karen Mayumi

    2006-01-01

    "Imagine a tenth of a mile of river front with an unbroken line of trees with fireflies on ever leaf flashing in synchronism. ... Then, if one's imagination is sufficiently vivid, he may form some conception of this amazing spectacle." So wrote the naturalist Hugh Smith. In this article we consider how one might model mathematically the…

  15. Relationship of follicle size and concentrations of estradiol among cows exhibiting or not exhibiting estrus during a fixed-time AI protocol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cows exhibiting estrus near the time of fixed-time AI had greater pregnancy success than cows showing no estrus. The objective of this study was to determine the relationship between follicle size and peak estradiol concentration between cows that did or did not exhibit estrus during a fixed-time AI...

  16. Ovarian reaction and estrus manifestation in delayed puberty gilts after treatment with equine chorionic gonadotropin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prolonged pre-insemination anestrus (estrus not detected until 8 mo of age, i.e. delayed puberty) is the major reason for culling about 30% of the total number of gilts selected for reproduction at the large breeding farm units in Vojvodina (Republic of Serbia). It is important to determine whether...

  17. Long-term prevention of estrus in the bitch and queen using chlormadinone acetate.

    PubMed

    Tamada, Hiromichi; Kawate, Noritoshi; Inaba, Toshio; Sawada, Tsutomu

    2003-05-01

    Estrus was prevented with weekly oral administration of 2 mg chlormadinone acetate for 2.0 to 9.8 y in bitches and queens. Abnormalities, including mammary or uterine disorders, or both, were noted in 7 out of 14 bitches and 9 out of 24 queens during this long-term treatment. PMID:12757134

  18. Long-term prevention of estrus in the bitch and queen using chlormadinone acetate

    PubMed Central

    Tamada, Hiromichi; Kawate, Noritoshi; Inaba, Toshio; Sawada, Tsutomu

    2003-01-01

    Estrus was prevented with weekly oral administration of 2 mg chlormadinone acetate for 2.0 to 9.8 y in bitches and queens. Abnormalities, including mammary or uterine disorders, or both, were noted in 7 out of 14 bitches and 9 out of 24 queens during this long-term treatment. PMID:12757134

  19. Role of exogenous estrogen in initiation of estrus and induction of an LH surge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Among cattle the LH surge that causes ovulation occurs shortly after the onset of a spontaneous estrus. In addition an injection of 100 'g of GnRH can induce an LH surge capable of inducing ovulation. We hypothesized that different preovulatory estradiol profiles would result in different ovulator...

  20. Methods of estrus detection and correlates of the reproductive cycle in the sun bear (Helarctos malayanus).

    PubMed

    Frederick, Cheryl; Kyes, Randall; Hunt, Kathleen; Collins, Darin; Durrant, Barbara; Wasser, Samuel K

    2010-10-15

    The objective was to explore multiple methods for detecting and characterizing the reproductive cycle of the sun bear (Helarctos malayanus). Thirteen H. m. euryspilus females, loaned from the Malaysian government to US zoos, were used. Fecal metabolite concentrations of estrogen and progesterone were compared to vaginal cytology, changes in genital appearance, and behavior (videotapes and zookeeper observations). Cytology and video behavior were characterized during five hormonally defined states: high, low, and baseline progesterone, estrus, and high estrogen. Among states, there were significant differences in cytology and behavior. Sexual, affiliative, and stereotypic behaviors were highest during estrus, whereas affiliative and social behaviors were lowest during high progesterone. In this captive breeding population, 30.8% of females cycled two or three times a year, 30.8% cycled once a year, and 38.5% did not cycle during this study. Inter-estrus intervals were (mean ± SEM) 115.7 ± 6.3 d (range, 101-131). Spearman rank correlations were significant between both ordinal sexual and affiliative behaviors and vulva swelling and color. Sexual behavior was significantly positively correlated with superficial and keratinized cells, but negatively correlated with parabasal and basophilic cells in cycling females (opposite pattern for appetitive behavior). In conclusion, data for cytology, vulva changes and behavior were consistent with, and complementary to, hormonal data; collectively, they delineated estrus and identified specific reproductive types. PMID:20688366

  1. Estrus response and fertility after a single cloprostenol treatment in dairy cows with various ovarian structures.

    PubMed

    Hatvani, Csilla; Balogh, Orsolya G; Endrődi, Tamás; Abonyi-Tóth, Zsolt; Holló, István; Kastelic, John P; Gábor, György

    2013-07-01

    The objective of this study was to determine rates of estrus and conception in lactating multiparous Holstein cows given 500 μg of cloprostenol intramuscularly after detection of the following ≥ 60 d after parturition: a solid corpus luteum (CL), a CL with a nonechodense cavity ≤ 20 mm in diameter (CLcav), a luteal cyst (cavity > 20 mm in diameter and a luteinized wall > 3 mm in diameter), or a follicular cyst (cavity > 20 mm and a luteinized wall ≤ 3 mm in diameter). The estrus rates were 335/419 (80.0%), 183/223 (82.1%), 170/182 (93.4%), and 44/87 (50.6%), respectively (P < 0.0001), and the conception rates 30 to 36 d after insemination among the estrous cows with an apparently normal mucus discharge were 130/285 (45.6%), 44/141 (31.2%), 39/79 (49.4%), and 19/30 (63.3%), respectively (P < 0.002). Compared with a solid CL, a CLcav did not affect the estrus rate but significantly reduced the conception rate (P < 0.05), and the estrus rates were significantly higher and lower in cows with a luteal or follicular cyst, respectively (P < 0.05). PMID:24101799

  2. Estrus response and fertility after a single cloprostenol treatment in dairy cows with various ovarian structures

    PubMed Central

    Hatvani, Csilla; Balogh, Orsolya G.; Endrődi, Tamás; Abonyi-Tóth, Zsolt; Holló, István; Kastelic, John P.; Gábor, György

    2013-01-01

    The objective of this study was to determine rates of estrus and conception in lactating multiparous Holstein cows given 500 μg of cloprostenol intramuscularly after detection of the following ≥ 60 d after parturition: a solid corpus luteum (CL), a CL with a nonechodense cavity ≤ 20 mm in diameter (CLcav), a luteal cyst (cavity > 20 mm in diameter and a luteinized wall > 3 mm in diameter), or a follicular cyst (cavity > 20 mm and a luteinized wall ≤ 3 mm in diameter). The estrus rates were 335/419 (80.0%), 183/223 (82.1%), 170/182 (93.4%), and 44/87 (50.6%), respectively (P < 0.0001), and the conception rates 30 to 36 d after insemination among the estrous cows with an apparently normal mucus discharge were 130/285 (45.6%), 44/141 (31.2%), 39/79 (49.4%), and 19/30 (63.3%), respectively (P < 0.002). Compared with a solid CL, a CLcav did not affect the estrus rate but significantly reduced the conception rate (P < 0.05), and the estrus rates were significantly higher and lower in cows with a luteal or follicular cyst, respectively (P < 0.05). PMID:24101799

  3. Estrus induction in anestrous mixed-breed goats using the "female-to-female effect".

    PubMed

    Rodríguez-Martínez, Rafael; Ángel-García, Oscar; Guillén-Muñoz, Juan Manuel; Robles-Trillo, Pedro Antonio; De Santiago-Miramontes, Maria de Los Angeles; Meza-Herrera, Cesar Alberto; Mellado, Miguel; Véliz, Francisco Gerardo

    2013-04-01

    A trial was conducted during the anestrous period in female goats to determine: (a) whether estrus can be induced in anestrous goats by administration of equine chorionic gonadotropic hormone (eCG) and PGF2α under pen conditions and (b) whether these sexually active female goats can elicit sexual arousal in sexually inactive bucks. One hundred and fifteen pluriparous, nonlactating mixed-breed female goats were randomly assigned to one of four treatment groups: (1) administration of a single dose of 240 IU of eCG, 50 μg PGF2α i.m., and 25 mg progesterone (P4) (eCG; n=30); (2) administration of P4 and exposure to female goats treated with eCG-PGF2α (P4; n=39); (3) administration of 0.5 ml saline and P4 (Sal; n=23); and (4) P4 plus exposure to female goats treated with saline (Con; n=23). After hormone administration, all goats were put together with adult sexually inactive bucks for 15 days. The percentage of goats in estrus during these 15 days was similar in eCG-treated animals and untreated animals exposed to the eCG animals (97 and 95%). Pregnancy rate was also similar (63 vs. 64%) between these two groups. eCG-treated goats exhibited estrus earlier (P<0.05) than the treated goats in contact with the eCG goats. Furthermore, eCG-treated goats had larger litters (1.9 ± 0.2 vs. 1.6 ± 0.1, P<0.05) than the untreated goats in contact with the eCG goats. These results show that fertile estrus can be induced in anestrous female goats by exposing them to female goats induced to estrus with eCG. This female-female interaction triggers the stimulation cycle leading to the sexual arousal of bucks. PMID:23135982

  4. The effect of subclinical ketosis on activity at estrus and reproductive performance in dairy cattle.

    PubMed

    Rutherford, Andrew J; Oikonomou, Georgios; Smith, Robert F

    2016-06-01

    Our aims were to investigate the influence of subclinical ketosis (SCK) on physical activity at estrus using a neck accelerometer device and on future reproductive performance. Two hundred three Holstein-Friesian cows were studied on 3dairy farms in Northwest England between September 2013 and March 2014. Seventeen percent (35 of 203) of the enrolled cows were affected with SCK between 7 and 21d in milk, defined as a blood β-hydroxybutyrate concentration of 1.2 to 2.9mmol/L. Time to event analyses and multivariable regression analyses were used to assess the effect of SCK on reproductive performance and activity at estrus. The SCK cows exhibited a lower peak activity (measured as the number of standard deviations above mean activity) and shorter duration in activity clusters associated with first estrus and first insemination postpartum, compared with non-SCK cows. Peak activity and cluster duration associated with the insemination that led to a pregnancy were not different between SCK and non-SCK cows. Calving to first estrus, calving to first insemination, and calving to pregnancy intervals were prolonged in SCK cows. First insemination was 4.3 times (95% confidence interval=1.6 to 15.0) less likely to be successful in SCK cows compared with non-SCK cows. Adjusted mean number of inseminations per pregnancy was 2.8 for SCK cows and 2.0 for non-SCK cows. The current study confirms the long-lasting effects of SCK on reproductive efficiency. Furthermore, it is indicated that physical activity around estrus is reduced by SCK in early lactation, but this negative effect appears to diminish as cows progress through lactation. PMID:26995121

  5. Effects of fixed time AI and AI at detected estrus on conception rate in smallholder zebu and crossbred heifers and cows subjected to double PGF2α administration.

    PubMed

    Gugssa, Tadesse; Ashebir, Gebregiorgis; Yayneshet, Tesfay

    2016-08-01

    The study was conducted to evaluate estrus response, time to the onset of estrus, and conception rate at fixed time AI and AI at detected estrus in local and crossbred heifers and cows subjected to double administration of PGF2α. One hundred twenty local (heifers, n = 27; cows, n = 33) and crossbreds (heifers, n = 21; cows, n = 39) were used for the study. About 63 and 85.7 % of the local and crossbred heifers, respectively, exhibited estrus. Similarly, all crossbred cows and 90.9 % of local cows showed estrus. Most heifers came to estrus between 48 and 72 h while cows exhibited behavioral signs of estrus between 72 and 96 h. AI at detected estrus resulted in higher conception rate than fixed time AI. Pregnancy per artificial insemination was higher in AI at detected estrus than fixed time AI. Accurate estrus detection followed by insemination are crucial factors in maximizing pregnancy, and this study has demonstrated that conception rate in smallholder heifers and cows should be inseminated following estrus detection to maximize the conception rate of the animals. PMID:27184042

  6. Factors affecting gestation length and estrus cycle characteristics in Spanish donkey breeds reared in southern Spain.

    PubMed

    Galisteo, J; Perez-Marin, C C

    2010-08-01

    This paper investigated gestation length and estrus cycle characteristics in three different Spanish donkey breeds (Andalusian, Zamorano-Leones, and Catalonian) kept on farm conditions in southern Spain, using data for ten consecutive breeding seasons. Gestation length was measured in 58 pregnancies. Ovarian ultrasonography was used to detect the ovulation, in order to ascertain true gestation length (ovulation-parturition). Pregnancy was diagnosed approximately 14-18 d after ovulation and confirmed on approximately day 60. Average gestation length was 362 +/-15.3 (SD) d, and no significant differences were observed between the three different breeds. Breeding season had a significant effect (P < 0.01), with longer gestation lengths when jennies were covered during the early period. Breed, age of jenny, year of birth, foal gender, month of breeding, and type of gestation had no significant effect on gestation length. After parturition, foal-heat was detected in 53.8% of the postpartum cycles studied (n = 78), and ovulation occurred on day 13.2 +/- 2.7. The duration of foal-heat was 4.7 +/-1.7 d, with a pregnancy rate of 40.5%. When subsequent estrus cycles were analyzed, the interovulatory interval (n = 68) and estrus duration (n = 258) were extended to a mean 23.8 +/- 3.5 and 5.7 +/- 2.2 d, respectively. Both variables were influenced by the year of study (P < 0.03 and P < 0.001), whereas month and season of ovulation (P < 0.005 and P < 0.009, respectively) affected only interovulatory intervals. Estrus duration was significantly longer than that observed at the foal-heat (P < 0.006), and the pregnancy rate was 65.8%. This study provides reference values for true gestation length and estrus cycle characteristics in Spanish jennies. Breeding season affected gestation length in farm conditions. Also, seasonal influence was observed on the length of the estrus cycle (i.e., interovulatory interval), although foal-heat was not affected by environmental factors. PMID

  7. Use of an electronic activity detection system to characterize estrus activity in crossbred beef heifers differing in follicle number

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increased numbers of antral follicles have been associated with decreased calving day, increased fertility, increased serum estradiol concentrations, increased serum progesterone concentrations, and increased estrus behavior in cattle. In addition, cows with increased fertility have been shown to h...

  8. Pre-service ultrasonic and manual evaluation of the reproductive organs of dairy cows presumed to be in estrus.

    PubMed

    Hansar, Endris; Lemma, Alemayehu; Yilma, Tefera

    2014-01-01

    Manual and ultrasonic evaluation of the the reproductive organs of 62 dairy cows and heifers belonging to smallholder farms was conducted. The objective was to assess the efficiency of visual estrus detection method in the dairy animals that were presented for artificial insemination. Data were collected on reproductive status, body condition, estrus signs, and findings of rectal examination. Thirty-three animals were inseminated after ultrasonic evaluation while 29 animals were inseminated after manual evaluation through rectal palpation. Pregnancy diagnosis was performed using ultrasound 30 days post insemination. The most frequently observed estrus signs by the dairy owners were mucus discharge (83.9%) and mounting (67.7%) while the most frequently confirmed physical signs of estrus by rectal examination were cervical opening (88.7%), and uterine turgidity (82.3%). The overall mean (±SD) diameter of the largest follicle was 12.9 ± 3.4 mm with an average number of 3.5 follicles per ovary. The overall pregnancy rate was 29%. Evaluation of post-insemination records showed a significant difference (P < 0.05) in the diameter of largest follicle between the pregnant (14.7 mm) and non-pregnant (12.1 mm) animals. The mean (±SD) time interval between the first observed estrus sign to service were 10.5 ± 7.0 hrs and 14.5 ± 10.0 hrs for pregnant and non-pregnant, respectively. The low pregnancy rate, delayed time of insemination, and the difference in the size of dominant follicle indicate the incompatibility between visual estrus detection and optimal time of insemination. This confirms the significance of improving estrus detection and the need for combining estrus signs with pre-service evaluation of the reproductive organs either manually or using ultrasound. PMID:25279320

  9. Conference lecture: influence of stress on estrus, gametes and early embryo development in the sow.

    PubMed

    Einarsson, S; Brandt, Y; Rodriguez-Martinez, H; Madej, A

    2008-11-01

    Systems with loose-housed sows have become common. Regrouping, which is commonly done after weaning and may coincide with many important reproductive events, causes stressful situations with elevated blood cortisol concentrations. Depending on group size, approximately 2-7 d are required for a new group of sows to become relatively stable. In a series of studies, the social stress after regrouping was simulated with repeated adrenocorticotrophic hormone (ACTH) treatments for approximately 48h. Sows were allocated into control and experimental groups, fitted with jugular catheters, and blood samples were collected every 2 or 4h. Follicular development and ovulation were monitored by transrectal ultrasonography every 4h. Simulated stress during pro-estrus prolonged estrus and disturbed the follicular growth and ovulation. Giving ACTH during estrus elevated concentrations of cortisol and progesterone, and changed the intraluminal environment, including exaggerated amounts of mucus in the UTJ and isthmus. Although ACTH had no effect on the time of ovulation (relative to onset of standing estrus), or on embryo development, fewer oocytes/embryos were retrieved from the ACTH group than from the control group (51% vs. 81%, P<0.05), and there was a tendency towards faster embryo transportation to the uterus. Short-term fasting after ovulation had an unfavourable effect on sperm numbers in UTJ/isthmus, cleavage rate of fertilized ova, as well as ova transport through the isthmic part of the oviduct. Treatment with ACTH after ovulation reduced numbers of spermatozoa at the zona pellucida and retarded cleavage rate of fertilized ova. Therefore, the timing of stress seemed to be an important factor regarding effects on reproductive events. PMID:18786720

  10. A 280-day tolerance-efficacy study with mibolerone for suppression of estrus in the cat.

    PubMed

    Burke, T J; Reynolds, H A; Sokolowski, J H

    1977-04-01

    Mibolerone, a synthetic anabolic steroid, prevented estrus in domesticated cats when orally given a daily dose of 50 microng over a 180-day period. Doses of 20 microng daily and 50 microng given once a week failed to prevent estrus. Treatment with the 50-microng dose each day for 6 months had no apparent effects on subsequent estrus, mating, queening, or litter size. Kittens born to queens which had been treated did not have obvious developmental defects. Systemic metabolic changes produced by treatment were detected only in thyroid function, as revealed in dose- and time-related changes in serum cholesterol concentrations, thyroid gland weights, and thyroid histology. Clinical evidence of thyroid dysfunction was not apparent during the 6 months of treatment. Clinical and microscopic evidence of slight masculinization was apparent in cats after 3 months of treatment with 20 or 50 microng per day. Masculinizing changes consisted of thickening of the cervical dermis and clitoral hypertrophy. Behavioral changes were not observed. The apparent mechanism of action of mibolerone in the cat is the suppression of the release of pituitary luteinizing hormone. PMID:851279

  11. Milk yield and estrous behavior during eight consecutive estruses in Holstein cows fed standardized or high energy diets and grouped according to live weight changes in early lactation.

    PubMed

    Gaillard, C; Barbu, H; Sørensen, M T; Sehested, J; Callesen, H; Vestergaard, M

    2016-04-01

    Cows managed for extended lactation go through several estruses before rebreeding. The aims of this study were (1) to quantify the effect of the first 8 estruses after calving on milk yield, milking frequency, and estrous behavioral activity, and (2) to determine the effects of early lactation live weight gain (LWG) as an indication of energy balance on milk yield, plasma insulin-like growth factor 1 (IGF-1) concentration, estrous behavioral activity, interval from calving to first estrus, between-estrus intervals, and pregnancy risk. Milk yield, live weight, and estrous behavioral activity were measured daily in 62 Holstein cows, 17 primiparous and 45 multiparous, managed for an 18-mo calving interval. Blood plasma obtained at wk 3, 5, 12, and 24 after calving was analyzed for IGF-1. Estrus was detected by use of milk progesterone profiles combined with visual observations (i.e., mounting behavior and other). The cows were divided into 2 groups: the cows having a negative LWG in each of the first 5wk postpartum and the cows having a positive LWG in at least 1 of the first 5wk after calving. The results indicate a similar decrease of 0.56kg of milk per day of estrus during each of the 8 consecutive estruses. The activity level was 17±1 movements per hour higher during the 8 estruses compared with the basic activity level. More cows expressed mounting behavior at estrus 8 than at estrus 2 (63.3 and 45.9%, respectively). The negative LWG cows had lower IGF-1 and higher milk production than the positive LWG cows. Both LWG groups had similar interval from calving to first estrus, on average 55 d. To conclude, the decrease in milk yield during estrus is marginal and similar in consecutive estruses. Moreover, estrous behavior is more highly expressed in the later estruses compared with the earlier estruses. Reproductive parameters (frequency of mounting, pregnancy risk, interval to first estrus, and between-estrus intervals) were not influenced by the live weight change

  12. Use of an anti-GnRF vaccine to suppress estrus in crossbred Iberian female pigs.

    PubMed

    Dalmau, A; Velarde, A; Rodríguez, P; Pedernera, C; Llonch, P; Fàbrega, E; Casal, N; Mainau, E; Gispert, M; King, V; Slootmans, N; Thomas, A; Mombarg, M

    2015-08-01

    Antibodies against GnRF elicited by vaccination with Improvac are expected to have the same effects on the gonads of female pigs as those observed in males and thus suppress estrus. The objective of this study was to evaluate whether a 3- or a 4-dose regimen of Improvac was effective in inducing and maintaining suppression of estrus in intact Iberian female pigs through 14 months of age. Sixty 18-week-old gilts were randomly assigned to one of the following three treatment groups: control (PBS injected), V3 (3-dose Improvac regimen), and V4 (4-dose Improvac regimen). Animals were tested for the presence of standing estrus in the presence of a boar three times per week until study completion at 60 weeks of age. Blood samples were regularly collected to determine the serum levels of anti-GnRF antibodies and progesterone. The weight and size of the uterus and the weight and activity of the ovaries were assessed at the time of euthanasia. For both treatment groups V3 and V4, a large reduction in the incidence of standing estrus was observed when compared to the control group (P < 0.0001). No significant differences between the V3 and V4 groups were observed. Both V3 and V4 groups had higher serum anti-GnRF antibody levels than the control group from 28 days after the first vaccination until the end of the study. In addition, both V3 and V4 groups had lower levels of progesterone than the control group from Day 112 until the end of the study (P < 0.0001 in all cases). Mean ovary weights at study end in treatment groups V3 and V4 were significantly lower (P < 0.0001) than those for the control group and not significantly different between the V3 and V4 groups. An onset of immunity of 2 weeks after the second vaccination and a long-lasting immunity of at least 20 weeks after the third vaccination were observed. In summary, both the 3-and 4-dose Improvac regimens were efficacious in reducing the incidence of standing estrus, serum progesterone levels, and the development

  13. Effects of different five-day progesterone-based synchronization protocols on the estrous response and follicular/luteal dynamics in dairy cows

    PubMed Central

    LÓPEZ-GATIUS, Fernando; LÓPEZ-HELGUERA, Irene; DE RENSIS, Fabio; GARCIA-ISPIERTO, Irina

    2015-01-01

    This study compared the responses shown by lactating dairy cows to four different P4-based protocols for AI at estrus. Cows with no estrous signs 96 h after progesterone intravaginal device (PRID) removal were subjected to fixed-time AI (FTAI), and their data were also included in the study. In Experiment I, follicular/luteal and endometrial dynamics were assessed every 12 h from the beginning of treatment until AI. The estrous response was examined in Experiment II, and fertility was assessed in both experiments. The protocols consisted of a PRID fitted for five days, along with the administration of different combinations of gonadotropin releasing hormone (GnRH), equine chorionic gonadotropin and a single or double dose (24 h apart) of prostaglandin F2α. In Experiment I (40 cows), animals receiving GnRH at the start of treatment showed a significantly higher ovulation rate during the PRID insertion period while estrus was delayed. In Experiment II (351 cows), according to the odds ratios, cows showing luteal activity at the time of treatment were less likely to show estrus than cows with no signs of luteal activity. Treatment affected the estrous response and the interval from PRID removal to estrus but did not affect conception rates 28–34 days post AI. Primiparous cows displayed a better estrous response than multiparous cows. Our findings reveal acceptable results of 5-day P4-based protocols for AI at estrus in high-producing dairy cows. Time from treatment to estrus emerged as a good guide for FTAI after a 5-day P4-based synchronization protocol. PMID:26211922

  14. Cyclical DNA Methyltransferase 3a Expression Is a Seasonal and Estrus Timer in Reproductive Tissues.

    PubMed

    Lynch, Eloise W J; Coyle, Chris S; Lorgen, Marlene; Campbell, Ewan M; Bowman, Alan S; Stevenson, Tyler J

    2016-06-01

    It is becoming clear that epigenetic modifications such as DNA methylation can be dynamic and, in many cases, reversible. Here we investigated the photoperiod and hormone regulation of DNA methylation in testes, ovaries, and uterine tissue across multiple time scales. We hypothesized that DNA methyltransferase 3a (dnmt3a) is driven by photoperiodic treatment and exhibits natural variation across the female reproductive cycle and that melatonin increases whereas estrogen reduces DNA methylation. We used Siberian hamsters (Phodopus sungorus) due to their robust changes in reproductive physiology across seasonal and estrus time scales. Our findings indicate that short-day (SD) winter-like conditions significantly increased global DNA methylation and dnmt3a expression in the testes. Using immunohistochemistry, we confirm that increased dnmt3a expression was primarily localized to spermatogonium. Conversely, the ovaries did not exhibit variation in DNA methylation or dnmt3a/3b expression. However, exposure to SD significantly increased uterine dnmt3a expression. We then determined that dnmt3a was significantly decreased during the estrus stage. Next, we ovariectomized females and subsequently identified that a single estrogen+progesterone injection was sufficient to rapidly inhibit dnmt3a and dnmt3b expression. Finally, we demonstrate that treatment of human embryonic kidney-293 cells with melatonin significantly increased both dnmt3a and dnmt3b expression, suggesting that long-duration nocturnal signaling in SD may be involved in the regulation of DNA methylation in both sexes. Overall, our data indicate that dnmt3a shows marked photoperiod and estrus plasticity that likely has broad downstream effects on the timing of the genomic control of reproductive function. PMID:27105384

  15. Cycle-Related Changes in Mood, Sexual Desire, and Sexual Activity in Oral Contraception-Using and Nonhormonal-Contraception-Using Couples.

    PubMed

    Elaut, Els; Buysse, Ann; De Sutter, Petra; Gerris, Jan; De Cuypere, Griet; T'Sjoen, Guy

    2016-01-01

    Findings on women's sexuality across the menstrual cycle are inconsistent. One relatively consistent finding is a midcycle and premenstrual peak in sexual desire in freely cycling women. Results on the cycle-related effects on sexual behavior are less clear. Large proportions of reproductive-aged women use combined oral contraception (COC), but studies on potential cycle-related shifts in sexual desire and behavior are sparse. A prospective diary study assessed sexual desire, sexual behavior, and mood in 89 heterosexual couples. Women were using one of four contraceptive methods: (1) nonhormonal contraception, (2) low-dose COC containing 20 mcg ethinylestradiol and 75 mcg gestoden or desogestrel, (3) COC containing 35 mcg ethinylestradiol and 2 mg cyproteronacetate, and (4) COC containing 30 mcg ethinylestradiol and 3 mg drospirenone. No cycle effects of sexual desire were established in the COC group, but frequency of sexual intercourse declined in the last days of active pill taking. These results were similar in both female and male partners. Negative affect did not covary with sexual desire. PMID:25420716

  16. Synchronized ovulation for first insemination improves reproductive performance and reduces cost per pregnancy in dairy heifers.

    PubMed

    Silva, T V; Lima, F S; Thatcher, W W; Santos, J E P

    2015-11-01

    The objectives were to evaluate the effects of synchronizing estrus and ovulation to implement a timed artificial insemination (AI) at first insemination on reproductive performance and cost per pregnancy in dairy heifers. Six hundred eleven Holsteins heifers at approximately 400 d of age from 3 farms were enrolled in the study. Six days before moving to the breeding pens, heifers were allocated randomly to AI after detected estrus from study d 0 to 84 (CON, n=306), or to timed AI for first AI followed by detected estrus for the remainder of the 84-d study (TAI, n=305). Heifers receiving TAI were enrolled in the 5-d timed AI protocol on study d -6 (d -6, GnRH and a progesterone insert; d -1, PGF2α and insert removal; d 0, PGF2α; d 2, GnRH + AI), and they were allowed to be bred the day before scheduled timed AI if detected in estrus. Starting on study d 0, estrus was detected daily. Heifers in estrus were inseminated on the same morning as detected estrus. Control heifers not inseminated by study d 7 received PGF2α and this treatment was repeated every 2 wk until AI. The study lasted 84 d to allow a period of breeding equivalent to four 21-d estrous cycles. A herd budget accounting for inputs for both treatments was created to determine the cost per pregnancy. Sensitivity analysis compared economic differences between the 2 treatments under different input scenarios when detection of estrus after the first AI varied from 50 to 80%. Interval to first AI was 8 d shorter for TAI than for CON. Pregnancy at first AI did not differ between treatments (CON=58.3 vs. TAI=62.8%). In contrast, TAI increased pregnancy per AI (P/AI) compared with CON in heifers inseminated with sex-sorted semen (CON=31.6 vs. TAI=54.8%). The 21-d cycle insemination rate was greater for TAI (91.4%) than for CON (82.4%), even when evaluated after the first 21 d in the study (CON=68.2 vs. TAI=77.1%). The increased insemination rate improved the 21-d cycle pregnancy rate from 47.9% in CON to 57

  17. Luteal P4 synthesis in early pregnant gilts after induction of estrus with PMSG/hCG.

    PubMed

    Blitek, Agnieszka; Szymanska, Magdalena; Pieczywek, Marta; Morawska-Pucinska, Ewa

    2016-03-01

    The present study was designed to examine whether an estrus induction with gonadotropins could affect luteal P4 synthesis in early pregnant gilts. Sixteen prepubertal gilts received 750IU of PMSG and 500IU of hCG 72h later. Prepubertal gilts in the control group (n=17) were observed daily for estrus behavior. All gilts were inseminated in their first estrus. Corpora lutea (CLs) were collected on days 10, 12 and 15 of pregnancy and analyzed for (1) the mRNA and protein expression of steroidogenic acute regulatory protein (StAR), cytochrome P450 family 11 subfamily A polypeptide 1 (CYP11A1), and 3β-hydroxysteroid dehydrogenase (3βHSD); (2) the tissue concentration of P4; and (3) the mRNA expression of luteinizing hormone receptor (LHR) and estrogen receptors (ESR1 and ESR2). Additionally, P4 concentration was analyzed in blood serum of all animals. PMSG/hCG injections to induce estrus decreased mRNA expression of StAR, CYP11A1 and 3βHSD on day 10 and CYP11A1 on day 12 of pregnancy compared with the control group, while CYP11A1 and 3βHSD proteins were down-regulated on day 10 in the hormonally-treated gilts. Concentrations of P4 in luteal tissue and blood serum were also lower in animals after gonadotropin-induced estrus. In contrast, LHR and ESR1 mRNA expression was greater in PMSG/hCG-treated than control gilts on day 15 of gestation. In conclusion, induction of estrus with a PMSG/hCG protocol in prepubertal gilts impaired expression of the luteal P4 synthesis system. Low P4 content may, in turn, induce local mechanisms involving LHR and ESR1 expression to support CL function. PMID:26781360

  18. Relationship of follicle size and concentrations of estradiol among cows that do and do not exhibit estrus during a fixed-time AI protocol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cows that exhibited estrus around the time of fixed-time AI had greater pregnancy success compared to cows that did not. The objective of this study was to determine the relationship between follicle size and peak estradiol concentration between cows that did or did not exhibit estrus during a fixed...

  19. Synchronizing redundant power oscillators

    NASA Technical Reports Server (NTRS)

    Jenson, K. J.

    1969-01-01

    Outputs of oscillators are synchronized by summing the power transformer phase voltages, the summed voltages are applied to the frequency determining inductors of the individual voltage-controlled power oscillators. The beat frequency is eliminated when synchronization is achieved.

  20. Impacts of incorporation of follicle stimulating hormone into an estrous synchronization protocol for timed artificial insemination of crossbred beef cattle.

    PubMed

    Gentry, G T; Walker, R S; Gentry, L R

    2016-05-01

    One-hundred-eighty crossbred beef cows and 66 crossbred beef heifers across three locations were stratified by body weight (BW), body condition score (BCS), and age (within location) to evaluate administration of follicle stimulating hormone (FSH) on Day 2 using a modified 7-day CO-Synch plus CIDR(®) protocol (Day 0=CIDR insertion) with timed-artificial insemination (TAI) at 72h (cows) or 54h (heifers) following CIDR removal. Estrous response following CIDR removal was determined using an Estrotect patch and TAI and final pregnancy rates were determined by transrectal ultrasonography 42-45days following TAI and ≥45days following removal of clean-up bulls. Estrous response rate, TAI and final pregnancy rates for cows were not affected (P≥0.65) by treatment. Cows that exhibited estrus had greater (P<0.01) TAI pregnancy rate (66%) than cows not exhibiting estrus (38%). There was an estrous response by postpartum length interaction (P=0.02) where cows exhibiting estrus and ≥55days postpartum had greater TAI pregnancy rates (75%) compared to cows not exhibiting estrus and <55days postpartum (39%) or ≥55days postpartum (28%). For heifers, timed AI (P=0.46) and final pregnancy rates (P=0.45) were similar across treatments and estrous response had no effect (P=0.30) on TAI pregnancy rates. In conclusion, the addition of FSH to the CO-Synch plus CIDR estrous synchronization protocol did not increase TAI pregnancy rates in beef cows or heifers. However, a positive estrous response to the synchronization protocol was associated with increased TAI pregnancy rates in cows. PMID:26968244

  1. A new automatic synchronizer

    SciTech Connect

    Malm, C.F.

    1995-12-31

    A phase lock loop automatic synchronizer, PLLS, matches generator speed starting from dead stop to bus frequency, and then locks the phase difference at zero, thereby maintaining zero slip frequency while the generator breaker is being closed to the bus. The significant difference between the PLLS and a conventional automatic synchronizer is that there is no slip frequency difference between generator and bus. The PLL synchronizer is most advantageous when the penstock pressure fluctuates the grid frequency fluctuates, or both. The PLL synchronizer is relatively inexpensive. Hydroplants with multiple units can economically be equipped with a synchronizer for each unit.

  2. Synchronization of chaotic systems

    SciTech Connect

    Pecora, Louis M.; Carroll, Thomas L.

    2015-09-15

    We review some of the history and early work in the area of synchronization in chaotic systems. We start with our own discovery of the phenomenon, but go on to establish the historical timeline of this topic back to the earliest known paper. The topic of synchronization of chaotic systems has always been intriguing, since chaotic systems are known to resist synchronization because of their positive Lyapunov exponents. The convergence of the two systems to identical trajectories is a surprise. We show how people originally thought about this process and how the concept of synchronization changed over the years to a more geometric view using synchronization manifolds. We also show that building synchronizing systems leads naturally to engineering more complex systems whose constituents are chaotic, but which can be tuned to output various chaotic signals. We finally end up at a topic that is still in very active exploration today and that is synchronization of dynamical systems in networks of oscillators.

  3. Synchronization of chaotic systems

    NASA Astrophysics Data System (ADS)

    Pecora, Louis M.; Carroll, Thomas L.

    2015-09-01

    We review some of the history and early work in the area of synchronization in chaotic systems. We start with our own discovery of the phenomenon, but go on to establish the historical timeline of this topic back to the earliest known paper. The topic of synchronization of chaotic systems has always been intriguing, since chaotic systems are known to resist synchronization because of their positive Lyapunov exponents. The convergence of the two systems to identical trajectories is a surprise. We show how people originally thought about this process and how the concept of synchronization changed over the years to a more geometric view using synchronization manifolds. We also show that building synchronizing systems leads naturally to engineering more complex systems whose constituents are chaotic, but which can be tuned to output various chaotic signals. We finally end up at a topic that is still in very active exploration today and that is synchronization of dynamical systems in networks of oscillators.

  4. Evidence for estrogen-dependent uterine serpin (SERPINA14) expression during estrus in the bovine endometrial glandular epithelium and lumen.

    PubMed

    Ulbrich, Susanne E; Frohlich, Thomas; Schulke, Katy; Englberger, Eva; Waldschmitt, Nadine; Arnold, Georg J; Reichenbach, Horst-Dieter; Reichenbach, Myriam; Wolf, Eckhard; Meyer, Heinrich H D; Bauersachs, Stefan

    2009-10-01

    Uterine secretions have a dominant impact on the environment in which embryo development takes place. The uterine serpins (SERPINA14, previously known as UTMP) are found most abundantly during pregnancy in the uterus of ruminants. Although progesterone is currently assumed to be the major regulator of SERPINA14 expression, our recent study of transcriptome changes in bovine endometrium during the estrous cycle unexpectedly detected a marked upregulation of SERPINA14 mRNA levels at estrus. The present study describes the full-length mRNA sequence, genomic organization, and putative promoter elements of the SERPINA14 gene. The SERPINA14 mRNA abundance was quantified by real-time RT-PCR in intercaruncular endometrium at several time points during the estrous cycle and early pregnancy. Highest levels were found at estrus, followed by a dramatic decrease and a moderate expression during the luteal phase. Transcript levels were higher in pregnant endometrium compared with controls at Day 18. At estrus, immunoreactive protein was localized in deep glandular epithelium, and Western blotting concomitantly showed the 52-kDa form in uterine flushings. SERPINA14 mRNA was significantly upregulated in glandular endometrial cells in vitro after stimulation with estradiol-17beta and progesterone, but not after interferon-tau treatment. Our results clearly demonstrate that SERPINA14 appears distinctly in bovine endometrium during the estrus phase. A supporting role toward providing a well-prepared endometrial environment for passing gametes, especially sperm, is assumed. PMID:19494250

  5. Evaluation of two progestogen-based estrous synchronization protocols in yearling heifers of Bos indicus × Bos taurus breeding.

    PubMed

    McKinniss, E N; Esterman, R D; Woodall, S A; Austin, B R; Hersom, M J; Thatcher, W W; Yelich, J V

    2011-06-01

    Yearling Bos indicus × Bos taurus heifers (n = 410) from three locations, were synchronized with either the Select Synch/CIDR+timed-AI (SSC+TAI) or 7-11+timed-AI (7-11+TAI) treatments. On Day 0 of the experiment, within each location, heifers were equally distributed to treatments by reproductive tract score (RTS; Scale 1-5: 1 = immature, 5 = estrous cycling) and body condition score. The 7-11+TAI treatment consisted of melengestrol acetate (0.5 mg/head/d) from Days 0 to 7, with PGF(2α) (25 mg im) on Day 7, GnRH (100 μg im) on Day 11, and PGF(2α) (25 mg im) on Day 18. The SSC+TAI heifers received the same carrier supplement (without MGA) from Days 0 to 7, and on Day 11 they were given 100 μg GnRH and an intravaginal CIDR (containing 1.38 g progesterone). The CIDR were removed on Day 18, concurrent with 25 mg PGF(2α) im For both treatments, estrus was visually detected for 1 h twice daily (0700 and 1600 h) for 72 h after PGF(2α), with AI done 6 to 12 h after a detected estrus. Non-responders were timed-AI and received GnRH (100 μg im) 72 to 76 h post PGF(2α). The 7-11+TAI heifers had a greater (P < 0.05) estrous response (55.2 vs 41.9%), conception rate (47.0 vs 31.3%), and synchronized pregnancy rate (33.5 vs 24.8%) compared to SSC+TAI heifers, respectively. Heifers exhibiting estrus at 60 h (61.7%) had a greater (P < 0.05) conception rate compared to heifers that exhibited estrus at ≤ 36 (35.3%), 48 (31.6%), and 72 h (36.2%), which were similar (P > 0.05) to each other. As RTS increased from ≤ 2 to ≥ 3, estrous response, conception rate, synchronized pregnancy rate, and 30 d pregnancy rate all increased (P < 0.05), irrespective of synchronization treatment. In conclusion, the 7-11+TAI treatment yielded greater synchronized pregnancy rates compared to SSC+TAI treatment in yearling Bos indicus × Bos taurus heifers. PMID:21356555

  6. Lactation feed disappearance and weaning to estrus interval for sows fed spray-dried plasma.

    PubMed

    Crenshaw, J D; Boyd, R D; Campbell, J M; Russell, L E; Moser, R L; Wilson, M E

    2007-12-01

    Four experiments involving 265, 410, 894, and 554 sows (Exp. 1 to 4, respectively) were conducted to determine the effect of spray-dried plasma (SDP) at 0 or 0.25% (Exp. 1 and 2) and 0 or 0.50% (Exp. 3 and 4) in lactation diets on average daily feed disappearance (FD), sum of sow BW, fetal and placental loss from d 110 gestation to weaning (SWL), litter size at weaning, litter weight at weaning, and average days from weaning to first estrus (WEI). Experiments 1, 3, and 4 were conducted during summer months, and Exp. 2 was conducted during fall to winter months. Experiment 1 used only parity 1 and parity 2 sows and Exp. 4 used only mature (>2 parities) sows, whereas Exp. 2 and 3 used all parity groups. Sows fed SDP in Exp. 1 had increased (P < 0.01) FD and a tendency for reduced (P = 0.06) SWL and WEI (P = 0.06). Sows fed SDP in Exp. 2 had a tendency for increased (P = 0.09) sow BW at weaning and reduced (P = 0.09) SWL, whereas other variables were not different between diets. Parity 1 and 2 sows fed SDP in Exp. 3 had increased (P < 0.01) FD, but mature sows fed SDP had reduced (P = 0.02) FD. Pig survival and litter size at weaning for all parity groups was not different between diets. The WEI for parity 1 sows fed SDP was reduced (P = 0.02) and tended to be reduced (P = 0.10) for mature sows fed SDP, but was not different between diets for parity 2 sows. More parity 1 sows fed SDP were detected (P = 0.01) in estrus 4 to 6 d after weaning, and fewer were detected (P < 0.01) in estrus 6 d after weaning compared with control parity 1 sows. In Exp. 4, FD was reduced (P < 0.01) for mature sows fed SDP; however, litter weight and average pig BW at weaning was increased (P < 0.01) with more (P < 0.01) marketable pigs (pig BW > 3.6 kg) weaned per litter. Relatively low dietary levels of SDP (0.25 to 0.50%) fed to parity 1 sows farrowed during summer months increased lactation FD and reduced WEI. Mature sows fed SDP during summer months consumed less lactation feed without

  7. Differential expression of epidermal growth factor and transforming growth factor beta isoforms in dog endometrium during different periods of the estrus cycle.

    PubMed

    Bukowska, D; Kempisty, B; Jackowska, M; Woźna, M; Antosik, P; Piotrowska, H; Jaśkowski, J M

    2011-01-01

    Both epidermal growth factor (EGF) and transforming growth factor (TGF) play an important physiological role in the processes of proliferation and differentiation of several different cell types. However, the expression profiles of these factors in domestic bitches endometrium are still poorly recognized. The aim of the present study was to identify and analyze the differential expression of these factors in various stages of the estrus cycle. Endometrial tissue from proestrus (n = 17), estrus (n = 10), day 10 diestrus (n = 15), day 35 diestrus (n = 18) and anestrus (n = 25) was collected soon after ovariohysterectomy. Total RNA was isolated from the endometrium by means of Chomczyński and Sacchi method, treated by DNase I, and reverse-transcribed into cDNA. Quantitative analysis of EGF, TGFbeta1, TGFbeta2, and TGFbeta3 cDNA was performed by real-time quantitative polymerase chain reaction (RT-PCR). EGF expression in canine endometrium was increased in the estrus stage as compared to proestrus (P < 0.05), day 10 diestrus (P < 0.05), day 35 diestrus (P < 0.01) and anestrus (P < 0.001). We also found the differences in EGF expression between day 10 and day 35 of estrus as well as between day 35 of estrus with anestrus (P < 0.05, P < 0.01, respectively). The TGFf1 transcript contents were also higher in estrus as compared to other stages (P < 0.01). The TGFbeta2 and TGFbeta3 in the estrus stage was increased compared to proestrus, day 10 diestrus, day 35 diestrus and anestrus (P < 0.05). We proved that expression of EGF and TGFbeta transcript isoforms is related to the phase of estrus in bitches and therefore may be regulated by specific hormone concentrations during these periods. Our results confirm the hypothesis that these growth factors play a role in the regulation of biochemical changes in the endometrial tissues during the estrus cycle. PMID:21721411

  8. Hepatic and Whole-Body Insulin Metabolism during Proestrus and Estrus in Mongrel Dogs.

    PubMed

    Yu, Erin Nz; Winnick, Jason J; Edgerton, Dale S; Scott, Melanie F; Smith, Marta S; Farmer, Ben; Williams, Phillip E; Cherrington, Alan D; Moore, Mary Courtney

    2016-01-01

    Insulin resistance occurs during various stages of the estrus cycle in dogs. To quantify the effects of proestrus-estrus (PE) and determine whether PE affects liver insulin sensitivity, 11 female mongrel dogs were implanted with sampling and intraportal infusion catheters. Five of the dogs (PE group) entered proestrus after surgery; those remaining in anestrus were controls. The dogs were fasted overnight, [3-(3)H]glucose and somatostatin were infused through peripheral veins, and glucagon was infused intraportally. Insulin was infused intraportally, with the rate adjusted to maintain arterial plasma glucose at basal levels (PE, 294±25 μU/kg/min; control, 223±21 μU/kg/min). Subsequently the insulin infusion rate was increased by 0.2 mU/kg/min for 120 min (P1) and then to 1.5 mU/kg/min for the last 120 min (P2); glucose was infused peripherally as needed to maintain euglycemia. Insulin concentrations did not differ between groups at any time; they increased 3 μU/mL over baseline during P1 and to 3 times baseline during P2. The glucose infusion rate in PE dogs during P2 was 63% of that in control dogs. Net hepatic glucose output and the endogenous glucose production rate declined 40% to 50% from baseline in both groups during P1; during P2, both groups exhibited a low rate of net hepatic glucose uptake with full suppression of endogenous glucose production. The glucose disappearance rate during P1 and P2 was 35% greater in control than PE dogs. Therefore, PE in canines is associated with loss of nonhepatic (primarily muscle) but not hepatic insulin sensitivity. PMID:27298249

  9. Synchronizing large systolic arrays

    SciTech Connect

    Fisher, A.L.; Kung, H.T.

    1982-04-01

    Parallel computing structures consist of many processors operating simultaneously. If a concurrent structure is regular, as in the case of systolic array, it may be convenient to think of all processors as operating in lock step. Totally synchronized systems controlled by central clocks are difficult to implement because of the inevitable problem of clock skews and delays. An alternate means of enforcing necessary synchronization is the use of self-timed, asynchronous schemes, at the cost of increased design complexity and hardware cost. Realizing that different circumstances call for different synchronization methods, this paper provides a spectrum of synchronization models; based on the assumptions made for each model, theoretical lower bounds on clock skew are derived, and appropriate or best-possible synchronization schemes for systolic arrays are proposed. This paper represents a first step towards a systematic study of synchronization problems for large systolic arrays.

  10. Synchronization of genetic oscillators

    NASA Astrophysics Data System (ADS)

    Zhou, Tianshou; Zhang, Jiajun; Yuan, Zhanjiang; Chen, Luonan

    2008-09-01

    Synchronization of genetic or cellular oscillators is a central topic in understanding the rhythmicity of living organisms at both molecular and cellular levels. Here, we show how a collective rhythm across a population of genetic oscillators through synchronization-induced intercellular communication is achieved, and how an ensemble of independent genetic oscillators is synchronized by a common noisy signaling molecule. Our main purpose is to elucidate various synchronization mechanisms from the viewpoint of dynamics, by investigating the effects of various biologically plausible couplings, several kinds of noise, and external stimuli. To have a comprehensive understanding on the synchronization of genetic oscillators, we consider three classes of genetic oscillators: smooth oscillators (exhibiting sine-like oscillations), relaxation oscillators (displaying jump dynamics), and stochastic oscillators (noise-induced oscillation). For every class, we further study two cases: with intercellular communication (including phase-attractive and repulsive coupling) and without communication between cells. We find that an ensemble of smooth oscillators has different synchronization phenomena from those in the case of relaxation oscillators, where noise plays a different but key role in synchronization. To show differences in synchronization between them, we make comparisons in many aspects. We also show that a population of genetic stochastic oscillators have their own synchronization mechanisms. In addition, we present interesting phenomena, e.g., for relaxation-type stochastic oscillators coupled to a quorum-sensing mechanism, different noise intensities can induce different periodic motions (i.e., inhomogeneous limit cycles).

  11. Synchronous Energy Technology

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The synchronous technology requirements for large space power systems are summarized. A variety of technology areas including photovoltaics, thermal management, and energy storage, and power management are addressed.

  12. Transient Uncoupling Induces Synchronization

    NASA Astrophysics Data System (ADS)

    Schröder, Malte; Mannattil, Manu; Dutta, Debabrata; Chakraborty, Sagar; Timme, Marc

    2015-07-01

    Finding conditions that support synchronization is a fertile and active area of research with applications across multiple disciplines. Here we present and analyze a scheme for synchronizing chaotic dynamical systems by transiently uncoupling them. Specifically, systems coupled only in a fraction of their state space may synchronize even if fully coupled they do not. While for many standard systems coupling strengths need to be bounded to ensure synchrony, transient uncoupling removes this bound and thus enables synchronization in an infinite range of effective coupling strengths. The presented coupling scheme therefore opens up the possibility to induce synchrony in (biological or technical) systems whose parameters are fixed and cannot be modified continuously.

  13. Synchronization via Hydrodynamic Interactions

    NASA Astrophysics Data System (ADS)

    Kendelbacher, Franziska; Stark, Holger

    2013-12-01

    An object moving in a viscous fluid creates a flow field that influences the motion of neighboring objects. We review examples from nature in the microscopic world where such hydrodynamic interactions synchronize beating or rotating filaments. Bacteria propel themselves using a bundle of rotating helical filaments called flagella which have to be synchronized in phase. Other micro-organisms are covered with a carpet of smaller filaments called cilia on their surfaces. They beat highly synchronized so that metachronal waves propagate along the cell surfaces. We explore both examples with the help of simple model systems and identify generic properties for observing synchronization by hydrodynamic interactions.

  14. Transient Uncoupling Induces Synchronization.

    PubMed

    Schröder, Malte; Mannattil, Manu; Dutta, Debabrata; Chakraborty, Sagar; Timme, Marc

    2015-07-31

    Finding conditions that support synchronization is a fertile and active area of research with applications across multiple disciplines. Here we present and analyze a scheme for synchronizing chaotic dynamical systems by transiently uncoupling them. Specifically, systems coupled only in a fraction of their state space may synchronize even if fully coupled they do not. While for many standard systems coupling strengths need to be bounded to ensure synchrony, transient uncoupling removes this bound and thus enables synchronization in an infinite range of effective coupling strengths. The presented coupling scheme therefore opens up the possibility to induce synchrony in (biological or technical) systems whose parameters are fixed and cannot be modified continuously. PMID:26274420

  15. Intra-cervical application of Misoprostol at estrus alters the content of cervical hyaluronan and the mRNA expression of follicle stimulating hormone receptor (FSHR), luteinizing hormone receptor (LHR) and cyclooxygenase-2 in the ewe.

    PubMed

    Leethongdee, S; Kershaw-Young, C M; Scaramuzzi, R J; Khalid, M

    2010-06-01

    The complex anatomy the of ovine cervix limits the success of transcervical artificial insemination in sheep, but Misoprostol (a PGE(1) analogue) relaxes the cervix and facilitates transcervical artificial insemination. However, the mechanism by which Misoprostol causes cervical relaxation is not known. This study examined if intra-cervical Misoprostol altered the hyaluronan content and the mRNA expression of COX-2, LHR, or FSHR in the cervix of the estrus ewe. Estrus was synchronized in cyclic ewes with progestagen pessaries and 48 h after sponge removal ewes were treated intra-cervically with 0 (controls), 200, or 400 microg Misoprostol. Hyaluronan content was determined by ELISA and mRNA expression of LHR, FSHR, and COX-2 was analyzed by in situ hybridization using digoxigenin-11-uridine-5'-triphosphate labeled riboprobes. The hyaluronan content of the cervix was significantly higher in sheep that received 200 (P<0.05) or 400 (P<0.05) microg Misoprostol compared to controls. Moreover, it was significantly (P<0.05) higher in the vaginal region compared to mid and uterine regions. Misoprostol increased (P<0.05) the mRNA expression of LHR and COX-2 but not FSHR. The expression for all three genes was highest in the vaginal region and lowest in uterine region. The luminal epithelium and circular smooth muscle layers had higher (P<0.05) expression for LHR, FSHR, and COX-2 mRNAs, and the sub-epithelial stroma had the lowest (P<0.05). We propose that the intra-cervical application of Misoprostol induces the mRNA expression of LHR, FSHR, and COX-2 through a positive feedback loop. The data suggest that softening of the cervix by Misoprostol is caused by an increase in the hyaluronan content of the cervix. PMID:20171717

  16. EEG synchronization and migraine

    NASA Astrophysics Data System (ADS)

    Stramaglia, Sebastiano; Angelini, Leonardo; Pellicoro, Mario; Hu, Kun; Ivanov, Plamen Ch.

    2004-03-01

    We investigate phase synchronization in EEG recordings from migraine patients. We use the analytic signal technique, based on the Hilbert transform, and find that migraine brains are characterized by enhanced alpha band phase synchronization in presence of visual stimuli. Our findings show that migraine patients have an overactive regulatory mechanism that renders them more sensitive to external stimuli.

  17. SONET synchronization: What's happening

    NASA Technical Reports Server (NTRS)

    Cubbage, Robert W.

    1993-01-01

    Almost everyone that has heard of SONET knows that the acronym stands for Synchronous Optical NETwork. There has been a host of magazine articles on SONET rings, SONET features, even SONET compatibility with digital radio. What has not been highly publicized is the critical relationship between SONET, network synchronization, and payload jitter. This topic is addressed.

  18. SONET synchronization: What's happening

    NASA Astrophysics Data System (ADS)

    Cubbage, Robert W.

    1993-06-01

    Almost everyone that has heard of SONET knows that the acronym stands for Synchronous Optical NETwork. There has been a host of magazine articles on SONET rings, SONET features, even SONET compatibility with digital radio. What has not been highly publicized is the critical relationship between SONET, network synchronization, and payload jitter. This topic is addressed.

  19. Enhance of the estrus and ovulation sychronism in ewes using protocols with progesterone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estrous synchronization in combination with artificial insemination is an important biotechnology that enables greater and more efficient use of cryopreserved germplasm. However, when using this technology fertility rates after fixed-time artificial insemination (FTAI) still exist because of variati...

  20. [Mechanism of the development of permanent estrus in rats after transplantation of the ovaries into a low temperature medium].

    PubMed

    Vunder, P A; Smetanina, M D

    1983-03-01

    Autotransplantation of the ovaries to the ears of adult rats induces permanent estrus following 5-7 days. Autotransplantation of the ovaries beneath the renal capsules makes the sexual cycle return to normal after the same period. Autotransplantation of the ovaries to the ears of infantile rats brings about pubertas precox followed by normal sexual cycle. Permanent estrus ensues only after 4 months. Transplantation of the ovaries from infantile rats to adult ones and vice versa has shown that age-related differences in the alterations seen in the sexual cycle in response to gonadal transplantation to the ears are caused by age-related differences in the recipients, precisely by those in the cyclic center. PMID:6681996

  1. A pre-synchronization program at early postpartum might increase the chances of Bos indicus cows cycling prior to 50 days regardless of the length of calf separation

    PubMed Central

    PÉREZ-TORRES, Libia; RUBIO, Ivette; CORRO, Manuel; COHEN, Abraham; ORIHUELA, Agustín; GALINA, Carlos S.; PABLOS, J. Luis

    2015-01-01

    The aim of this study was to establish if pre-synchronization would enhance the number of animals cycling prior to conventional breeding at 45 days irrespective of the length of calf separation. Multiparous Bos indicus cows were allotted in four groups (n = 10). Control group (C) dams remained with their calves; groups G24, G48 and G72, which were partially weaned for 24, 48 and 72 h, respectively, were estrus synchronized using a controlled internal drug. These procedures were performed at 25 days and again at 45 days postpartum. The number of follicles, presence of a corpus luteum and back fat thickness (BFT) were determined by ultrasound. The proportion of cows with estrus and ovulation at day 25 postpartum was statistically different between the control and treated groups, with the values being 20, 60, 50 and 70 for the control, G24, G48 and G72 groups respectively (P < 0.05). At days 45 postpartum, the proportion of cows with estrus and ovulation was different in group G48 compared with the other groups (P <0.05). The average BFT and body condition score for the four experimental groups in the two periods were similar (P >0.05). Animals with a higher proportion of follicles from 17 to 21 mm, BFT values above 3.5 mm and a regular body condition were significantly different regardless of whether the dams remained with their calves or were separated, regardless of the length of this event. It can be concluded that (1) a pre-synchronization program at day 25 could trigger the onset of ovarian activity and facilitate a breeding program at day 50 and (2) temporary weaning enhances the effect of a pre-synchronization program. PMID:25739397

  2. Phasic Contractions of the Mouse Vagina and Cervix at Different Phases of the Estrus Cycle and during Late Pregnancy

    PubMed Central

    Gravina, Fernanda S.; van Helden, Dirk F.; Kerr, Karen P.; de Oliveira, Ramatis B.; Jobling, Phillip

    2014-01-01

    Background/Aims The pacemaker mechanisms activating phasic contractions of vaginal and cervical smooth muscle remain poorly understood. Here, we investigate properties of pacemaking in vaginal and cervical tissues by determining whether: 1) functional pacemaking is dependent on the phase of the estrus cycle or pregnancy; 2) pacemaking involves Ca2+ release from sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) -dependent intracellular Ca2+ stores; and 3) c-Kit and/or vimentin immunoreactive ICs have a role in pacemaking. Methodology/Principal Findings Vaginal and cervical contractions were measured in vitro, as was the distribution of c-Kit and vimentin positive interstitial cells (ICs). Cervical smooth muscle was spontaneously active in estrus and metestrus but quiescent during proestrus and diestrus. Vaginal smooth muscle was normally quiescent but exhibited phasic contractions in the presence of oxytocin or the K+ channel blocker tetraethylammonium (TEA) chloride. Spontaneous contractions in the cervix and TEA-induced phasic contractions in the vagina persisted in the presence of cyclopiazonic acid (CPA), a blocker of the SERCA that refills intracellular SR Ca2+ stores, but were inhibited in low Ca2+ solution or in the presence of nifedipine, an inhibitor of L-type Ca2+channels. ICs were found in small numbers in the mouse cervix but not in the vagina. Conclusions/Significance Cervical smooth muscle strips taken from mice in estrus, metestrus or late pregnancy were generally spontaneously active. Vaginal smooth muscle strips were normally quiescent but could be induced to exhibit phasic contractions independent on phase of the estrus cycle or late pregnancy. Spontaneous cervical or TEA-induced vaginal phasic contractions were not mediated by ICs or intracellular Ca2+ stores. Given that vaginal smooth muscle is normally quiescent then it is likely that increases in hormones such as oxytocin, as might occur through sexual stimulation, enhance the

  3. Effects of altering the dose and timing of triptorelin when given as an intravaginal gel for advancing and synchronizing ovulation in weaned sows.

    PubMed

    Knox, R V; Taibl, J N; Breen, S M; Swanson, M E; Webel, S K

    2014-08-01

    Previous studies have shown that triptorelin gel (TG) given intravaginally in gel form is effective for advancing the time of ovulation in weaned sows. Three experiments were performed to determine the effects of altering the dose and timing of administration of intravaginal TG for advancing and synchronizing ovulation in weaned sows. In all experiments, estrus was detected twice or three times daily and ultrasound was performed to determine ovulation at 8-hour intervals. In experiment 1, sows (n = 131) received intravaginal gel containing 0 (Placebo), 25, 100, or 200 μg of TG at 96 hours after weaning and sows were inseminated on each day of standing estrus. Wean-to-estrus interval and duration of estrus were correlated (P < 0.0001) with estrus duration longer in TG (P < 0.05) compared with Placebo. More sows ovulated (P < 0.001) by 48 hours after treatment with 200 (81%), 100 (64%), and 25 μg (63%) of TG compared with Placebo (42%). The farrowing rate and total pigs born did not differ (P > 0.10). In experiment 2, sows (n = 126) received 200 μg of TG at 72, 84, or 96 hours after weaning or were untreated (Control-96). Sows receiving TG were inseminated once 24 to 28 hours after treatment. Control-96 sows were inseminated on each day of standing estrus. Wean-to-estrus interval was not affected by treatment, but wean-to-ovulation interval was reduced (P < 0.05) by TG-72 and TG-84 compared with TG-96 and Control-96. More sows ovulated 40 hours after treatment (P < 0.001) with TG-72 (56.5%) and TG-84 (32.2%) compared with TG-96 and Control-96 (13%) and for all TG treatments 48 hours after treatment (64%) compared with Control-96 (34%, P < 0.05). The farrowing rate was lower (P < 0.05) for sows assigned to TG-72 and TG-84 compared with TG-96 and Control-96, whereas the number of liveborn pigs did not differ (P > 0.10). In experiment 3, sows (n = 113) were assigned to receive no treatment (Control), intravaginal gel alone (Placebo), or 200 μg of TG given

  4. Synchronous Discrete Harmonic Oscillator

    SciTech Connect

    Antippa, Adel F.; Dubois, Daniel M.

    2008-10-17

    We introduce the synchronous discrete harmonic oscillator, and present an analytical, numerical and graphical study of its characteristics. The oscillator is synchronous when the time T for one revolution covering an angle of 2{pi} in phase space, is an integral multiple N of the discrete time step {delta}t. It is fully synchronous when N is even. It is pseudo-synchronous when T/{delta}t is rational. In the energy conserving hyperincursive representation, the phase space trajectories are perfectly stable at all time scales, and in both synchronous and pseudo-synchronous modes they cycle through a finite number of phase space points. Consequently, both the synchronous and the pseudo-synchronous hyperincursive modes of time-discretization provide a physically realistic and mathematically coherent, procedure for dynamic, background independent, discretization of spacetime. The procedure is applicable to any stable periodic dynamical system, and provokes an intrinsic correlation between space and time, whereby space-discretization is a direct consequence of background-independent time-discretization. Hence, synchronous discretization moves the formalism of classical mechanics towards that of special relativity. The frequency of the hyperincursive discrete harmonic oscillator is ''blue shifted'' relative to its continuum counterpart. The frequency shift has the precise value needed to make the speed of the system point in phase space independent of the discretizing time interval {delta}t. That is the speed of the system point is the same on the polygonal (in the discrete case) and the circular (in the continuum case) phase space trajectories.

  5. Tissue and serum concentrations of amikacin after intramuscular and intrauterine administration to mares in estrus.

    PubMed Central

    Orsini, J A; Park, M I; Spencer, P A

    1996-01-01

    Concentrations of amikacin in endometrial tissue and plasma were studied in mares in estrus after intrauterine infusion of 1.0 or 2.0 g once a day for 3 consecutive d, and after 9.7 or 14.5 mg/kg body weight (BW) had been injected intramuscularly once a day for 3 consecutive d to determine concentrations of amikacin sulfate in plasma and endometrial tissues, and whether parenteral administration provides any advantages over intramuscular infusion. No amikacin was detected in serum at the 1.0 g dose. At the infusion dose of 2.0 g once a day, very low levels of serum amikacin were detected at 1 and 4 h postinfusion on the 1st treatment day. Amikacin was found to penetrate the endometrium after intramuscular injection; however, the levels attained were not as high as those achieved following intrauterine infusion. Based on the tissue and serum concentrations of amikacin, an intrauterine infusion at a dose of 4.4 mg/kg BW/d would appear to be an appropriate therapeutic regimen for the treatment of gram-negative endometritis. PMID:8681283

  6. Amygdala Kindling Alters Estrus Cycle and Ovarian Morphology in the Rat.

    PubMed

    Pan, Juan; Zhang, Lingwu; Wang, Feng; Liu, Dan; Li, P Andy; Sun, Tao

    2013-11-01

    The objective of this study is to explore the effects of amygdala kindling on estrus cycle and ovarian morphology. Thirty-five female rats at the age of 8 weeks were randomly designated to electrode kindled, sham-kindled, and normal controls. Kindled rats were implanted with kindling electrodes in the left basolateral amygdala and kindled by brief suprathreshold stimulations with a bipolar electrode. Estrous cycles were daily monitored through vaginal smears. Electrographic and behavioral seizures were recorded and ovarian morphology was evaluated by light and electron microscopies. Our results showed that the kindled rats lost their ovarian periodicity displayed significant ovarian enlargement. H&E staining revealed increased number of growing follicles and total follicles, as well as polycysts in the ovaries of the kindled animals compared to sham and control animals. Ultrastructural study detected numerous apoptotic granulosa cells in growing follicles and thecal cell hyperplasia with secretary granules in the thecal cells in the kindled rats. The results suggest that amygdala kindling is a risk factor for the development of polycystic ovary syndrome. PMID:25285307

  7. Amygdala Kindling Alters Estrus Cycle and Ovarian Morphology in the Rat

    PubMed Central

    Pan, Juan; Zhang, Lingwu; Wang, Feng; Liu, Dan

    2014-01-01

    The objective of this study is to explore the effects of amygdala kindling on estrus cycle and ovarian morphology. Thirty-five female rats at the age of 8 weeks were randomly designated to electrode kindled, sham-kindled, and normal controls. Kindled rats were implanted with kindling electrodes in the left basolateral amygdala and kindled by brief suprathreshold stimulations with a bipolar electrode. Estrous cycles were daily monitored through vaginal smears. Electrographic and behavioral seizures were recorded and ovarian morphology was evaluated by light and electron microscopies. Our results showed that the kindled rats lost their ovarian periodicity displayed significant ovarian enlargement. H&E staining revealed increased number of growing follicles and total follicles, as well as polycysts in the ovaries of the kindled animals compared to sham and control animals. Ultrastructural study detected numerous apoptotic granulosa cells in growing follicles and thecal cell hyperplasia with secretary granules in the thecal cells in the kindled rats. The results suggest that amygdala kindling is a risk factor for the development of polycystic ovary syndrome. PMID:25285307

  8. Expression of estrus modifies the gene expression profile in reproductive tissues on Day 19 of gestation in beef cows.

    PubMed

    Davoodi, S; Cooke, R F; Fernandes, A C C; Cappellozza, B I; Vasconcelos, J L M; Cerri, R L A

    2016-03-01

    The aim of this study was to test the effect of expression of estrus at artificial insemination (AI) on endometrium, conceptus, and CL gene expression of beef cows. Thirty-six multiparous nonlactating Nelore cows were enrolled on an estradiol- and progesterone (P4)-based timed AI protocol (AI = Day 0) and then slaughtered for the endometrium, CL, and conceptus collection on Day 19. The animals were retrospectively grouped on the basis of cows that (1) showed signs of estrus near AI (n = 19; estrus) and (2) did not show any signs of estrus (n = 17; nonestrus). Body condition score, blood sampling, and ultrasound examination were performed on Days 0, 7, and 18 of the experiment followed by messenger RNA extraction and quantitative reverse transcription polymerase chain reaction analysis of 58 target genes. Data were checked for normality and analyzed by ANOVA for repeated measures using proc GLM, MIXED, and UNIVARIATE of SAS. Only pregnant cows were included in the analyses (n = 12; nonestrus, n = 11). Estrous expression had no correlation with parameters such as body condition score, preovulatory follicle and CL diameter, P4 concentration in plasma on Days 7 and 18 after AI, and interferon-tau concentration in the uterine flushing (P > 0.15); however, a significant increase was observed in conceptus size from cows that expressed estrus (P = 0.02; 38.3 ± 2.8 vs. 28.2 ± 2.9 mm). The majority of transcripts affected by estrous expression in the endometrium belong to the immune system and adhesion molecule family (MX1, MX2, MYL12A, MMP19, CXCL10, IGLL1, and SLPI; P ≤ 0.05), as well as those related with prostaglandin synthesis (OTR and COX-2; P ≤ 0.05). Genes related to apoptosis, P4 synthesis, and prostaglandin receptor were downregulated (CYP11A, BAX, and FPr; P < 0.05) in the CL tissue of cows that expressed estrus. In addition, four genes were identified as differentially expressed in the 19-day-old conceptus from cows that expressed

  9. Binary synchronous simulator

    NASA Technical Reports Server (NTRS)

    Rogers, J. R., III

    1980-01-01

    Flexible simulator for trouble-shooting data transmission system uses binary synchronous communications protocol to produce error-free transmission of data between two points. Protocol may be used to replace display generator or be directly fed to display generator.

  10. Advanced synchronous luminescence system

    DOEpatents

    Vo-Dinh, Tuan

    1997-01-01

    A method and apparatus for determining the condition of tissue or otherwise making chemical identifications includes exposing the sample to a light source, and using a synchronous luminescence system to produce a spectrum that can be analyzed for tissue condition.

  11. Synchronization in complex networks

    SciTech Connect

    Arenas, A.; Diaz-Guilera, A.; Moreno, Y.; Zhou, C.; Kurths, J.

    2007-12-12

    Synchronization processes in populations of locally interacting elements are in the focus of intense research in physical, biological, chemical, technological and social systems. The many efforts devoted to understand synchronization phenomena in natural systems take now advantage of the recent theory of complex networks. In this review, we report the advances in the comprehension of synchronization phenomena when oscillating elements are constrained to interact in a complex network topology. We also overview the new emergent features coming out from the interplay between the structure and the function of the underlying pattern of connections. Extensive numerical work as well as analytical approaches to the problem are presented. Finally, we review several applications of synchronization in complex networks to different disciplines: biological systems and neuroscience, engineering and computer science, and economy and social sciences.

  12. Synchronization in complex networks

    NASA Astrophysics Data System (ADS)

    Arenas, Alex; Díaz-Guilera, Albert; Kurths, Jurgen; Moreno, Yamir; Zhou, Changsong

    2008-12-01

    Synchronization processes in populations of locally interacting elements are the focus of intense research in physical, biological, chemical, technological and social systems. The many efforts devoted to understanding synchronization phenomena in natural systems now take advantage of the recent theory of complex networks. In this review, we report the advances in the comprehension of synchronization phenomena when oscillating elements are constrained to interact in a complex network topology. We also take an overview of the new emergent features coming out from the interplay between the structure and the function of the underlying patterns of connections. Extensive numerical work as well as analytical approaches to the problem are presented. Finally, we review several applications of synchronization in complex networks to different disciplines: biological systems and neuroscience, engineering and computer science, and economy and social sciences.

  13. Avoided Crossing and Synchronization

    NASA Astrophysics Data System (ADS)

    Sekii, T.; Shibahashi, H.

    2013-12-01

    We examine avoided crossing of stellar pulsations in the nonlinear regime, where synchronization may occur, based on a simple model of weakly coupled van der Pol oscillators with close frequencies. For this simple case, avoided crossing is unaffected in the sense that there is a frequency difference between the symmetric and antisymmetric modes, but as a result of synchronization, unlike the linear oscillations case, the system can vibrate in only one of the modes.

  14. Variations in the vulvar temperature of sows during proestrus and estrus as determined by infrared thermography and its relation to ovulation.

    PubMed

    Simões, Vasco G; Lyazrhi, Faouzi; Picard-Hagen, Nicole; Gayrard, Véronique; Martineau, Guy-Pierre; Waret-Szkuta, Agnès

    2014-11-01

    The prediction of ovulation time is one of the most important and yet difficult processes in pig production, and it has a considerable impact on the fertility of the herd and litter size. The objective of this study was to assess the vulvar skin temperature of sows during proestrus and estrus using infrared thermography and to establish a possible relationship between the variations in vulvar temperature and ovulation. The experimental group comprised 36 crossbred Large White × Landrace females, of which 6 were gilts and 30 were multiparous sows. Estrus was detected twice daily and the temperature was obtained every 6 hours from the vulvar area and from two control points in the gluteal area (Gluteal skin temperature [GST]). A third variable, vulvar-gluteal temperature (VGT) was obtained from the difference between the vulvar skin temperature and the GST values. The animals were divided into two subgroups: group A consisting of 11 animals with estrus detected at 6:00 AM, Day 4 postweaning, and group B comprising seven animals with estrus detected at 6:00 AM, Day 5 post-weaning. Both groups showed a similar trend in the VGT. The VGT increased during the proestrus, reaching a peak 24 hours before estrus in group A and 48 hours before estrus in group B. The VGT then decreased markedly reaching the lowest value in groups A and B, respectively, 12 and 6 hours after estrus. Although the time of ovulation was only estimated on the basis of a literature review, the matching between the temporal variations of the VGT values and the predicted time of the peak of estradiol secretion that ultimately leads to the ovulation processes suggests that the VGT values represent a potential predictive marker of the ovulatory events. PMID:25159660

  15. Single fixed-time artificial insemination in gilts and weaned sows using pLH at estrus onset administered through vulvar submucosal route.

    PubMed

    Ulguim, R R; Fontana, D L; Bernardi, M L; Wentz, I; Bortolozzo, F P

    2016-09-01

    This study evaluated the use of a single fixed-time artificial insemination (FTAI) in gilts and weaned sows using 2.5 mg of porcine luteinizing hormone (pLH) administered through vulvar submucosal route, at the onset of estrus. In experiment 1 (Exp.1), 318 pubertal gilts were assigned to two groups: control-G-no hormonal application and artificial inseminations (AIs) at 12, 36, and 60 hours after the onset of estrus if they were still in standing estrus; and FTAI-G-use of pLH at the onset of estrus and a single FTAI 12 hours later. In experiment 2 (Exp. 2), 309 weaned sows were assigned to three groups: Control-S-no hormone application and AIs at 0, 24, and 48 hours after the onset of estrus if they were still in standing estrus; FTAI-NH-no hormone application and a single FTAI at 24 hours after the onset of estrus, and FTAI-pLH-use of pLH at the onset of estrus and a single FTAI 24 hours later. Transabdominal real time B-mode ultrasonography was performed to determine whether the insemination had been performed within 24 hours before ovulation, considered as the optimal interval. In Exp. 1, ultrasound evaluation (12-hour intervals) was carried out to determine the interval between the onset of estrus and ovulation. In both experiments, 2 × 10(9) sperm cells in 80 mL were used to perform cervical and postcervical deposition of semen in gilts and sows, respectively. Compared with control-G, FTAI-G gilts had shorter (P < 0.05) duration of estrus (57.7 vs. 61.2 hours) and interval between the onset of estrus and ovulation (36.3 vs. 42.3 hours). The adjusted farrowing rate (AFR) was lower (P < 0.05) in FTAI-G (86.0%) compared with control-G (93.5%), but total piglets born (TPB) did not differ between these groups (12.3 vs. 12.5 piglets). Within the FTAI-G group, the AFR was lower (P < 0.05) in the presence (50.0%) than in the absence (94.9%) of semen backflow during AI. Also in the FTAI-G group, the insemination outside the optimal interval reduced (P

  16. Synchronization and Artificial Insemination Strategies in Dairy Herds.

    PubMed

    Stevenson, Jeffrey S

    2016-07-01

    Timed artificial insemination (AI) programs are commonly used in the dairy industry for lactating cows, but less so in replacement heifers. Excellent programs using combinations of prostaglandin F2α and gonadotropin-releasing hormone in protocols relying on timed AI without detection of estrus or in protocols that combine timed AI with inseminations performed after detected estrus are able to achieve acceptable pregnancy percentages. In herds with excellent estrus detection, timed AI programs serve as a failsafe system to address cows or heifers not yet inseminated after a defined period of estrus detection. PMID:27039693

  17. Synchronization in Superradiant Lasers

    NASA Astrophysics Data System (ADS)

    Cox, Kevin; Weiner, Joshua; Bohnet, Justin; Thompson, James

    2015-05-01

    Superradiant (or bad-cavity) lasers based on highly forbidden transitions in cold atoms are expected to produce light with coherence properties exceeding the state-of-the-art, finding applications in optical atomic clocks and other precision measurements. We study experimentally and theoretically the response of a superradiant Raman laser to an applied coherent drive. We observe two forms of synchronization (injection locking) between the superradiant ensemble and the applied drive: one attractive and one repulsive in nature, in which the atomic spin degrees of freedom play a crucial role in determining the dynamics. Additionally, we present time dynamics and steady state behavior of two interacting superradiant lasers. Understanding the synchronization physics of superradiant lasers could inform future implementations with technologically relevant phase noise properties and explorations for understanding synchronization in a quantum regime.

  18. Optimistic barrier synchronization

    NASA Technical Reports Server (NTRS)

    Nicol, David M.

    1992-01-01

    Barrier synchronization is fundamental operation in parallel computation. In many contexts, at the point a processor enters a barrier it knows that it has already processed all the work required of it prior to synchronization. The alternative case, when a processor cannot enter a barrier with the assurance that it has already performed all the necessary pre-synchronization computation, is treated. The problem arises when the number of pre-sychronization messages to be received by a processor is unkown, for example, in a parallel discrete simulation or any other computation that is largely driven by an unpredictable exchange of messages. We describe an optimistic O(log sup 2 P) barrier algorithm for such problems, study its performance on a large-scale parallel system, and consider extensions to general associative reductions as well as associative parallel prefix computations.

  19. The expression of epidermal growth factor receptors and their ligands (epidermal growth factor, neuregulin, amphiregulin) in the bitch uterus during the estrus cycle.

    PubMed

    Sağsöz, Hakan; Liman, Narin; Saruhan, Berna Güney; Küçükaslan, İbrahim

    2014-06-30

    In order to study the possible role of EGFR receptors in the bitch reproductive process, we have analyzed the expression pattern and localization of EGFR receptors and some of their ligands epidermal growth factor (EGF), neuregulin (NRG), amphiregulin (AREG), in the uterus during the estrus cycle using immunohistochemistry. The immunostaining for receptors and ligands of EGFR/ligand system was confined to membrane and cytoplasm of the target cells. Variations were observed, not only at the different stages of the estrous cycle, but also in the different tissue compartments of the uterus. However, it was detected that the immunostainings for NRG and AREG in the different cells do not show important differences at stages of the estrus cycle. In the luminal epithelium, strong immunostaining for ErbB1/HER1, ErbB2/HER2, ErbB4/HER4 and EGF was found at estrus. In the glandular epithelium, strong immunostaining for ErbB4/HER4 was observed at diestrus, while strong immunostaining for EGF was detected in both of estrus and diestrus. ErbB3/HER3 immunoreactivity in the stromal cells was higher at diestrus and anestrus, while ErbB4/HER4 immunoreactivity was lower at anestrus. In the myometrium, the highest levels of immunoreactivity of ErbB2/HER2 were found at estrus, while ErbB3/HER3 immunoreactivity was higher at anestrus. EGF immunoreactivity was lower at anestrus compared to other stage of cycle. Altered EGFR/ligand system expression during the estrus cycle suggests this growth factor system is a potent regulator of proliferation and differentiation events during preparation for implantation of bitch uterus. PMID:24813021

  20. Postpartum interval to estrus and patterns of LH and progesterone in first-calf suckled beef cows exposed to mature bulls.

    PubMed

    Custer, E E; Berardinelli, J G; Short, R E; Wehrman, M; Adair, R

    1990-05-01

    Two trials were conducted in which Angus x Hereford first-calf cows were assigned randomly at calving to one of two treatments: exposure to mature penile-blocked bulls (BE) or isolation from bulls (NE). In Trial 1 (BE, n = 38; NE, n = 37), cow to bull ratio increased from 12:1 to 19:1 over a 14-d period; in Trial 2 (BE, n = 25; NE, n = 24), this ratio was maintained at 13:1. In both trials, blood samples were collected weekly for progesterone and ovaries and uteri of cows were examined rectally. Cows were observed for estrus twice daily (am:pm) beginning 10 d after calving. In Trial 2, intensive blood sampling for LH began 10 d after calving (eight cows per treatment) and continued at weekly intervals until estrus or the end of the trial. Postpartum weight change, condition score change and time to uterine involution did not differ (P greater than .10) between treatments in either trial. Interval to estrus was shorter (P less than .05) for BE cows than for NE cows in both trials. A greater proportion (P less than .05) of BE cows exhibited estrus by 60 and 90 d after calving and showed an increase in progesterone before first estrus. Mean and baseline LH concentrations and amplitude, frequency and duration of LH pulses were not altered (P greater than .10) by bull exposure. In conclusion, exposing first-calf suckled beef cows to bulls after calving hastened resumption of estrous cycles. Bull exposure did not alter patterns of LH concentrations but did increase proportions of cows that showed increased progesterone before first estrus. PMID:2365649

  1. Effects of GnRH administered to cows at the onset of estrus on timing of ovulation, endocrine responses, and conception.

    PubMed

    Kaim, M; Bloch, A; Wolfenson, D; Braw-Tal, R; Rosenberg, M; Voet, H; Folman, Y

    2003-06-01

    Two experiments examined effects of GnRH administered within 3 h after onset of estrus (OE) on ovulation and conception in dairy cows. In experiment 1, 46 cows received either saline, 250 microg of GnRH, or 10 microg of the GnRH analogue, Buserelin. Cows were observed for estrus, blood samples were collected, and ovulations were monitored by ultrasound. In controls, 76% of cows had intervals from estrus to ovulation of < or = 30 h and 24% had intervals > 30 h. Treatment with either GnRH or GnRH analogue (data combined) increased magnitude of LH surges and decreased intervals from estrus to LH surge or to ovulation. Treated cows all ovulated < or = 30 h after OE. Among control cows, plasma estradiol concentrations before estrus correlated positively with amplitudes of LH surges. Higher plasma progesterone was observed in the subsequent estrous cycle in GnRH-treated cows compared to control cows with delayed ovulations. Experiment 2 included 152 primiparous and 211 multiparous cows in summer and winter. Injection of GnRH analogue at OE increased conception rates (CR) from 41.3 to 55.5% across seasons. In summer, GnRH treatment increased CR from 35.1 to 51.6%. Across seasons, GnRH increased CR from 36.0 to 61.5% in cows with lower body condition at insemination and GnRH increased CR (63.2 vs. 42.2%) in primiparous cows compared to controls. Use of GnRH eliminated differences in CR for cows inseminated early or late relative to OE and increased CR in cows having postpartum reproductive disorders. In conclusion, GnRH at onset of estrus increased LH surges, prevented delayed ovulation, and may increase subsequent progesterone concentrations. Treatments with GnRH increased conception in primiparous cows, during summer, and in cows with lower body condition. PMID:12836937

  2. Synchronized time stamp support

    SciTech Connect

    Kowalkowski, J.

    1994-02-16

    New software has been added to IOC core to maintain time stamps. The new software has the ability to maintain time stamps over all IOCs on a network. The purpose of this paper is to explain how EPICS will synchronize the time stamps. In addition, this paper will explain how to configure and use the new EPICS time stamp support software.

  3. Advanced synchronous luminescence system

    DOEpatents

    Vo-Dinh, T.

    1997-02-04

    A method and apparatus are disclosed for determining the condition of tissue or otherwise making chemical identifications includes exposing the sample to a light source, and using a synchronous luminescence system to produce a spectrum that can be analyzed for tissue condition. 14 figs.

  4. Implementing the Synchronous Classroom

    ERIC Educational Resources Information Center

    Furman, Jan A.

    2010-01-01

    This commentary describes an action research project conducted by selected staff at the Northern Valley Regional High School District in New Jersey. The project focused on the idea of developing a synchronous classroom to provide world language learning opportunities to students. Relevant research is provided as are ideas regarding logistics and…

  5. Estrous synchronization strategies to optimize beef heifer reproductive performance after reproductive tract scoring.

    PubMed

    Kasimanickam, Ramanathan K; Whittier, William D; Hall, John B; Kastelic, John P

    2016-08-01

    Three experiments comparing four estrous synchronization protocols were conducted to determine estrous expression rate and artificial insemination pregnancy rate (AI-PR) in heifers with a range (1-5) of reproductive tract scores (RTSs). At enrollment (Day 0), 1783 Angus cross beef heifers from six locations were given body condition score and RTS. The four protocols were: (1) HRTS-DPGF group-heifers with RTS 5 received prostaglandin F2α (PGF; Dinoprost 25 mg; im) on Days 0 and 14; (2) HRTS-CIDR-PGF group-heifers with RTS 5 received a CIDR (1.3-g progesterone) insert on Day 7, followed by CIDR removal and PGF on Day 14; (3) LRTS-CIDR-PGF group-heifers with RTS 4 or less received a CIDR insert on Day 7, followed by CIDR removal and PGF on Day 14; and (4) HRTS-Select-Synch group-heifers with RTS 5 received 100 μg of gonadorelin diacetate tetrahydrate (gonadotropin releasing homone; im) on Day 7 and PGF on Day 14. In all groups, heifers observed in estrus were artificially inseminated (within 120 hours after PGF) using the AM-PM rule. In Experiment 1, estrus expression rates were 82.2% (282/343) and 88.5% (184/208) for HRTS-DPGF and LRTS-CIDR-PGF, respectively (P < 0.05), whereas AI-PR were 51.3% (176/343) and 59.1% (123/208; P < 0.1). In Experiment 2, estrus expression rates were 79.6 (168/211), 86.9 (186/214) and 84.2% (176/209) for HRTS-DPGF, HRTS-CIDR-PGF, and LRTS-CIDR-PGF groups (P > 0.1) and AI-PR were 52.1 (110/211), 60.3 (129/214), and 58.4% (122/209; P > 0.05). In Experiment 3, estrus expression rates were 77.5 (131/169), 85.5 (142/166), and 83.3% (219/263) for HRTS-DPGF, HRTS-Select-Synch and LRTS-CIDR-PGF (P > 0.05) and AI-PR were 53.3 (90/169), 60.2 (100/166), and 58.6% (154/263; P > 0.1). Overall, estrus expression rates for HRTS-DPGF, HRTS-Select-Synch, LRTS-CIDR-PGF, and HRTS-CIDR-PGF groups were 80.4 (581/723), 85.5 (142/166), 85.1 (579/680), and 86.9% (186/214), respectively; higher for heifers in LRTS-CIDR-PGF and HRTS-CIDR-PGF groups

  6. Ovarian follicle apoptosis at the onset of standing estrus in virgin and repeat-breeder dairy heifers.

    PubMed

    Båge, R; Bosu, W T; Rodríguez-Martínez, H

    2001-09-15

    There is evidence that repeat breeding in dairy cattle can be caused by both extrinsic, environmental factors and intrinsic, animal factors. In repeat-breeder heifers (RBH), disturbed endocrine patterns and estrous events result in a subsequent decreased fertility associated with delayed ovulation. Whether infertility is also due to the presence of an unsuitable follicular environment impairing normal fertilization, remains to be determined. At the onset of standing estrus, ovaries were obtained from 7 strictly defined RBH and 5 virgin heifers (VH) of the Swedish Red and White breed. Detection of apoptosis in the preovulatory and three subordinate follicle walls was done by using the TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling) technique at light microscopy level. The follicles were histologically assessed for degree of atresia. The ultrastructure of the follicle wall and recovered oocytes was studied using transmission electron microscopy. The overall degree of apoptosis in membrana granulosa and theca interna of preovulatory and subordinate follicles did not differ between RBH and VH, but the numbers of TUNEL-positive cells differed significantly between preovulatory and subordinate follicles in both RBH and VH. There was a strong relationship between density of apoptotic cells and degree of atresia. No differences in follicle wall apoptosis nor morphology were detectable, suggesting that repeat breeder heifers enter standing estrus with the same morphological prerequisites as normal animals, considering follicular structure. PMID:11665874

  7. Changes in the sexual behavior and testosterone levels of male rats in response to daily interactions with estrus females

    PubMed Central

    Shulman, Leanne M.; Spritzer, Mark D.

    2014-01-01

    Male rat sexual behavior has been intensively studied over the past 100 years, but few studies have examined how sexual behavior changes over the course of several days of interactions. In this experiment, adult male rats (n = 12) were given daily access to estrus females for 30 min per day for 15 consecutive days and control males did not interact with females. Ovariectomized females were induced into estrus with hormonal injections, and males interacted with a different female each day. The amount of sexual activity (mounts, intromissions, and ejaculations) was found to cycle with a period of approximately 4 days in most male rats. Additionally, blood was collected every other day following sexual interactions to assess serum testosterone levels. Testosterone was found to peak on the first day of interaction and then fell back to near the level of control rats that did not interact with females. Following the initial peak, testosterone concentrations fluctuated less in males exposed to females than in controls. Sexual activity was not found to predict testosterone concentration. We conclude that when male rats have daily sexual interactions, sexual behavior tends to show cyclic changes and testosterone is significantly elevated only on the first day of interactions. PMID:24813700

  8. Immunohistochemical determination of estrogen receptor-α in canine vaginal biopsies throughout proestrus, estrus, and early diestrus.

    PubMed

    Ithurralde, Javier; Costas, Ana Laura; Pessina, Paula; Cueto, Enrique; Fila, Danilo; Meikle, Ana

    2013-10-15

    The aim of this study was to describe the presence of estrogen receptor-α (ERα) in several vaginal histological compartments in healthy adult bitches throughout three estrous cycle stages (proestrus, estrus, and early diestrus) and to relate ERα presence with serum progesterone and estradiol-17β concentrations. For this purpose, serial blood samples and vaginal biopsies were taken from five bitches every 48 hours, starting at the clinical onset of proestrus, marked by the beginning of serosanguineous vaginal secretion. Serum progesterone and estradiol-17β concentrations were determined by RIA, whereas detection of steroid receptors was carried out through immunohistochemistry. Subjective image analysis was conducted by two independent observers in the following histological compartments: superficial, intermediate, and deep epithelia and superficial (loose) and deep (dense) stroma (connective tissue). Nuclear ERα immunoreactivity was detected in every histological compartment and estrous cycle stage studied. ERα expression varied among histological compartments and during stages of the cycle. Receptor expression was associated with estradiol-17β and progesterone serum profiles. Most relevant cyclic changes were detected in the superficial and deep epithelia and in the dense connective tissue. The highest ERα expression was detected during diestrus, although each compartment had a different pattern throughout the other cycle stages. Thus, vaginal ERα expression in the bitch varied throughout proestrus, estrus, and early diestrus according to the histological compartment involved. PMID:23953742

  9. Effects of a commercial canine gonadotropin releasing hormone vaccine on estrus suppression and estrous behavior in mares.

    PubMed

    Donovan, C E; Hazzard, T; Schmidt, A; LeMieux, J; Hathaway, F; Kutzler, M A

    2013-11-01

    We investigated the effect of immunization against gonadotropin releasing hormone (GnRH) using a commercial canine GnRH vaccine on estrus suppression and unwanted estrous behavior in mares. In experiment 1, mares were immunized (n = 6) twice with vaccine (5 mL) given intramuscularly 4 weeks apart or received a control diluent (n = 5). Transrectal ultrasonographic examination of the reproductive tracts was performed three days a week for 40 weeks after initial vaccination. Blood samples were collected weekly for GnRH antibody titer and progesterone concentration determination. In experiment 2, privately-owned mares (n = 12) were immunized twice with vaccine (1 mL) given intramuscularly 4 weeks apart. Blood samples were collected prior to each vaccination as well as 12 and 20 weeks after initial treatment, and transrectal ultrasonographic examinations of the reproductive tracts were performed 12 weeks after the first vaccination. Vaccinated mares in experiment 1 responded with a GnRH antibody titer, progesterone concentrations significantly lower than controls, and cessation of ovarian activity. Vaccinated mares in experiment 2 also responded with a GnRH antibody titer, progesterone concentrations that remained basal for the duration of the study, and cessation of ovarian activity. Owners of vaccinated mares in experiment 2 reported that the number of unwanted estrous behaviors present before vaccination significantly decreased following vaccination. In conclusion, GnRH immunization using a canine GnRH vaccine is an effective method for suppressing estrus and unwanted estrous behavior. PMID:24083943

  10. Changes in the sexual behavior and testosterone levels of male rats in response to daily interactions with estrus females.

    PubMed

    Shulman, Leanne M; Spritzer, Mark D

    2014-06-22

    Male rat sexual behavior has been intensively studied over the past 100 years, but few studies have examined how sexual behavior changes over the course of several days of interactions. In this experiment, adult male rats in the experimental group (n=12) were given daily access to estrus females for 30 min per day for 15 consecutive days while control males (n=11) did not interact with females. Ovariectomized females were induced into estrus with hormonal injections, and males interacted with a different female each day. The amount of sexual activity (mounts, intromissions, and ejaculations) was found to cycle with a period of approximately 4 days in most male rats. Additionally, blood was collected every other day following sexual interactions to assess serum testosterone levels. Testosterone was found to peak on the first day of interaction and then fell back to near the level of control rats that did not interact with females. Following the initial peak, testosterone concentrations fluctuated less in males exposed to females than in controls. Sexual activity was not found to predict testosterone concentration. We conclude that when male rats have daily sexual interactions, sexual behavior tends to show cyclic changes and testosterone is significantly elevated only on the first day of interactions. PMID:24813700

  11. Alternative programs for synchronizing and resynchronizing ovulation in beef cattle.

    PubMed

    Bó, Gabriel A; de la Mata, José Javier; Baruselli, Pietro S; Menchaca, Alejo

    2016-07-01

    Fixed-time artificial insemination (FTAI) has been regarded as the most useful method to increase the number of cows inseminated in a given herd. The main treatments for FTAI in beef cattle are based on the use of progesterone-releasing devices and GnRH or estradiol to synchronize follicle wave emergence, with a mean pregnancy per AI (P/AI) around 50%. However, more recent protocols based on GnRH (named 5-day Co-Synch) or estradiol (named J-Synch) that reduce the period of progesterone device insertion and extend the period from device removal to FTAI have been reported to improve P/AI in beef cattle. Furthermore, treatments to resynchronize ovulation for a second FTAI in nonpregnant cows have provided the opportunity to do sequential inseminations and achieve high P/AI in a breeding season, reducing or even eliminating the need for clean-up bulls. In summary, FTAI protocols have facilitated the widespread application of AI in beef cattle, primarily by eliminating the necessity of estrus detection in beef herds. PMID:27180326

  12. Non-hormonal systemic therapy in men with hormone-refractory prostate cancer and metastases: a systematic review from the Cancer Care Ontario Program in Evidence-based Care's Genitourinary Cancer Disease Site Group

    PubMed Central

    Winquist, Eric; Waldron, Tricia; Berry, Scott; Ernst, D Scott; Hotte, Sébastien; Lukka, Himu

    2006-01-01

    Background Prostate cancer that has recurred after local therapy or disseminated distantly is usually treated with androgen deprivation therapy; however, most men will eventually experience disease progression within 12 to 20 months. New data emerging from randomized controlled trials (RCTs) of chemotherapy provided the impetus for a systematic review addressing the following question: which non-hormonal systemic therapies are most beneficial for the treatment of men with hormone-refractory prostate cancer (HRPC) and clinical evidence of metastases? Methods A systematic review was performed to identify RCTs or meta-analyses examining first-line non-hormonal systemic (cytotoxic and non-cytotoxic) therapy in patients with HRPC and metastases that reported at least one of the following endpoints: overall survival, disease control, palliative response, quality of life, and toxicity. Excluded were RCTs of second-line hormonal therapies, bisphosphonates or radiopharmaceuticals, or randomized fewer than 50 patients per trial arm. MEDLINE, EMBASE, the Cochrane Library, and the conference proceedings of the American Society of Clinical Oncology were searched for relevant trials. Citations were screened for eligibility by four reviewers and discrepancies were handled by consensus. Results Of the 80 RCTs identified, 27 met the eligibility criteria. Two recent, large trials reported improved overall survival with docetaxel-based chemotherapy compared to mitoxantrone-prednisone. Improved progression-free survival and rates of palliative and objective response were also observed. Compared with mitoxantrone, docetaxel treatment was associated with more frequent mild toxicities, similar rates of serious toxicities, and better quality of life. More frequent serious toxicities were observed when docetaxel was combined with estramustine. Three trials reported improved time-to-disease progression, palliative response, and/or quality of life with mitoxatrone plus corticosteroid

  13. Synchronously deployable truss structure

    NASA Technical Reports Server (NTRS)

    Bush, H. G. (Inventor); Mikulas, M., Jr. (Inventor); Wallsom, E. (Inventor)

    1986-01-01

    A collapsible-expandable truss structure, including first and second spaced surface truss layers having an attached core layer is described. The surface truss layers are composed of a plurality of linear struts arranged in multiple triangular configurations. Each linear strut is hinged at the center and hinge connected at each end to a nodular joint. A passive spring serves as the expansion force to move the folded struts from a stowed collapsed position to a deployed operative final truss configuration. A damper controls the rate of spring expansion for the synchronized deployment of the truss as the folded configuration is released for deployment by the restrain belts. The truss is synchronously extended under the control of motor driven spools.

  14. Synchronization and hydrodynamic interactions

    NASA Astrophysics Data System (ADS)

    Powers, Thomas; Qian, Bian; Breuer, Kenneth

    2008-03-01

    Cilia and flagella commonly beat in a coordinated manner. Examples include the flagella that Volvox colonies use to move, the cilia that sweep foreign particles up out of the human airway, and the nodal cilia that set up the flow that determines the left-right axis in developing vertebrate embryos. In this talk we present an experimental study of how hydrodynamic interactions can lead to coordination in a simple idealized system: two nearby paddles driven with fixed torques in a highly viscous fluid. The paddles attain a synchronized state in which they rotate together with a phase difference of 90 degrees. We discuss how synchronization depends on system parameters and present numerical calculations using the method of regularized stokeslets.

  15. Breeding capacity, behavior and fertility of bulls with Brahman genetic influence during synchronized breeding of beef females.

    PubMed

    Williams, G L

    1988-07-01

    The objective of this experiment was to evaluate the feasibility of using bulls of Brahman-derived breeds for synchronized breeding of females treated with Syncro-Mate-B (SMB). Suckled, postpartum cows (n = 261) and virgin heifers (n = 227) were given the standard SMB treatment. Calves were removed from cows for 48 h beginning at implant removal, and individual bulls were placed in pens with 15 to 20 females (x = 1:15.7 ) for 48 h beginning at implant removal. Bulls (n = 31) were 18 to 36 mo of age and had scored satisfactorily on a breeding soundness evaluation (BSE). The mean +/- SEM percentage of females in estrus, percentage of estrous females serviced and percentage of total females serviced were 77.2 +/- 2.4, 72.9 +/- 2.9 and 55.7 +/- 3%, respectively. Total average services per bull was 23.6 +/- 1.6; however, average number of individuals serviced was only 8.6 +/- 0.42. Mean +/- SEM percentage of females conceiving of those serviced, percentage conceiving of those in estrus and percentage conceiving of total females available were 57.3 +/- 3.7, 40.6 +/- 2.6 and 32.6 +/- 2.5%, respectively. Mean BSE scores of eight Simbrah bulls tested immediately before and 5 d after synchronized breeding did not differ (P > 0.05). These data suggest that the conception rate of Brahman-influenced bulls servicing SMB-synchronized cows is within the normal range. However, the total number of individual females serviced and the total pregnancy rate under the protocol employed was low. This occurred because all estrous females were not inseminated, and some bulls exhibited unpredicted low fertility. PMID:16726447

  16. Digital Synchronizer without Metastability

    NASA Technical Reports Server (NTRS)

    Simle, Robert M.; Cavazos, Jose A.

    2009-01-01

    A proposed design for a digital synchronizing circuit would eliminate metastability that plagues flip-flop circuits in digital input/output interfaces. This metastability is associated with sampling, by use of flip-flops, of an external signal that is asynchronous with a clock signal that drives the flip-flops: it is a temporary flip-flop failure that can occur when a rising or falling edge of an asynchronous signal occurs during the setup and/or hold time of a flip-flop. The proposed design calls for (1) use of a clock frequency greater than the frequency of the asynchronous signal, (2) use of flip-flop asynchronous preset or clear signals for the asynchronous input, (3) use of a clock asynchronous recovery delay with pulse width discriminator, and (4) tying the data inputs to constant logic levels to obtain (5) two half-rate synchronous partial signals - one for the falling and one for the rising edge. Inasmuch as the flip-flop data inputs would be permanently tied to constant logic levels, setup and hold times would not be violated. The half-rate partial signals would be recombined to construct a signal that would replicate the original asynchronous signal at its original rate but would be synchronous with the clock signal.

  17. Superinsulator and quantum synchronization.

    SciTech Connect

    Vinokur, V. M.; Baturina, T. I.; Fistul, M. V.; Mironov, A. Yu.; Baklanov, M. R.; Strunk, C.; Materials Science Division; Inst. Semiconductor Physics; Univ. Regensburg; Ruhr-Univ. Bochum; IMEC

    2008-04-01

    Synchronized oscillators are ubiquitous in nature, and synchronization plays a key part in various classical and quantum phenomena. Several experiments have shown that in thin superconducting films, disorder enforces the droplet-like electronic texture 'superconducting islands immersed into a normal matrix' and that tuning disorder drives the system from superconducting to insulating behavior. In the vicinity of the transition, a distinct state forms: a Cooper-pair insulator, with thermally activated conductivity. It results from synchronization of the phase of the superconducting order parameter at the islands across the whole system. Here we show that at a certain finite temperature, a Cooper-pair insulator undergoes a transition to a superinsulating state with infinite resistance. We present experimental evidence of this transition in titanium nitride films and show that the superinsulating state is dual to the superconducting state: it is destroyed by a sufficiently strong critical magnetic field, and breaks down at some critical voltage that is analogous to the critical current in superconductors.

  18. Emergency Response Synchronization Matrix

    Energy Science and Technology Software Center (ESTSC)

    1999-06-01

    An emergency response to a disaster is complex, requiring the rapid integration, coordination, and synchronization of multiple levels of governmental and non-governmental organizations from numerous jurisdictions into a unified community response. For example, a community’s response actions to a fixed site hazardous materials incident could occur in an area extending from an on-site storage location to points 25 or more miles away. Response actions are directed and controlled by local governments and agencies situated withinmore » the response area, as well as by state and federal operaticns centers quite removed from the area of impact. Time is critical and the protective action decision-making process is greatly compressed. The response community must carefully plan and coordinate response operations in order to have confidence that they will be effectively implemented when faced with the potentially catastrophic nature of such releases. A graphical depiction of the entire response process via an emergency response synchronization matrix is an effective tool in optimizing the planning, exercising, and implementation of emergency plans. This system—based approach to emergency planning depicts how a community organizes its response tasks across space and time in relation to hazard actions. It provides the opportunity to make real—time adjustments as necessary for maximizing the often limited resources in protecting area residents. A response must involve the entire community and must not be limited by individual jurisdictions and organizations acting on their own without coordination, integration, and synchronization.« less

  19. Synchronization of Eukaryotic Flagella

    NASA Astrophysics Data System (ADS)

    Goldstein, Raymond E.

    2012-11-01

    From unicellular organisms as small as a few microns to the largest vertebrates on earth we find groups of beating flagella or cilia that exhibit striking spatio-temporal organization. This may take the form of precise frequency and phase locking as frequently found in the swimming of green algae, or beating with long-wavelength phase modulations known as metachronal waves, seen in ciliates and in our respiratory systems. The remarkable similarity in the underlying molecular structure of flagella across the whole eukaryotic world leads naturally to the hypothesis that a similarly universal mechanism might be responsible for synchronization. Although this mechanism is poorly understood, one appealing hypothesis is that it results from hydrodynamic interactions between flagella. In this talk I will describe a synthesis of recent experimental and theoretical studies of this issue that have provided the strongest evidence to date for the hydrodynamic origin of flagellar synchronization. At the unicellular level this includes studies of the beating of the two flagella of the wild type unicellular alga Chlamydomonas reinhardtii in their native state and under conditions of regrowth following autotomy, and of the flagellar dominance mutant ptx1, which displays unusual anti-phase synchronization. Analysis of the related multicellular organism Volvox carteri shows it to be an ideal model organism for the study of metachronal waves. Supported by BBSRC, EPSRC, ERC, and The Wellcome Trust.

  20. Socially synchronized circadian oscillators

    PubMed Central

    Bloch, Guy; Herzog, Erik D.; Levine, Joel D.; Schwartz, William J.

    2013-01-01

    Daily rhythms of physiology and behaviour are governed by an endogenous timekeeping mechanism (a circadian ‘clock’). The alternation of environmental light and darkness synchronizes (entrains) these rhythms to the natural day–night cycle, and underlying mechanisms have been investigated using singly housed animals in the laboratory. But, most species ordinarily would not live out their lives in such seclusion; in their natural habitats, they interact with other individuals, and some live in colonies with highly developed social structures requiring temporal synchronization. Social cues may thus be critical to the adaptive function of the circadian system, but elucidating their role and the responsible mechanisms has proven elusive. Here, we highlight three model systems that are now being applied to understanding the biology of socially synchronized circadian oscillators: the fruitfly, with its powerful array of molecular genetic tools; the honeybee, with its complex natural society and clear division of labour; and, at a different level of biological organization, the rodent suprachiasmatic nucleus, site of the brain's circadian clock, with its network of mutually coupled single-cell oscillators. Analyses at the ‘group’ level of circadian organization will likely generate a more complex, but ultimately more comprehensive, view of clocks and rhythms and their contribution to fitness in nature. PMID:23825203

  1. Metabolism of energy substrates of in vitro and in vivo derived embryos from ewes synchronized and super ovulated with norgestomet and porcine follicle stimulating hormone

    PubMed Central

    2012-01-01

    The synchronization and ovulatory responses of Sangsari cross bred ewes and metabolism of energy substrates in 8-cell stage embryos to hatched blastocysts stage produced in vitro or in vivo were investigated. Ewes were assigned randomly to receive 37.5 IU of porcine follicle stimulating hormone (FSH-P) daily for the 3 days preceding implant removal (Day 0). Synchronization of estrus was carried out using a 1.5 mg norgestomet (Crestar) ear implant for 12 days. Ewes in estrus were mated two to three times with rams of proven fertility. At the time of first mating each ewe was administered 1000 IU of human chorionic gonadotrophin (hCG) to induce ovulation. Surgical embryo recovery was performed on Days 4 and 6 after onset of estrus (Day 0) and recovered embryos were subjected to comparative metabolism studies with in vitro derived embryos at the same stage of development. The number of corpora lutea (CL), unovulated follicles and overall ovarian activity were recorded for each ewe during the breeding and non-breeding seasons. While the pattern of oxidation was similar among in vitro and in vivo derived embryos, a low pyruvate to lactate ratio was the preferred substrate of embryos derived in vitro. A high level of production of CO2 and lactate resulted from a stress response to the suboptimal culture environment. The first marked increase in the metabolism of glucose by ovine embryos was detected in compact morula stage, but there was no significant increase in the oxidation of glucose after the morula stage. Two different concentrations of glucose were compared, but this did not affect metabolism. However, the rate of incorporation and metabolism of glucose tended to be higher at the 0.56 mmol/L glucose dosage. PMID:23157819

  2. Estrus behavior, ovarian dynamics, and progesterone secretion in Criollo cattle during estrous cycles with two and three follicular waves.

    PubMed

    Quezada-Casasola, Andrés; Avendaño-Reyes, Leonel; Macías-Cruz, Ulises; Ramírez-Godínez, José Alejandro; Correa-Calderón, Abelardo

    2014-04-01

    In beef and dairy cattle, the number of follicular waves affects endocrine, ovarian, and behavioral events during a normal estrous cycle. However, in Mexican-native Criollo cattle, a shortly and recently domesticated breed, the association between wave patterns and follicular development has not been studied. The objective of this study was to evaluate the effect of number of follicular waves in an estrous cycle on development of anovulatory and ovulatory follicles, corpus luteum (CL) development and functionality, as well as estrual behavior in Criollo cows. Ovarian follicular activities of 22 cycling multiparous Criollo cows were recorded daily by transrectal ultrasound examinations during a complete estrous cycle. Additionally, blood samples were collected daily to determine serum progesterone concentrations. Only two- (n = 17, 77.3%) and three-wave follicular (n = 5, 22.7%) patterns were observed. Duration of estrus, length of estrous cycle, and length of follicular and luteal phases were similar (P > 0.05) between cycles of two and three waves. Two-wave cows ovulated earlier (P < 0.05) after detection of estrus than three-wave cows. Detected day and maximum diameter of first anovulatory follicle were not affected (P > 0.05) by number of waves. Growth rate of first dominant follicle was higher (P < 0.05) in three-wave cycles. Onset of regression of the first dominant follicle was earlier (P < 0.01) in cycles with three waves than in those with two waves. In two-wave cycles, ovulatory follicles were detected earlier (P < 0.01) and had lower (P < 0.01) growth rate than in three-wave cycles. Development (i.e., maximum diameter and volume) and functionality (minimum and maximum progesterone concentration) of CL were similar (P > 0.05) between two- and three-wave patterns. In conclusion, Criollo cows have two or three follicular waves per estrous cycle, which alters partially ovulatory follicle development and ovulation time after detection of estrus. Length of

  3. Reproductive outcomes of Alpine goats primed with progesterone and treated with human chorionic gonadotropin during the anestrus-to-estrus transition season.

    PubMed

    Alvarado-Espino, A S; Meza-Herrera, C A; Carrillo, E; González-Álvarez, V H; Guillen-Muñoz, J M; Ángel-García, O; Mellado, M; Véliz-Deras, F G

    2016-04-01

    This study aimed to determine the possible effects of a single injection of human chorionic gonadotropin (hCG) as a means for estrus induction in acyclic French-Alpine goats during the reproductive transition period at 25°N, 103°W. The potential effects of hCG upon ovarian function and reproductive performance of goats were also assessed. Multiparous acyclic French-Alpine goats (n = 39; 37.4 ± 8 .5 kg) were primed with 20mg progesterone (P4) 1 day prior to hCG administration. Thereafter, does were treated either with saline (hCG-0; n = 10), 50 (hCG-50; n = 9), 100 (hCG-100; n = 10), or 300 IU of hCG (hCG-300; n = 10). Ovarian structures and pregnancy were monitored by transrectal ultrasonography. In addition, after hCG application, goats were monitored twice daily (0800 and 1800 h) to detect estrus signs, with the use of aproned, sexually active bucks treated with testosterone. Goats were bred 12h after the onset of estrus. Two days after hCG administration, the number of large follicles was higher (P < 0.05) in the hCG-50 and hCG-300 groups (1.7 ± 0.1 and 1.8 ± 0.2, respectively) compared with the hCG-100 and hCG-0 groups (1.4 ± 0.2 and 1.1 ± 0.1, respectively). Although none of the hCG-0-goats depicted estrus, the estrus response from the hCG-50, hCG-100, and hCG-300 groups over the 7-d breeding period was 67%, 100%, and 90%, respectively (P > 0.05), being always accompanied by ovulation. Pregnancy rate (67, 100, and 70%), kidding rate (55%, 80%, and 70%), and litter size (1.6 ± 0.5, 1.5 ± 0.5, and 1.5 ± 0.5) for hCG-50, hCG-100, and hCG-300, respectively, did not differ among the hCG-treated does. Therefore, the combined use of P4-priming plus a 100-IU hCG injection is an effective protocol for inducing estrus in non-cycling Alpine goats during the anestrus-to-estrus transition period, which is of key importance for both goat producers and industrializers. PMID:26944772

  4. The period of the follicular phase during which the uterus of mares shows estrus-like echotexture influences the subsequent pregnancy rate.

    PubMed

    Mateu-Sánchez, S; Newcombe, J R; Garcés-Narro, C; Cuervo-Arango, J

    2016-10-01

    The interval from both spontaneous and prostaglandin (PGF)-induced luteolysis to ovulation is greatly variable in mares. Several reports have shown a positive association between the length of the interval from PGF treatment to ovulation (ITO) and the subsequent pregnancy rate (PR). However, it is not known whether this association also occurs in estrous cycles with spontaneous luteolysis. The main objective of this study was to determine the effect of the duration of estrus-like echotexture of the uterus during the follicular phase on the subsequent PR in both spontaneous and PGF-induced cycles. A total of 768 estrous cycles from 325 thoroughbred mares were analyzed (401 estruses were induced with exogenous PGF and 367 cycles were not treated with PGF). The following factors were taken into account to determine the effect on PR: age of the mare, stallion, year of breeding, month of season, reproductive status of the mare, use of PGF treatment, duration of follicular phase with estrus-like echotexture, interovulatory interval (IOI; in spontaneous cycles), and ITO (in PGF-induced cycles). The age of the mare (P = 0.017), mare status (P = 0.031), the ITO (P = 0.041), and the duration of the follicular phase with estrus-like echotexture (P < 0.001) influenced the PR. The PR increased with the duration of estrus and of endometrial edema in both PGF-induced and spontaneous cycles. The correlation between the duration of endometrial edema and the IOI and ITO was positive (r = 0.5) and significant (P < 0.05). PMID:27298152

  5. Potential role for GnRH in the synchronization of follicular emergence before the superovulatory Day 0 protocol.

    PubMed

    Balaro, M F A; Fonseca, J F; Barbosa, T G B; Souza-Fabjan, J M G; Figueira, L M; Teixeira, T A; Carvalheira, L R; Brandão, F Z

    2016-01-01

    The ability of gonadotropin-releasing hormone (GnRH) to synchronize ovulation and new follicular wave emergence before a "superovulatory Day 0" protocol was assessed in Santa Inês ewes. For estrus synchronization, a 60-mg medroxyprogesterone acetate sponge was inserted for 6 d. One day before sponge removal, 37.5-μg d-cloprostenol and 300 IU equine chorionic gonadotropin were injected intramuscularly (i.m.). After sponge removal, ewes were assigned to the following 3 groups: (1) GC-1 mL saline at 12 h (n = 10); (2) G24h-0.025-mg lecirelin (GnRH agonist) i.m. at 24 h (n = 10); or (3) G36h-0.025-mg lecirelin i.m. at 36 h (n = 9). Ovarian ultrasonography was conducted to assess follicular dynamics. Blood was collected to determine plasma concentrations of progesterone and estradiol. Females from G36h and GC had a greater (P < 0.05) estrous response than those from the G24h group (78.0 and 90.0 vs 0.0%, respectively). Ewes from G24h and G36h had earlier (P < 0.05) ovulation (48.0 ± 10.2 and 56.7 ± 5.7 h) compared with those from Gc (64.1 ± 9.7 h). The mean number of ovulations per ewe was greater (P < 0.05) in Gc (1.9 ± 0.6) and G36h (2.0 ± 1.0) than G24h (1.2 ± 0.4). Plasma concentrations of progesterone and estradiol differed over time. Follicular growth during the postovulatory day was affected (P < 0.05) by day of the estrus cycle as well as by the interaction (P < 0.05) of treatment and day of the estrus cycle. There was a larger (P < 0.05) population of medium follicles during the first 24 h after the ovulation in G24h compared with Gc, and there was an absence of large follicles in G36h between 36 and 72 h after ovulation. In conclusion, the use of GnRH agonist at 36 h more efficiently synchronized ovulation and promoted the absence of dominant follicles during early diestrus and may be used at the start of superovulatory treatment at 80 h in Santa Inês ewes. PMID:26343000

  6. Increased TRH and TRH-like peptide release in rat brain and peripheral tissues during proestrus/estrus.

    PubMed

    Pekary, A E; Sattin, Albert

    2014-02-01

    Women are at greater risk for major depression, PTSD, and other anxiety disorders. ERβ-selective agonists for the treatment of these disorders are the focus of pharmacologic development and clinical testing. Estradiol and its metabolites contribute to the neuroprotective effects of this steroid class, particularly in men, due to local conversion of testosterone to estiradiol in key brain regions which are predisposed to neurodegenerative diseases. We have used young adult female Sprague-Dawley rats to assess the role of TRH and TRH-like peptides, with the general structure pGlu-X-Pro-NH2 where "X" can be any amino acid residue, as mediators of the neurobiochemical effects of estradiol. The neuroprotective TRH and TRH-like peptides are coreleased with excitotoxic glutamate by glutamatergic neurons which contribute importantly to the regulation of the estrus cycle. The levels of TRH and TRH-like peptides during proestrus and/or estrus in the 12 brain regions analyzed were significantly decreased (due to accelerated release) 106 times but increased only 25 times when compared to the corresponding levels during diestrus days 1 and 2. These changes, listed by brain region in the order of decreasing number of significant decreases (↓) and/or increases (↑), were: striatum (20↓,1↑), medulla oblongata (16↓,2↑), amygdala (14↓,1↑), cerebellum (13↓,1↑), hypothalamus (12↓,1↑), entorhinal cortex (6↓,6↑), posterior cingulate (10↓,1↑), frontal cortex (3↓,5↑), nucleus accumbens (5↓,3↑), hippocampus (5↓,2↑), anterior cingulate (2↓,1↑), and piriform cortex (1↑). In peripheral tissues the corresponding changes were: ovaries (23↓), uterus (16↓,1↑), adrenals (11↓,3↑), and pancreas (1↓,6↑). We conclude that these peptides may be downstream mediators of some of the therapeutic effects of estrogen. PMID:24296042

  7. Estrus, ovulation, and serum progesterone, estradiol, and LH concentrations in mares after an increased photoperiod during winter.

    PubMed

    Oxender, W D; Noden, P A; Hafs, H D

    1977-02-01

    On December 11, 1974, 15 seasonally anestrous mares were assigned at random to 1 of 3 experimental groups: outdoor-control, indoor-control, or indoor light-treated (a 16-hour photo-period). This experiment was terminated on April 21, 1975. The five mares in the indoor light-treated group ovulated 59.0+/-6.9 days later, which was 74 days earlier (P less than 0.01) than 2 of the 5 outdoor-controls (the other 3 ovulated after April 21 during a subsequent experiment) and 50 days earlier (P less than 0.05) than the indoor-controls. Durations of the 1st estrus for the 3 groups of mares were 13.3+/-3.6, 8.4+/-2.0, and 6.0+/-1.0 days for the indoor light-treated, indoor-control, and outdoor-control groups, respectively. The indoor light-treated mares averaged 4.2 estrous cycles before April 21, the indoor-control mares averaged 1.4 estrous cycles, and 2 of 5 outdoor-control mares ovulated 1 time during the experiment. The peripheral blood luteinizing hormone (LH), estradiol, and progesterone concentrations were minimal during winter anestrous. The hormone changes normally associated with estrous cycle activity in mares--maximal estradiol and luteinizing hormone concentrations near ovulation and maximal progesterone concentration during diestrus--were observed in all mares beginning at the 1st estrus. Hair loss was observed earlier in the light-treated mares, than in either of the other groups. In conclusion, a 16-hour photo-period initiated in early December for anestrous brood mares caused endocrinologically normal estrous cycles to begin within 2 months. This may allow breeding and foaling considerably earlier than normally expected. PMID:557304

  8. Speed of complex network synchronization

    NASA Astrophysics Data System (ADS)

    Grabow, C.; Grosskinsky, S.; Timme, M.

    2011-12-01

    Synchrony is one of the most common dynamical states emerging on networks. The speed of convergence towards synchrony provides a fundamental collective time scale for synchronizing systems. Here we study the asymptotic synchronization times for directed networks with topologies ranging from completely ordered, grid-like, to completely disordered, random, including intermediate, partially disordered topologies. We extend the approach of master stability functions to quantify synchronization times. We find that the synchronization times strongly and systematically depend on the network topology. In particular, at fixed in-degree, stronger topological randomness induces faster synchronization, whereas at fixed path length, synchronization is slowest for intermediate randomness in the small-world regime. Randomly rewiring real-world neural, social and transport networks confirms this picture.

  9. Breathing synchronization in interconnected networks

    PubMed Central

    Louzada, V. H. P.; Araújo, N. A. M.; Andrade, J. S.; Herrmann, H. J.

    2013-01-01

    Global synchronization in a complex network of oscillators emerges from the interplay between its topology and the dynamics of the pairwise interactions among its numerous components. When oscillators are spatially separated, however, a time delay appears in the interaction which might obstruct synchronization. Here we study the synchronization properties of interconnected networks of oscillators with a time delay between networks and analyze the dynamics as a function of the couplings and communication lag. We discover a new breathing synchronization regime, where two groups appear in each network synchronized at different frequencies. Each group has a counterpart in the opposite network, one group is in phase and the other in anti-phase with their counterpart. For strong couplings, instead, networks are internally synchronized but a phase shift between them might occur. The implications of our findings on several socio-technical and biological systems are discussed. PMID:24256765

  10. Sun synchronous solar refrigeration

    NASA Astrophysics Data System (ADS)

    The primary goal of this project was to prototype a complete Sun Synchronous Solar Powered Refrigerator. The key element to the technology is the development of the hermetic motor compressor assembly. The prototype was to be developed to either the stage where Polar Products could receive additional venture capital or to the point whereby Polar could use their own capital to manufacture the systems. Our goal was to construct a prototype which would be the next step to a proven and market ready product. To demonstrate the technology under laboratory conditions was a very minimal goal.

  11. Huygens synchronization of two clocks

    PubMed Central

    Oliveira, Henrique M.; Melo, Luís V.

    2015-01-01

    The synchronization of two pendulum clocks hanging from a wall was first observed by Huygens during the XVII century. This type of synchronization is observed in other areas, and is fundamentally different from the problem of two clocks hanging from a moveable base. We present a model explaining the phase opposition synchronization of two pendulum clocks in those conditions. The predicted behaviour is observed experimentally, validating the model. PMID:26204557

  12. Huygens synchronization of two clocks.

    PubMed

    Oliveira, Henrique M; Melo, Luís V

    2015-01-01

    The synchronization of two pendulum clocks hanging from a wall was first observed by Huygens during the XVII century. This type of synchronization is observed in other areas, and is fundamentally different from the problem of two clocks hanging from a moveable base. We present a model explaining the phase opposition synchronization of two pendulum clocks in those conditions. The predicted behaviour is observed experimentally, validating the model. PMID:26204557

  13. FPGA based fast synchronous serial multi-wire links synchronization

    NASA Astrophysics Data System (ADS)

    Pozniak, Krzysztof T.

    2013-10-01

    The paper debates synchronization method of multi-wire, serial link of constant latency, by means of pseudo-random numbers generators. The solution was designed for various families of FPGA circuits. There were debated synchronization algorithm and functional structure of parameterized transmitter and receiver modules. The modules were realized in VHDL language in a behavioral form.

  14. Robust Sliding Window Synchronizer Developed

    NASA Technical Reports Server (NTRS)

    Chun, Kue S.; Xiong, Fuqin; Pinchak, Stanley

    2004-01-01

    The development of an advanced robust timing synchronization scheme is crucial for the support of two NASA programs--Advanced Air Transportation Technologies and Aviation Safety. A mobile aeronautical channel is a dynamic channel where various adverse effects--such as Doppler shift, multipath fading, and shadowing due to precipitation, landscape, foliage, and buildings--cause the loss of symbol timing synchronization.

  15. Digital synchronization and communication techniques

    NASA Technical Reports Server (NTRS)

    Lindsey, William C.

    1992-01-01

    Information on digital synchronization and communication techniques is given in viewgraph form. Topics covered include phase shift keying, modems, characteristics of open loop digital synchronizers, an open loop phase and frequency estimator, and a digital receiver structure using an open loop estimator in a decision directed architecture.

  16. Asynchronous & Synchronous E-Learning

    ERIC Educational Resources Information Center

    Hrastinski, Stefan

    2008-01-01

    An ongoing debate addresses the usefulness of asynchronous versus synchronous e-learning. "Asynchronous e-learning," commonly facilitated by media such as e-mail and discussion boards, supports work relations among learners and with teachers, even when participants cannot be online at the same time. "Synchronous e-learning," commonly supported by…

  17. Pattern of induced estrus and conception rate following Ovsynch and Ovsynch based gonadotropin-releasing hormone treatments initiated on day 6 of estrous cycle in repeat breeding crossbred cows

    PubMed Central

    Ahmed, N.; Kathiresan, D.; Ahmed, F. A.; Lalrintluanga, K.; Mayengbam, P.; Gali, J. M.

    2016-01-01

    Aim: The aim was to evaluate the estrus response, incidence of accessory corpus luteum formation and fertility following different hormonal protocols in repeat breeding crossbred cows. Materials and Methods: This study was carried out on 24 repeat breeding crossbred cows allotted into four groups. Cows of Group I was not given any treatment, Group II was treated with gonadotropin-releasing hormone (GnRH) injection on day 6 post-estrus, Group III was treated with Ovsynch protocol, and Group IV was treated with Ovsynch based GnRH treatment. Estrus responses such as duration, onset, percentage, and intensity of estrus were recorded during the study. The incidence of accessory corpus luteum was recorded per rectally on day 7 after first and additional GnRH of Ovsynch treatment. The conception rate for all groups was calculated by the absence of estrus and on day 45 after artificial insemination (AI) per rectum. Serum samples were collected at AI and day 12 post-AI in Group I and II. Serum samples were also collected at GnRH, Prostaglandin F2α (PGF2α), timed AI (TAI) and day 12 post-TAI in Group III and IV. Results: Ovsynch and Ovsynch based GnRH treatments are resulted in 100.00% induction of estrus after the PGF2α injection. Onset of induced estrus after the PGF2α injection for Group III and IV was recorded as 48.750±0.713 and 51.472±1.989 h, respectively, and it was not significant. There was no significant difference in duration of estrus among the groups. The incidence of intermediate estrus intensity was found to be highest. All the cows showed the incidence of formation of accessory corpus luteum subsequent to GnRH treatment on day 6 of the estrous cycle in Group II, III, and IV. The conception rate was 0.00%, 16.67%, 50.00%, and 50.00% in Group I, II, III, and IV, respectively. Conclusion: Ovsynch and Ovsynch based GnRH treatments initiated on day 6 of estrous cycle capable of responding with a higher percentage of ovulation and formation of accessory

  18. Twin engine synchronizer

    SciTech Connect

    Kobus, J.R.

    1988-05-03

    This patent describes an apparatus for synchronizing the speeds of two engines, each having its own throttle level connected by an associated cable to a respective hand throttle lever, comprising moving means carried by the throttle lever of one of the engines for moving the throttle lever of the one engine independently of its associated cable and its respective hand throttle lever to increase or decrease the speed of the one engine until the speed of the one engine matches the speed of the other engine. The moving means moves the throttle lever of the one engine without moving its associated cable or its respective hand throttle lever, and actuating means mounted remote from the throttle lever of the one engine for actuating the moving means.

  19. Synchronization in neural nets

    NASA Technical Reports Server (NTRS)

    Vidal, Jacques J.; Haggerty, John

    1988-01-01

    The paper presents an artificial neural network concept (the Synchronizable Oscillator Networks) where the instants of individual firings in the form of point processes constitute the only form of information transmitted between joining neurons. In the model, neurons fire spontaneously and regularly in the absence of perturbation. When interaction is present, the scheduled firings are advanced or delayed by the firing of neighboring neurons. Networks of such neurons become global oscillators which exhibit multiple synchronizing attractors. From arbitrary initial states, energy minimization learning procedures can make the network converge to oscillatory modes that satisfy multi-dimensional constraints. Such networks can directly represent routing and scheduling problems that consist of ordering sequences of events.

  20. Synchronous anorectal melanoma

    PubMed Central

    Balicevic, Drinko; Tomic, Karla; Bekavac-Beslin, Miroslav; Kovacevic, Igor; Mijic, August; Belicza, Mladen; Kruslin, Bozo

    2006-01-01

    Anorectal melanoma is a very rare tumor with poor prognosis. Rectal bleeding is the most frequent symptom and surgical treatment ranges from local excision to radical abdominoperineal resection. We report a case of a 75-years-old male patient who presented with a history of recurrent rectal bleeding, and whose histopathological diagnosis was melanoma. Macroscopically, we found two distinct tumors in anorectal region, 0.5 cm and 1.5 cm from dentate line. The first one was pedunculated, on a thin stalk, measuring 1 cm in greatest diameter, and the second one was sessile and nodular measuring up to 2.8 cm in largest diameter. Microscopic examination and immunohistochemical analysis of both tumors confirmed the diagnosis of melanoma. This case represents multiple synchronous primary melanoma of the anorectal region, with a possibility that one of the lesions is primary melanoma and the second one is a satellite lesion. PMID:16733870

  1. Explosive synchronization is discontinuous

    NASA Astrophysics Data System (ADS)

    Vlasov, Vladimir; Zou, Yong; Pereira, Tiago

    2015-07-01

    Spontaneous explosive is an abrupt transition to collective behavior taking place in heterogeneous networks when the frequencies of the nodes are positively correlated with the node degree. This explosive transition was conjectured to be discontinuous. Indeed, numerical investigations reveal a hysteresis behavior associated with the transition. Here, we analyze explosive synchronization in star graphs. We show that in the thermodynamic limit the transition to (and out of) collective behavior is indeed discontinuous. The discontinuous nature of the transition is related to the nonlinear behavior of the order parameter, which in the thermodynamic limit exhibits multiple fixed points. Moreover, we unravel the hysteresis behavior in terms of the graph parameters. Our numerical results show that finite-size graphs are well described by our predictions.

  2. Changes in PSA Kinetics Predict Metastasis-Free Survival in Men with PSA-Recurrent Prostate Cancer Treated with Non-Hormonal Agents: Combined Analysis of 4 Phase II Trials

    PubMed Central

    Antonarakis, Emmanuel S.; Zahurak, Marianna L.; Lin, Jianqing; Keizman, Daniel; Carducci, Michael A.; Eisenberger, Mario A.

    2011-01-01

    Background Several phase II trials in men with non-castrate PSA-recurrent prostate cancer have assessed the impact of novel non-hormonal agents on PSA kinetics. However, it is unknown whether changes in PSA kinetics influence metastasis-free survival (MFS). Methods We performed a retrospective post hoc analysis of 146 men treated in four phase II trials examining the investigational agents marimastat (a matrix metalloproteinase inhibitor; n=39), imatinib (a tyrosine kinase inhibitor; n=25), ATN-224 (a copper/zinc-superoxide dismutase inhibitor; n=22), and lenalidomide (an antiangiogenic/immunomodulatory drug; n=60). We investigated factors influencing MFS, including within-subject changes in PSA kinetics (PSA slope, doubling time, and velocity) before and after treatment initiation. Results After a median follow-up of 16.8 months, 70 patients (47.9%) developed metastases. In multivariable Cox regression models, factors that were independently predictive of MFS after adjusting for age and other clinical prognostic variables were baseline PSA doubling time (PSADT) (P=.05), baseline PSA slope (P=.01), on-study change in PSADT (P=.02), and on-study change in PSA slope (P=.03). In a landmark Kaplan-Meier analysis, median MFS was 63.5 months (95% CI 34.6–not reached) and 28.9 months (95% CI 13.5–68.0) for men with or without any decrease in PSA slope by 6 months after treatment, respectively. Conclusions This hypothesis-generating analysis suggests that within-subject changes in PSADT and PSA slope after initiation of experimental therapy may correlate with MFS in men with biochemically-recurrent prostate cancer. If validated in prospective trials, changes in PSA kinetics may represent a reasonable intermediate endpoint for screening new agents in these patients. PMID:21960118

  3. Pharmacokinetics of eCG and induction of fertile estrus in bitches using eCG followed by hCG.

    PubMed

    Stornelli, M C; García Mitacek, M C; Giménez, F; Bonaura, M C; Videla Dorna, I; de la Sota, R L; Stornelli, M A

    2012-09-15

    The aim was to design a protocol combining eCG followed by hCG for estrus induction in the bitch. In Experiment 1, three ovariohysterectomized bitches received 10 000 IU of eCG iv, and 15 days later 10 000 IU of eCG im. Blood samples were taken up to 144 h after each injection to measure eCG concentrations. In Experiment 2, 25 healthy, intact late anestrous bitches were assigned to one of five doses of eCG (5, 10, 15, 20, 44, or 50 IU/kg eCG im; [TRT5-TRT50]). Sexual behavior (SB), clinical signs of estrus (CSE) and vaginal cytology (VC) samples were obtained and scored before eCG administration and every other day until onset of estrus, or for 14 days. In Experiment 3, intact late anestrous bitches were assigned to a treatment group (TRT; n = 16) and received eCG (50 IU/kg im) followed by hCG (500 IU im) 7 days later; or to a placebo group (PLA; n = 8) where they received 1 mL saline solution im. All bitches that were induced in estrus were mated or AI with fresh semen. In Experiment 1, maximum observed concentration (C(max)) eCG were similar between im and iv routes (6.1 ± 0.9 vs. 8.6 ± 0.5 IU/mL, P > 0.08), whereas time for maximum observed concentration (T(max.)) was longer for im compared to iv routes (17.5 ± 0.5 vs. 11.6 ± 0.3 h, P < 0.01). The area under the curve (AUC) was similar for im and iv routes (P > 0.48), and eCG was detectable in serum for at least 144 h for both routes. In Experiment 2, 3 days or 3 to 5 days after treatment, all bitches in TRT50 had higher scores compared to TRT5-44 animals (P < 0.01). In TRT50, the mean interval from treatment to estrus was 4.0 ± 0.4 days. In Experiment 3, the mean interval from treatment to estrus was shorter in the TRT group compared to the PLA group (4.1 ± 3.3 vs. 68.5 ± 4.4 days, P < 0.01). The previous interestrus interval was similar for TRT and PLA groups (199.6 ± 7.2 vs. 197.5 ± 10.2 days), but the new interestrus interval was shorter for the TRT compared to the PLA group (164.0 ± 7.2 vs. 212

  4. Ovarian-cell-like cells from skin stem cells restored estradiol production and estrus cycling in ovariectomized mice.

    PubMed

    Park, Bong-Wook; Pan, Bo; Toms, Derek; Huynh, Evanna; Byun, June-Ho; Lee, Yeon-Mi; Shen, Wei; Rho, Gyu-Jin; Li, Julang

    2014-07-15

    Reduction of estradiol production and high serum concentrations of follicular stimulating hormone (FSH) are endocrine disorders associated with premature ovarian failure. Here, we report that transplantation of ovarian-like cells differentiated from stem cells restored endogenous serum estradiol levels. Stem cells were isolated from postnatal mouse skin and differentiated into ovarian-cell-like cells that are consistent with female germ, and ovarian follicle somatic cells. The ovarian-cell-like cells were transplanted into ovariectomized mice (Cell Trans), whereas control mice were subjected to bilateral ovariectomies without cell transplantation (OVX). Using vaginal cytology analysis, it was revealed that in 13 out of 19 Cell Trans mice, estrus cycles were restored around 8 weeks after cell transplantation and were maintained until 16 weeks post-transplantation, whereas in the OVX group, all mice were arrested at metestrus/diestrus of the estrus cycle. The uterine weight in the Cell Trans group was similar to sham operation mice (Sham OP), while severe uterine atrophy and a decreased uterine weight were observed in the OVX group. Histologically, ectopic follicle-like structures and blood vessels were found within and around the transplants. At 12-14 weeks after cell transplantation, mean serum estradiol level in Cell Trans mice (178.0±35 pg/mL) was comparable to that of the Sham OP group (188.9±29 pg/mL), whereas it was lower in the OVX group (59.0±4 pg/mL). Serum FSH concentration increased in the OVX group (1.62±0.32 ng/mL) compared with the Sham OP group (0.39±0.34 ng/mL). Cell Trans mice had a similar FSH level (0.94±0.23 ng/mL; P<0.05) to Sham OP mice. Our results suggest that ovarian somatic cells differentiated from stem cells are functional in vivo. In addition to providing insights into the function of ovarian somatic cells derived from stem cells, our study may offer potential therapeutic means for patients with hypo-estradiol levels

  5. Nutritional recommendations for synchronized swimming.

    PubMed

    Robertson, Sherry; Benardot, Dan; Mountjoy, Margo

    2014-08-01

    The sport of synchronized swimming is unique, because it combines speed, power, and endurance with precise synchronized movements and high-risk acrobatic maneuvers. Athletes must train and compete while spending a great amount of time underwater, upside down, and without the luxury of easily available oxygen. This review assesses the scientific evidence with respect to the physiological demands, energy expenditure, and body composition in these athletes. The role of appropriate energy requirements and guidelines for carbohydrate, protein, fat, and micronutrients for elite synchronized swimmers are reviewed. Because of the aesthetic nature of the sport, which prioritizes leanness, the risks of energy and macronutrient deficiencies are of significant concern. Relative Energy Deficiency in Sport and disordered eating/eating disorders are also of concern for these female athletes. An approach to the healthy management of body composition in synchronized swimming is outlined. Synchronized swimmers should be encouraged to consume a well-balanced diet with sufficient energy to meet demands and to time the intake of carbohydrate, protein, and fat to optimize performance and body composition. Micronutrients of concern for this female athlete population include iron, calcium, and vitamin D. This article reviews the physiological demands of synchronized swimming and makes nutritional recommendations for recovery, training, and competition to help optimize athletic performance and to reduce risks for weight-related medical issues that are of particular concern for elite synchronized swimmers. PMID:24667278

  6. Synchronized defibrillation for ventricular fibrillation

    PubMed Central

    Manoharan, Ganesh; Navarro, Cesar; Walsh, Simon J; Allen, John D; Anderson, John McC; Adgey, AA Jennifer

    2012-01-01

    Objective: Optimization of defibrillation success is important to improve efficacy and minimize post-shock sequelae. Previous work has suggested an improvement in shock success when an intracardiac shock is delivered synchronized to the upslope of a VF wave. We investigated the efficacy of transthoracic defibrillation success using a novel external biphasic defibrillator which delivers shocks synchronized to the upslope of the surface ECG. Methods: A prospective, controlled, randomized study in a research institute laboratory of male and female pigs (54.2±1.8 kg). Ventricular fibrillation (VF) was induced in 10 anaesthetized and ventilated pigs. Shocks were delivered randomly from a biphasic defibrillator in synchronized or non-synchronized mode via self-adhesive electrode pads following 30 s of VF. Energy settings at 50, 70, 80, and 100J were randomly tested. VF amplitude, impedance, and shock outcome were recorded and analysed digitally. Results: A total of 300 shocks were delivered. Synchronized shocks were delivered on the upslope of the VF wave in 99% of cases. There was no significant difference in shock success between shocks delivered in synchronized or non-synchronized modes (p=0.695). There was no significant difference in the amplitude of VF between successful and unsuccessful shocks (p=0.163). Furthermore, there was no association between shock success and transthoracic impedance. Conclusion: The novel defibrillator used in this study was able to consistently deliver shocks on the upslope portion of the VF wave but did not show an improvement in shock success. PMID:24062919

  7. Synchronization in an evolving network

    NASA Astrophysics Data System (ADS)

    Singh, R. K.; Bagarti, Trilochan

    2015-09-01

    In this work we study the dynamics of Kuramoto oscillators on a stochastically evolving network whose evolution is governed by the phases of the individual oscillators and degree distribution. Synchronization is achieved after a threshold connection density is reached. This cumulative effect of topology and dynamics has many real-world implications, where synchronization in a system emerges as a collective property of its components in a self-organizing manner. The synchronous state remains stable as long as the connection density remains above the threshold value, with additional links providing resilience against network fluctuations.

  8. Time synchronized video systems

    NASA Technical Reports Server (NTRS)

    Burnett, Ron

    1994-01-01

    The idea of synchronizing multiple video recordings to some type of 'range' time has been tried to varying degrees of success in the past. Combining this requirement with existing time code standards (SMPTE) and the new innovations in desktop multimedia however, have afforded an opportunity to increase the flexibility and usefulness of such efforts without adding costs over the traditional data recording and reduction systems. The concept described can use IRIG, GPS or a battery backed internal clock as the master time source. By converting that time source to Vertical Interval Time Code or Longitudinal Time Code, both in accordance with the SMPTE standards, the user will obtain a tape that contains machine/computer readable time code suitable for use with editing equipment that is available off-the-shelf. Accuracy on playback is then determined by the playback system chosen by the user. Accuracies of +/- 2 frames are common among inexpensive systems and complete frame accuracy is more a matter of the users' budget than the capability of the recording system.

  9. Comparison of the pregnancy rates and costs per calf born after fixed-time artificial insemination or artificial insemination after estrus detection in Bos indicus heifers.

    PubMed

    Edwards, S A A; Bo, G A; Chandra, K A; Atkinson, P C; McGowan, M R

    2015-01-01

    This study compared pregnancy rates (PRs) and costs per calf born after fixed-time artificial insemination (FTAI) or AI after estrus detection (i.e., estrus detection and AI, EDAI), before and after a single PGF2α treatment in Bos indicus (Brahman-cross) heifers. On Day 0, the body weight, body condition score, and presence of a CL (46% of heifers) were determined. The heifers were then alternately allocated to one of two FTAI groups (FTAI-1, n = 139) and (FTAI-2, n = 141) and an EDAI group (n = 273). Heifers in the FTAI groups received an intravaginal progesterone-releasing device (IPRD; 0.78 g of progesterone) and 1 mg of estradiol benzoate intramuscularly (im) on Day 0. Eight days later, the IPRD was removed and heifers received 500 μg of PGF2α and 300 IU of eCG im; 24 hours later, they received 1 mg estradiol benzoate im and were submitted to FTAI 30 to 34 hours later (54 and 58 hours after IPRD removal). Heifers in the FTAI-2 group started treatment 8 days after those in the FTAI-1 group. Heifers in the EDAI group were inseminated approximately 12 hours after the detection of estrus between Days 4 and 9 at which time the heifers that had not been detected in estrus received 500 μg of PGF2α im and EDAI continued until Day 13. Heifers in the FTAI groups had a higher overall PR (proportion pregnant as per the entire group) than the EDAI group (34.6% vs. 23.2%; P = 0.003), however, conception rate (PR of heifers submitted for AI) tended to favor the estrus detection group (34.6% vs. 44.1%; P = 0.059). The cost per AI calf born was estimated to be $267.67 and $291.37 for the FTAI and EDAI groups, respectively. It was concluded that in Brahman heifers typical of those annually mated in northern Australia FTAI compared with EDAI increases the number of heifers pregnant and reduces the cost per calf born. PMID:25284281

  10. Body condition loss and increased serum levels of nonesterified fatty acids enhance progesterone levels at estrus and reduce estrous activity and insemination rates in postpartum dairy cows.

    PubMed

    Lüttgenau, J; Purschke, S; Tsousis, G; Bruckmaier, R M; Bollwein, H

    2016-03-01

    Data from 96 Holstein Friesian cows on a commercial dairy farm were used to investigate whether body condition and serum levels of nonesterified fatty acids (NEFAs) postpartum (pp) affect progesterone (P4) levels, estrous activity, and fertility in dairy cows. The examination period started 14 days before the expected calving date and ended either when a cow was inseminated or at a maximum of 90 days pp. Body condition score (BCS; 1-5 scale) and backfat thickness (BFT) were determined every 2 weeks. Blood for analysis of NEFA and P4 concentrations was sampled weekly during the first 35 days pp and then every 48 hours until an ovulation was observed. Transrectal ultrasonography of the ovaries started at 21 days pp and was performed after blood sampling. If cows were not inseminated because of silent ovulation, sampling and ultrasonography continued on Days 7, 14, and 18 after ovulation and again every 48 hours until the next ovulation. Estrous activity was continuously measured with the Heatime estrus detection system. Pregnancy controls were performed ultrasonographically 28 and 42 days after AI. Cows with increased NEFA levels at 28 days pp had an increased risk of maintaining minimum P4 levels above 0.4 ng/mL at first recognized estrus (P = 0.03). Higher NEFA levels at Day 7 were associated with lower probability for a cow to have elevated P4 levels (≥2 ng/mL) by Day 35 pp, indicating delayed commencement of luteal activity (C-LA). Estrous activity was not influenced (P > 0.10) by minimum P4 concentrations at estrus, but more animals with C-LA until Day 35 pp showed estrous activity compared to cows without C-LA throughout this period (P = 0.006). Estrous activity was lower in cows with a low BCS 14 days pp (P = 0.02) and with a low BFT 42 days pp (P = 0.03). Moreover, the probability to exhibit estrus was reduced with higher NEFA levels at 21 days pp (P = 0.01). Eighty-five cows were inseminated and 37 (44%) got pregnant after insemination. Higher NEFA levels

  11. Synchronous motion modulates animacy perception.

    PubMed

    Takahashi, Kohske; Watanabe, Katsumi

    2015-01-01

    Visual motion serves as a cue for high-level percepts. The present study reports novel modulation of animacy perception through synchronous motion. A target dot moving along a random trajectory was presented. The trajectory was generated based on a variant of 1/f noise; hence, the dot could be perceived as animate. Participants were asked to rate the strength of perceived animacy and perceived intention from the target dot. Several task-irrelevant dots surrounding the target were also presented. Results indicated that perceived animacy and intention were drastically weakened when surrounding dots created synchronous motion with the target dot as compared to when surrounding dots did not create synchronous motion. A series of follow-up experiments replicated these results and revealed specific characteristics of this modulation. The present findings suggest synchronous visual motion serves as a strong modulator of animacy perception. PMID:26114680

  12. Generic Conditions for Hydrodynamic Synchronization

    NASA Astrophysics Data System (ADS)

    Uchida, Nariya; Golestanian, Ramin

    2011-02-01

    Synchronization of actively oscillating organelles such as cilia and flagella facilitates self-propulsion of cells and pumping fluid in low Reynolds number environments. To understand the key mechanism behind synchronization induced by hydrodynamic interaction, we study a model of rigid-body rotors making fixed trajectories of arbitrary shape under driving forces that are arbitrary functions of the phase. For a wide class of geometries, we obtain the necessary and sufficient conditions for synchronization of a pair of rotors. We also find a novel synchronized pattern with an oscillating phase shift. Our results shed light on the role of hydrodynamic interactions in biological systems, and could help in developing efficient mixing and transport strategies in microfluidic devices.

  13. Synchronization by small time delays

    NASA Astrophysics Data System (ADS)

    Pruessner, G.; Cheang, S.; Jensen, H. J.

    2015-02-01

    Synchronization is a phenomenon observed in all of the living and in much of the non-living world, for example in the heart beat, Huygens' clocks, the flashing of fireflies and the clapping of audiences. Depending on the number of degrees of freedom involved, different mathematical approaches have been used to describe it, most prominently integrate-and-fire oscillators and the Kuramoto model of coupled oscillators. In the present work, we study a very simple and general system of smoothly evolving oscillators, which continue to interact even in the synchronized state. We find that under very general circumstances, synchronization generically occurs in the presence of a (small) time delay. Strikingly, the synchronization time is inversely proportional to the time delay.

  14. Optimistic barrier synchronization. Contractor report

    SciTech Connect

    Nicol, D.M.

    1992-07-01

    Barrier synchronization is a fundamental operation in parallel computation. In many contexts, at the point a processor enters a barrier it knows that is has already processed all work required of it prior to the synchronization. This paper treats the alternative case, when a processor cannot enter a barrier with the assurance that it has already performed all necessary pre-synchronization computation. The proble marises when the number of pre-synchronization messages to be received by a processor is unknown, for example, in a parallel discrete simulation or any other computation that is largely driven by an unpredictable exchange of messages. The authors describe an optimistic O(log2P) barrier algorithm for such problems, study its performance on a large-scale parallel system, and consider extensions to general associative reductions, as well as associative parallel prefix computations.

  15. Synchronous identification of friendly targets

    DOEpatents

    Telle, John M.; Roger, Stutz A.

    1998-01-01

    A synchronous communication targeting system for use in battle. The present invention includes a transceiver having a stabilizing oscillator, a synchronous amplifier and an omnidirectional receiver, all in electrical communication with each other. A remotely located beacon is attached to a blackbody radiation source and has an amplitude modulator in electrical communication with a optical source. The beacon's amplitude modulator is set so that the optical source transmits radiation frequency at approximately the same or lower amplitude than that of the blackbody radiation source to which the beacon is attached. The receiver from the transceiver is adapted to receive frequencies approximately at or below blackbody radiation signals and sends such signals to the synchronous amplifier. The synchronous amplifier then rectifies and amplifies those signals which correspond to the predetermined frequency to therefore identify whether the blackbody radiation source is friendly or not.

  16. Synchronous Photodiode-Signal Sampler

    NASA Technical Reports Server (NTRS)

    Primus, Howard K.

    1988-01-01

    Synchronous sampling circuit increases signal-to-noise ratio of measurements of chopped signal of known phase and frequency in presence of low-frequency or dc background noise. Used with linear array of photoelectric sensors for locating edge of metal plate. Multiplexing circuit cycles through 16 light-emitting-diode/photodiode pairs, under computer control. Synchronized with multiplexer so edge detector makes one background-subtracted signal measurement per emitter/detector pair in turn.

  17. Synchronizing Rotation Of A Heavy Load

    NASA Technical Reports Server (NTRS)

    Ratliff, Roger

    1991-01-01

    Drive system rotates large-inertia load at constant low speed. Simple setup of motors, pulleys, and belts provides both torque and synchronism. Induction motor drives two loads: rotating instrument and slightly lagging synchronous motor. Provides ample torque to start and maintain rotation, and synchronous motor ensures rotation synchronized with ac power supply.

  18. Synchronous reactive programming in Ptolemy

    SciTech Connect

    Boulanger, F.; Vidal-Naquet, G.

    1996-12-31

    Synchronous reactive languages allow a high level deterministic description of reactive systems such as control-command systems. Their well defined mathematical semantics makes it possible to check formal properties on the control of a system. In previous work, we developed an object-oriented execution model for synchronous reactive modules. This model is implemented as a set of tools and a C++ class library, and allows us to use object-oriented methodologies and tools for the design of complex applications with both transformational and reactive parts. Among these design tools, the Ptolemy system stands as an object-oriented framework that supports various execution models, or {open_quotes}domains{close_quotes}. We are currently working on a translator from the output format of the Lustre and Esterel compilers to the Ptolemy language. Since no existing domain matches the reactive synchronous execution model, we also plan to develop a SEC (Synchronous Execution and Communication) domain. Such a domain will provide support for the execution of synchronous modules in Ptolemy. One of the most interesting features of Ptolemy is the communication between domains. Therefore we discuss the interface of the SEC domain to other domains to determine the meaning of communications between them. The main goal is to allow the use of synchronous reactive modules for the control of the behavior of data-flow or discrete event processes.

  19. Synchronization configurations of two coupled double pendula

    NASA Astrophysics Data System (ADS)

    Koluda, Piotr; Perlikowski, Przemyslaw; Czolczynski, Krzysztof; Kapitaniak, Tomasz

    2014-04-01

    We consider the synchronization of two self-excited double pendula hanging from a horizontal beam which can roll on the parallel surface. We show that such pendula can obtain four different robust synchronous configurations. Our approximate analytical analysis allows to derive the synchronization conditions and explains the observed types of synchronizations. We consider the energy balance in the system and show how the energy is transferred between the pendula via the oscillating beam allowing the pendula' synchronization.

  20. Noncoherent DTTLs for Symbol Synchronization

    NASA Technical Reports Server (NTRS)

    Simon, Marvin; Tkacenko, Andre

    2007-01-01

    Noncoherent data-transition tracking loops (DTTLs) have been proposed for use as symbol synchronizers in digital communication receivers. [Communication- receiver subsystems that can perform their assigned functions in the absence of synchronization with the phases of their carrier signals ( carrier synchronization ) are denoted by the term noncoherent, while receiver subsystems that cannot function without carrier synchronization are said to be coherent. ] The proposal applies, more specifically, to receivers of binary phase-shift-keying (BPSK) signals generated by directly phase-modulating binary non-return-to-zero (NRZ) data streams onto carrier signals having known frequencies but unknown phases. The proposed noncoherent DTTLs would be modified versions of traditional DTTLs, which are coherent. The symbol-synchronization problem is essentially the problem of recovering symbol timing from a received signal. In the traditional, coherent approach to symbol synchronization, it is necessary to establish carrier synchronization in order to recover symbol timing. A traditional DTTL effects an iterative process in which it first generates an estimate of the carrier phase in the absence of symbol-synchronization information, then uses the carrier-phase estimate to obtain an estimate of the symbol-synchronization information, then feeds the symbol-synchronization estimate back to the carrier-phase-estimation subprocess. In a noncoherent symbol-synchronization process, there is no need for carrier synchronization and, hence, no need for iteration between carrier-synchronization and symbol- synchronization subprocesses. The proposed noncoherent symbolsynchronization process is justified theoretically by a mathematical derivation that starts from a maximum a posteriori (MAP) method of estimation of symbol timing utilized in traditional, coherent DTTLs. In that MAP method, one chooses the value of a variable of interest (in this case, the offset in the estimated symbol

  1. Synchronous Bilateral Breast Cancers

    PubMed Central

    Subramanyan, Annapurneswari; Radhakrishna, Selvi

    2015-01-01

    Background Bilateral breast cancer (BBC) is not an uncommon entity in contemporary breast clinics. Improved life expectancy after breast cancer treatment and routine use of contra-lateral breast mammography has led to increased incidence of BBC. Our study objective was to define the epidemiological and tumour characteristics of BBC in India. Materials and Methods A total of 1251 breast cancer patients were treated during the period January 2007 to March 2015 and 30 patients were found to have BBC who constituted the study population (60 tumour samples). Synchronous bilateral breast cancers (SBC) was defined as two tumours diagnosed within an interval of 6 months and a second cancer diagnosed after 6 months was labelled as metachronous breast cancer (MBC). Analyses of patient and tumour characteristics were done in this prospective data base of BBC patients. Results Median patient age was 66 years (range 39-85). Majority of the patients had SBC (n=28) and in 12 patients the second tumour was clinically occult and detected only by mammography of the contra-lateral breast. The second tumour was found at lower tumour size compared to the first in 73% of cases and was negative for axillary metastasis in 80% of cases (24/30). Infiltrating ductal carcinoma was the commonest histological type (n=51) and majority of the tumours were ER/PR positive (50/60). Her2 was overexpressed in 13 tumours (21%). Over 70% (22/30) of patients had similar histology in both breasts and amongst them grade concordance was present in about 69% (15/22) of patients. Concordance rates of ER, PR and Her2 statuses were 83%, 80% and 90% respectively. Bilateral mastectomy was the commonest surgery performed in 80% of the patients followed by bilateral breast conservation in 13%. At the end of study period, 26 patients were alive and disease free. Median survival was 29 months (range 3-86 months). Conclusion In most patients with BBC, the second tumour is identified at an early stage than index

  2. Influence of estrus expression prior to fixed-time AI on embryo survival to maternal recognition of pregnancy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estradiol has been reported to play a critical role in pregnancy establishment and embryonic survival. Our objective was to focus on the role of preovulatory estradiol in embryo survival from fertilization to maternal recognition of pregnancy. Beef cows (n = 29) were synchronized with the CO-Synch p...

  3. Effect of Amniotic-Fluid Ingestion on Vaginal-Cervical-Stimulation-Induced Fos Expression in Female Rats During Estrus

    PubMed Central

    Hoey, Robert F.; Hurley, Seth W.; Daniels, Derek; Kristal, Mark B.

    2011-01-01

    Placental Opioid-Enhancing Factor (POEF) is a substance found in amniotic fluid (AF) that, when ingested, potentiates opioid-mediated, but not non-opioid-mediated, hypoalgesia. Vaginal-cervical stimulation (VCS) produces a stimulus-bound, partially opioid-mediated hypoalgesia that previous research has shown to be potentiated by AF ingestion. To understand the mechanism of opioid enhancement by POEF we investigated the pattern of neural activation after a bout of VCS that produced hypoalgesia, with and without co-administration of AF. Specifically, virgin Long-Evans rats showing vaginal estrus were handled briefly (control) or received VCS (75 g pressure, 1 min), in a pattern that approximated early parturition rather than copulation, using a spring-loaded glass-rod probe. Rats were given an orogastric infusion (0.25 ml) of either AF or 0.9% saline resulting in four groups (VCS or handling; AF or saline). Rats were perfused 90 min after treatment and tissue was processed by immunohistochemistry for Fos. The number of Fos-immunoreactive cells was counted in structures previously shown to express Fos in response to VCS (the medial preoptic area, MPOA; the ventrolateral portion of the ventromedial hypothalamic nucleus, vlVMH; the arcuate nucleus, ARC). We found that this pattern of VCS did not produce a significant increase in Fos expression in the MPOA and vlVMH unless it was paired with AF. VCS produced a significant increase in Fos in the ARC. The interaction of AF and VCS on Fos expression in the MPOA suggests that POEF may enhance vaginal-cervical sensory input at parturition to facilitate sensitization of the MPOA, and presumably facilitate maternal-behavior onset. PMID:21184750

  4. Bodily synchronization underlying joke telling

    PubMed Central

    Schmidt, R. C.; Nie, Lin; Franco, Alison; Richardson, Michael J.

    2014-01-01

    Advances in video and time series analysis have greatly enhanced our ability to study the bodily synchronization that occurs in natural interactions. Past research has demonstrated that the behavioral synchronization involved in social interactions is similar to dynamical synchronization found generically in nature. The present study investigated how the bodily synchronization in a joke telling task is spread across different nested temporal scales. Pairs of participants enacted knock–knock jokes and times series of their bodily activity were recorded. Coherence and relative phase analyses were used to evaluate the synchronization of bodily rhythms for the whole trial as well as at the subsidiary time scales of the whole joke, the setup of the punch line, the two-person exchange and the utterance. The analyses revealed greater than chance entrainment of the joke teller’s and joke responder’s movements at all time scales and that the relative phasing of the teller’s movements led those of the responder at the longer time scales. Moreover, this entrainment was greater when visual information about the partner’s movements was present but was decreased particularly at the shorter time scales when explicit gesturing in telling the joke was performed. In short, the results demonstrate that a complex interpersonal bodily “dance” occurs during structured conversation interactions and that this “dance” is constructed from a set of rhythms associated with the nested behavioral structure of the interaction. PMID:25177287

  5. Follicular populations and luteal function in dairy heifers treated with a controlled internal drug release insert for 14 days as a method to synchronize the estrous cycle before prostaglandin F₂α treatment and artificial insemination.

    PubMed

    Escalante, R C; Poock, S E; Lucy, M C

    2013-06-01

    Progesterone-containing controlled internal drug release (CIDR) inserts are used to synchronize the estrous cycle before PGF2α is administered for timed AI (14dCIDR-PGF2α program). The program, initially designed for beef cattle, was recently shown to be efficacious in dairy heifers. We hypothesized that the 14-d CIDR treatment would synchronize the estrous cycle in dairy heifers and result in a uniformly sized corpus luteum (CL) and largest follicle (LF) at the time of PGF2α treatment. Holstein (n=110) or Holstein × Guernsey (n=4) dairy heifers were assigned to 2 treatments: (1) 14dCIDR-PGF2α [CIDR in for 14 d, CIDR out for 16d, PGF2α and AI after observed estrus (n=57)] or (2) control [PGF2α and AI after observed estrus (n=57)]. Regardless of treatment, additional PGF2α injections were administered at 14-d intervals to heifers that were not seen in estrus. Ovarian ultrasonography and blood sampling were done on d 0 (CIDR administered), 14 (day CIDR removed), 19 (5d after CIDR removed), 30 (PGF2α administered), and 44 (second PGF2α dose administered to heifers that were not detected in estrus after the first PGF2α). Compared with control (untreated), more CIDR-treated heifers were categorized as having a small CL (≤ 9.9 mm) and large LF (15.0-19.9 mm) on d 14 (CIDR removal) and, as expected, a greater percentage of CIDR-treated heifers were in estrus during the 5d after the CIDR removal compared with control heifers (75.4 vs. 22.8%, respectively). On d 19, the CIDR-treated heifers had apparently ovulated based on disappearance of LF and appearance of small CL. On d 30 (PGF2α administration), 89% of 14dCIDR-PGF2α heifers had CL that were ≥ 20 mm in diameter compared with 55% for control. Presence of larger CL on d 30 was associated with greater concentrations of plasma progesterone in 14dCIDR-PGF2α compared with control (10.5 ± 0.5 vs. 5.0 ± 0.6 ng/mL, respectively). The percentages of heifers with LF in the smallest category (≤ 9.9 mm) tended

  6. Chaotic synchronization system and electrocardiogram

    NASA Astrophysics Data System (ADS)

    Pei, Liuqing; Dai, Xinlai; Li, Baodong

    1997-01-01

    A mathematical model of chaotic synchronization of the heart-blood flow coupling dynamics is proposed, which is based on a seven dimension nonlinear dynamical system constructed by three subsystems of the sinoatrial node natural pacemaker, the cardiac relaxation oscillator and the dynamics of blood-fluid in heart chambers. The existence and robustness of the self-chaotic synchronization of the system are demonstrated by both methods of theoretical analysis and numerical simulation. The spectrum of Lyapunov exponent, the Lyapunov dimension and the Kolmogorov entropy are estimated when the system was undergoing the state of self-chaotic synchronization evolution. The time waveform of the dynamical variable, which represents the membrane potential of the cardiac integrative cell, shows a shape which is similar to that of the normal electrocardiogram (ECG) of human, thus implies that the model possesses physiological significance functionally.

  7. Linear Synchronous Motor Repeatability Tests

    SciTech Connect

    Ward, C.R.

    2002-10-18

    A cart system using linear synchronous motors was being considered for the Plutonium Immobilization Plant (PIP). One of the applications in the PIP was the movement of a stack of furnace trays, filled with the waste form (pucks) from a stacking/unstacking station to several bottom loaded furnaces. A system was ordered to perform this function in the PIP Ceramic Prototype Test Facility (CPTF). This system was installed and started up in SRTC prior to being installed in the CPTF. The PIP was suspended and then canceled after the linear synchronous motor system was started up. This system was used to determine repeatability of a linear synchronous motor cart system for the Modern Pit Facility.

  8. Digital data detection and synchronization

    NASA Technical Reports Server (NTRS)

    Noack, T. L.; Morris, J. F.

    1973-01-01

    The primary accomplishments have been in the analysis and simulation of receivers and bit synchronizers. It has been discovered that tracking rate effects play, a rather fundamental role in both receiver and synchronizer performance, but that data relating to recorder time-base-error, for the proper characterization of this phenomenon, is in rather short supply. It is possible to obtain operationally useful tape recorder time-base-error data from high signal-to-noise ratio tapes using synchronizers with relatively wideband tracking loops. Low signal-to-noise ratio tapes examined in the same way would not be synchronizable. Additional areas of interest covered are receiver false lock, cycle slipping, and other unusual phenomena, which have been described to some extent in this and earlier reports and simulated during the study.

  9. Remote synchronization in star networks

    NASA Astrophysics Data System (ADS)

    Bergner, A.; Frasca, M.; Sciuto, G.; Buscarino, A.; Ngamga, E. J.; Fortuna, L.; Kurths, J.

    2012-02-01

    We study phase synchronization in a network motif with a starlike structure in which the central node's (the hub's) frequency is strongly detuned against the other peripheral nodes. We find numerically and experimentally a regime of remote synchronization (RS), where the peripheral nodes form a phase synchronized cluster, while the hub remains free with its own dynamics and serves just as a transmitter for the other nodes. We explain the mechanism for this RS by the existence of a free amplitude and also show that systems with a fixed or constant amplitude, such as the classic Kuramoto phase oscillator, are not able to generate this phenomenon. Further, we derive an analytic expression which supports our explanation of the mechanism.

  10. Effects of breed, age, season, and multiple ovulations on cyclic, PGF2α-induced, and postpartum estrus characteristics in Spanish jennies.

    PubMed

    Perez-Marin, C C; Galisteo, I; Perez-Rico, A; Galisteo, J

    2016-04-01

    This retrospective, population-based, cross-sectional study analyzed data for a total of 104 jennies reared in southern Spain over the period 1995 to 2014. Intervals to ovulation and incidence of multiple ovulation and pregnancy were charted for spontaneous, PGF2α-induced, and postpartum estrous cycles. In spontaneous estrous cycles, the interovulatory interval varied as a function of breed (P < 0.03) and month of ovulation (P < 0.01), and duration of estrus signs was longer in older jennies (0.04). Spontaneous cycles were also associated with higher ovulation rates from September to January (P < 0.006). When PGF2α was used to induce the estrus, not only did estrus signs last longer in old (P < 0.004) and in polyovular (0.02) jennies but old jennies also displayed significantly higher ovulation rates (P < 0.03). In postpartum jennies, no variations were observed as a function of any of the independent variables analyzed. Comparison of ovulation rates between different types of cycle revealed that postpartum jennies exhibited significantly lower ovulation rates (1.32 ± 0.07) and a lower incidence of multiple ovulation (30.4%) than spontaneous (1.62 ± 0.04, 55.0%) and PGF2α-induced (1.74 ± 0.08, 65.5%) groups. No differences were observed in the incidence of ovulation or pregnancy depending on the location of ovulation in polyovular cycles, and ovulation occurred at similar rates in the right and left ovaries. These findings shed further light on reproductive physiology in jennies and may be of value in improving animal management. PMID:26747577

  11. Global Synchronization of a New Chua's System

    NASA Astrophysics Data System (ADS)

    Zhou, Guopeng; Liu, Di; Huang, Jinhua; Liao, Xiaoxin

    The problem of global synchronization control for a class of new Chua's system is studied in this paper. Several linear controllers are proposed to realize the global exponential synchronization of two Chua's systems. Decoupling feedback control method is used to make Chua's system global exponential synchronized. Global exponential synchronization with respect to (w.r.t) partial state variables is studied when one of the error variables is zero. Finally, an adaptive synchronization controller is designed to make the response and the driven systems synchronized. Moreover, the estimate errors of the uncertain parameters converge to zero since the persistent excitation condition holds. Additionally, numerical simulations show the effectiveness of the proposed controllers.

  12. Simulating synchronization in neuronal networks

    NASA Astrophysics Data System (ADS)

    Fink, Christian G.

    2016-06-01

    We discuss several techniques used in simulating neuronal networks by exploring how a network's connectivity structure affects its propensity for synchronous spiking. Network connectivity is generated using the Watts-Strogatz small-world algorithm, and two key measures of network structure are described. These measures quantify structural characteristics that influence collective neuronal spiking, which is simulated using the leaky integrate-and-fire model. Simulations show that adding a small number of random connections to an otherwise lattice-like connectivity structure leads to a dramatic increase in neuronal synchronization.

  13. State observer for synchronous motors

    DOEpatents

    Lang, Jeffrey H.

    1994-03-22

    A state observer driven by measurements of phase voltages and currents for estimating the angular orientation of a rotor of a synchronous motor such as a variable reluctance motor (VRM). Phase voltages and currents are detected and serve as inputs to a state observer. The state observer includes a mathematical model of the electromechanical operation of the synchronous motor. The characteristics of the state observer are selected so that the observer estimates converge to the actual rotor angular orientation and velocity, winding phase flux linkages or currents.

  14. Cooperative Synchronization in Wireless Networks

    NASA Astrophysics Data System (ADS)

    Etzlinger, Bernhard; Wymeersch, Henk; Springer, Andreas

    2014-06-01

    Synchronization is a key functionality in wireless network, enabling a wide variety of services. We consider a Bayesian inference framework whereby network nodes can achieve phase and skew synchronization in a fully distributed way. In particular, under the assumption of Gaussian measurement noise, we derive two message passing methods (belief propagation and mean field), analyze their convergence behavior, and perform a qualitative and quantitative comparison with a number of competing algorithms. We also show that both methods can be applied in networks with and without master nodes. Our performance results are complemented by, and compared with, the relevant Bayesian Cram\\'er-Rao bounds.

  15. Optimized multiparty quantum clock synchronization

    SciTech Connect

    Ben-Av, Radel; Exman, Iaakov

    2011-07-15

    A multiparty protocol for distributed quantum clock synchronization has been claimed to provide universal limits on the clock accuracy, viz., that accuracy monotonically decreases with the number n of party members. But this is only true for synchronization when one limits oneself to W states. This work shows that the usage of Z (Symmetric Dicke) states, a generalization of W states, results in improved accuracy, having a maximum when Left-Floor n/2 Right-Floor of its members have their qubits with a |1> eigenstate.

  16. Synchronization in an optomechanical cavity.

    PubMed

    Shlomi, Keren; Yuvaraj, D; Baskin, Ilya; Suchoi, Oren; Winik, Roni; Buks, Eyal

    2015-03-01

    We study self-excited oscillations (SEO) in an on-fiber optomechanical cavity. Synchronization is observed when the optical power that is injected into the cavity is periodically modulated. A theoretical analysis based on the Fokker-Planck equation evaluates the expected phase space distribution (PSD) of the self-oscillating mechanical resonator. A tomography technique is employed for extracting PSD from the measured reflected optical power. Time-resolved state tomography measurements are performed to study phase diffusion and phase locking of the SEO. The detuning region inside which synchronization occurs is experimentally determined and the results are compared with the theoretical prediction. PMID:25871175

  17. Synchronization with sound propagation delays

    NASA Astrophysics Data System (ADS)

    Haché, A.

    2010-04-01

    Complex systems that synchronize with acoustic signals, like chanting crowds and musical ensembles, have the intrinsic ability to maintain synchrony without external aid or visual cues, even when spread over wide areas. According to two models, the counterintuitive self-synchronization happens when the system's components have a spatial distribution that is sufficiently uniform. The roles of system size and density are examined for arrangements in 1, 2 and 3 dimensions. Asynchrony is predicted to become vanishingly small at high densities, and results suggest ways on how to minimize asynchrony in real-world situations.

  18. Forced synchronization of quasiperiodic oscillations

    NASA Astrophysics Data System (ADS)

    Stankevich, N. V.; Kurths, J.; Kuznetsov, A. P.

    2015-01-01

    A model of a generator of quasiperiodic oscillations forced by a periodic pulse sequence is studied. We analyze synchronization when the autonomous generator demonstrates periodic, quasiperiodic, respective weakly chaotic oscillations. For the forced quasiperiodic oscillations a picture of synchronization, consisting of small-scale and large-scale structures was uncovered. It even includes the existence of stable the three-frequency tori. For the regime of weak chaos a partial destruction of this features and of the regime of three-frequency tori are found.

  19. Efficacy of the Ovsynch protocol for synchronization of ovulation and fixed-time artificial insemination in Murrah buffaloes (Bubalus bubalis).

    PubMed

    Paul, Vijay; Prakash, B S

    2005-09-15

    Two experiments were conducted to assess the timing and synchrony of ovulation, plasma LH concentrations, and pregnancy rate in Murrah buffaloes (Bubalus bubalis) treated with the Ovsynch (GnRH-PGF(2 alpha)-GnRH) protocol. In Experiment 1, 10 non-lactating cycling buffaloes received 10 microg of a GnRH analogue i.m. (buserelin acetate) without regard to the stage of the estrous cycle (day of treatment, day 0), followed by 25mg of PGF(2 alpha) i.m. (dinoprost thromethamine) 7 days later. A second-treatment of the same GnRH analogue (10 microg, i.m.) was given 48 h after PGF(2 alpha). Ovulation was confirmed by transrectal palpation (at 2-h intervals) from the second-GnRH treatment to detection of ovulation or up to 96 h after the second-GnRH treatment. Plasma LH concentrations were determined in blood samples collected at 15-min intervals for 6h, starting at the second-GnRH treatment, and thereafter at 2-h intervals until 2h after detection of ovulation. Ovulation occurred in 9/10 buffalo (90%) 23.3+/-1.3h (mean+/-S.E.M.; range 20--32 h) after the second-GnRH treatment. Peak LH concentrations 13.5+/-3.5 ng/mL (range 3.9--40.0 ng/mL) occurred 2.1+/-0.1h (range 1.2-3.0 h) after the second-GnRH treatment. In Experiment 2, 15 lactating, cycling buffaloes were subjected to the Ovsynch protocol, with fixed-time AI 12 and 24h after the second-GnRH treatment and 75 lactating buffaloes were inseminated, approximately 12h after detection of spontaneous estrus. Pregnancy rates were 33.3% for TAI and were 30.7% for buffaloes inseminated following spontaneous estrus (P=0.84). In conclusion, the Ovsynch protocol effectively synchronized ovulation in Murrah buffaloes and resulted in conception rates (to two fixed-time inseminations) that were comparable to those achieved with a single AI after detection of spontaneous estrus. PMID:16125551

  20. Synchronization by elastic neuronal latencies

    NASA Astrophysics Data System (ADS)

    Vardi, Roni; Timor, Reut; Marom, Shimon; Abeles, Moshe; Kanter, Ido

    2013-01-01

    Psychological and physiological considerations entail that formation and functionality of neuronal cell assemblies depend upon synchronized repeated activation such as zero-lag synchronization. Several mechanisms for the emergence of this phenomenon have been suggested, including the global network quantity, the greatest common divisor of neuronal circuit delay loops. However, they require strict biological prerequisites such as precisely matched delays and connectivity, and synchronization is represented as a stationary mode of activity instead of a transient phenomenon. Here we show that the unavoidable increase in neuronal response latency to ongoing stimulation serves as a nonuniform gradual stretching of neuronal circuit delay loops. This apparent nuisance is revealed to be an essential mechanism in various types of neuronal time controllers, where synchronization emerges as a transient phenomenon and without predefined precisely matched synaptic delays. These findings are described in an experimental procedure where conditioned stimulations were enforced on a circuit of neurons embedded within a large-scale network of cortical cells in vitro, and are corroborated and extended by simulations of circuits composed of Hodgkin-Huxley neurons with time-dependent latencies. These findings announce a cortical time scale for time controllers based on tens of microseconds stretching of neuronal circuit delay loops per spike. They call for a reexamination of the role of the temporal periodic mode in brain functionality using advanced in vitro and in vivo experiments.

  1. Sports Medicine Meets Synchronized Swimming.

    ERIC Educational Resources Information Center

    Wenz, Betty J.; And Others

    This collection of articles contains information about synchronized swimming. Topics covered include general physiology and cardiovascular conditioning, flexibility exercises, body composition, strength training, nutrition, coach-athlete relationships, coping with competition stress and performance anxiety, and eye care. Chapters are included on…

  2. Tweaking synchronization by connectivity modifications.

    PubMed

    Schultz, Paul; Peron, Thomas; Eroglu, Deniz; Stemler, Thomas; Ramírez Ávila, Gonzalo Marcelo; Rodrigues, Francisco A; Kurths, Jürgen

    2016-06-01

    Natural and man-made networks often possess locally treelike substructures. Taking such tree networks as our starting point, we show how the addition of links changes the synchronization properties of the network. We focus on two different methods of link addition. The first method adds single links that create cycles of a well-defined length. Following a topological approach, we introduce cycles of varying length and analyze how this feature, as well as the position in the network, alters the synchronous behavior. We show that in particular short cycles can lead to a maximum change of the Laplacian's eigenvalue spectrum, dictating the synchronization properties of such networks. The second method connects a certain proportion of the initially unconnected nodes. We simulate dynamical systems on these network topologies, with the nodes' local dynamics being either discrete or continuous. Here our main result is that a certain number of additional links, with the relative position in the network being crucial, can be beneficial to ensure stable synchronization. PMID:27415259

  3. Tweaking synchronization by connectivity modifications

    NASA Astrophysics Data System (ADS)

    Schultz, Paul; Peron, Thomas; Eroglu, Deniz; Stemler, Thomas; Ramírez Ávila, Gonzalo Marcelo; Rodrigues, Francisco A.; Kurths, Jürgen

    2016-06-01

    Natural and man-made networks often possess locally treelike substructures. Taking such tree networks as our starting point, we show how the addition of links changes the synchronization properties of the network. We focus on two different methods of link addition. The first method adds single links that create cycles of a well-defined length. Following a topological approach, we introduce cycles of varying length and analyze how this feature, as well as the position in the network, alters the synchronous behavior. We show that in particular short cycles can lead to a maximum change of the Laplacian's eigenvalue spectrum, dictating the synchronization properties of such networks. The second method connects a certain proportion of the initially unconnected nodes. We simulate dynamical systems on these network topologies, with the nodes' local dynamics being either discrete or continuous. Here our main result is that a certain number of additional links, with the relative position in the network being crucial, can be beneficial to ensure stable synchronization.

  4. Synchronous Parallel Kinetic Monte Carlo

    SciTech Connect

    Mart?nez, E; Marian, J; Kalos, M H

    2006-12-14

    A novel parallel kinetic Monte Carlo (kMC) algorithm formulated on the basis of perfect time synchronicity is presented. The algorithm provides an exact generalization of any standard serial kMC model and is trivially implemented in parallel architectures. We demonstrate the mathematical validity and parallel performance of the method by solving several well-understood problems in diffusion.

  5. Speed control for synchronous motors

    NASA Technical Reports Server (NTRS)

    Packard, H.; Schott, J.

    1981-01-01

    Feedback circuit controls fluctuations in speed of synchronous ac motor. Voltage proportional to phase angle is developed by phase detector, rectified, amplified, compared to threshold, and reapplied positively or negatively to motor excitation circuit. Speed control reduces wow and flutter of audio turntables and tape recorders, and enhances hunting in gyroscope motors.

  6. Fermi Timing and Synchronization System

    SciTech Connect

    Wilcox, R.; Staples, J.; Doolittle, L.; Byrd, J.; Ratti, A.; Kaertner, F.X.; Kim, J.; Chen, J.; Ilday, F.O.; Ludwig, F.; Winter, A.; Ferianis, M.; Danailov, M.; D'Auria, G.

    2006-07-19

    The Fermi FEL will depend critically on precise timing of its RF, laser and diagnostic subsystems. The timing subsystem to coordinate these functions will need to reliably maintain sub-100fs synchronicity between distant points up to 300m apart in the Fermi facility. The technology to do this is not commercially available, and has not been experimentally demonstrated in a working facility. Therefore, new technology must be developed to meet these needs. Two approaches have been researched by different groups working with the Fermi staff. At MIT, a pulse transmission scheme has been developed for synchronization of RF and laser devices. And at LBL, a CW transmission scheme has been developed for RF and laser synchronization. These respective schemes have advantages and disadvantages that will become better understood in coming years. This document presents the work done by both teams, and suggests a possible system design which integrates them both. The integrated system design provides an example of how choices can be made between the different approaches without significantly changing the basic infrastructure of the system. Overall system issues common to any synchronization scheme are also discussed.

  7. PCM synchronization by word stuffing

    NASA Technical Reports Server (NTRS)

    Butman, S.

    1969-01-01

    When a transmitted word, consisting of a number of pulses, is detected and removed from the data stream, the space left by the removal is eliminated by a memory buffer. This eliminates the need for a clock synchronizer thereby removing instability problems.

  8. Synchronous navigation for CT colonography

    NASA Astrophysics Data System (ADS)

    Huang, Adam; Summers, Ronald M.; Roy, Dave

    2006-03-01

    We present a synchronous navigation module for CT colonography (CTC) reading. The need for such a system arises because most CTC protocols require a patient to be scanned in both supine and prone positions to increase sensitivity in detecting colonic polyps. However, existing clinical practices are limited to reading one scan at a time. Such limitation is due to the fact that building a reference system between scans for the highly flexible colon is a nontrivial task. The conventional centerline approach, generating only the longitudinal distance along the colon, falls short in providing the necessary orientation information to synchronize the virtual navigation cameras in both scanned positions. In this paper we describe a synchronous navigation system by using the teniae coli as anatomical references. Teniae coli are three parallel bands of longitudinal smooth muscle on the surface of the colon. They are morphologically distinguishable and form a piecewise triple helix structure from the appendix to the sigmoid colon. Because of these characteristics, they are ideal references to synchronize virtual cameras in both scanned positions. Our new navigation system consists of two side-by-side virtual colonoscopic view panels (for the supine and prone data sets respectively) and one single camera control unit (which controls both the supine and prone virtual cameras). The capability to examine the same colonic region simultaneously in both scanned images can raise an observer's confidence in polyp identification and potentially improve the performance of CT colonography.

  9. Sensorimotor Synchronization across the Life Span

    ERIC Educational Resources Information Center

    Drewing, Knut; Aschersleben, Gisa; Li, Shu-Chen

    2006-01-01

    The present study investigates the contribution of general processing resources as well as other more specific factors to the life-span development of sensorimotor synchronization and its component processes. Within a synchronization tapping paradigm, a group of 286 participants, 6 to 88 years of age, were asked to synchronize finger taps with…

  10. High speed synchronizer card utilizing VLSI technology

    NASA Technical Reports Server (NTRS)

    Speciale, Nicholas; Wunderlich, Kristin

    1988-01-01

    A generic synchronizer card capable of providing standard NASA communication block telemetry frame synchronization and quality control was fabricated using VLSI technology. Four VLSI chip sets are utilized to shrink all the required functions into a single synchronizer card. The application of VLSI technology to telemetry systems resulted in an increase in performance and a decrease in cost and size.

  11. Delay synchronization of temporal Boolean networks

    NASA Astrophysics Data System (ADS)

    Wei, Qiang; Xie, Cheng-jun; Liang, Yi; Niu, Yu-jun; Lin, Da

    2016-01-01

    This paper investigates the delay synchronization between two temporal Boolean networks base on semi-tensor product method, which improve complete synchronization. Necessary and sufficient conditions for delay synchronization are drawn base on algebraic expression of temporal Boolean networks. A example is presented to show the effectiveness of theoretical analysis.

  12. Non-invasive detection and monitoring of estrus, pregnancy and the postpartum period in pygmy loris (Nycticebus pygmaeus) using fecal estrogen metabolites.

    PubMed

    Jurke, M H; Czekala, N M; Fitch-Snyder, H

    1997-01-01

    Estrone-conjugates (E1C) were measured in the feces of six female pygmy lorises (Nycticebus pygmaeus) during estrus (n = 12), pregnancy (n = 4) and the postpartum period (n = 3). Noninvasive feces collection permitted frequent sampling throughout estrus and pregnancy, without disturbance of animals. The estrous period was defined as an increase in fecal E1C levels above an average of 70 ng/g feces with peaks above 100 ng/g feces obtained in consecutive fecal samples collected over a 6- to 11-day period between the end of July and the first third of October. Comparison of the periovulatory profile of E1C and the stage of labial opening of the vagina revealed a high agreement (P < 0.001). In all pregnant females, an E1C rise was found approximately 47 days postestrus, the source of which may be the growing fetal placental unit. Estimated gestation lengths ranged between 187 and 198 days (n = 4). PMID:9050368

  13. Targeting engineering synchronization in chaotic systems

    NASA Astrophysics Data System (ADS)

    Bhowmick, Sourav K.; Ghosh, Dibakar

    2016-07-01

    A method of targeting engineering synchronization states in two identical and mismatch chaotic systems is explained in detail. The method is proposed using linear feedback controller coupling for engineering synchronization such as mixed synchronization, linear and nonlinear generalized synchronization and targeting fixed point. The general form of coupling design to target any desire synchronization state under unidirectional coupling with the help of Lyapunov function stability theory is derived analytically. A scaling factor is introduced in the coupling definition to smooth control without any loss of synchrony. Numerical results are done on two mismatch Lorenz systems and two identical Sprott oscillators.

  14. Inhomogeneity induces relay synchronization in complex networks

    NASA Astrophysics Data System (ADS)

    Gambuzza, Lucia Valentina; Frasca, Mattia; Fortuna, Luigi; Boccaletti, Stefano

    2016-04-01

    Relay synchronization is a collective state, originally found in chains of interacting oscillators, in which uncoupled dynamical units synchronize through the action of mismatched inner nodes that relay the information but do not synchronize with them. It is demonstrated herein that relay synchronization is not limited to such simple motifs, rather it can emerge in larger and arbitrary network topologies. In particular, we show how this phenomenon can be observed in networks of chaotic systems in the presence of some mismatched units, the relay nodes, and how it is actually responsible for an enhancement of synchronization in the network.

  15. Analysis of remote synchronization in complex networks

    NASA Astrophysics Data System (ADS)

    Gambuzza, Lucia Valentina; Cardillo, Alessio; Fiasconaro, Alessandro; Fortuna, Luigi; Gómez-Gardeñes, Jesus; Frasca, Mattia

    2013-12-01

    A novel regime of synchronization, called remote synchronization, where the peripheral nodes form a phase synchronized cluster not including the hub, was recently observed in star motifs [Bergner et al., Phys. Rev. E 85, 026208 (2012)]. We show the existence of a more general dynamical state of remote synchronization in arbitrary networks of coupled oscillators. This state is characterized by the synchronization of pairs of nodes that are not directly connected via a physical link or any sequence of synchronized nodes. This phenomenon is almost negligible in networks of phase oscillators as its underlying mechanism is the modulation of the amplitude of those intermediary nodes between the remotely synchronized units. Our findings thus show the ubiquity and robustness of these states and bridge the gap from their recent observation in simple toy graphs to complex networks.

  16. Producing Newborn Synchronous Mammalian Cells

    NASA Technical Reports Server (NTRS)

    Gonda, Steve R.; Helmstetter, Charles E.; Thornton, Maureen

    2008-01-01

    A method and bioreactor for the continuous production of synchronous (same age) population of mammalian cells have been invented. The invention involves the attachment and growth of cells on an adhesive-coated porous membrane immersed in a perfused liquid culture medium in a microgravity analog bioreactor. When cells attach to the surface divide, newborn cells are released into the flowing culture medium. The released cells, consisting of a uniform population of synchronous cells are then collected from the effluent culture medium. This invention could be of interest to researchers investigating the effects of the geneotoxic effects of the space environment (microgravity, radiation, chemicals, gases) and to pharmaceutical and biotechnology companies involved in research on aging and cancer, and in new drug development and testing.

  17. Synchronous clock stopper for microprocessor

    NASA Technical Reports Server (NTRS)

    Kitchin, David A. (Inventor)

    1985-01-01

    A synchronous clock stopper circuit for inhibiting clock pulses to a microprocessor in response to a stop request signal, and for reinstating the clock pulses in response to a start request signal thereby to conserve power consumption of the microprocessor when used in an environment of limited power. The stopping and starting of the microprocessor is synchronized, by a phase tracker, with the occurrences of a predetermined phase in the instruction cycle of the microprocessor in which the I/O data and address lines of the microprocessor are of high impedance so that a shared memory connected to the I/O lines may be accessed by other peripheral devices. The starting and stopping occur when the microprocessor initiates and completes, respectively, an instruction, as well as before and after transferring data with a memory. Also, the phase tracker transmits phase information signals over a bus to other peripheral devices which signals identify the current operational phase of the microprocessor.

  18. Multiobjective synchronization of coupled systems

    NASA Astrophysics Data System (ADS)

    Tang, Yang; Wang, Zidong; Wong, W. K.; Kurths, Jürgen; Fang, Jian-an

    2011-06-01

    In this paper, multiobjective synchronization of chaotic systems is investigated by especially simultaneously minimizing optimization of control cost and convergence speed. The coupling form and coupling strength are optimized by an improved multiobjective evolutionary approach that includes a hybrid chromosome representation. The hybrid encoding scheme combines binary representation with real number representation. The constraints on the coupling form are also considered by converting the multiobjective synchronization into a multiobjective constraint problem. In addition, the performances of the adaptive learning method and non-dominated sorting genetic algorithm-II as well as the effectiveness and contributions of the proposed approach are analyzed and validated through the Rössler system in a chaotic or hyperchaotic regime and delayed chaotic neural networks.

  19. Parallel integrated frame synchronizer chip

    NASA Technical Reports Server (NTRS)

    Ghuman, Parminder Singh (Inventor); Solomon, Jeffrey Michael (Inventor); Bennett, Toby Dennis (Inventor)

    2000-01-01

    A parallel integrated frame synchronizer which implements a sequential pipeline process wherein serial data in the form of telemetry data or weather satellite data enters the synchronizer by means of a front-end subsystem and passes to a parallel correlator subsystem or a weather satellite data processing subsystem. When in a CCSDS mode, data from the parallel correlator subsystem passes through a window subsystem, then to a data alignment subsystem and then to a bit transition density (BTD)/cyclical redundancy check (CRC) decoding subsystem. Data from the BTD/CRC decoding subsystem or data from the weather satellite data processing subsystem is then fed to an output subsystem where it is output from a data output port.

  20. Synchronous Earth Observatory Satellite /SEOS/

    NASA Technical Reports Server (NTRS)

    Walter, L. S.

    1974-01-01

    NASA/GSFC is currently studying the applications and technical requirements for a Synchronous Earth Observations Satellite (SEOS). Such a satellite would combine the relatively high resolution and multi-spectral capability of the Earth Resources Technology Satellite (ERTS) with the on-station continuous monitoring of the Synchronous Meteorological Satellite (SMS). SEOS capability is geared to perform disaster warning of tornadoes and floods as well as to monitor transient phenomena affecting earth resources (e.g., green waves and algae blooms). The heart of the system is a Large Earth Survey Telescope (LEST) which has a designed 1.5 meter diameter. Spectral bands in the visible, near- and far-infrared have been selected to optimize SEOS utility. A microwave sounder will be used in conjunction with the LEST for meteorological applications.

  1. Synchronization of electronic genetic networks.

    PubMed

    Wagemakers, Alexandre; Buldú, Javier M; García-Ojalvo, Jordi; Sanjuán, Miguel A F

    2006-03-01

    We describe a simple analog electronic circuit that mimics the behavior of a well-known synthetic gene oscillator, the repressilator, which represents a set of three genes repressing one another. Synchronization of a population of such units is thoroughly studied, with the aim to compare the role of global coupling with that of global forcing on the population. Our results show that coupling is much more efficient than forcing in leading the gene population to synchronized oscillations. Furthermore, a modification of the proposed analog circuit leads to a simple electronic version of a genetic toggle switch, which is a simple network of two mutual repressor genes, where control by external forcing is also analyzed. PMID:16599758

  2. Digital-data receiver synchronization

    DOEpatents

    Smith, Stephen F.; Turner, Gary W.

    2005-08-02

    Digital-data receiver synchronization is provided with composite phase-frequency detectors, mutually cross-connected comparison feedback or both to provide robust reception of digital data signals. A single master clock can be used to provide frequency signals. Advantages can include fast lock-up time in moderately to severely noisy conditions, greater tolerance to noise and jitter when locked, and improved tolerance to clock asymmetries.

  3. New Solutions for Synchronized Domineering

    NASA Astrophysics Data System (ADS)

    Bahri, Sahil; Kruskal, Clyde P.

    Cincotti and Iida invented the game of Synchronized Domineering, and analyzed a few special cases. We develop a more general technique of analysis, and obtain results for many more special cases. We obtain complete results for board sizes 3 ×n, 5 ×n, 7 ×n, and 9 ×n (for n large enough) and partial results for board sizes 2×n, 4 ×n, and 6 ×n.

  4. Intonation contour in synchronous speech

    NASA Astrophysics Data System (ADS)

    Wang, Bei; Cummins, Fred

    2003-10-01

    Synchronous Speech (Syn-S), obtained by having pairs of speakers read a prepared text together, has been shown to result in interesting properties in the temporal domain, especially in the reduction of inter-speaker variability in supersegmental timing [F. Cummins, ARLO 3, 7-11 (2002)]. Here we investigate the effect of synchronization among speakers on the intonation contour, with a view to informing models of intonation. Six pairs of speakers (all females) read a short text (176 words) both synchronously and solo. Results show that (1) the pitch accent height above a declining baseline is reduced in Syn-S, compared with solo speech, while the pitch accent location is consistent across speakers in both conditions; (2) in contrast to previous findings on duration matching, there is an asymmetry between speakers, with one speaker exerting a stronger influence on the observed intonation contour than the other; (3) agreement on the boundaries of intonational phrases is greater in Syn-S and intonation contours are well matched from the first syllable of the phrase and throughout.

  5. Network synchronization in hippocampal neurons.

    PubMed

    Penn, Yaron; Segal, Menahem; Moses, Elisha

    2016-03-22

    Oscillatory activity is widespread in dynamic neuronal networks. The main paradigm for the origin of periodicity consists of specialized pacemaking elements that synchronize and drive the rest of the network; however, other models exist. Here, we studied the spontaneous emergence of synchronized periodic bursting in a network of cultured dissociated neurons from rat hippocampus and cortex. Surprisingly, about 60% of all active neurons were self-sustained oscillators when disconnected, each with its own natural frequency. The individual neuron's tendency to oscillate and the corresponding oscillation frequency are controlled by its excitability. The single neuron intrinsic oscillations were blocked by riluzole, and are thus dependent on persistent sodium leak currents. Upon a gradual retrieval of connectivity, the synchrony evolves: Loose synchrony appears already at weak connectivity, with the oscillators converging to one common oscillation frequency, yet shifted in phase across the population. Further strengthening of the connectivity causes a reduction in the mean phase shifts until zero-lag is achieved, manifested by synchronous periodic network bursts. Interestingly, the frequency of network bursting matches the average of the intrinsic frequencies. Overall, the network behaves like other universal systems, where order emerges spontaneously by entrainment of independent rhythmic units. Although simplified with respect to circuitry in the brain, our results attribute a basic functional role for intrinsic single neuron excitability mechanisms in driving the network's activity and dynamics, contributing to our understanding of developing neural circuits. PMID:26961000

  6. Effects of synchronization treatments on ovarian follicular dynamics, corpus luteum growth, and circulating steroid hormone concentrations in lactating dairy cows.

    PubMed

    Herlihy, M M; Crowe, M A; Diskin, M G; Butler, S T

    2012-02-01

    Lactating dairy cows (n=57) ≥45 d postpartum at first service were enrolled in a randomized complete block design study to evaluate treatments to synchronize estrus and ovulation. At 10 d before artificial insemination (AI), animals were randomly assigned to 1 of 3 treatments: (1) d -10 GnRH (GnRH1; 10 μg of buserelin, i.m.) and controlled internal drug release insert [CIDR, 1.38 g of progesterone (P4)]; d -3 PGF(2α) (PGF; 25 mg of dinoprost, i.m.); d -2 CIDR out; and AI at observed estrus (CIDR_OBS); (2) same as CIDR_OBS, but GnRH (GnRH2) 36 h after CIDR out and timed AI (TAI) 18 h later (CIDR_TAI); or (3) same as CIDR_TAI, but no CIDR (Ovsynch). Transrectal ultrasound was used to assess follicle size before ovulation and on d 4, 8, and 15 after the presumptive day of estrus (d 0) to measure the corpus luteum (CL). Blood samples were collected to determine concentrations of estradiol (E2; d -10, -9, -3, -2, -1, and 0) and P4 (d -10, -9, -2, -1, 0, 1, 4, 6, 8, 11, and 15). No treatment differences were observed in either circulating concentrations of P4 or the ovulatory response to GnRH1 at the onset of synchronization treatments. Circulating concentrations of P4 were greater for CIDR_OBS and CIDR_TAI compared with Ovsynch at 24 h after CIDR insertion (5.34 and 4.98 vs. 1.75 ng/mL) and immediately before CIDR removal (1.65 and 1.48 vs. 0.40 ng/mL). Peak circulating concentrations of E2 were greater for CIDR_OBS compared with Ovsynch (3.85 vs. 2.39 pg/mL), but CIDR_TAI (2.82 pg/mL) did not differ from either CIDR_OBS or Ovsynch. The interval from PGF injection to peak circulating E2 did not differ between CIDR_TAI and Ovsynch (52.1 vs. 49.8 h). Both CIDR_TAI and Ovsynch, however, had shorter intervals from PGF injection to peak circulating E2 concentrations compared with CIDR_OBS (67.8 h). The diameter of the dominant follicle before ovulation was greater for CIDR_OBS compared with Ovsynch (18.5 vs. 16.0 mm) but CIDR_TAI (17.1 mm) did not differ from either of

  7. The somatotropic axis during the physiological estrus cycle in dairy heifers--Effect on hepatic expression of GHR and SOCS2.

    PubMed

    Mense, K; Meyerholz, M; Gil Araujo, M; Lietzau, M; Knaack, H; Wrenzycki, C; Hoedemaker, M; Piechotta, M

    2015-04-01

    Pituitary growth hormone (GH) release and hepatic insulin-like growth factor-I (IGF-I) production increase after an injection of 17β-estradiol (E2) in ovariectomized dairy cattle. However, whether endogenous sexual steroid hormones also influence the hepatic GH receptor (GHR) signaling pathway during a physiological estrus cycle remains unclear. The aim of this study was to analyze the hepatic GHR signaling pathway during the luteal phase and after a period of increased E2 concentrations (after ovulation) as well as in 7 heifers before ovulation. Ovarian ultrasounds were performed daily during repeated physiological cycles (n = 56) of 30 Holstein Friesian heifers to determine ovulation [before ovulation (n = 7, bOv) and after ovulation 24-60 h after the appearance of estrus signs (n = 49, aOv)] and luteal phase (CLP; d 12 ± 1 after ovulation). Blood samples and liver biopsies were obtained, and blood concentrations of E2, P4, insulin-like growth factor (IGF)-I, IGF-II, and GH were measured. In the liver biopsies, we determined mRNA expression of the estrogen receptor α (ERα), GHR, Janus kinase 2 (JAK2), signal transducer and activator of transcription 5B (STAT5B), suppressor of cytokine signaling (SOCS)2 and 3, IGF-I, and IGF-II by quantitative reverse transcription-PCR. The concentration of E2 was higher bOv than aOv and CLP, as expected. The concentrations of IGF-I and GH were higher bOv and aOv compared with CLP. In contrast, concentrations of IGF-II were lower aOv compared with bOv and CLP. The mRNA expression of GHR was higher in liver biopsies obtained bOv compared with aOv and CLP. Notably, the expression of SOCS2 was higher bOv than aOv and in the CLP. Increased hepatic expression of SOCS2 during estrus was detectable when IGF-I concentrations were high; this result might indicate that SOCS2 expression attenuates the GHR signal transduction pathway during the phase of increased pituitary GH release. In conclusion, hepatic GHR and SOCS2 mRNA expression

  8. Fertility of holstein dairy heifers after synchronization of ovulation and timed AI or AI after removed tail chalk.

    PubMed

    Rivera, H; Lopez, H; Fricke, P M

    2004-07-01

    Nonlactating Holstein dairy heifers (n=352) 13 mo of age were managed using a 42-d artificial insemination (AI) breeding period in which they received AI after removed tail chalk evaluated once daily. At AI breeding period onset (d 0), heifers were randomly assigned to receive synchronization of ovulation (100 microg of GnRH, d 0; 25 mg of PGF2alpha, d 6; 100 microg of GnRH, d 8) and timed AI (TAI; d 8) and AI after removed tail chalk for the entire AI breeding period (GPG; n=175), or AI after removed tail chalk for the entire AI breeding period (TC; n=177). As expected, 17.7% (31/175) of GPG heifers received AI after removed tail chalk before scheduled TAI. Pregnancy rate per artificial insemination (PR/AI) at approximately 30 d after first AI tended to be greater for TC (46.5%) than for GPG (38.3%) heifers. No treatment x inseminator interaction was detected; however, overall PR/AI was low for heifers in both treatments due to variation among the 3 inseminators (24.8, 30.0, and 58.0%). Pregnancy loss from approximately 30 to approximately 75 d after first AI was 10% and did not differ between treatments. Based on survival analysis, days to first AI was greater for TC than for GPG heifers, whereas days to pregnancy across the 42-d AI breeding period did not differ between treatments. Overall, 81.2% of GPG heifers receiving TAI synchronized luteal regression and ovulated within 48 h after the second GnRH injection. We conclude that this synchronization protocol can yield acceptable fertility in dairy heifers if AI to estrus is conducted between treatment with GnRH and PGF2alpha and AI efficiency is optimized. PMID:15328217

  9. Compatibility of motion facilitates visuomotor synchronization.

    PubMed

    Hove, Michael J; Spivey, Michael J; Krumhansl, Carol L

    2010-12-01

    Prior research indicates that synchronized tapping performance is very poor with flashing visual stimuli compared with auditory stimuli. Three finger-tapping experiments compared flashing visual metronomes with visual metronomes containing a spatial component, either compatible, incompatible, or orthogonal to the tapping action. In Experiment 1, synchronization success rates increased dramatically for spatiotemporal sequences of both geometric and biological forms over flashing sequences. In Experiment 2, synchronization performance was best when target sequences and movements were directionally compatible (i.e., simultaneously down), followed by orthogonal stimuli, and was poorest for incompatible moving stimuli and flashing stimuli. In Experiment 3, synchronization performance was best with auditory sequences, followed by compatible moving stimuli, and was worst for flashing and fading stimuli. Results indicate that visuomotor synchronization improves dramatically with compatible spatial information. However, an auditory advantage in sensorimotor synchronization persists. PMID:20695698

  10. A chimeric path to neuronal synchronization

    SciTech Connect

    Essaki Arumugam, Easwara Moorthy; Spano, Mark L.

    2015-01-15

    Synchronization of neuronal activity is associated with neurological disorders such as epilepsy. This process of neuronal synchronization is not fully understood. To further our understanding, we have experimentally studied the progression of this synchronization from normal neuronal firing to full synchronization. We implemented nine FitzHugh-Nagumo neurons (a simplified Hodgkin-Huxley model) via discrete electronics. For different coupling parameters (synaptic strengths), the neurons in the ring were either unsynchronized or completely synchronized when locally coupled in a ring. When a single long-range connection (nonlocal coupling) was introduced, an intermediate state known as a chimera appeared. The results indicate that (1) epilepsy is likely not only a dynamical disease but also a topological disease, strongly tied to the connectivity of the underlying network of neurons, and (2) the synchronization process in epilepsy may not be an “all or none” phenomenon, but can pass through an intermediate stage (chimera)

  11. A chimeric path to neuronal synchronization

    NASA Astrophysics Data System (ADS)

    Essaki Arumugam, Easwara Moorthy; Spano, Mark L.

    2015-01-01

    Synchronization of neuronal activity is associated with neurological disorders such as epilepsy. This process of neuronal synchronization is not fully understood. To further our understanding, we have experimentally studied the progression of this synchronization from normal neuronal firing to full synchronization. We implemented nine FitzHugh-Nagumo neurons (a simplified Hodgkin-Huxley model) via discrete electronics. For different coupling parameters (synaptic strengths), the neurons in the ring were either unsynchronized or completely synchronized when locally coupled in a ring. When a single long-range connection (nonlocal coupling) was introduced, an intermediate state known as a chimera appeared. The results indicate that (1) epilepsy is likely not only a dynamical disease but also a topological disease, strongly tied to the connectivity of the underlying network of neurons, and (2) the synchronization process in epilepsy may not be an "all or none" phenomenon, but can pass through an intermediate stage (chimera).

  12. Synchronizing noisy nonidentical oscillators by transient uncoupling

    NASA Astrophysics Data System (ADS)

    Tandon, Aditya; Schröder, Malte; Mannattil, Manu; Timme, Marc; Chakraborty, Sagar

    2016-09-01

    Synchronization is the process of achieving identical dynamics among coupled identical units. If the units are different from each other, their dynamics cannot become identical; yet, after transients, there may emerge a functional relationship between them—a phenomenon termed "generalized synchronization." Here, we show that the concept of transient uncoupling, recently introduced for synchronizing identical units, also supports generalized synchronization among nonidentical chaotic units. Generalized synchronization can be achieved by transient uncoupling even when it is impossible by regular coupling. We furthermore demonstrate that transient uncoupling stabilizes synchronization in the presence of common noise. Transient uncoupling works best if the units stay uncoupled whenever the driven orbit visits regions that are locally diverging in its phase space. Thus, to select a favorable uncoupling region, we propose an intuitive method that measures the local divergence at the phase points of the driven unit's trajectory by linearizing the flow and subsequently suppresses the divergence by uncoupling.

  13. Explosive synchronization coexists with classical synchronization in the Kuramoto model.

    PubMed

    Danziger, Michael M; Moskalenko, Olga I; Kurkin, Semen A; Zhang, Xiyun; Havlin, Shlomo; Boccaletti, Stefano

    2016-06-01

    Explosive synchronization has recently been reported in a system of adaptively coupled Kuramoto oscillators, without any conditions on the frequency or degree of the nodes. Here, we find that, in fact, the explosive phase coexists with the standard phase of the Kuramoto oscillators. We determine this by extending the mean-field theory of adaptively coupled oscillators with full coupling to the case with partial coupling of a fraction f. This analysis shows that a metastable region exists for all finite values of f > 0, and therefore explosive synchronization is expected for any perturbation of adaptively coupling added to the standard Kuramoto model. We verify this theory with GPU-accelerated simulations on very large networks (N ∼ 10(6)) and find that, in fact, an explosive transition with hysteresis is observed for all finite couplings. By demonstrating that explosive transitions coexist with standard transitions in the limit of f → 0, we show that this behavior is far more likely to occur naturally than was previously believed. PMID:27369869

  14. Explosive synchronization coexists with classical synchronization in the Kuramoto model

    NASA Astrophysics Data System (ADS)

    Danziger, Michael M.; Moskalenko, Olga I.; Kurkin, Semen A.; Zhang, Xiyun; Havlin, Shlomo; Boccaletti, Stefano

    2016-06-01

    Explosive synchronization has recently been reported in a system of adaptively coupled Kuramoto oscillators, without any conditions on the frequency or degree of the nodes. Here, we find that, in fact, the explosive phase coexists with the standard phase of the Kuramoto oscillators. We determine this by extending the mean-field theory of adaptively coupled oscillators with full coupling to the case with partial coupling of a fraction f. This analysis shows that a metastable region exists for all finite values of f > 0, and therefore explosive synchronization is expected for any perturbation of adaptively coupling added to the standard Kuramoto model. We verify this theory with GPU-accelerated simulations on very large networks (N ˜ 106) and find that, in fact, an explosive transition with hysteresis is observed for all finite couplings. By demonstrating that explosive transitions coexist with standard transitions in the limit of f → 0, we show that this behavior is far more likely to occur naturally than was previously believed.

  15. Differences in Retinal Structure and Function between Aging Male and Female Sprague-Dawley Rats are Strongly Influenced by the Estrus Cycle

    PubMed Central

    Chaychi, Samaneh; Polosa, Anna; Lachapelle, Pierre

    2015-01-01

    Purpose Biological sex and age are considered as two important factors that may influence the function and structure of the retina, an effect that might be governed by sexual hormones such as estrogen. The purpose of this study was to delineate the influence that biological sex and age exert on the retinal function and structure of rodents and also clarify the effect that the estrus cycle might exert on the retinal function of female rats. Method The retinal function of 50 normal male and female albino Sprague-Dawley (SD) rats was investigated with the electroretinogram (ERG) at postnatal day (P) 30, 60, 100, 200, and 300 (n = 5–6 male and female rats/age). Following the ERG recording sessions, retinal histology was performed in both sexes. In parallel, the retinal function of premenopausal and menopausal female rats aged P540 were also compared. Results Sex and age-related changes in retinal structure and function were observed in our animal model. However, irrespective of age, no significant difference was observed in ERG and retinal histology obtained from male and female rats. Notwithstanding the above we did however notice that between P60 and P200 there was a gradual increase in ERG amplitudes of female rats compared to males. Furthermore, the ERG of premenopausal female rats aged 18 months old (P540) was larger compared to age-matched menopausal female rats as well as that of male rats. Conclusion Our results showed that biological sex and age can influence the retinal function and structure of albino SD rats. Furthermore, we showed that cycled female rats have better retinal function compared to the menopausal female rats suggesting a beneficial effect of the estrus cycle on the retinal function. PMID:26317201

  16. Nondestructive synchronous beam current monitor

    SciTech Connect

    Covo, Michel Kireeff

    2014-12-15

    A fast current transformer is mounted after the deflectors of the Berkeley 88-Inch Cyclotron. The measured signal is amplified and connected to the input of a lock-in amplifier. The lock-in amplifier performs a synchronous detection of the signal at the cyclotron second harmonic frequency. The magnitude of the signal detected is calibrated against a Faraday cup and corresponds to the beam intensity. It has exceptional resolution, long term stability, and can measure the beam current leaving the cyclotron as low as 1 nA.

  17. Synchronous Sampling for Distributed Experiments

    NASA Astrophysics Data System (ADS)

    Wittkamp, M.; Ettl, J.

    2015-09-01

    Sounding Rocket payloads, especially for atmospheric research, often consists of several independent sensors or experiments with different objectives. The data of these sensors can be combined in the post processing to improve the scientific results of the flight. One major requirement for this data-correlation is a common timeline for the measurements of the distributed experiments. Within this paper we present two ways to achieve absolute timing for asynchronously working experiments. The synchronization process is using the Global Positioning System (GPS) and a standard serial communication protocol for transport of timestamps and flight-states.

  18. Mutual synchronization of weakly coupled gyrotrons

    SciTech Connect

    Rozental, R. M.; Glyavin, M. Yu.; Sergeev, A. S.; Zotova, I. V.; Ginzburg, N. S.

    2015-09-15

    The processes of synchronization of two weakly coupled gyrotrons are studied within the framework of non-stationary equations with non-fixed longitudinal field structure. With the allowance for a small difference of the free oscillation frequencies of the gyrotrons, we found a certain range of parameters where mutual synchronization is possible while a high electronic efficiency is remained. It is also shown that synchronization regimes can be realized even under random fluctuations of the parameters of the electron beams.

  19. Complexity and synchronization in stochastic chaotic systems

    NASA Astrophysics Data System (ADS)

    Son Dang, Thai; Palit, Sanjay Kumar; Mukherjee, Sayan; Hoang, Thang Manh; Banerjee, Santo

    2016-02-01

    We investigate the complexity of a hyperchaotic dynamical system perturbed by noise and various nonlinear speech and music signals. The complexity is measured by the weighted recurrence entropy of the hyperchaotic and stochastic systems. The synchronization phenomenon between two stochastic systems with complex coupling is also investigated. These criteria are tested on chaotic and perturbed systems by mean conditional recurrence and normalized synchronization error. Numerical results including surface plots, normalized synchronization errors, complexity variations etc show the effectiveness of the proposed analysis.

  20. Desynchronization of stochastically synchronized chemical oscillators

    SciTech Connect

    Snari, Razan; Tinsley, Mark R. E-mail: kshowalt@wvu.edu; Faramarzi, Sadegh; Showalter, Kenneth E-mail: kshowalt@wvu.edu; Wilson, Dan; Moehlis, Jeff; Netoff, Theoden Ivan

    2015-12-15

    Experimental and theoretical studies are presented on the design of perturbations that enhance desynchronization in populations of oscillators that are synchronized by periodic entrainment. A phase reduction approach is used to determine optimal perturbation timing based upon experimentally measured phase response curves. The effectiveness of the perturbation waveforms is tested experimentally in populations of periodically and stochastically synchronized chemical oscillators. The relevance of the approach to therapeutic methods for disrupting phase coherence in groups of stochastically synchronized neuronal oscillators is discussed.

  1. Synchronization of Micromechanical Oscillators Using Light

    NASA Astrophysics Data System (ADS)

    Zhang, Mian; Wiederhecker, Gustavo S.; Manipatruni, Sasikanth; Barnard, Arthur; McEuen, Paul; Lipson, Michal

    2012-12-01

    Synchronization, the emergence of spontaneous order in coupled systems, is of fundamental importance in both physical and biological systems. We demonstrate the synchronization of two dissimilar silicon nitride micromechanical oscillators, that are spaced apart by a few hundred nanometers and are coupled through an optical cavity radiation field. The tunability of the optical coupling between the oscillators enables one to externally control the dynamics and switch between coupled and individual oscillation states. These results pave a path toward reconfigurable synchronized oscillator networks.

  2. Desynchronization of stochastically synchronized chemical oscillators.

    PubMed

    Snari, Razan; Tinsley, Mark R; Wilson, Dan; Faramarzi, Sadegh; Netoff, Theoden Ivan; Moehlis, Jeff; Showalter, Kenneth

    2015-12-01

    Experimental and theoretical studies are presented on the design of perturbations that enhance desynchronization in populations of oscillators that are synchronized by periodic entrainment. A phase reduction approach is used to determine optimal perturbation timing based upon experimentally measured phase response curves. The effectiveness of the perturbation waveforms is tested experimentally in populations of periodically and stochastically synchronized chemical oscillators. The relevance of the approach to therapeutic methods for disrupting phase coherence in groups of stochastically synchronized neuronal oscillators is discussed. PMID:26723155

  3. Desynchronization of stochastically synchronized chemical oscillators

    NASA Astrophysics Data System (ADS)

    Snari, Razan; Tinsley, Mark R.; Wilson, Dan; Faramarzi, Sadegh; Netoff, Theoden Ivan; Moehlis, Jeff; Showalter, Kenneth

    2015-12-01

    Experimental and theoretical studies are presented on the design of perturbations that enhance desynchronization in populations of oscillators that are synchronized by periodic entrainment. A phase reduction approach is used to determine optimal perturbation timing based upon experimentally measured phase response curves. The effectiveness of the perturbation waveforms is tested experimentally in populations of periodically and stochastically synchronized chemical oscillators. The relevance of the approach to therapeutic methods for disrupting phase coherence in groups of stochastically synchronized neuronal oscillators is discussed.

  4. Tape-recorded Lectures With Slide Synchronization

    ERIC Educational Resources Information Center

    Goodhue, D.

    1969-01-01

    Describes "Taped Explanation Slide Synchronization" programs used for individual study or group showing in college zoology. Discusses preparation of programs, class organization, equipment, and costs. (EB)

  5. Pilotless Frame Synchronization Using LDPC Code Constraints

    NASA Technical Reports Server (NTRS)

    Jones, Christopher; Vissasenor, John

    2009-01-01

    A method of pilotless frame synchronization has been devised for low- density parity-check (LDPC) codes. In pilotless frame synchronization , there are no pilot symbols; instead, the offset is estimated by ex ploiting selected aspects of the structure of the code. The advantag e of pilotless frame synchronization is that the bandwidth of the sig nal is reduced by an amount associated with elimination of the pilot symbols. The disadvantage is an increase in the amount of receiver data processing needed for frame synchronization.

  6. Synchronization on small-world networks

    NASA Astrophysics Data System (ADS)

    Hong, H.; Choi, M. Y.; Kim, Beom Jun

    2002-02-01

    We investigate collective synchronization in a system of coupled oscillators on small-world networks. The order parameters that measure synchronization of phases and frequencies are introduced and analyzed by means of dynamic simulations and finite-size scaling. Phase synchronization is observed to emerge in the presence of even a tiny fraction P of shortcuts and to display saturated behavior for P>~0.5. This indicates that the same synchronizability as the random network (P=1) can be achieved with relatively small number of shortcuts. The transient behavior of the synchronization, obtained from the measurement of the relaxation time, is also discussed.

  7. Calculation principles for a synchronous electromagnetic clutch

    NASA Technical Reports Server (NTRS)

    Panasenkov, M. A.

    1978-01-01

    A detailed explanation of the calculation principles, for a synchronous salient-pole electromagnetic clutch with lumped excitation windings is supplied by direct current. Practical recommendations are given.

  8. Fission Yeast Cell Cycle Synchronization Methods.

    PubMed

    Tormos-Pérez, Marta; Pérez-Hidalgo, Livia; Moreno, Sergio

    2016-01-01

    Fission yeast cells can be synchronized by cell cycle arrest and release or by size selection. Cell cycle arrest synchronization is based on the block and release of temperature-sensitive cell cycle mutants or treatment with drugs. The most widely used approaches are cdc10-129 for G1; hydroxyurea (HU) for early S-phase; cdc25-22 for G2, and nda3-KM311 for mitosis. Cells can also be synchronized by size selection using centrifugal elutriation or a lactose gradient. Here we describe the methods most commonly used to synchronize fission yeast cells. PMID:26519320

  9. Noise-induced transitions in optomechanical synchronization

    NASA Astrophysics Data System (ADS)

    Weiss, Talitha; Kronwald, Andreas; Marquardt, Florian

    2016-01-01

    We study how quantum and thermal noise affects synchronization of two optomechanical limit-cycle oscillators. Classically, in the absence of noise, optomechanical systems tend to synchronize either in-phase or anti-phase. Taking into account the fundamental quantum noise, we find a regime where fluctuations drive transitions between these classical synchronization states. We investigate how this ‘mixed’ synchronization regime emerges from the noiseless system by studying the classical-to-quantum crossover and we show how the time scales of the transitions vary with the effective noise strength. In addition, we compare the effects of thermal noise to the effects of quantum noise.

  10. Synchronization and Partial Synchronization Experiments with Networks of Time-Delay Coupled Hindmarsh-Rose Neurons

    NASA Astrophysics Data System (ADS)

    Steur, Erik; Murguia, Carlos; Fey, Rob H. B.; Nijmeijer, Henk

    2016-06-01

    We study experimentally synchronization and partial synchronization in networks of Hindmarsh-Rose model neurons that interact through linear time-delay couplings. Our experimental setup consists of electric circuit board realizations of the Hindmarsh-Rose model neuron and a coupling interface in which the interaction between the circuits is defined. With this experimental setup we test the predictive value of theoretical results about synchronization and partial synchronization in networks.

  11. Synchronously pumped nuclear magnetic oscillator

    NASA Astrophysics Data System (ADS)

    Korver, Anna; Thrasher, Daniel; Bulatowicz, Michael; Walker, Thad

    2015-05-01

    We present progress towards a synchronously pumped nuclear magnetic oscillator. Alkali frequency shifts and quadrupole shifts are the dominant systematic effects in dual Xe isotope co-magnetometers. By synchronously pumping the Xe nuclei using spin-exchange with an oscillating Rb polarization, the Rb and Xe spins precess transverse to the longitudinal bias field. This configuration is predicted to be insensitive to first order quadrupole interactions and alkali spin-exchange frequency shifts. A key feature that allows co-precession of the Rb and Xe spins, despite a ~ 1000 fold ratio of their gyromagnetic ratios, is to apply the bias field in the form of a sequence of Rb 2 π pulses whose repetition frequency is equal to the Rb Larmor frequency. The 2 π pulses result in an effective Rb magnetic moment of zero, while the Xe precession depends only on the time average of the pulsed field amplitude. Polarization modulation of the pumping light at the Xe NMR frequency allows co-precession of the Rb and Xe spins. We will present our preliminary experimental studies of this new approach to NMR of spin-exchange pumped Xe. Support by the NSF and Northrop Grumman Co.

  12. Gait synchronization in Caenorhabditis elegans

    PubMed Central

    Yuan, Jinzhou; Raizen, David M.; Bau, Haim H.

    2014-01-01

    Collective motion is observed in swarms of swimmers of various sizes, ranging from self-propelled nanoparticles to fish. The mechanisms that govern interactions among individuals are debated, and vary from one species to another. Although the interactions among relatively large animals, such as fish, are controlled by their nervous systems, the interactions among microorganisms, which lack nervous systems, are controlled through physical and chemical pathways. Little is known, however, regarding the mechanism of collective movements in microscopic organisms with nervous systems. To attempt to remedy this, we studied collective swimming behavior in the nematode Caenorhabditis elegans, a microorganism with a compact nervous system. We evaluated the contributions of hydrodynamic forces, contact forces, and mechanosensory input to the interactions among individuals. We devised an experiment to examine pair interactions as a function of the distance between the animals and observed that gait synchronization occurred only when the animals were in close proximity, independent of genes required for mechanosensation. Our measurements and simulations indicate that steric hindrance is the dominant factor responsible for motion synchronization in C. elegans, and that hydrodynamic interactions and genotype do not play a significant role. We infer that a similar mechanism may apply to other microscopic swimming organisms and self-propelled particles. PMID:24778261

  13. Synchronizing with music: intercultural differences.

    PubMed

    Drake, Carolyn; Ben El Heni, Jamel

    2003-11-01

    The way in which listeners perceive music changes throughout childhood, but little is known about the factors responsible for these changes. One factor, explicit music training, has received considerable attention, with studies indicating that musicians demonstrate a more complex hierarchical mental representation for music and superior temporal organizational skills. But does acculturation-the passive exposure to a particular type of music since birth-also influence the acquisition of these skills? We compared the music synchronization performance of Tunisian and French subjects with music from these two contrasting musical cultures. Twelve musical excerpts were selected from the two popular music cultures, matched for perceived tempo, complexity, and familiarity, and subjects were asked to tap in time with the music. Tapping mode (rate and hierarchical level) varied with subjects' familiarity with the musical idiom, as evidenced by an interaction between musical culture and type of music: participants synchronized at higher hierarchical levels (and over a wider range) with music from their own culture than with an unfamiliar type of music. Thus, passive acculturation as well as explicit music tuition influence our perception and cognition of music. PMID:14681167

  14. High accuracy time transfer synchronization

    NASA Technical Reports Server (NTRS)

    Wheeler, Paul J.; Koppang, Paul A.; Chalmers, David; Davis, Angela; Kubik, Anthony; Powell, William M.

    1995-01-01

    In July 1994, the U.S. Naval Observatory (USNO) Time Service System Engineering Division conducted a field test to establish a baseline accuracy for two-way satellite time transfer synchronization. Three Hewlett-Packard model 5071 high performance cesium frequency standards were transported from the USNO in Washington, DC to Los Angeles, California in the USNO's mobile earth station. Two-Way Satellite Time Transfer links between the mobile earth station and the USNO were conducted each day of the trip, using the Naval Research Laboratory(NRL) designed spread spectrum modem, built by Allen Osborne Associates(AOA). A Motorola six channel GPS receiver was used to track the location and altitude of the mobile earth station and to provide coordinates for calculating Sagnac corrections for the two-way measurements, and relativistic corrections for the cesium clocks. This paper will discuss the trip, the measurement systems used and the results from the data collected. We will show the accuracy of using two-way satellite time transfer for synchronization and the performance of the three HP 5071 cesium clocks in an operational environment.

  15. Multiple-access channels without synchronization

    NASA Technical Reports Server (NTRS)

    Mceliece, R. J.; Posner, E. C.

    1977-01-01

    This paper discusses models for multiple-access communications which take into account the fact that the channel users may not be able to synchronize their transmissions. It is shown that for a broad class of such channels, the capacity region is the same as it would be with user synchronization. Some open problems are discussed.

  16. Examining Interactivity in Synchronous Virtual Classrooms

    ERIC Educational Resources Information Center

    Martin, Florence; Parker, Michele A.; Deale, Deborah F.

    2012-01-01

    Interaction is crucial to student satisfaction in online courses. Adding synchronous components (virtual classroom technologies) to online courses can facilitate interaction. In this study, interaction within a synchronous virtual classroom was investigated by surveying 21 graduate students in an instructional technology program in the…

  17. Development of Network Synchronization Predicts Language Abilities.

    PubMed

    Doesburg, Sam M; Tingling, Keriann; MacDonald, Matt J; Pang, Elizabeth W

    2016-01-01

    Synchronization of oscillations among brain areas is understood to mediate network communication supporting cognition, perception, and language. How task-dependent synchronization during word production develops throughout childhood and adolescence, as well as how such network coherence is related to the development of language abilities, remains poorly understood. To address this, we recorded magnetoencephalography while 73 participants aged 4-18 years performed a verb generation task. Atlas-guided source reconstruction was performed, and phase synchronization among regions was calculated. Task-dependent increases in synchronization were observed in the theta, alpha, and beta frequency ranges, and network synchronization differences were observed between age groups. Task-dependent synchronization was strongest in the theta band, as were differences between age groups. Network topologies were calculated for brain regions associated with verb generation and were significantly associated with both age and language abilities. These findings establish the maturational trajectory of network synchronization underlying expressive language abilities throughout childhood and adolescence and provide the first evidence for an association between large-scale neurophysiological network synchronization and individual differences in the development of language abilities. PMID:26401810

  18. Quasars as very-accurate clock synchronizers

    NASA Technical Reports Server (NTRS)

    Hurd, W. J.; Goldstein, R. M.

    1975-01-01

    Quasars can be employed to synchronize global data communications, geophysical measurements, and atomic clocks. It is potentially two to three orders of magnitude better than presently-used Moon-bounce system. Comparisons between quasar and clock pulses are used to develop correction or synchronization factors for station clocks.

  19. Synchronization Properties of Random Piecewise Isometries

    NASA Astrophysics Data System (ADS)

    Gorodetski, Anton; Kleptsyn, Victor

    2016-08-01

    We study the synchronization properties of the random double rotations on tori. We give a criterion that show when synchronization is present in the case of random double rotations on the circle and prove that it is always absent in dimensions two and higher.

  20. A k-mode synchronization methodology for multiple satellite networks

    NASA Astrophysics Data System (ADS)

    Sharifi, M. Hossein; Arozullah, Mohammed

    The authors describe a k-mode burst synchronization methodology that can improve the synchronization performance of the digital communication networks with bursty dynamic users. The method is suitable for the applications such as centralized and distributed multiple satellite networking, where the system supports a large number of low-orbit user satellites. In the mobile networking environment usually there is no network synchronization and the users are highly dynamic. Therefore, more stringent analysis of the system synchronization performance is required. The methodology defined provides flexibility of selecting the k-synchronization stage, which provides a more stable synchronization. The major features of this synchronization method are: a) the synchronizer avoids returning to bit-by-bit comparison mode from higher modes for small errors; b) since there are many modes with different synchronization levels, the synchronizer provides a more stable synchronization; and c) the synchronizer is more stable in environments with burst noise or jamming.

  1. Chaos synchronization in networks of semiconductor superlattices

    NASA Astrophysics Data System (ADS)

    Li, Wen; Aviad, Yaara; Reidler, Igor; Song, Helun; Huang, Yuyang; Biermann, Klaus; Rosenbluh, Michael; Zhang, Yaohui; Grahn, Holger T.; Kanter, Ido

    2015-11-01

    Chaos synchronization has been demonstrated as a useful building block for various tasks in secure communications, including a source of all-electronic ultrafast physical random number generators based on room temperature spontaneous chaotic oscillations in a DC-biased weakly coupled GaAs/Al0.45Ga0.55As semiconductor superlattice (SSL). Here, we experimentally demonstrate the emergence of several types of chaos synchronization, e.g. leader-laggard, face-to-face and zero-lag synchronization in network motifs of coupled SSLs consisting of unidirectional and mutual coupling as well as self-feedback coupling. Each type of synchronization clearly reflects the symmetry of the topology of its network motif. The emergence of a chaotic SSL without external feedback and synchronization among different structured SSLs open up the possibility for advanced secure multi-user communication methods based on large networks of coupled SSLs.

  2. Interdependencies of Neural Impulse Pattern and Synchronization

    NASA Astrophysics Data System (ADS)

    Braun, Hans; Postnova, Svetlana; Schneider, Horst

    2008-03-01

    Neuronal synchronization plays a crucial role in many physiological functions such as information binding and wake-sleep transitions as well as in pathophysiological processes like Parkinson's disease and epileptic seizures. The occurrence of synchronized activity is often associated with significant alterations of the neuronal impulse pattern, mostly with a transition from tonic firing to burst discharges. We have used Hodgkin-Huxley type simulations to study how alterations of individual neurons' dynamics influence the synchronization in electrotonic coupled networks. The individual neurons have been tuned from tonic firing to bursting with chaotic dynamics in between. Our results demonstrate that these transitions have significant impact on the neurons' synchronization. Vice versa, the synchronization state can essentially modify the impulse pattern. The most remarkably effects appear when the individual neurons operate in a periodically tonic firing regime close to the transition to chaos.

  3. Clustering versus non-clustering phase synchronizations.

    PubMed

    Liu, Shuai; Zhan, Meng

    2014-03-01

    Clustering phase synchronization (CPS) is a common scenario to the global phase synchronization of coupled dynamical systems. In this work, a novel scenario, the non-clustering phase synchronization (NPS), is reported. It is found that coupled systems do not transit to the global synchronization until a certain sufficiently large coupling is attained, and there is no clustering prior to the global synchronization. To reveal the relationship between CPS and NPS, we further analyze the noise effect on coupled phase oscillators and find that the coupled oscillator system can change from CPS to NPS with the increase of noise intensity or system disorder. These findings are expected to shed light on the mechanism of various intriguing self-organized behaviors in coupled systems. PMID:24697366

  4. Clustering versus non-clustering phase synchronizations

    SciTech Connect

    Liu, Shuai; Zhan, Meng

    2014-03-15

    Clustering phase synchronization (CPS) is a common scenario to the global phase synchronization of coupled dynamical systems. In this work, a novel scenario, the non-clustering phase synchronization (NPS), is reported. It is found that coupled systems do not transit to the global synchronization until a certain sufficiently large coupling is attained, and there is no clustering prior to the global synchronization. To reveal the relationship between CPS and NPS, we further analyze the noise effect on coupled phase oscillators and find that the coupled oscillator system can change from CPS to NPS with the increase of noise intensity or system disorder. These findings are expected to shed light on the mechanism of various intriguing self-organized behaviors in coupled systems.

  5. Amplitude dynamics favors synchronization in complex networks

    PubMed Central

    Gambuzza, Lucia Valentina; Gómez-Gardeñes, Jesus; Frasca, Mattia

    2016-01-01

    In this paper we study phase synchronization in random complex networks of coupled periodic oscillators. In particular, we show that, when amplitude dynamics is not negligible, phase synchronization may be enhanced. To illustrate this, we compare the behavior of heterogeneous units with both amplitude and phase dynamics and pure (Kuramoto) phase oscillators. We find that in small network motifs the behavior crucially depends on the topology and on the node frequency distribution. Surprisingly, the microscopic structures for which the amplitude dynamics improves synchronization are those that are statistically more abundant in random complex networks. Thus, amplitude dynamics leads to a general lowering of the synchronization threshold in arbitrary random topologies. Finally, we show that this synchronization enhancement is generic of oscillators close to Hopf bifurcations. To this aim we consider coupled FitzHugh-Nagumo units modeling neuron dynamics. PMID:27108847

  6. Decoder synchronization for deep space missions

    NASA Technical Reports Server (NTRS)

    Statman, J. I.; Cheung, K.-M.; Chauvin, T. H.; Rabkin, J.; Belongie, M. L.

    1994-01-01

    The Consultative Committee for Space Data Standards (CCSDS) recommends that space communication links employ a concatenated, error-correcting, channel-coding system in which the inner code is a convolutional (7,1/2) code and the outer code is a (255,223) Reed-Solomon code. The traditional implementation is to perform the node synchronization for the Viterbi decoder and the frame synchronization for the Reed-Solomon decoder as separate, sequential operations. This article discusses a unified synchronization technique that is required for deep space missions that have data rates and signal-to-noise ratios (SNR's) that are extremely low. This technique combines frame synchronization in the bit and symbol domains and traditional accumulated-metric growth techniques to establish a joint frame and node synchronization. A variation on this technique is used for the Galileo spacecraft on its Jupiter-bound mission.

  7. Synchronization of noisy systems by stochastic signals

    SciTech Connect

    Neiman, A.; Schimansky-Geier, L.; Moss, F.; Schimansky-Geier, L.; Shulgin, B.; Collins, J.J.

    1999-07-01

    We study, in terms of synchronization, the {ital nonlinear response} of noisy bistable systems to a stochastic external signal, represented by Markovian dichotomic noise. We propose a general kinetic model which allows us to conduct a full analytical study of the nonlinear response, including the calculation of cross-correlation measures, the mean switching frequency, and synchronization regions. Theoretical results are compared with numerical simulations of a noisy overdamped bistable oscillator. We show that dichotomic noise can instantaneously synchronize the switching process of the system. We also show that synchronization is most pronounced at an optimal noise level{emdash}this effect connects this phenomenon with aperiodic stochastic resonance. Similar synchronization effects are observed for a stochastic neuron model stimulated by a stochastic spike train. {copyright} {ital 1999} {ital The American Physical Society}

  8. Decoder synchronization for deep space missions

    NASA Astrophysics Data System (ADS)

    Statman, J. I.; Cheung, K.-M.; Chauvin, T. H.; Rabkin, J.; Belongie, M. L.

    1994-02-01

    The Consultative Committee for Space Data Standards (CCSDS) recommends that space communication links employ a concatenated, error-correcting, channel-coding system in which the inner code is a convolutional (7,1/2) code and the outer code is a (255,223) Reed-Solomon code. The traditional implementation is to perform the node synchronization for the Viterbi decoder and the frame synchronization for the Reed-Solomon decoder as separate, sequential operations. This article discusses a unified synchronization technique that is required for deep space missions that have data rates and signal-to-noise ratios (SNR's) that are extremely low. This technique combines frame synchronization in the bit and symbol domains and traditional accumulated-metric growth techniques to establish a joint frame and node synchronization. A variation on this technique is used for the Galileo spacecraft on its Jupiter-bound mission.

  9. Decoder Synchronization for Deep Space Missions

    NASA Astrophysics Data System (ADS)

    Statman, J. I.; Cheung, K.-M.; Chauvin, T. H.; Rabkin, J.; Belongie, M. L.

    1993-10-01

    The Consultative Committee for Space Data Standards (CCSDS) recommends that space communication links employ a concatenated, error-correcting, channel-coding system in which the inner code is a convolutional (7,1/2) code and the outer code is a (255,223) Reed-Solomon code. The traditional implementation is to perform the node synchronization for the Viterbi decoder and the frame synchronization for the Reed-Solomon decoder as separate, sequential operations. This article discusses a unified synchronization technique that is required for deep space missions that have data. rates and signal -to-noise ratios (SNRs) that are extremely low. This technique combines frame synchronization in the bit and symbol domains and traditional accumulated-metric growth techniques to establish a joint frame and node synchronization. A variation on this technique is used for the Galileo spacecraft on its Jupiter-bound mission.

  10. Pulse code modulated signal synchronizer

    NASA Technical Reports Server (NTRS)

    Kobayashi, H. S. (Inventor)

    1974-01-01

    A bit synchronizer for a split phase PCM transmission is reported that includes three loop circuits which receive incoming phase coded PCM signals. In the first loop, called a Q-loop, a generated, phase coded, PCM signal is multiplied with the incoming signals, and the frequency and phase of the generated signal are nulled to that of the incoming subcarrier signal. In the second loop, called a B-loop, a circuit multiplies a generated signal with incoming signals to null the phase of the generated signal in a bit phase locked relationship to the incoming signal. In a third loop, called the I-loop, a phase coded PCM signal is multiplied with the incoming signals for decoding the bit information from the PCM signal. A counter means is used for timing of the generated signals and timing of sample intervals for each bit period.

  11. Spiking optical patterns and synchronization

    NASA Astrophysics Data System (ADS)

    Rosenbluh, Michael; Aviad, Yaara; Cohen, Elad; Khaykovich, Lev; Kinzel, Wolfgang; Kopelowitz, Evi; Yoskovits, Pinhas; Kanter, Ido

    2007-10-01

    We analyze the time resolved spike statistics of a solitary and two mutually interacting chaotic semiconductor lasers whose chaos is characterized by apparently random, short intensity spikes. Repulsion between two successive spikes is observed, resulting in a refractory period, which is largest at laser threshold. For time intervals between spikes greater than the refractory period, the distribution of the intervals follows a Poisson distribution. The spiking pattern is highly periodic over time windows corresponding to the optical length of the external cavity, with a slow change of the spiking pattern as time increases. When zero-lag synchronization between two lasers is established, the statistics of the nearly perfectly matched spikes are not altered. The similarity of these features to those found in complex interacting neural networks, suggests the use of laser systems as simpler physical models for neural networks.

  12. Collapse of Synchronization in a Memristive Network

    NASA Astrophysics Data System (ADS)

    Lü, Mi; Wang, Chun-Ni; Tang, Jun; Ma, Jun

    2015-12-01

    For an oscillating circuit or coupled circuits, damage in electric devices such as inductor, resistance, memristor even capacitor can cause breakdown or collapse of the circuits. These damage could be associated with external attack or aging in electric devices, and then the bifurcation parameters could be deformed from normal values. Resonators or signal generators are often synchronized to produce powerful signal series and this problem could be investigated by using synchronization in network. Complete synchronization could be induced by linear coupling in a two-dimensional network of identical oscillators when the coupling intensity is beyond certain threshold. The collective behavior and synchronization state are much dependent on the bifurcation parameters. Any slight fluctuation in parameter and breakdown in bifurcation parameter can cause transition of synchronization even collapse of synchronization in the network. In this paper, a two-dimensional network composed of the resonators coupled with memristors under nearest-neighbor connection is designed, and the network can reach complete synchronization by carefully selecting coupling intensity. The network keeps synchronization after certain transient period, then a bifurcation parameter in a resonator is switched from the previous value and the adjacent resonators (oscillators) are affected in random. It is found that the synchronization area could be invaded greatly in a diffusive way. The damage area size is much dependent on the selection of diffusive period of damage and deformation degree in the parameter. Indeed, the synchronization area could keep intact at largest size under intermediate deformation degree and coupling intensity. Supported by the National Natural Science of China under Grant Nos. 11265008 and 11365014

  13. Reproductive performance of dairy cows managed with a program aimed at increasing insemination of cows in estrus based on increased physical activity and fertility of timed artificial inseminations.

    PubMed

    Giordano, J O; Stangaferro, M L; Wijma, R; Chandler, W C; Watters, R D

    2015-04-01

    The objective of this study was to compare the reproductive performance of lactating dairy cows using a treatment (TRT) program for second and subsequent artificial insemination (AI) services aimed at (1) increasing AI upon estrus detection based on increased physical activity (AIAct) and (2) increasing fertility of timed AI (TAI) services for cows not AIAct through presynchronization of the estrous cycle and improved physiological milieu before TAI. Cows in the control (CON) group were managed with a program that combined AIAct and TAI after the Ovsynch protocol. After nonpregnancy diagnosis (NPD) by transrectal ultrasonography at 31 ± 3 d after AI, cows received the following treatments: (1) CON (n=634), AIAct any time after a previous AI and resynchronization with the Ovsynch-56 protocol (GnRH-7d-PGF2α-56 h-GnRH-16 h-TAI) 1d after NPD, or (2) TRT (n = 616): cows with a corpus luteum (CL) ≥ 20 mm (TRT-CL) received a PGF2α injection 1d after NPD, whereas cows with no CL or a CL < 20 mm (TRT-NoCL) received a GnRH injection 3d after NPD. Cows in TRT-CL and TRT-NoCL not AIAct were enrolled in a 5-d Ovsynch + progesterone protocol (GnRH + controlled internal drug release-5d-PGF2α + controlled internal drug release removal-24 h-PGF2α -32 h-GnRH-16 h-TAI) 9 and 7d after the PGF2α or GnRH injection, respectively, to receive TAI. The hazard of pregnancy up to 270 DIM was similar for cows in the CON and TRT group (hazard ratio = 1.07, 95% CI = 0.95 to 1.21), but it was affected by parity (primiparous greater than multiparous cows). Median days to pregnancy for the CON and TRT group were 111 and 110 d, respectively. When evaluated after 104 DIM (first time point at which cows were affected by the treatments), the hazard of pregnancy was similar for the CON and TRT group (hazard ratio = 1.15, 95% CI = 0.95 to 1.39). Based on this analysis, median days to pregnancy for the CON and TRT group were 161 and 178 d, respectively. Thus, in spite of increasing the proportion

  14. Impact of thermal stress on the efficiency of ovulation synchronization protocols in Holstein cows.

    PubMed

    El-Tarabany, Mahmoud S; El-Tarabany, Akram A

    2015-09-01

    The objective of this study was to evaluate the impact of thermal stress on the efficiency of three different protocols to synchronize time of ovulation in purebred Holstein cows under subtropical Egyptian conditions. The influence of temperature humidity index (THI) on the conception, pregnancy, embryonic loss and early abortion rates were investigated. Conception and pregnancy rates using the CIDRsynch and Presynch (37.5% and 33.9%; 29.5 and 29. 6%, respectively) were significantly greater than that for cows expressing spontaneous estrus (SE) and with use of the Ovsynch (28.5% and 24.3%; 21.6% and 24.6%, respectively) treatment regimen. Conception and pregnancy rates using the Ovsynch protocol were significantly decreased from 31.6% and 26.3% at the lesser THI to 11.5% and 9.9%, respectively than at the greater THI [crude odds ratio (COR) = 0.28 and 0.32; P = 0.001 and 0.004, respectively]. However, conception (P/AI at 28 days) and pregnancy (P/AI at 75 days) rates using the Presynch protocol were significantly reduced at either the lesser or greater THI (COR = 0.47 and 0.42; 0.48 and 0.34, respectively). Embryonic loss rate with the Presynch group was significantly increased from 11.5% at the lesser THI to 22.2% at the greater THI (COR = 2.28; P = 0.039). In contrast, conception, pregnancy and embryonic loss rates did not differ significantly (P > 0.05) with the CIDRsynch protocol at the different THI. Results from the present study indicate that use of the CIDRsynch protocol may provide consistent and satisfactory conception and pregnancy rates in Holstein cows under subtropical environmental conditions. PMID:26297623

  15. Transmission of chimeric HIV by mating in conventional mice: prevention by pre-exposure antiretroviral therapy and reduced susceptibility during estrus

    PubMed Central

    Hadas, Eran; Chao, Wei; He, Hongxia; Saini, Manisha; Daley, Eleen; Saifuddin, Mohammed; Bentsman, Galina; Ganz, Eric; Volsky, David J.; Potash, Mary Jane

    2013-01-01

    SUMMARY Heterosexual transmission accounts for the majority of new human immunodeficiency virus (HIV) cases worldwide. The current approach to investigate HIV heterosexual transmission in animals involves application of virus stock to the vaginal surface, a method that does not reproduce the physiological conditions of vaginal intercourse that influence the rate of transmission. We have previously described efficient infection of conventional mice using EcoHIV/NL4-3 and EcoHIV/NDK, chimeric HIV molecular clones constructed to express all HIV structural and regulatory genes except envelope, which is replaced by a rodent-tropic envelope gene. Here we investigated whether EcoHIV/NDK-infected male mice transmit virus to females during coitus, and the sensitivity of this transmission to HIV pre-exposure prophylaxis and the estrus state. Our general approach was to allow mating between EcoHIV/NDK-infected male mice and uninfected females for 1–7 nights. At 1–6 weeks after mating, mice were euthanized and virus burdens were measured by quantitative PCR (qPCR) amplification of HIV RNA or DNA in peritoneal macrophages, inguinal lymph node cells, spleen cells or vas deferens, or by ELISA for antibodies to HIV Gag. We found that 70–100% of female mice mated to EcoHIV/NDK-infected males acquired infection. Pericoital treatment of females with either 2′,3′-dideoxcytidine (ddC) or tenofovir largely prevented their EcoHIV/NDK infection by mating (P<0.05 and P<0.003, respectively). In males, T cells were dispensable for virus transmission. The rate of EcoHIV/NDK sexual transmission to females in estrus declined sharply (P=0.003) but their infection by injection was unaffected, indicating that the local environment in the female reproductive tract influences susceptibility to HIV. We conclude that this system of EcoHIV/NDK transmission during mouse mating reproduces key features of heterosexual transmission of HIV in humans and can be used to investigate its biology and

  16. Periodic and aperiodic synchronization in skilled action.

    PubMed

    Cummins, Fred

    2011-01-01

    Synchronized action is considered as a manifestation of shared skill. Most synchronized behaviors in humans and other animals are based on periodic repetition. Aperiodic synchronization of complex action is found in the experimental task of synchronous speaking, in which naive subjects read a common text in lock step. The demonstration of synchronized behavior without a periodic basis is presented as a challenge for theoretical understanding. A unified treatment of periodic and aperiodic synchronization is suggested by replacing the sequential processing model of cognitivist approaches with the more local notion of a task-specific sensorimotor coordination. On this view, skilled action is the imposition of constraints on the co-variation of movement and sensory flux such that the boundary conditions that define the skill are met. This non-cognitivist approach originates in the work of John Dewey. It allows a unification of the treatment of sensorimotor synchronization in simple rhythmic behavior and in complex skilled behavior and it suggests that skill sharing is a uniquely human trait of considerable import. PMID:22232583

  17. V123 BEAM SYNCHRONOUS ENCODER MODULE.

    SciTech Connect

    KERNER,T.; CONKLING,C.R.; OERTER,B.

    1999-03-29

    The V123 Synchronous Encoder Module transmits events to distributed trigger modules and embedded decoders around the RHIC rings where they are used to provide beam instrumentation triggers [1,2,3]. The RHIC beam synchronous event link hardware is mainly comprised of three VMEbus board designs, the central input modules (V201), and encoder modules (V123), and the distributed trigger modules (V124). Two beam synchronous links, one for each ring, are distributed via fiber optics and fanned out via twisted wire pair cables. The V123 synchronizes with the RF system clock derived from the beam bucket frequency and a revolution fiducial pulse. The RF system clock is used to create the beam synchronous event link carrier and events are synchronized with the rotation fiducial. A low jitter RF clock is later recovered from this carrier by phase lock loops in the trigger modules. Prioritized hardware and software triggers fill up to 15 beam event code transmission slots per revolution while tracking the ramping RF acceleration frequency and storage frequency. The revolution fiducial event is always the first event transmitted which is used to synchronize the firing of the abort kicker and to locate the first bucket for decoders distributed about the ring.

  18. System Synchronizes Recordings from Separated Video Cameras

    NASA Technical Reports Server (NTRS)

    Nail, William; Nail, William L.; Nail, Jasper M.; Le, Doung T.

    2009-01-01

    A system of electronic hardware and software for synchronizing recordings from multiple, physically separated video cameras is being developed, primarily for use in multiple-look-angle video production. The system, the time code used in the system, and the underlying method of synchronization upon which the design of the system is based are denoted generally by the term "Geo-TimeCode(TradeMark)." The system is embodied mostly in compact, lightweight, portable units (see figure) denoted video time-code units (VTUs) - one VTU for each video camera. The system is scalable in that any number of camera recordings can be synchronized. The estimated retail price per unit would be about $350 (in 2006 dollars). The need for this or another synchronization system external to video cameras arises because most video cameras do not include internal means for maintaining synchronization with other video cameras. Unlike prior video-camera-synchronization systems, this system does not depend on continuous cable or radio links between cameras (however, it does depend on occasional cable links lasting a few seconds). Also, whereas the time codes used in prior video-camera-synchronization systems typically repeat after 24 hours, the time code used in this system does not repeat for slightly more than 136 years; hence, this system is much better suited for long-term deployment of multiple cameras.

  19. Periodic and Aperiodic Synchronization in Skilled Action

    PubMed Central

    Cummins, Fred

    2011-01-01

    Synchronized action is considered as a manifestation of shared skill. Most synchronized behaviors in humans and other animals are based on periodic repetition. Aperiodic synchronization of complex action is found in the experimental task of synchronous speaking, in which naive subjects read a common text in lock step. The demonstration of synchronized behavior without a periodic basis is presented as a challenge for theoretical understanding. A unified treatment of periodic and aperiodic synchronization is suggested by replacing the sequential processing model of cognitivist approaches with the more local notion of a task-specific sensorimotor coordination. On this view, skilled action is the imposition of constraints on the co-variation of movement and sensory flux such that the boundary conditions that define the skill are met. This non-cognitivist approach originates in the work of John Dewey. It allows a unification of the treatment of sensorimotor synchronization in simple rhythmic behavior and in complex skilled behavior and it suggests that skill sharing is a uniquely human trait of considerable import. PMID:22232583

  20. Physiological Synchronization in a Vigilance Dual Task.

    PubMed

    Guastello, Stephen J

    2016-01-01

    The synchronization of autonomic arousal levels and other physio-logical responses between people is a potentially important component of work team performance, client-therapist relationships, and other types of human interaction. This study addressed several problems: What statistical models are viable for identifying synchronization for loosely coupled human systems? How is the level of synchronization related to psychosocial variables such as empathy, subjective ratings of workload, and actual performance? Participants were 70 undergraduates who worked in pairs on a vigilance dual task in which they watched a virtual reality security camera, rang a bell when they saw the target intruder, and completed a jig-saw puzzle. Event rates either increased or decreased during the 90 min work period. The average R2 values for each person were .66, .66, .62, and .53 for the linear autoregressive model, linear autoregressive model with a synchronization component, the nonlinear autoregressive model, and the nonlinear autoregressive model with a synchronization component, respectively. All models were more accurate at a lag of 20 sec compared to 50 sec or customized lag lengths. Although the linear models were more accurate overall, the nonlinear synchronization parameters were more often related to psychological variables and performance. In particular, greater synchronization was observed with the nonlinear model when the target event rate increased, compared to when it decreased, which was expected from the general theory of synchronization. Nonlinear models were also more effective for uncovering inhibitory or dampening relationships between the co-workers as well as mutually excitatory relationships. Future research should explore the comparative model results for tasks that induce higher levels of synchronization and involve different types of internal group coordination. PMID:26639921

  1. Synchronization of eukaryotic cells by periodic forcing.

    PubMed

    Battogtokh, Dorjsuren; Aihara, Kazuyuki; Tyson, John J

    2006-04-14

    We study a cell population described by a minimal mathematical model of the eukaryotic cell cycle subject to periodic forcing that simultaneously perturbs the dynamics of the cell cycle engine and cell growth, and we show that the population can be synchronized in a mode-locked regime. By simplifying the model to two variables, for the phase of cell cycle progression and the mass of the cell, we calculate the Lyapunov exponents to obtain the parameter window for synchronization. We also discuss the effects of intrinsic mitotic fluctuations, asymmetric division, and weak mutual coupling on the pace of synchronization. PMID:16712125

  2. Conditional ramsey spectroscopy with synchronized atoms.

    PubMed

    Xu, Minghui; Holland, M J

    2015-03-13

    We investigate Ramsey spectroscopy performed on a synchronized ensemble of two-level atoms. The synchronization is induced by the collective coupling of the atoms to a heavily damped mode of an optical cavity. We show that, in principle, with this synchronized system it is possible to observe Ramsey fringes indefinitely, even in the presence of spontaneous emission and other sources of individual-atom dephasing. This could have important consequences for atomic clocks and a wide range of precision metrology applications. PMID:25815931

  3. Complex Synchronization Phenomena in Ecological Systems

    NASA Astrophysics Data System (ADS)

    Stone, Lewi; Olinky, Ronen; Blasius, Bernd; Huppert, Amit; Cazelles, Bernard

    2002-07-01

    Ecological and biological systems provide us with many striking examples of synchronization phenomena. Here we discuss a number of intriguing cases and attempt to explain them taking advantage of a modelling framework. One main focus will concern synchronized ecological end epidemiological cycles which have Uniform Phase growth associated with their regular recurrence, and Chaotic Amplitudes - a feature we term UPCA. Examples come from different areas and include decadal cycles of small mammals, recurrent viral epidemics such as childhood infections (eg., measles), and seasonally driven phytoplankton blooms observed in lakes and the oceans. A more detailed theoretical analysis of seasonally synchronized chaotic population cycles is presented.

  4. Are feedback loops destructive to synchronization?

    NASA Astrophysics Data System (ADS)

    Sheshbolouki, A.; Zarei, M.; Sarbazi-Azad, H.

    2015-08-01

    We study the effects of directionality on synchronization of dynamical networks. Performing the linear stability analysis and the numerical simulation of the Kuramoto model in directed networks, we show that balancing in- and out-degrees of all nodes enhances the synchronization of sparse networks, especially in networks with high clustering coefficient and homogeneous degree distribution. Furthermore, by omitting all the feedback loops, we show that while hierarchical directed acyclic graphs are structurally highly synchronizable, their global synchronization is too sensitive to the choice of natural frequencies and is strongly affected by noise.

  5. Synchronization Phenomena and Epoch Filter of Electroencephalogram

    NASA Astrophysics Data System (ADS)

    Matani, Ayumu

    Nonlinear electrophysiological synchronization phenomena in the brain, such as event-related (de)synchronization, long distance synchronization, and phase-reset, have received much attention in neuroscience over the last decade. These phenomena contain more electrical than physiological keywords and actually require electrical techniques to capture with electroencephalography (EEG). For instance, epoch filters, which have just recently been proposed, allow us to investigate such phenomena. Moreover, epoch filters are still developing and would hopefully generate a new paradigm in neuroscience from an electrical engineering viewpoint. Consequently, electrical engineers could be interested in EEG once again or from now on.

  6. Quantum Clock Synchronization with a Single Qudit

    PubMed Central

    Tavakoli, Armin; Cabello, Adán; Żukowski, Marek; Bourennane, Mohamed

    2015-01-01

    Clock synchronization for nonfaulty processes in multiprocess networks is indispensable for a variety of technologies. A reliable system must be able to resynchronize the nonfaulty processes upon some components failing causing the distribution of incorrect or conflicting information in the network. The task of synchronizing such networks is related to Byzantine agreement (BA), which can classically be solved using recursive algorithms if and only if less than one-third of the processes are faulty. Here we introduce a nonrecursive quantum algorithm, based on a quantum solution of the detectable BA, which achieves clock synchronization in the presence of arbitrary many faulty processes by using only a single quantum system. PMID:25613754

  7. Multistability of synchronous regimes in rotator ensembles.

    PubMed

    Kryukov, A K; Petrov, V S; Osipov, G V; Kurths, J

    2015-12-01

    We study collective dynamics in rotator ensembles and focus on the multistability of synchronous regimes in a chain of coupled rotators. We provide a detailed analysis of the number of coexisting regimes and estimate in particular, the synchronization boundary for different types of individual frequency distribution. The number of wave-based regimes coexisting for the same parameters and its dependence on the chain length are estimated. We give an analytical estimation for the synchronization frequency of the in-phase regime for a uniform individual frequency distribution. PMID:26723160

  8. Synchronization System for Next Generation Light Sources

    SciTech Connect

    Zavriyev, Anton

    2014-03-27

    An alternative synchronization technique – one that would allow explicit control of the pulse train including its repetition rate and delay is clearly desired. We propose such a scheme. Our method is based on optical interferometry and permits synchronization of the pulse trains generated by two independent mode-locked lasers. As the next generation x-ray sources will be driven by a clock signal derived from a mode-locked optical source, our technique will provide a way to synchronize x-ray probe with the optical pump pulses.

  9. Using GLONASS signal for clock synchronization

    NASA Technical Reports Server (NTRS)

    Gouzhva, Yuri G.; Gevorkyan, Arvid G.; Bogdanov, Pyotr P.; Ovchinnikov, Vitaly V.

    1994-01-01

    Although in accuracy parameters GLONASS is correlated with GPS, using GLONASS signals for high-precision clock synchronization was, up to the recent time, of limited utility due to the lack of specialized time receivers. In order to improve this situation, in late 1992 the Russian Institute of Radionavigation and Time (RMT) began to develop a GLONASS time receiver using as a basis the airborne ASN-16 receiver. This paper presents results of estimating user clock synchronization accuracy via GLONASS signals using ASN-16 receiver in the direct synchronization and common-view modes.

  10. Suppressing explosive synchronization by contrarians

    NASA Astrophysics Data System (ADS)

    Zhang, Xiyun; Guan, Shuguang; Zou, Yong; Chen, Xiaosong; Liu, Zonghua

    2016-01-01

    Explosive synchronization (ES) has recently received increasing attention and studies have mainly focused on the conditions of its onset so far. However, its inverse problem, i.e. the suppression of ES, has not been systematically studied so far. As ES is usually considered to be harmful in certain circumstances such as the cascading failure of power grids and epileptic seizure, etc., its suppression is definitely important and deserves to be studied. We here study this inverse problem by presenting an efficient approach to suppress ES from a first-order to second-order transition, without changing the intrinsic network structure. We find that ES can be suppressed by only changing a small fraction of oscillators into contrarians with negative couplings and the critical fraction for the transition from the first order to the second order increases with both the network size and the average degree. A brief theory is presented to explain the underlying mechanism. This finding underlines the importance of our method to improve the understanding of neural interactions underlying cognitive processes.

  11. Synchronization Model for Pulsating Variables

    NASA Astrophysics Data System (ADS)

    Takahashi, S.; Morikawa, M.

    2013-12-01

    A simple model is proposed, which describes the variety of stellar pulsations. In this model, a star is described as an integration of independent elements which interact with each other. This interaction, which may be gravitational or hydrodynamic, promotes the synchronization of elements to yield a coherent mean field pulsation provided some conditions are satisfied. In the case of opacity driven pulsations, the whole star is described as a coupling of many heat engines. In the case of stochastic oscillation, the whole star is described as a coupling of convection cells, interacting through their flow patterns. Convection cells are described by the Lorentz model. In both models, interactions of elements lead to various pulsations, from irregular to regular. The coupled Lorenz model also describes a light curve which shows a semi-regular variability and also shows a low-frequency enhancement proportional to 1/f in its power spectrum. This is in agreement with observations (Kiss et al. 2006). This new modeling method of ‘coupled elements’ may provide a powerful description for a variety of stellar pulsations.

  12. Genes in the GABA Pathway Increase in the Lateral Thalamus of Sprague-Dawley Rats During the Proestrus/Estrus Phase.

    PubMed

    Umorin, Mikhail; Stinson, Crystal; Bellinger, Larry L; Kramer, Phillip R

    2016-05-01

    Pain can vary over the estrous cycle as a result of changes in estradiol concentration but the mechanism causing this variation is unclear. Because the thalamus is important in pain control, gene expression in the lateral thalamus (ventral posteromedial, ventral posterolateral, reticular thalamic nuclei) was screened at different phases of the estrous cycle. Gene expression changes in Sprague-Dawley rats were further analyzed by real-time PCR and ELISA and plasma estradiol levels were measured by RIAs at different phases of the estrous cycle. Our results indicated that both the RNA and protein expression of glutamate decarboxylase 1 and 2 (GAD1, GAD2), GABA(A) receptor-associated protein like 1 (GABARAPL1), and vesicular GABA transporter (VGAT) significantly increased in the lateral thalamus when plasma estradiol levels were elevated. Estradiol levels were elevated during the proestrus and estrus phases of the estrous cycle. Estrogen receptor α (ERα) was observed to be co-localized in thalamic cells and thalamic infusion of an ERα antagonist significantly reduced GAD1 and VGAT transcript. GAD1, GAD2, GABARAPL1, and VGAT have been shown to effect neuronal responses suggesting that attenuation of pain during the estrous cycle can be dependent, in part, through estradiol induced changes in thalamic gene expression. PMID:26388520

  13. Remote bistatic receiver synchronization using DLL techniques

    NASA Astrophysics Data System (ADS)

    Aguasca, A.; Broquetas, A.; Fdez de Muniain, J.; Ambros, A.

    An experimental staggered pulse repetition frequency synchronizer, based on a delay-lock loop (DLL) was tested using a transmitter signal simulator that simulates the staggering sequence windowed by the antenna beam. The measured system performance ensures synchronization with a 30-ms direct illumination, with an accumulated delay error in the order of the resolution cell positioning error in range. An artificial time expansion of the received pulses is performed in order to reduce the acquisition time synchronization. A bistatic radar synchronization method based on DLL was is analyzed by linearization of the different parts and signals involved. The parameters that degrade system performance are obtained. And some solutions are represented in order to minimize their effects.

  14. Quantum Synchronization of three-level atoms

    NASA Astrophysics Data System (ADS)

    He, Peiru; Rey, Ana Maria; Holland, Murray

    2015-05-01

    Recent studies show that quantum synchronization, the spontaneous alignment of the quantum phase between different oscillators, can be used to build superradiant lasers with ultranarrow linewidth. We theoretically investigate the effect of quantum synchronization on many coupled three-level atoms where there are richer phase diagrams than the standard two-level system. This three-level model allows two-color ultranarrow coherent light to be produced where more than one phase must be simultaneously synchronized. Of particular interest, we study the V-type geometry that is relevant to current 87 Sr experiments in JILA. As well as the synchronization phenomenon, we explore other quantum effects such as photon correlations and squeezing. This work is supported by the DARPA QuASAR program, the NSF, and NIST.

  15. Stochastic Hydrodynamic Synchronization in Rotating Energy Landscapes

    NASA Astrophysics Data System (ADS)

    Koumakis, N.; Di Leonardo, R.

    2013-04-01

    Hydrodynamic synchronization provides a general mechanism for the spontaneous emergence of coherent beating states in independently driven mesoscopic oscillators. A complete physical picture of those phenomena is of definite importance to the understanding of biological cooperative motions of cilia and flagella. Moreover, it can potentially suggest novel routes to exploit synchronization in technological applications of soft matter. We demonstrate that driving colloidal particles in rotating energy landscapes results in a strong tendency towards synchronization, favoring states where all beads rotate in phase. The resulting dynamics can be described in terms of activated jumps with transition rates that are strongly affected by hydrodynamics leading to an increased probability and lifetime of the synchronous states. Using holographic optical tweezers we quantitatively verify our predictions in a variety of spatial configurations of rotors.

  16. Method and system for downhole clock synchronization

    DOEpatents

    Hall, David R.; Bartholomew, David B.; Johnson, Monte; Moon, Justin; Koehler, Roger O.

    2006-11-28

    A method and system for use in synchronizing at least two clocks in a downhole network are disclosed. The method comprises determining a total signal latency between a controlling processing element and at least one downhole processing element in a downhole network and sending a synchronizing time over the downhole network to the at least one downhole processing element adjusted for the signal latency. Electronic time stamps may be used to measure latency between processing elements. A system for electrically synchronizing at least two clocks connected to a downhole network comprises a controlling processing element connected to a synchronizing clock in communication over a downhole network with at least one downhole processing element comprising at least one downhole clock. Preferably, the downhole network is integrated into a downhole tool string.

  17. On the Synchronization of Acoustic Gravity Waves

    NASA Astrophysics Data System (ADS)

    Lonngren, Karl E.; Bai, Er-Wei

    Using the model proposed by Stenflo, we demonstrate that acoustic gravity waves found in one region of space can be synchronized with acoustic gravity waves found in another region of space using techniques from modern control theory.

  18. Controlling synchronous patterns in complex networks

    NASA Astrophysics Data System (ADS)

    Lin, Weijie; Fan, Huawei; Wang, Ying; Ying, Heping; Wang, Xingang

    2016-04-01

    Although the set of permutation symmetries of a complex network could be very large, few of them give rise to stable synchronous patterns. Here we present a general framework and develop techniques for controlling synchronization patterns in complex network of coupled chaotic oscillators. Specifically, according to the network permutation symmetry, we design a small-size and weighted network, namely the control network, and use it to control the large-size complex network by means of pinning coupling. We argue mathematically that for any of the network symmetries, there always exists a critical pinning strength beyond which the unstable synchronous pattern associated to this symmetry can be stabilized. The feasibility of the control method is verified by numerical simulations of both artificial and real-world networks and demonstrated experimentally in systems of coupled chaotic circuits. Our studies show the controllability of synchronous patterns in complex networks of coupled chaotic oscillators.

  19. Synchronous correlation matrices and Connes' embedding conjecture

    NASA Astrophysics Data System (ADS)

    Dykema, Kenneth J.; Paulsen, Vern

    2016-01-01

    In the work of Paulsen et al. [J. Funct. Anal. (in press); preprint arXiv:1407.6918], the concept of synchronous quantum correlation matrices was introduced and these were shown to correspond to traces on certain C*-algebras. In particular, synchronous correlation matrices arose in their study of various versions of quantum chromatic numbers of graphs and other quantum versions of graph theoretic parameters. In this paper, we develop these ideas further, focusing on the relations between synchronous correlation matrices and microstates. We prove that Connes' embedding conjecture is equivalent to the equality of two families of synchronous quantum correlation matrices. We prove that if Connes' embedding conjecture has a positive answer, then the tracial rank and projective rank are equal for every graph. We then apply these results to more general non-local games.

  20. [Synchronous carcinomas of the colon and rectum].

    PubMed

    Mandarano, R; Ciccone, A

    1995-12-01

    The authors base their observations on 3 cases of synchronous carcinoma of the large intestine and 1 case of association of cancer on polyps and synchronous colorectal carcinoma. After a short review of the etiopathogenetic and diagnostic aspects, they focus attention in particular on the various types on surgical approach which synchronous carcinoma of the large intestine offer to surgeons. The authors underline that numerous forms of surgery exist which are often complex and difficult, especially if multiple neoplasia involve separate colic segments and above all if they affect the distal rectal section. In conclusion, they affirm that the association of cancer on polyps and synchronous colorectal carcinoma is not rare and should be treated using combined endoscopic and surgical therapy. To the precise colic exeresis should be followed by endoscopic resection in the case of a scissil, villous polyps with high non-differentiated neoplastic tissue laying close on the endoscopic plane of section. PMID:8725069

  1. Synchronization in chaotic oscillators by cyclic coupling

    NASA Astrophysics Data System (ADS)

    Olusola, O. I.; Njah, A. N.; Dana, S. K.

    2013-07-01

    We introduce a type of cyclic coupling to investigate synchronization of chaotic oscillators. We derive analytical solutions of the critical coupling for stable synchronization under the cyclic coupling for the Rössler system and the Lorenz oscillator as paradigmatic illustration. Based on the master stability function (MSF) approach, the analytical results on critical coupling are verified numerically. An enhancing effect in terms of lowering the critical coupling or enlarging the synchronization window in a critical coupling space is noticed. The cyclic coupling is also applied in other models, Hindmarsh-Rose model, Sprott system, Chen system and forced Duffing system to confirm the enhancing effect. The cyclic coupling allows tuning of two coupling constants in reverse directions when an optimal control of synchronization is feasible.

  2. Optimal Synchronization of a Memristive Chaotic Circuit

    NASA Astrophysics Data System (ADS)

    Kountchou, Michaux; Louodop, Patrick; Bowong, Samuel; Fotsin, Hilaire; Kurths, Jurgen

    2016-06-01

    This paper deals with the problem of optimal synchronization of two identical memristive chaotic systems. We first study some basic dynamical properties and behaviors of a memristor oscillator with a simple topology. An electronic circuit (analog simulator) is proposed to investigate the dynamical behavior of the system. An optimal synchronization strategy based on the controllability functions method with a mixed cost functional is investigated. A finite horizon is explicitly computed such that the chaos synchronization is achieved at an established time. Numerical simulations are presented to verify the effectiveness of the proposed synchronization strategy. Pspice analog circuit implementation of the complete master-slave-controller systems is also presented to show the feasibility of the proposed scheme.

  3. Analysis of FDDI synchronous traffic delays

    NASA Technical Reports Server (NTRS)

    Johnson, Marjory J.

    1988-01-01

    The Fiber Distributed Data Interface (FDDI) high-speed token-ring protocol provides support for two classes of service: synchronous, to support applications which require deterministic access to the channel, and asynchronous, to support applications which do not have such stringent response-time requirements. The purpose of this paper is to determine how to set ring parameters to support synchronous traffic most efficiently. Both theoretical results and results obtained from a simulation study are presented.

  4. Automated ILA design for synchronous sequential circuits

    NASA Technical Reports Server (NTRS)

    Liu, M. N.; Liu, K. Z.; Maki, G. K.; Whitaker, S. R.

    1991-01-01

    An iterative logic array (ILA) architecture for synchronous sequential circuits is presented. This technique utilizes linear algebra to produce the design equations. The ILA realization of synchronous sequential logic can be fully automated with a computer program. A programmable design procedure is proposed to fullfill the design task and layout generation. A software algorithm in the C language has been developed and tested to generate 1 micron CMOS layouts using the Hewlett-Packard FUNGEN module generator shell.

  5. Empirical synchronized flow in oversaturated city traffic.

    PubMed

    Kerner, Boris S; Hemmerle, Peter; Koller, Micha; Hermanns, Gerhard; Klenov, Sergey L; Rehborn, Hubert; Schreckenberg, Michael

    2014-09-01

    Based on a study of anonymized GPS probe vehicle traces measured by personal navigation devices in vehicles randomly distributed in city traffic, empirical synchronized flow in oversaturated city traffic has been revealed. It turns out that real oversaturated city traffic resulting from speed breakdown in a city in most cases can be considered random spatiotemporal alternations between sequences of moving queues and synchronized flow patterns in which the moving queues do not occur. PMID:25314485

  6. Flagellar Synchronization Independent of Hydrodynamic Interactions

    NASA Astrophysics Data System (ADS)

    Friedrich, Benjamin M.; Jülicher, Frank

    2012-09-01

    Inspired by the coordinated beating of the flagellar pair of the green algae Chlamydomonas, we study theoretically a simple, mirror-symmetric swimmer, which propels itself at low Reynolds number by a revolving motion of a pair of spheres. We show that perfect synchronization between these two driven spheres can occur due to the motion of the swimmer and local hydrodynamic friction forces. Hydrodynamic interactions, though crucial for net propulsion, contribute little to synchronization for this free-moving swimmer.

  7. Empirical synchronized flow in oversaturated city traffic

    NASA Astrophysics Data System (ADS)

    Kerner, Boris S.; Hemmerle, Peter; Koller, Micha; Hermanns, Gerhard; Klenov, Sergey L.; Rehborn, Hubert; Schreckenberg, Michael

    2014-09-01

    Based on a study of anonymized GPS probe vehicle traces measured by personal navigation devices in vehicles randomly distributed in city traffic, empirical synchronized flow in oversaturated city traffic has been revealed. It turns out that real oversaturated city traffic resulting from speed breakdown in a city in most cases can be considered random spatiotemporal alternations between sequences of moving queues and synchronized flow patterns in which the moving queues do not occur.

  8. Synchronized Flashing Lights For Approach And Docking

    NASA Technical Reports Server (NTRS)

    Book, Michael L.; Howard, Richard T.; Bryan, Thomas C.; Bell, Joseph L.

    1994-01-01

    Proposed optoelectronic system for guiding vehicle in approaching and docking with another vehicle includes active optical targets (flashing lights) on approached vehicle synchronized with sensor and image-processing circuitry on approaching vehicle. Conceived for use in automated approach and docking of two spacecraft. Also applicable on Earth to manually controlled and automated approach and docking of land vehicles, aircraft, boats, and submersible vehicles, using GPS or terrestrial broadcast time signals for synchronization. Principal advantage: optical power reduced, with consequent enhancement of safety.

  9. Synchronization of coupled large-scale Boolean networks

    SciTech Connect

    Li, Fangfei

    2014-03-15

    This paper investigates the complete synchronization and partial synchronization of two large-scale Boolean networks. First, the aggregation algorithm towards large-scale Boolean network is reviewed. Second, the aggregation algorithm is applied to study the complete synchronization and partial synchronization of large-scale Boolean networks. Finally, an illustrative example is presented to show the efficiency of the proposed results.

  10. An algorithm for the automatic synchronization of Omega receivers

    NASA Technical Reports Server (NTRS)

    Stonestreet, W. M.; Marzetta, T. L.

    1977-01-01

    The Omega navigation system and the requirement for receiver synchronization are discussed. A description of the synchronization algorithm is provided. The numerical simulation and its associated assumptions were examined and results of the simulation are presented. The suggested form of the synchronization algorithm and the suggested receiver design values were surveyed. A Fortran of the synchronization algorithm used in the simulation was also included.

  11. Optimal synchronization of directed complex networks

    NASA Astrophysics Data System (ADS)

    Skardal, Per Sebastian; Taylor, Dane; Sun, Jie

    2016-09-01

    We study optimal synchronization of networks of coupled phase oscillators. We extend previous theory for optimizing the synchronization properties of undirected networks to the important case of directed networks. We derive a generalized synchrony alignment function that encodes the interplay between the network structure and the oscillators' natural frequencies and serves as an objective measure for the network's degree of synchronization. Using the generalized synchrony alignment function, we show that a network's synchronization properties can be systematically optimized. This framework also allows us to study the properties of synchrony-optimized networks, and in particular, investigate the role of directed network properties such as nodal in- and out-degrees. For instance, we find that in optimally rewired networks, the heterogeneity of the in-degree distribution roughly matches the heterogeneity of the natural frequency distribution, but no such relationship emerges for out-degrees. We also observe that a network's synchronization properties are promoted by a strong correlation between the nodal in-degrees and the natural frequencies of oscillators, whereas the relationship between the nodal out-degrees and the natural frequencies has comparatively little effect. This result is supported by our theory, which indicates that synchronization is promoted by a strong alignment of the natural frequencies with the left singular vectors corresponding to the largest singular values of the Laplacian matrix.

  12. Frame Synchronization Without Attached Sync Markers

    NASA Technical Reports Server (NTRS)

    Hamkins, Jon

    2011-01-01

    We describe a method to synchronize codeword frames without making use of attached synchronization markers (ASMs). Instead, the synchronizer identifies the code structure present in the received symbols, by operating the decoder for a handful of iterations at each possible symbol offset and forming an appropriate metric. This method is computationally more complex and doesn't perform as well as frame synchronizers that utilize an ASM; nevertheless, the new synchronizer acquires frame synchronization in about two seconds when using a 600 kbps software decoder, and would take about 15 milliseconds on prototype hardware. It also eliminates the need for the ASMs, which is an attractive feature for short uplink codes whose coding gain would be diminished by the overheard of ASM bits. The lack of ASMs also would simplify clock distribution for the AR4JA low-density parity-check (LDPC) codes and adds a small amount to the coding gain as well (up to 0.2 dB).

  13. Explosive synchronization transitions in complex neural networks

    NASA Astrophysics Data System (ADS)

    Chen, Hanshuang; He, Gang; Huang, Feng; Shen, Chuansheng; Hou, Zhonghuai

    2013-09-01

    It has been recently reported that explosive synchronization transitions can take place in networks of phase oscillators [Gómez-Gardeñes et al. Phys. Rev. Lett. 106, 128701 (2011)] and chaotic oscillators [Leyva et al. Phys. Rev. Lett. 108, 168702 (2012)]. Here, we investigate the effect of a microscopic correlation between the dynamics and the interacting topology of coupled FitzHugh-Nagumo oscillators on phase synchronization transition in Barabási-Albert (BA) scale-free networks and Erdös-Rényi (ER) random networks. We show that, if natural frequencies of the oscillations are positively correlated with node degrees and the width of the frequency distribution is larger than a threshold value, a strong hysteresis loop arises in the synchronization diagram of BA networks, indicating the evidence of an explosive transition towards synchronization of relaxation oscillators system. In contrast to the results in BA networks, in more homogeneous ER networks, the synchronization transition is always of continuous type regardless of the width of the frequency distribution. Moreover, we consider the effect of degree-mixing patterns on the nature of the synchronization transition, and find that the degree assortativity is unfavorable for the occurrence of such an explosive transition.

  14. Quantum synchronization in an optomechanical system based on Lyapunov control

    NASA Astrophysics Data System (ADS)

    Li, Wenlin; Li, Chong; Song, Heshan

    2016-06-01

    We extend the concepts of quantum complete synchronization and phase synchronization, which were proposed in A. Mari et al., Phys. Rev. Lett. 111, 103605 (2013), 10.1103/PhysRevLett.111.103605, to more widespread quantum generalized synchronization. Generalized synchronization can be considered a necessary condition or a more flexible derivative of complete synchronization, and its criterion and synchronization measure are proposed and analyzed in this paper. As examples, we consider two typical generalized synchronizations in a designed optomechanical system. Unlike the effort to construct a special coupling synchronization system, we purposefully design extra control fields based on Lyapunov control theory. We find that the Lyapunov function can adapt to more flexible control objectives, which is more suitable for generalized synchronization control, and the control fields can be achieved simply with a time-variant voltage. Finally, the existence of quantum entanglement in different generalized synchronizations is also discussed.

  15. Self synchronization of surface discharges

    NASA Astrophysics Data System (ADS)

    Allegraud, Katia; Rousseau, Antoine

    2008-10-01

    Surface dielectric barrier discharges (SDBD) are mainly investigated for airflow control. In this paper, they are used to study surface processes in dielectric barrier discharges. A previous study has shown the self triggered behavior of a SDBD: the plasma initiates through several simultaneous and adjacent filaments around the electrode [1]. This phenomenon has been investigated under the name of collective effects, where the light of a first filament can trigger the ignitions its neighbors [1, 2]. It allows initiating several tens of streamers during a current peak of ˜50 ns. In the present study, we propose to investigate the self synchronization of the discharge in a two electrodes system: the setup consists of two high voltage electrodes on the same glass plate. A third electrode, under the plate, is grounded. ICCD measurements show that the discharge appears simultaneously on both electrodes on a 50 ns time scale. Nanosecond resolved measurements of the streamers propagation reveal that the ignitions on one electrode can be delayed by few nanoseconds in respect to the other one. This means that the discharge from a first electrode can trigger the second one. Finally, iCCD measurements allow calculating the streamers propagation velocity, varying from 3.4x10^7 cm/s at the beginning of the propagation to 0.7x10^7cm/s at the end of the propagation [3]. [1] K. Allegraud, O. Guaitella, A. Rousseau, J. Phys. D. : Appl. Phys. 40 7698--7706 (2007) [2] O. Guaitella, F. Thevenet, C. Guillard, A. Rousseau, J. Phys. D.: Appl. Phys. 39 2964--72 (2006) [3] K. Allegraud, A. Rousseau, submitted to IEEE Transactions on Dielectrics and Electrical Insulation

  16. Nonlinear Chemical Dynamics and Synchronization

    NASA Astrophysics Data System (ADS)

    Li, Ning

    Alan Turing's work on morphogenesis, more than half a century ago, continues to motivate and inspire theoretical and experimental biologists even today. That said, there are very few experimental systems for which Turing's theory is applicable. In this thesis we present an experimental reaction-diffusion system ideally suited for testing Turing's ideas in synthetic "cells" consisting of microfluidically produced surfactant-stabilized emulsions in which droplets containing the Belousov-Zhabotinsky (BZ) oscillatory chemical reactants are dispersed in oil. The BZ reaction has become the prototype of nonlinear dynamics in chemistry and a preferred system for exploring the behavior of coupled nonlinear oscillators. Our system consists of a surfactant stabilized monodisperse emulsion of drops of aqueous BZ solution dispersed in a continuous phase of oil. In contrast to biology, here the chemistry is understood, rate constants are measured and interdrop coupling is purely diffusive. We explore a large set of parameters through control of rate constants, drop size, spacing, and spatial arrangement of the drops in lines and rings in one-dimension (1D) and hexagonal arrays in two-dimensions (2D). The Turing model is regarded as a metaphor for morphogenesis in biology but not for prediction. Here, we develop a quantitative and falsifiable reaction-diffusion model that we experimentally test with synthetic cells. We quantitatively establish the extent to which the Turing model in 1D describes both stationary pattern formation and temporal synchronization of chemical oscillators via reaction-diffusion and in 2D demonstrate that chemical morphogenesis drives physical differentiation in synthetic cells.

  17. A survey of synchronization methods for parallel computers

    SciTech Connect

    Dinning, A. )

    1989-07-01

    This article examines how traditional synchronization methods influence the design of MIMD multiprocessors. This particular class of architectures is one in which high-level synchronization plays an important role. Although vector processors, dataflow machines, and single instruction, multiple-data (SIMD) computers are highly synchronized, their synchronization is generally an explicit part of the control flow and is executed as part of every instruction. In MIMD multiprocessors, synchronization must occur on demand, so more sophisticated schemes are needed.

  18. Synchronous states of slowly rotating pendula

    NASA Astrophysics Data System (ADS)

    Kapitaniak, Marcin; Czolczynski, Krzysztof; Perlikowski, Przemysław; Stefanski, Andrzej; Kapitaniak, Tomasz

    2014-08-01

    Coupled systems that contain rotating elements are typical in physical, biological and engineering applications and for years have been the subject of intensive studies. One problem of scientific interest, which among others occurs in such systems is the phenomenon of synchronization of different rotating parts. Despite different initial conditions, after a sufficiently long transient, the rotating parts move in the same way - complete synchronization, or a permanent constant shift is established between their displacements, i.e., the angles of rotation - phase synchronization. Synchronization occurs due to dependence of the periods of rotating elements motion and the displacement of the base on which these elements are mounted. We review the studies on the synchronization of rotating pendula and compare them with the results obtained for oscillating pendula. As an example we consider the dynamics of the system consisting of n pendula mounted on the movable beam. The pendula are excited by the external torques which are inversely proportional to the angular velocities of the pendula. As the result of such excitation each pendulum rotates around its axis of rotation. It has been assumed that all pendula rotate in the same direction or in the opposite directions. We consider the case of slowly rotating pendula and estimate the influence of the gravity on their motion. We classify the synchronous states of the identical pendula and observe how the parameters mismatch can influence them. We give evidence that synchronous states are robust as they exist in the wide range of system parameters and can be observed in a simple experiment.

  19. Markers of criticality in phase synchronization

    PubMed Central

    Botcharova, Maria; Farmer, Simon F.; Berthouze, Luc

    2014-01-01

    The concept of the brain as a critical dynamical system is very attractive because systems close to criticality are thought to maximize their dynamic range of information processing and communication. To date, there have been two key experimental observations in support of this hypothesis: (i) neuronal avalanches with power law distribution of size and (ii) long-range temporal correlations (LRTCs) in the amplitude of neural oscillations. The case for how these maximize dynamic range of information processing and communication is still being made and because a significant substrate for information coding and transmission is neural synchrony it is of interest to link synchronization measures with those of criticality. We propose a framework for characterizing criticality in synchronization based on an analysis of the moment-to-moment fluctuations of phase synchrony in terms of the presence of LRTCs. This framework relies on an estimation of the rate of change of phase difference and a set of methods we have developed to detect LRTCs. We test this framework against two classical models of criticality (Ising and Kuramoto) and recently described variants of these models aimed to more closely represent human brain dynamics. From these simulations we determine the parameters at which these systems show evidence of LRTCs in phase synchronization. We demonstrate proof of principle by analysing pairs of human simultaneous EEG and EMG time series, suggesting that LRTCs of corticomuscular phase synchronization can be detected in the resting state and experimentally manipulated. The existence of LRTCs in fluctuations of phase synchronization suggests that these fluctuations are governed by non-local behavior, with all scales contributing to system behavior. This has important implications regarding the conditions under which one should expect to see LRTCs in phase synchronization. Specifically, brain resting states may exhibit LRTCs reflecting a state of readiness facilitating

  20. Disrupted Intrinsic Local Synchronization in Poststroke Aphasia

    PubMed Central

    Yang, Mi; Li, Jiao; Yao, Dezhong; Chen, Huafu

    2016-01-01

    Abstract Evidence has accumulated from the task-related and task-free (i.e., resting state) studies that alternations of intrinsic neural networks exist in poststroke aphasia (PSA) patients. However, information is lacking on the changes in the local synchronization of spontaneous functional magnetic resonance imaging blood–oxygen level-dependent fluctuations in PSA at rest. We investigated the altered intrinsic local synchronization using regional homogeneity (ReHo) on PSA (n = 17) and age- and sex-matched healthy controls (HCs) (n = 20). We examined the correlations between the abnormal ReHo values and the aphasia severity and language performance in PSA. Compared with HCs, the PSA patients exhibited decreased intrinsic local synchronization in the right lingual gyrus, the left calcarine, the left cuneus, the left superior frontal gyrus (SFG), and the left medial of SFG. The local synchronization (ReHo value) in the left medial of SFG was positively correlated with aphasia severity (r = 0.55, P = 0.027) and the naming scores of Aphasia Battery of Chinese (r = 0.66, P = 0.005). This result is consistent with the important role of this value in language processing even in the resting state. The pathogenesis of PSA may be attributed to abnormal intrinsic local synchronous in multiple brain regions. PMID:26986152

  1. Adaptive Deadband Synchronization for a Spacecraft Formation

    NASA Technical Reports Server (NTRS)

    Scharf, Daniel; Hadaegh, Fred; Kang, Bryan

    2007-01-01

    A paper discusses general problems in estimation and control of the states (positions, attitudes, and velocities) of spacecraft flying in formation, then addresses the particular formation-flying-control problem of synchronization of deadbands. The paper presents a deadband synchronization algorithm for the case in which the spacecraft are equipped with pulse-width-modulated thrusters for maintaining their required states. The algorithm synchronizes thruster-firing times across all six degrees of freedom of all the spacecraft. The algorithm is scalable, inherently adapts to disturbances, and does not require knowledge of spacecraft masses and disturbance forces. In this algorithm, one degree of freedom of one spacecraft is designated the leader, and all other degrees of freedom of all spacecraft as followers. The Cassini adaptive optimum deadband drift controller is the subalgorithm for control in each degree of freedom, and the adaptation is run until each spacecraft achieves a specified drift period. The adaptation is critical because a different disturbance affects each different degree of freedom. Then the leader communicates its thruster-firing starting times to the followers. Then, for each follower, a deadband-synchronization subalgorithm determines the shift needed to synchronize its drift period with that of the leader.

  2. Model bridging chimera state and explosive synchronization

    NASA Astrophysics Data System (ADS)

    Zhang, Xiyun; Bi, Hongjie; Guan, Shuguang; Liu, Jinming; Liu, Zonghua

    2016-07-01

    Global synchronization and partial synchronization are the two distinctive forms of synchronization in coupled oscillators and have been well studied in recent decades. Recent attention on synchronization is focused on the chimera state (CS) and explosive synchronization (ES), but little attention has been paid to their relationship. Here we study this topic by presenting a model to bridge these two phenomena, which consists of two groups of coupled oscillators, and its coupling strength is adaptively controlled by a local order parameter. We find that this model displays either CS or ES in two limits. In between the two limits, this model exhibits both CS and ES, where CS can be observed for a fixed coupling strength and ES appears when the coupling is increased adiabatically. Moreover, we show both theoretically and numerically that there are a variety of CS basin patterns for the case of identical oscillators, depending on the distributions of both the initial order parameters and the initial average phases. This model suggests a way to easily observe CS, in contrast to other models having some (weak or strong) dependence on initial conditions.

  3. Disrupted Intrinsic Local Synchronization in Poststroke Aphasia.

    PubMed

    Yang, Mi; Li, Jiao; Yao, Dezhong; Chen, Huafu

    2016-03-01

    Evidence has accumulated from the task-related and task-free (i.e., resting state) studies that alternations of intrinsic neural networks exist in poststroke aphasia (PSA) patients. However, information is lacking on the changes in the local synchronization of spontaneous functional magnetic resonance imaging blood-oxygen level-dependent fluctuations in PSA at rest.We investigated the altered intrinsic local synchronization using regional homogeneity (ReHo) on PSA (n = 17) and age- and sex-matched healthy controls (HCs) (n = 20). We examined the correlations between the abnormal ReHo values and the aphasia severity and language performance in PSA.Compared with HCs, the PSA patients exhibited decreased intrinsic local synchronization in the right lingual gyrus, the left calcarine, the left cuneus, the left superior frontal gyrus (SFG), and the left medial of SFG. The local synchronization (ReHo value) in the left medial of SFG was positively correlated with aphasia severity (r = 0.55, P = 0.027) and the naming scores of Aphasia Battery of Chinese (r = 0.66, P = 0.005). This result is consistent with the important role of this value in language processing even in the resting state.The pathogenesis of PSA may be attributed to abnormal intrinsic local synchronous in multiple brain regions. PMID:26986152

  4. Hydrodynamic Synchronization of Light Driven Microrotors

    NASA Astrophysics Data System (ADS)

    Di Leonardo, R.; Búzás, A.; Kelemen, L.; Vizsnyiczai, G.; Oroszi, L.; Ormos, P.

    2012-07-01

    Hydrodynamic synchronization is a fundamental physical phenomenon by which self-sustained oscillators communicate through perturbations in the surrounding fluid and converge to a stable synchronized state. This is an important factor for the emergence of regular and coordinated patterns in the motions of cilia and flagella. When dealing with biological systems, however, it is always hard to disentangle internal signaling mechanisms from external purely physical couplings. We have used the combination of two-photon polymerization and holographic optical trapping to build a mesoscale model composed of chiral propellers rotated by radiation pressure. The two microrotors can be synchronized by hydrodynamic interactions alone although the relative torques have to be finely tuned. Dealing with a micron sized system we treat synchronization as a stochastic phenomenon and show that the phase lag between the two microrotors is distributed according to a stationary Fokker-Planck equation for an overdamped particle over a tilted periodic potential. Synchronized states correspond to minima in this potential whose locations are shown to depend critically on the detailed geometry of the propellers.

  5. Robust microcircuit synchronization by inhibitory connections

    PubMed Central

    Szücs, Attila; Huerta, Ramon; Rabinovich, Mikhail I.; Selverston, Allen I.

    2009-01-01

    SUMMARY Microcircuits in different brain areas share similar architectural and biophysical properties with compact motor network known as central pattern generators (CPGs). Consequently, CPGs have been suggested as valuable biological models for the understanding of microcircuit dynamics and particularly, their synchronization. In the present paper we use a well known compact motor network, the lobster pyloric CPG to study principles of intercircuit synchronization. We couple separate pyloric circuits obtained from two animals via artificial synapses and observe how their synchronization depends on the topology and kinetic parameters of the computer-generated synapses. Stable in-phase synchronization appears when electrically coupling the pacemaker groups of the two networks, but reciprocal inhibitory connections produce more robust and regular cooperative activity. Contralateral inhibitory connections offer effective synchronization and flexible setting of the burst phases of the interacting networks. We also show that a conductance-based mathematical model of the coupled circuits correctly reproduces the observed dynamics illustrating the generality of the phenomena. PMID:19217380

  6. The transition to chaotic phase synchronization

    NASA Astrophysics Data System (ADS)

    Mosekilde, E.; Laugesen, J. L.; Zhusubaliyev, Zh. T.

    2012-08-01

    The transition to chaotic phase synchronization for a periodically driven spiral-type chaotic oscillator is known to involve a dense set of saddle-node bifurcations. By following the synchronization transition through the cascade of period-doubling bifurcations in a forced Rössler system, this paper describes how these saddle-node bifurcations arise and how their characteristic cyclic organisation develops. We identify the cycles that are involved in the various saddle-node bifurcations and descibe how the formation of multi-layered resonance cycles in the synchronization domain is related to the torus doubling bifurcations that take place outside this domain. By examining a physiology-based model of the blood flow regulation to the individual functional unit (nephron) of the kidney we demonstrate how a similar bifurcation structure may arise in this system as a response to a periodically varying arterial blood pressure. The paper finally discusses how an alternative transition to chaotic phase synchronization may occur in the mutual synchronization of two chaotically oscillating period-doubling systems.

  7. Brain activities during synchronized tapping task.

    PubMed

    Hiroyasu, Tomoyuki; Murakami, Akiho; Mao Gto; Yokouchi, Hisatake

    2015-08-01

    This study aims to investigate how people process information about other people to determine a response during human-to-human cooperative work. As a preliminary study, the mechanism of cooperative work was examined using interaction between a machine and a human. This machine was designed to have an "other person" model that simulates an emotional model of another person. The task performed in the experiment was a synchronized tapping task. Two models were prepared for this experiment, a simple model that does not employ the other person model and a synchronized model that employs the other person model. Subjects performed cooperative work with these machines. During the experiment, brain activities were measured using functional near-infrared spectroscopy. It was observed that the left inferior frontal gyrus was activated more with the synchronized model than the simple model. PMID:26737670

  8. Pinning synchronization of a mobile agent network

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Sun, You-xian

    2009-11-01

    We investigate the problem of controlling a group of mobile agents in a plane in order to move them towards a desired orbit via pinning control, in which each agent is associated with a chaotic oscillator coupled with those of neighboring agents, and the pinning strategy is to have the common linear feedback acting on a small fraction of agents by random selection. We explore the effects of the pinning probability, feedback gains and agent density in the pinning synchronization of a mobile agent network under a fast-switching constraint, and perform numerical simulations for validation. In particular, we show that there exists a critical pinning density for network synchronization with an unbounded region: above the threshold, the dynamical network can be controlled by pinning; below it, anarchy prevails. And for the network with a single bounded synchronization region, pinning control has little effect as regards enhancing network synchronizability.

  9. Microscopic dynamics of synchronization in driven colloids

    PubMed Central

    Juniper, Michael P.N.; Straube, Arthur V.; Besseling, Rut; Aarts, Dirk G.A.L.; Dullens, Roel P.A.

    2015-01-01

    Synchronization of coupled oscillators has been scrutinized for over three centuries, from Huygens' pendulum clocks to physiological rhythms. One such synchronization phenomenon, dynamic mode locking, occurs when naturally oscillating processes are driven by an externally imposed modulation. Typically only averaged or integrated properties are accessible, leaving underlying mechanisms unseen. Here, we visualize the microscopic dynamics underlying mode locking in a colloidal model system, by using particle trajectories to produce phase portraits. Furthermore, we use this approach to examine the enhancement of mode locking in a flexible chain of magnetically coupled particles, which we ascribe to breathing modes caused by mode-locked density waves. Finally, we demonstrate that an emergent density wave in a static colloidal chain mode locks as a quasi-particle, with microscopic dynamics analogous to those seen for a single particle. Our results indicate that understanding the intricate link between emergent behaviour and microscopic dynamics is key to controlling synchronization. PMID:25994921

  10. Trigger delay compensation of beam synchronous sampling

    SciTech Connect

    Steimel, J.

    1996-05-01

    One of the problems of providing beam feedback in a large accelerator is the lack of beam synchronous trigger signals far from the RF signal source. IF single bucket resolutions are required, a cable extending from the RF source to the other side of the accelerator will not provide a synchronous signal if the RF frequency changes significantly with respect to the cable delay. This paper offers a solution to this problem by locking to the RF, at the remote location, using a digital phase locked loop. Then, the digitized frequency value is used to calculate the phase shift required to remain synchronized to the beam. Results are shown for phase lock to the Fermilab Main Ring RF. 1 ref., 4 figs.

  11. Unstable attractors induce perpetual synchronization and desynchronization.

    PubMed

    Timme, Marc; Wolf, Fred; Geisel, Theo

    2003-03-01

    Common experience suggests that attracting invariant sets in nonlinear dynamical systems are generally stable. Contrary to this intuition, we present a dynamical system, a network of pulse-coupled oscillators, in which unstable attractors arise naturally. From random initial conditions, groups of synchronized oscillators (clusters) are formed that send pulses alternately, resulting in a periodic dynamics of the network. Under the influence of arbitrarily weak noise, this synchronization is followed by a desynchronization of clusters, a phenomenon induced by attractors that are unstable. Perpetual synchronization and desynchronization lead to a switching among attractors. This is explained by the geometrical fact, that these unstable attractors are surrounded by basins of attraction of other attractors, whereas the full measure of their own basin is located remote from the attractor. Unstable attractors do not only exist in these systems, but moreover dominate the dynamics for large networks and a wide range of parameters. PMID:12675444

  12. Synchronous characterization of semiconductor microcavity laser beam.

    PubMed

    Wang, T; Lippi, G L

    2015-06-01

    We report on a high-resolution double-channel imaging method used to synchronously map the intensity- and optical-frequency-distribution of a laser beam in the plane orthogonal to the propagation direction. The synchronous measurement allows us to show that the laser frequency is an inhomogeneous distribution below threshold, but that it becomes homogeneous across the fundamental Gaussian mode above threshold. The beam's tails deviations from the Gaussian shape, however, are accompanied by sizeable fluctuations in the laser wavelength, possibly deriving from manufacturing details and from the influence of spontaneous emission in the very low intensity wings. In addition to the synchronous spatial characterization, a temporal analysis at any given point in the beam cross section is carried out. Using this method, the beam homogeneity and spatial shape, energy density, energy center, and the defects-related spectrum can also be extracted from these high-resolution pictures. PMID:26133832

  13. Synchronization tracking in pulse position modulation receiver

    NASA Technical Reports Server (NTRS)

    Vilnrotter, Victor A.

    1987-01-01

    A clock pulse generator for decoding pulse position modulation in an optical communication receiver is synchronized by a delay tracking loop which multiplies impulses of a data pulse by the square wave clock pulses from the generator to produce positive impulses when the clock pulse is of one level, and negative impulses when the clock pulse is of another level. A delay tracking loop integrates the impulses and produces an error signal that adjusts the delay so the clock pulses will be synchronized with data pulses. A dead-time tau sub d is provided between data pulses of an interval tau sub p in the data pulse period tau. When synchronized, the average number of positive impulses integrated will equal the average number of negative impulses over the continuous stream of data pulses.

  14. Elastic interactions synchronize beating in cardiomyocytes.

    PubMed

    Cohen, Ohad; Safran, Samuel A

    2016-07-13

    Motivated by recent experimental results, we study theoretically the synchronization of the beating phase and frequency of two nearby cardiomyocyte cells. Each cell is represented as an oscillating force dipole in an infinite, viscoelastic medium and the propagation of the elastic signal within the medium is predicted. We examine the steady-state beating of two nearby cells, and show that elastic interactions result in forces that synchronize the phase and frequency of beating in a manner that depends on their mutual orientation. The theory predicts both in-phase and anti-phase steady-state beating depending on the relative cell orientations, as well as how synchronized beating varies with substrate elasticity and the inter-cell distance. These results suggest how mechanics plays a role in cardiac efficiency, and may be relevant for the design of cardiomyocyte based micro devices and other biomedical applications. PMID:27352146

  15. Synchronous characterization of semiconductor microcavity laser beam

    SciTech Connect

    Wang, T. Lippi, G. L.

    2015-06-15

    We report on a high-resolution double-channel imaging method used to synchronously map the intensity- and optical-frequency-distribution of a laser beam in the plane orthogonal to the propagation direction. The synchronous measurement allows us to show that the laser frequency is an inhomogeneous distribution below threshold, but that it becomes homogeneous across the fundamental Gaussian mode above threshold. The beam’s tails deviations from the Gaussian shape, however, are accompanied by sizeable fluctuations in the laser wavelength, possibly deriving from manufacturing details and from the influence of spontaneous emission in the very low intensity wings. In addition to the synchronous spatial characterization, a temporal analysis at any given point in the beam cross section is carried out. Using this method, the beam homogeneity and spatial shape, energy density, energy center, and the defects-related spectrum can also be extracted from these high-resolution pictures.

  16. Microscopic dynamics of synchronization in driven colloids.

    PubMed

    Juniper, Michael P N; Straube, Arthur V; Besseling, Rut; Aarts, Dirk G A L; Dullens, Roel P A

    2015-01-01

    Synchronization of coupled oscillators has been scrutinized for over three centuries, from Huygens' pendulum clocks to physiological rhythms. One such synchronization phenomenon, dynamic mode locking, occurs when naturally oscillating processes are driven by an externally imposed modulation. Typically only averaged or integrated properties are accessible, leaving underlying mechanisms unseen. Here, we visualize the microscopic dynamics underlying mode locking in a colloidal model system, by using particle trajectories to produce phase portraits. Furthermore, we use this approach to examine the enhancement of mode locking in a flexible chain of magnetically coupled particles, which we ascribe to breathing modes caused by mode-locked density waves. Finally, we demonstrate that an emergent density wave in a static colloidal chain mode locks as a quasi-particle, with microscopic dynamics analogous to those seen for a single particle. Our results indicate that understanding the intricate link between emergent behaviour and microscopic dynamics is key to controlling synchronization. PMID:25994921

  17. Maximum entropy model for business cycle synchronization

    NASA Astrophysics Data System (ADS)

    Xi, Ning; Muneepeerakul, Rachata; Azaele, Sandro; Wang, Yougui

    2014-11-01

    The global economy is a complex dynamical system, whose cyclical fluctuations can mainly be characterized by simultaneous recessions or expansions of major economies. Thus, the researches on the synchronization phenomenon are key to understanding and controlling the dynamics of the global economy. Based on a pairwise maximum entropy model, we analyze the business cycle synchronization of the G7 economic system. We obtain a pairwise-interaction network, which exhibits certain clustering structure and accounts for 45% of the entire structure of the interactions within the G7 system. We also find that the pairwise interactions become increasingly inadequate in capturing the synchronization as the size of economic system grows. Thus, higher-order interactions must be taken into account when investigating behaviors of large economic systems.

  18. The Scheme of Beam Synchronization in MEIC

    SciTech Connect

    Zhang, Yuhong; Derbenev, Yaroslav S.; Hutton, Andrew M.

    2013-06-01

    Synchronizing colliding beams at single or multiple collision points is a critical R&D issue in the design of a medium energy electron-ion collider (MEIC) at Jefferson Lab. The path-length variation due to changes in the ion energy, which varies over 20 to 100 GeV, could be more than several times the bunch spacing. The scheme adopted in the present MEIC baseline is centered on varying the number of bunches (i.e., harmonic number) stored in the collider ring. This could provide a set of discrete energies for proton or ions such that the beam synchronization condition is satisfied. To cover the ion energy between these synchronized values, we further propose to vary simultaneously the electron ring circumference and the frequency of the RF systems in both collider rings. We also present in this paper the requirement of frequency tunability of SRF cavities to support the scheme.

  19. Synchronization trigger control system for flow visualization

    NASA Technical Reports Server (NTRS)

    Chun, K. S.

    1987-01-01

    The use of cinematography or holographic interferometry for dynamic flow visualization in an internal combustion engine requires a control device that globally synchronizes camera and light source timing at a predefined shaft encoder angle. The device is capable of 0.35 deg resolution for rotational speeds of up to 73 240 rpm. This was achieved by implementing the shaft encoder signal addressed look-up table (LUT) and appropriate latches. The developed digital signal processing technique achieves 25 nsec of high speed triggering angle detection by using direct parallel bit comparison of the shaft encoder digital code with a simulated angle reference code, instead of using angle value comparison which involves more complicated computation steps. In order to establish synchronization to an AC reference signal whose magnitude is variant with the rotating speed, a dynamic peak followup synchronization technique has been devised. This method scrutinizes the reference signal and provides the right timing within 40 nsec. Two application examples are described.

  20. Clocking and synchronization circuits in multiprocessor systems

    SciTech Connect

    Jeong, Deog-Kyoon.

    1989-01-01

    Microprocessors based on RISC (Reduced Instruction Set Computer) concepts have demonstrated an ability to provide more computing power at a given level of integration than conventional microprocessors. The next step is multiprocessors composed of RISC processing elements. Communication bandwidth among such microprocessors is critical in achieving efficient hardware utilization. This thesis focuses on the communication capability of VLSI circuits and presents new circuit techniques as a guide to build an interconnection network of VLSI microprocessors. Two of the most prominent problems in a synchronous system, which most of the current computer systems are based on, have been clock skew and synchronization failure. A new concept called self-timed systems solves such problems but has not been accepted in microprocessor implementations yet because of its complex design procedure and increased overhead. With this in mind, this thesis concentrates on a system in which individual synchronous subsystems are connected asynchronously. Synchronous subsystems operate with a better control over clock skew using a phase locked loop (PLL) technique. Communication among subsystems is done asynchronously with a controlled synchronization failure rate. One advantage is that conventional VLSI design methodologies which are more efficient can still be applied. Circuit techniques for PLL-based clock generation are described along with stability criteria. The main objective of the circuit is to realize a zero delay buffer. Experimental results show the feasibility of such circuits in VLSI. Synchronizer circuit configurations in both bipolar and MOS technology that best utilize each device, or overcome the technology limit using a bandwidth doubling technique are shown. Interface techniques including handshake mechanisms in such a system are also described.

  1. Epileptiform synchronization in the cingulate cortex

    PubMed Central

    Panuccio, Gabriella; Curia, Giulia; Colosimo, Alfredo; Cruccu, Giorgio; Avoli, Massimo

    2016-01-01

    Summary Purpose The anterior cingulate cortex (ACC)— which plays a role in pain, emotions and behavior— can generate epileptic seizures. To date, little is known on the neuronal mechanisms leading to epileptiform synchronization in this structure. Therefore, we investigated the role of excitatory and inhibitory synaptic transmission in epileptiform activity in this cortical area. In addition, since the ACC presents with a high density of opioid receptors, we studied the effect of opioid agonism on epileptiform synchronization in this brain region. Methods We used field and intracellular recordings in conjunction with pharmacological manipulations to characterize the epileptiform activity generated by the rat ACC in a brain slice preparation. Results Bath-application of the convulsant 4- aminopyridine (4AP, 50 μM) induced both brief and prolonged periods of epileptiform synchronization resembling interictal- and ictal-like discharges, respectively. Interictal events could occur more frequently before the onset of ictal activity that was contributed by N-methyl-D-aspartate (NMDA) receptors. Mu-opioid receptor activation abolished 4AP-induced ictal events and markedly reduced the occurrence of the pharmacologically isolated GABAergic synchronous potentials. Ictal discharges were replaced by interictal events during GABAergic antagonism; this GABA-independent activity was influenced by subsequent mu-opioid agonist application. Conclusions Our results indicate that both glutamatergic and GABAergic signaling contribute to epileptiform synchronization leading to the generation of electrographic ictal events in the ACC. In addition, mu-opioid receptors appear to modulate both excitatory and inhibitory mechanisms, thus influencing epileptiform synchronization in the ACC. PMID:19178556

  2. Measures of Quantum Synchronization in Continuous Variable Systems

    NASA Astrophysics Data System (ADS)

    Mari, A.; Farace, A.; Didier, N.; Giovannetti, V.; Fazio, R.

    2013-09-01

    We introduce and characterize two different measures which quantify the level of synchronization of coupled continuous variable quantum systems. The two measures allow us to extend to the quantum domain the notions of complete and phase synchronization. The Heisenberg principle sets a universal bound to complete synchronization. The measure of phase synchronization is, in principle, unbounded; however, in the absence of quantum resources (e.g., squeezing) the synchronization level is bounded below a certain threshold. We elucidate some interesting connections between entanglement and synchronization and, finally, discuss an application based on quantum optomechanical systems.

  3. Measures of quantum synchronization in continuous variable systems.

    PubMed

    Mari, A; Farace, A; Didier, N; Giovannetti, V; Fazio, R

    2013-09-01

    We introduce and characterize two different measures which quantify the level of synchronization of coupled continuous variable quantum systems. The two measures allow us to extend to the quantum domain the notions of complete and phase synchronization. The Heisenberg principle sets a universal bound to complete synchronization. The measure of phase synchronization is, in principle, unbounded; however, in the absence of quantum resources (e.g., squeezing) the synchronization level is bounded below a certain threshold. We elucidate some interesting connections between entanglement and synchronization and, finally, discuss an application based on quantum optomechanical systems. PMID:25166668

  4. Robust hyperchaotic synchronization via analog transmission line

    NASA Astrophysics Data System (ADS)

    Sadoudi, S.; Tanougast, C.

    2016-02-01

    In this paper, a novel experimental chaotic synchronization technique via analog transmission is discussed. We demonstrate through Field-Programmable Gate Array (FPGA) implementation design the robust synchronization of two embedded hyperchaotic Lorenz generators interconnected with an analog transmission line. The basic idea of this work consists in combining a numerical generation of chaos and transmitting it with an analog signal. The numerical chaos allows to overcome the callback parameter mismatch problem and the analog transmission offers robust data security. As application, this technique can be applied to all families of chaotic systems including time-delayed chaotic systems.

  5. Carrying Synchronous Voice Data On Asynchronous Networks

    NASA Technical Reports Server (NTRS)

    Bergman, Larry A.

    1990-01-01

    Buffers restore synchronism for internal use and permit asynchronism in external transmission. Proposed asynchronous local-area digital communication network (LAN) carries synchronous voice, data, or video signals, or non-real-time asynchronous data signals. Network uses double buffering scheme that reestablishes phase and frequency references at each node in network. Concept demonstrated in token-ring network operating at 80 Mb/s, pending development of equipment operating at planned data rate of 200 Mb/s. Technique generic and used with any LAN as long as protocol offers deterministic (or bonded) access delays and sufficient capacity.

  6. Synchronization system for Gamma-4 electrophysical facility

    NASA Astrophysics Data System (ADS)

    Grishin, A. V.; Nazarenko, S. T.; Kozachek, A. V.; Kalashnikov, D. A.; Glushkov, S. L.; Mironychev, B. P.; Martynov, V. M.; Turutin, V. V.; Kul'dyushov, D. A.; Pavlov, V. S.; Demanov, V. A.; Shikhanova, T. F.; Esaeva, Yu. A.

    2015-01-01

    A synchronization system for the Gamma-4 four-module electrophysical facility has been developed. It has been shown that the synchronization system should provide triggering (with precision not worse than ±3 ns) of the high-voltage gas-filled trigatron-type switches of the facility modules (144 spark gaps with an operating voltage of 1 MV), the pre-pulse switches of the modules (24 spark gaps with an operating voltage of 3 MV) and eight Arkad'ev-Marx generators (40 spark gaps with an operating voltage of 100 kV).

  7. Synchronous generator wind energy conversion control system

    SciTech Connect

    Medeiros, A.L.R.; Lima, A.M.N.; Jacobina, C.B.; Simoes, F.J.

    1996-12-31

    This paper presents the performance evaluation and the design of the control system of a WECS (Wind Energy Conversion System) that employs a synchronous generator based on its digital simulation. The WECS discussed in this paper is connected to the utility grid through two Pulse Width Modulated (PWM) power converters. The structure of the proposed WECS enables us to achieve high performance energy conversion by: (i) maximizing the wind energy capture and (ii) minimizing the reactive power flowing between the grid and the synchronous generator. 8 refs., 19 figs.

  8. Network response synchronization enhanced by synaptic plasticity

    NASA Astrophysics Data System (ADS)

    Lobov, S.; Simonov, A.; Kastalskiy, I.; Kazantsev, V.

    2016-02-01

    Synchronization of neural network response on spatially localized periodic stimulation was studied. The network consisted of synaptically coupled spiking neurons with spike-timing-dependent synaptic plasticity (STDP). Network connectivity was defined by time evolving matrix of synaptic weights. We found that the steady-state spatial pattern of the weights could be rearranged due to locally applied external periodic stimulation. A method for visualization of synaptic weights as vector field was introduced to monitor the evolving connectivity matrix. We demonstrated that changes in the vector field and associated weight rearrangements underlay an enhancement of synchronization range.

  9. [Synchronized, oscillatory brain activity in visual perception].

    PubMed

    Braunitzer, Gábor

    2008-09-30

    The present study investigates one of the most promising developments of the brain-mind question, namely the possible links between synchronized oscillatory brain activity and certain (visual) perceptual processes. Through a review of the relevant literature, the author introduces the reader to the most important theories of coherent perception ('binding'), and makes an attempt to show how synchronization of EEG-registrable oscillatory activities from various frequency bands might explain binding. Finally, a number of clinical problems are also mentioned, regarding which the presented theoretical framework might deserve further consideration. PMID:18841649

  10. Impulsive synchronization of networked nonlinear dynamical systems

    NASA Astrophysics Data System (ADS)

    Jiang, Haibo; Bi, Qinsheng

    2010-06-01

    In this Letter, we investigate the problem of impulsive synchronization of networked multi-agent systems, where each agent can be modeled as an identical nonlinear dynamical system. Firstly, an impulsive control protocol is designed for network with fixed topology based on the local information of agents. Then sufficient conditions are given to guarantee the synchronization of the networked nonlinear dynamical system by using algebraic graph theory and impulsive control theory. Furthermore, how to select the discrete instants and impulsive constants is discussed. The case that the topologies of the networks are switching is also considered. Numerical simulations show the effectiveness of our theoretical results.

  11. A relativistic analysis of clock synchronization

    NASA Technical Reports Server (NTRS)

    Thomas, J. B.

    1974-01-01

    The relativistic conversion between coordinate time and atomic time is reformulated to allow simpler time calculations relating analysis in solar-system barycentric coordinates (using coordinate time) with earth-fixed observations (measuring earth-bound proper time or atomic time.) After an interpretation of terms, this simplified formulation, which has a rate accuracy of about 10 to the minus 15th power, is used to explain the conventions required in the synchronization of a world wide clock network and to analyze two synchronization techniques-portable clocks and radio interferometry. Finally, pertinent experiment tests of relativity are briefly discussed in terms of the reformulated time conversion.

  12. Delayed self-synchronization in homoclinic chaos

    NASA Astrophysics Data System (ADS)

    Arecchi, F. T.; Meucci, R.; Allaria, E.; di Garbo, A.; Tsimring, L. S.

    2002-04-01

    The chaotic spike train of a homoclinic dynamical system is self-synchronized by applying a time-delayed correction proportional to the laser output intensity. Due to the sensitive nature of the homoclinic chaos to external perturbations, stabilization of very long-periodic orbits is possible. On these orbits, the dynamics appears chaotic over a finite time, but then it repeats with a recurrence time that is slightly longer than the delay time. The effect, called delayed self-synchronization, displays analogies with neurodynamic events that occur in the buildup of long-term memories.

  13. A Three-day PGF2α Plus eCG-based Fixed-time AI Protocol Improves Fertility Compared with Spontaneous Estrus in Dairy Cows with Silent Ovulation

    PubMed Central

    GARCIA-ISPIERTO, Irina; LÓPEZ-GATIUS, Fernando

    2013-01-01

    Abstract This study was designed to test the treatment with prostaglandin F2α (PGF2α) plus equine chorionic gonadotrophin (eCG) and GnRH 48 h later (PEG protocol) followed by fixed-time AI (FTAI) in dairy cows with silent ovulation (cows with a mature corpus luteum and no signs of estrus detected in the preceding 21 days). In Experiment I, ovulation following the PEG protocol monitored in 24 cows with silent ovulation was recorded in 83% of the cows 36 h after GnRH treatment. In Experiment II, control cows were artificially inseminated during spontaneous estrus (4615 AI), while cows in the PEG group (1266 AI) were subjected to FTAI 24 h after GnRH treatment. Binary logistic regression revealed a significant effect of the interactions of treatment by season, by parity or by repeat breeding syndrome (>3 AI) on the conception rate. The conception rate was negatively affected by the warm season and age in controls but not in treated cows, whereas repeat breeder cows in the control and PEG groups were less (by a factor of 0.7) or more (by a factor of 1.5) likely to become pregnant, respectively, than the remaining animals. Moreover, the likelihood of twin pregnancy was lower in multiparous PEG (by a factor of 0.4) cows than in the remaining cows. This protocol, besides overcoming the negative effects of heat stress and age on the conception rate, increased fertility in repeat breeder cows compared with spontaneous estrus. Moreover, this treatment regimen reduced the twin pregnancy rate in multiparous cows. PMID:23698789

  14. Slow-wave synchronous pick-up and kicker

    SciTech Connect

    DiMassa, G.

    1988-01-01

    Slow-wave synchronous pick-up (PU) and Kicker (K) are proposed for the stochastic cooling of bunched beams in RHIC. A corrugated waveguide is used to support a slow wave that is synchronous with the beam.

  15. DEVELOPMENT OF A BATTERY-OPERATED PORTABLE SYNCHRONOUS LUMINESCENCE SPECTROFLUOROMETER

    EPA Science Inventory

    A battery-operated synchronous luminescence spectrofluorometer was developed for on-site analysis of groundwater or hazardous waste sites. he instrument is suited for emission, excitation, or synchronous fluorescence measurements. he instrument is suited for trace analysis of imp...

  16. Compatibility of Motion Facilitates Visuomotor Synchronization

    ERIC Educational Resources Information Center

    Hove, Michael J.; Spivey, Michael J.; Krumhansl, Carol L.

    2010-01-01

    Prior research indicates that synchronized tapping performance is very poor with flashing visual stimuli compared with auditory stimuli. Three finger-tapping experiments compared flashing visual metronomes with visual metronomes containing a spatial component, either compatible, incompatible, or orthogonal to the tapping action. In Experiment 1,…

  17. Regulation features of superconducting synchronous generator

    SciTech Connect

    Ilyushin, K.V.; Mironov, O.M.

    1981-01-01

    The characteristics of a transient in the rotor of a superconducting synchronous generator during regulation are considered. The critical-state region is determined for the magnetic system and the trajectory of the critical point in the region occupied by the superconductor is found.

  18. Synchronicity and the meaning-making psyche.

    PubMed

    Colman, Warren

    2011-09-01

    This paper contrasts Jung's account of synchronicity as evidence of an objective principle of meaning in Nature with a view that emphasizes human meaning-making. All synchronicities generate indicative signs but only where this becomes a 'living symbol' of a transcendent intentionality at work in a living universe does synchronicity generate the kind of symbolic meaning that led Jung to posit the existence of a Universal Mind. This is regarded as a form of personal, experiential knowledge belonging to the 'imaginal world of meaning' characteristic of the 'primordial mind', as opposed to the 'rational world of knowledge' in which Jung attempted to present his experiences as if they were empirically and publicly verifiable. Whereas rational knowledge depends on a form of meaning in which causal chains and logical links are paramount, imaginal meaning is generated by forms of congruent correspondence-a feature that synchronicity shares with metaphor and symbol-and the creation of narratives by means of retroactive organization of its constituent elements. PMID:21884094

  19. Blending Online Asynchronous and Synchronous Learning

    ERIC Educational Resources Information Center

    Yamagata-Lynch, Lisa C.

    2014-01-01

    In this article I will share a qualitative self-study about a 15-week blended 100% online graduate level course facilitated through synchronous meetings on Blackboard Collaborate and asynchronous discussions on Blackboard. I taught the course at the University of Tennessee (UT) during the spring 2012 semester and the course topic was online…

  20. Angular Synchronization by Eigenvectors and Semidefinite Programming

    PubMed Central

    Singer, A.

    2010-01-01

    The angular synchronization problem is to obtain an accurate estimation (up to a constant additive phase) for a set of unknown angles θ1, …, θn from m noisy measurements of their offsets θi − θj mod 2π. Of particular interest is angle recovery in the presence of many outlier measurements that are uniformly distributed in [0, 2π) and carry no information on the true offsets. We introduce an efficient recovery algorithm for the unknown angles from the top eigenvector of a specially designed Hermitian matrix. The eigenvector method is extremely stable and succeeds even when the number of outliers is exceedingly large. For example, we successfully estimate n = 400 angles from a full set of m=(4002) offset measurements of which 90% are outliers in less than a second on a commercial laptop. The performance of the method is analyzed using random matrix theory and information theory. We discuss the relation of the synchronization problem to the combinatorial optimization problem Max-2-Lin mod L and present a semidefinite relaxation for angle recovery, drawing similarities with the Goemans-Williamson algorithm for finding the maximum cut in a weighted graph. We present extensions of the eigenvector method to other synchronization problems that involve different group structures and their applications, such as the time synchronization problem in distributed networks and the surface reconstruction problems in computer vision and optics. PMID:21179593

  1. Training Synchronous Collaborative E-Learning

    ERIC Educational Resources Information Center

    Bliesener, Thomas

    2006-01-01

    In order to promote cooperation among students who work separately on their computers at home, the University of Essen has developed training courses with experienced tutors to teach students the required sensitivity and practical skills for tele-collaboration in small groups. A core problem in synchronous collaborative e-learning with speech…

  2. Suppressed Carrier Synchronizers for ISI Channels

    NASA Technical Reports Server (NTRS)

    Hinedi, Sami M.; Simon, Marvin K.

    1996-01-01

    We demonstrate a class of suppressed carrier synchronization loops that are motivated by MAP estimation theory and in the presence of ISI outperform the conventional I-Q loop which is designed on the basis of zero ISI (wideband assumption). The measure of comparison used is the so-called.

  3. High power synchronous altitude satellite system

    SciTech Connect

    Keigler, J.E.

    1981-12-01

    The design and attitude control system of the illustrated momentum stabilized synchronous altitude spacecraft are such that relatively large amounts of electrical power may be derived from its sun oriented planar solar array. The system is illustrated and the control of the spacecraft to stabilize it about all three axes with respect to the sun is described.

  4. Control of Abnormal Synchronization in Neurological Disorders

    PubMed Central

    Popovych, Oleksandr V.; Tass, Peter A.

    2014-01-01

    In the nervous system, synchronization processes play an important role, e.g., in the context of information processing and motor control. However, pathological, excessive synchronization may strongly impair brain function and is a hallmark of several neurological disorders. This focused review addresses the question of how an abnormal neuronal synchronization can specifically be counteracted by invasive and non-invasive brain stimulation as, for instance, by deep brain stimulation for the treatment of Parkinson’s disease, or by acoustic stimulation for the treatment of tinnitus. On the example of coordinated reset (CR) neuromodulation, we illustrate how insights into the dynamics of complex systems contribute to successful model-based approaches, which use methods from synergetics, non-linear dynamics, and statistical physics, for the development of novel therapies for normalization of brain function and synaptic connectivity. Based on the intrinsic multistability of the neuronal populations induced by spike timing-dependent plasticity (STDP), CR neuromodulation utilizes the mutual interdependence between synaptic connectivity and dynamics of the neuronal networks in order to restore more physiological patterns of connectivity via desynchronization of neuronal activity. The very goal is to shift the neuronal population by stimulation from an abnormally coupled and synchronized state to a desynchronized regime with normalized synaptic connectivity, which significantly outlasts the stimulation cessation, so that long-lasting therapeutic effects can be achieved. PMID:25566174

  5. Clock Synchronization for Multihop Wireless Sensor Networks

    ERIC Educational Resources Information Center

    Solis Robles, Roberto

    2009-01-01

    In wireless sensor networks, more so generally than in other types of distributed systems, clock synchronization is crucial since by having this service available, several applications such as media access protocols, object tracking, or data fusion, would improve their performance. In this dissertation, we propose a set of algorithms to achieve…

  6. Synchronized flow in oversaturated city traffic

    NASA Astrophysics Data System (ADS)

    Kerner, Boris S.; Klenov, Sergey L.; Hermanns, Gerhard; Hemmerle, Peter; Rehborn, Hubert; Schreckenberg, Michael

    2013-11-01

    Based on numerical simulations with a stochastic three-phase traffic flow model, we reveal that moving queues (moving jams) in oversaturated city traffic dissolve at some distance upstream of the traffic signal while transforming into synchronized flow. It is found that, as in highway traffic [Kerner, Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.85.036110 85, 036110 (2012)], such a jam-absorption effect in city traffic is explained by a strong driver's speed adaptation: Time headways (space gaps) between vehicles increase upstream of a moving queue (moving jam), resulting in moving queue dissolution. It turns out that at given traffic signal parameters, the stronger the speed adaptation effect, the shorter the mean distance between the signal location and the road location at which moving queues dissolve fully and oversaturated traffic consists of synchronized flow only. A comparison of the synchronized flow in city traffic found in this Brief Report with synchronized flow in highway traffic is made.

  7. Symbol synchronization in convolutionally coded systems

    NASA Technical Reports Server (NTRS)

    Baumert, L. D.; Mceliece, R. J.; Van Tilborg, H. C. A.

    1979-01-01

    Alternate symbol inversion is sometimes applied to the output of convolutional encoders to guarantee sufficient richness of symbol transition for the receiver symbol synchronizer. A bound is given for the length of the transition-free symbol stream in such systems, and those convolutional codes are characterized in which arbitrarily long transition free runs occur.

  8. Circuit increases capability of hysteresis synchronous motor

    NASA Technical Reports Server (NTRS)

    Markowitz, I. N.

    1967-01-01

    Frequency and phase detector circuit enables a hysteresis synchronous motor to drive a load of given torque value at a precise speed determined by a stable reference. This technique permits driving larger torque loads with smaller motors and lower power drain.

  9. Synchronous charge-constrained electroquasistatic generator

    NASA Technical Reports Server (NTRS)

    Melcher, J. R.

    1969-01-01

    Electroquasistatic generator depends on electroquasistatic interactions to provide synchronous operation. The generator employs a moving insulating belt, with an ac electric potential source to establish positively and negatively charged regions on the belt. The field effect of the charges on the belt creates an ac output voltage.

  10. Synchronizing Heavily Encoded Data in Bad Weather

    NASA Technical Reports Server (NTRS)

    Swanson, L.

    1985-01-01

    Deep space missions choose a data rate to ensure reliable communication under most conditions. Certain critical data can be more heavily encoded, to be decoded under particularly bad atmospheric conditions. It is shown that, in such a system, finding and synchronizing critical data will not be a problem.

  11. Student Perceptions of Online Synchronous Courses.

    ERIC Educational Resources Information Center

    Cereijo, Maria Victora Perez; Tyler-Wood, Tandra; Young, Jon

    This study identified student reasons for participating in synchronous Web-based learning environments. Students were interviewed after completing a series of surveys designed to elicit their perceptions of the strengths and weaknesses of the delivery methodology. Responses indicated that both convenience and learning enhancement were considered…

  12. Behavior Matching in Multimodal Communication Is Synchronized

    ERIC Educational Resources Information Center

    Louwerse, Max M.; Dale, Rick; Bard, Ellen G.; Jeuniaux, Patrick

    2012-01-01

    A variety of theoretical frameworks predict the resemblance of behaviors between two people engaged in communication, in the form of coordination, mimicry, or alignment. However, little is known about the time course of the behavior matching, even though there is evidence that dyads synchronize oscillatory motions (e.g., postural sway). This study…

  13. Hypothesis test for synchronization: Twin surrogates revisited

    NASA Astrophysics Data System (ADS)

    Romano, M. Carmen; Thiel, Marco; Kurths, Jürgen; Mergenthaler, Konstantin; Engbert, Ralf

    2009-03-01

    The method of twin surrogates has been introduced to test for phase synchronization of complex systems in the case of passive experiments. In this paper we derive new analytical expressions for the number of twins depending on the size of the neighborhood, as well as on the length of the trajectory. This allows us to determine the optimal parameters for the generation of twin surrogates. Furthermore, we determine the quality of the twin surrogates with respect to several linear and nonlinear statistics depending on the parameters of the method. In the second part of the paper we perform a hypothesis test for phase synchronization in the case of experimental data from fixational eye movements. These miniature eye movements have been shown to play a central role in neural information processing underlying the perception of static visual scenes. The high number of data sets (21 subjects and 30 trials per person) allows us to compare the generated twin surrogates with the "natural" surrogates that correspond to the different trials. We show that the generated twin surrogates reproduce very well all linear and nonlinear characteristics of the underlying experimental system. The synchronization analysis of fixational eye movements by means of twin surrogates reveals that the synchronization between the left and right eye is significant, indicating that either the centers in the brain stem generating fixational eye movements are closely linked, or, alternatively that there is only one center controlling both eyes.

  14. VLBI clock synchronization. [for atomic clock rate

    NASA Technical Reports Server (NTRS)

    Counselman, C. C., III; Shapiro, I. I.; Rogers, A. E. E.; Hinteregger, H. F.; Knight, C. A.; Whitney, A. R.; Clark, T. A.

    1977-01-01

    The potential accuracy of VLBI (very long baseline interferometry) for clock epoch and rate comparisons was demonstrated by results from long- and short-baseline experiments. It was found that atomic clocks at widely separated sites (several thousand kilometers apart) can be synchronized to within several nanoseconds from a few minutes of VLBI observations and to within one nanosecond from several hours of observations.

  15. An Online Synchronous Test for Professional Interpreters

    ERIC Educational Resources Information Center

    Chen, Nian-Shing; Ko, Leong

    2010-01-01

    This article is based on an experiment designed to conduct an interpreting test for multiple candidates online, using web-based synchronous cyber classrooms. The test model was based on the accreditation test for Professional Interpreters produced by the National Accreditation Authority of Translators and Interpreters (NAATI) in Australia.…

  16. Iron loss calculation for synchronous reluctance machines

    SciTech Connect

    Leonardi, F.; Matsuo, T.; Lipo, T.A.

    1995-12-31

    A numerical method for iron loss calculation is presented in this paper. The method is suitable for any synchronous and most dc machines, especially if the current waveforms are known a priori . This technique will be principally useful for high speed machines and in particular for the synchronous reluctance machines and in particular for the synchronous reluctance machine, where the iron losses are often an important issue. The calculation is based on Finite Element Analysis, which provides the flux density waveforms in the iron, and on the Fourier Analysis of these waveforms. Several Finite Element Simulations are necessary to obtain the induced voltage versus time waveforms. To reduce the post-processing time the majority of the elements of the model are grouped together to create super elements. Also the periodicity of the motor can be used to reduce the number of required simulations. The method is applied to the calculation of the iron losses of a synchronous reluctance generator, and a number of interesting results are discussed in the paper.

  17. Quantitative analysis of chaotic synchronization by means of coherence

    NASA Astrophysics Data System (ADS)

    Shabunin, A.; Astakhov, V.; Kurths, J.

    2005-07-01

    We use an index of chaotic synchronization based on the averaged coherence function for the quantitative analysis of the process of the complete synchronization loss in unidirectionally coupled oscillators and maps. We demonstrate that this value manifests different stages of the synchronization breaking. It is invariant to time delay and insensitive to small noise and distortions, which can influence the accessible signals at measurements. Peculiarities of the synchronization destruction in maps and oscillators are investigated.

  18. Chaotic Synchronization of Multi-neurons in External Electrical Stimulation.

    PubMed

    Jiang, Wang; Dengbin; Xiangyang, Fei; Feng, Dong

    2005-01-01

    The synchronization of n(n≥3) neurons coupled with gap junction in external electrical stimulation is investigated. In this paper, the coupled model is established on the basis of nonlinear cable model, and then the relation of coupling strength of the gap junction and the synchronization is discussed in detail. The sufficient condition of complete synchronization is attained from rigorously mathematical derivation. The synchronizations of periodic neurons and chaotic neurons are studied respectively. PMID:17282643

  19. Short communication: Field fertility in Holstein bulls: Can type of breeding strategy (artificial insemination following estrus versus timed artificial insemination) alter service sire fertility?

    PubMed

    Batista, E O S; Vieira, L M; Sá Filho, M F; Carvalho, P D; Rivera, H; Cabrera, V; Wiltbank, M C; Baruselli, P S; Souza, A H

    2016-03-01

    The aim of this study was to compare pregnancy per artificial insemination (P/AI) from service sires used on artificial insemination after estrus detection (EAI) or timed artificial insemination (TAI) breedings. Confirmed artificial insemination outcome records from 3 national data centers were merged and used as a data source. Criteria edits were herd's overall P/AI within 20 and 60%, a minimum of 30 breedings reported per herd-year, service sires that were used in at least 10 different herds with no more than 40% of the breedings performed in a single herd, breeding records from lactating Holstein cows receiving their first to fifth postpartum breedings occurring within 45 to 375 d in milk, and cows with 1 to 5 lactations producing a minimum of 6,804 kg. Initially 1,142,859 breeding records were available for analysis. After editing, a subset of the data (n=857,539) was used to classify breeding codes into either EAI or TAI based on weekly insemination profile in each individual herd. The procedure HPMIXED of SAS was used and took into account effects of state, farm, cow identification, breeding month, year, parity, days in milk at breeding, and service sire. This model was used independently for the 2 types osires f breeding codes (EAI vs. TAI), and service sire P/AI rankings within each breeding code were performed for sires with >700 breedings (94 sires) and for with >1,000 breedings (n=56 sires) following both EAI and TAI. Correlation for service sire fertility rankings following EAI and TAI was performed with the PROC CORR of SAS. Service sire P/AI rankings produced with EAI and TAI were 0.81 (for sires with >700 breedings) and 0.84 (for sires with >1,000 breedings). In addition, important changes occurred in service sire P/AI ranking to EAI and TAI for sires with less than 10,000 recorded artificial inseminations. In conclusion, the type of breeding strategy (EAI or TAI) was associated with some changes in service sire P/AI ranking, but ranking changes

  20. Synchronization of bursting neurons with delayed chemical synapses

    NASA Astrophysics Data System (ADS)

    Burić, Nikola; Todorović, Kristina; Vasović, Nebojša

    2008-09-01

    The synchronization of bursting Hindmarsh-Rose neurons coupled by a time-delayed fast threshold modulation synapse was studied. It is shown that there is a domain of the coupling parameter and nonzero time-lag values such that the bursting neurons are exactly synchronized. Furthermore, and contrary to the case of electrical synapses, such synchronous bursting is stochastically stable.

  1. 40 CFR 93.128 - Traffic signal synchronization projects.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Traffic signal synchronization..., Funded or Approved Under Title 23 U.S.C. or the Federal Transit Laws § 93.128 Traffic signal synchronization projects. Traffic signal synchronization projects may be approved, funded, and implemented...

  2. 40 CFR 93.128 - Traffic signal synchronization projects.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Traffic signal synchronization projects..., Funded or Approved Under Title 23 U.S.C. or the Federal Transit Laws § 93.128 Traffic signal synchronization projects. Traffic signal synchronization projects may be approved, funded, and implemented...

  3. 40 CFR 93.128 - Traffic signal synchronization projects.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Traffic signal synchronization..., Funded or Approved Under Title 23 U.S.C. or the Federal Transit Laws § 93.128 Traffic signal synchronization projects. Traffic signal synchronization projects may be approved, funded, and implemented...

  4. 40 CFR 93.128 - Traffic signal synchronization projects.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Traffic signal synchronization..., Funded or Approved Under Title 23 U.S.C. or the Federal Transit Laws § 93.128 Traffic signal synchronization projects. Traffic signal synchronization projects may be approved, funded, and implemented...

  5. 40 CFR 93.128 - Traffic signal synchronization projects.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Traffic signal synchronization..., Funded or Approved Under Title 23 U.S.C. or the Federal Transit Laws § 93.128 Traffic signal synchronization projects. Traffic signal synchronization projects may be approved, funded, and implemented...

  6. 21 CFR 892.1970 - Radiographic ECG/respirator synchronizer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic ECG/respirator synchronizer. 892.1970... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1970 Radiographic ECG/respirator synchronizer. (a) Identification. A radiographic ECG/respirator synchronizer is a device intended to be used...

  7. Synchronous Control Method and Realization of Automated Pharmacy Elevator

    NASA Astrophysics Data System (ADS)

    Liu, Xiang-Quan

    Firstly, the control method of elevator's synchronous motion is provided, the synchronous control structure of double servo motor based on PMAC is accomplished. Secondly, synchronous control program of elevator is implemented by using PMAC linear interpolation motion model and position error compensation method. Finally, the PID parameters of servo motor were adjusted. The experiment proves the control method has high stability and reliability.

  8. LPS-Challenged TNFα Production, Prostaglandin Secretion, and TNFα/TNFRs Expression in the Endometrium of Domestic Cats in Estrus or Diestrus, and in Cats with Pyometra or Receiving Medroxyprogesterone Acetate

    PubMed Central

    Jursza, Ewelina; Szóstek, Anna Z.; Kowalewski, Mariusz P.; Boos, Alois; Okuda, Kiyoshi; Siemieniuch, Marta J.

    2014-01-01

    Progesterone (P4) derivatives which are commonly used to block the cyclicity of domestic cats disturb the endocrine balance in the endometrium. The aims of this study were (i) to examine whether lipopolysaccharide (LPS) is responsible for enhancement of tumor necrosis factor-α (TNFα) secretion by the feline endometrial epithelial and stromal cells in vitro, (ii) to know whether immunolocalization of TNFα/TNFR1 and TNFR2 differs in cats at estrus or diestrus, receiving medroxyprogesterone acetate and suffering from pyometra, and (iii) to determine if TNFα-challenged prostaglandin secretion is stopped by prostaglandin synthases inhibitors. A total of 37 domestic adult cats in estrus or diestrus, receiving octane medroxyprogesterone or having clinical symptoms of pyometra, were enrolled in this study. The results obtained showed a distinct increase in LPS-challenged TNFα secretion in endometrial epithelial, but not stromal cells. TNFα augmented PG secretion was blocked by phospholipase A2 (PLA2) and cyclooxygeanase-2 (COX-2), but not by mitogen-activated protein kinase (MAPK) inhibitor. TNFα/TNFR1 and 2 protein expressions were limited mostly to the surface and glandular epithelium. TNFα/TNFRs protein was upregulated in the inflammatory uterus and hence may be involved in development of pathologic changes in the endometrial glands in cats receiving exogenous P4 as a hormonal contraceptive. PMID:25028529

  9. LPS-challenged TNFα production, prostaglandin secretion, and TNFα/TNFRs expression in the endometrium of domestic cats in estrus or diestrus, and in cats with pyometra or receiving medroxyprogesterone acetate.

    PubMed

    Jursza, Ewelina; Szóstek, Anna Z; Kowalewski, Mariusz P; Boos, Alois; Okuda, Kiyoshi; Siemieniuch, Marta J

    2014-01-01

    Progesterone (P4) derivatives which are commonly used to block the cyclicity of domestic cats disturb the endocrine balance in the endometrium. The aims of this study were (i) to examine whether lipopolysaccharide (LPS) is responsible for enhancement of tumor necrosis factor-α (TNFα) secretion by the feline endometrial epithelial and stromal cells in vitro, (ii) to know whether immunolocalization of TNFα/TNFR1 and TNFR2 differs in cats at estrus or diestrus, receiving medroxyprogesterone acetate and suffering from pyometra, and (iii) to determine if TNFα-challenged prostaglandin secretion is stopped by prostaglandin synthases inhibitors. A total of 37 domestic adult cats in estrus or diestrus, receiving octane medroxyprogesterone or having clinical symptoms of pyometra, were enrolled in this study. The results obtained showed a distinct increase in LPS-challenged TNFα secretion in endometrial epithelial, but not stromal cells. TNFα augmented PG secretion was blocked by phospholipase A2 (PLA2) and cyclooxygeanase-2 (COX-2), but not by mitogen-activated protein kinase (MAPK) inhibitor. TNFα/TNFR1 and 2 protein expressions were limited mostly to the surface and glandular epithelium. TNFα/TNFRs protein was upregulated in the inflammatory uterus and hence may be involved in development of pathologic changes in the endometrial glands in cats receiving exogenous P4 as a hormonal contraceptive. PMID:25028529

  10. Synchronization in the network of chaotic microwave oscillators

    NASA Astrophysics Data System (ADS)

    Moskalenko, O.; Phrolov, N.; Koronovskii, A.; Hramov, A.

    2013-10-01

    Time scale synchronization in networks of chaotic microwave oscillators with the different topologies of the links between nodes has been studied. As a node element of the network the one-dimensional distributed model of the low-voltage vircator has been used. To characterize the degree of synchronization in the whole network the synchronization index has been introduced. The transition to the synchronous regime is shown to take place via cluster time scale synchronization. Meanwhile, the spectral structure of the output signals is complicated sufficiently which allows using such devices in a number of practical applications.

  11. Studying synchronization to a musical beat in nonhuman animals.

    PubMed

    Patel, Aniruddh D; Iversen, John R; Bregman, Micah R; Schulz, Irena

    2009-07-01

    The recent discovery of spontaneous synchronization to music in a nonhuman animal (the sulphur-crested cockatoo Cacatua galerita eleonora) raises several questions. How does this behavior differ from nonmusical synchronization abilities in other species, such as synchronized frog calls or firefly flashes? What significance does the behavior have for debates over the evolution of human music? What kinds of animals can synchronize to musical rhythms, and what are the key methodological issues for research in this area? This paper addresses these questions and proposes some refinements to the "vocal learning and rhythmic synchronization hypothesis." PMID:19673824

  12. Synchronization of two self-excited double pendula

    NASA Astrophysics Data System (ADS)

    Koluda, P.; Perlikowski, P.; Czolczynski, Krzysztof; Kapitaniak, T.

    2014-04-01

    We consider the synchronization of two self-excited double pendula. We show that such pendula hanging on the same beam can have four different synchronous configurations. Our approximate analytical analysis allows us to derive the synchronization conditions and explain the observed types of synchronization. We consider an energy balance in the system and describe how the energy is transferred between the pendula via the oscillating beam, allowing thus the pendula synchronization. Changes and stability ranges of the obtained solutions with increasing and decreasing masses of the pendula are shown using path-following.

  13. Synchronization in complex dynamical networks coupled with complex chaotic system

    NASA Astrophysics Data System (ADS)

    Wei, Qiang; Xie, Cheng-Jun; Wang, Bo

    2015-11-01

    This paper investigates synchronization in complex dynamical networks with time delay and perturbation. The node of complex dynamical networks is composed of complex chaotic system. A complex feedback controller is designed to realize different component of complex state variable synchronize up to different scaling complex function when complex dynamical networks realize synchronization. The synchronization scaling function is changed from real field to complex field. Synchronization in complex dynamical networks with constant delay and time-varying coupling delay are investigated, respectively. Numerical simulations show the effectiveness of the proposed method.

  14. Signal processing techniques for synchronization of wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Lee, Jaehan; Wu, Yik-Chung; Chaudhari, Qasim; Qaraqe, Khalid; Serpedin, Erchin

    2010-11-01

    Clock synchronization is a critical component in wireless sensor networks, as it provides a common time frame to different nodes. It supports functions such as fusing voice and video data from different sensor nodes, time-based channel sharing, and sleep wake-up scheduling, etc. Early studies on clock synchronization for wireless sensor networks mainly focus on protocol design. However, clock synchronization problem is inherently related to parameter estimation, and recently, studies of clock synchronization from the signal processing viewpoint started to emerge. In this article, a survey of latest advances on clock synchronization is provided by adopting a signal processing viewpoint. We demonstrate that many existing and intuitive clock synchronization protocols can be interpreted by common statistical signal processing methods. Furthermore, the use of advanced signal processing techniques for deriving optimal clock synchronization algorithms under challenging scenarios will be illustrated.

  15. System and method for time synchronization in a wireless network

    DOEpatents

    Gonia, Patrick S.; Kolavennu, Soumitri N.; Mahasenan, Arun V.; Budampati, Ramakrishna S.

    2010-03-30

    A system includes multiple wireless nodes forming a cluster in a wireless network, where each wireless node is configured to communicate and exchange data wirelessly based on a clock. One of the wireless nodes is configured to operate as a cluster master. Each of the other wireless nodes is configured to (i) receive time synchronization information from a parent node, (ii) adjust its clock based on the received time synchronization information, and (iii) broadcast time synchronization information based on the time synchronization information received by that wireless node. The time synchronization information received by each of the other wireless nodes is based on time synchronization information provided by the cluster master so that the other wireless nodes substantially synchronize their clocks with the clock of the cluster master.

  16. Spontaneous synchronization of arm motion between Japanese macaques

    PubMed Central

    Nagasaka, Yasuo; Chao, Zenas C.; Hasegawa, Naomi; Notoya, Tomonori; Fujii, Naotaka

    2013-01-01

    Humans show spontaneous synchronization of movements during social interactions; this coordination has been shown to facilitate smooth communication. Although human studies exploring spontaneous synchronization are increasing in number, little is known about this phenomenon in other species. In this study, we examined spontaneous behavioural synchronization between monkeys in a laboratory setting. Synchronization was quantified by changes in button-pressing behaviour while pairs of monkeys were facing one another. Synchronization between the monkeys was duly observed and it was participant-partner dependent. Further tests confirmed that the speed of button pressing changed to harmonic or sub-harmonic levels in relation to the partner's speed. In addition, the visual information from the partner induced a higher degree of synchronization than auditory information. This study establishes advanced tasks for testing social coordination in monkeys, and illustrates ways in which monkeys coordinate their actions to establish synchronization. PMID:23359601

  17. Social argumentation in online synchronous communication

    NASA Astrophysics Data System (ADS)

    Angiono, Ivan

    In education, argumentation has an increasing importance because it can be used to foster learning in various fields including philosophy, history, sciences, and mathematics. Argumentation is also at the heart of scientific inquiry. Many educational technology researchers have been interested in finding out how technologies can be employed to improve students' learning of argumentation. Therefore, many computer-based tools or argumentation systems have been developed to assist students in their acquisition of argumentation skills. While the argumentation systems incorporating online debating tools present a good resource in formal settings, there is limited research revealing what argumentative skills students are portraying in informal online settings without the presence of a moderator. This dissertation investigates the nature of argumentative practices in a massively multiplayer online game where the system successfully incorporates the authentic use of online synchronous communication tools and the patterns that emerge from the interplay between a number of contextual variables including synchronicity, interest, authenticity, and topical knowledge.

  18. Synchronous motor with HTS-2G wires

    NASA Astrophysics Data System (ADS)

    Dezhin, D.; Ilyasov, R.; Kozub, S.; Kovalev, K.; Verzhbitsky, L.

    2014-05-01

    One of the applications of new high-temperature superconductor materials (HTS) is field coils for synchronous electrical machines. The use of YBCO 2G HTS tapes (HTS-2G) allows increasing of magnetic flux density in the air gap, which will increase the output power and reduce the dimensions of the motor. Such motors with improved characteristics can be successfully used in transportation as traction motor. In MAI-based "Center of Superconducting machines and devices" with the support of "Rosatom" has been designed and tested a prototype of the 50 kW synchronous motor with radial magnetic flux from a field-coils based on HTS-2G tapes. The experimental and theoretical results are presented.

  19. Forced synchronization of autonomous dynamical Boolean networks

    SciTech Connect

    Rivera-Durón, R. R. Campos-Cantón, E.; Campos-Cantón, I.; Gauthier, Daniel J.

    2015-08-15

    We present the design of an autonomous time-delay Boolean network realized with readily available electronic components. Through simulations and experiments that account for the detailed nonlinear response of each circuit element, we demonstrate that a network with five Boolean nodes displays complex behavior. Furthermore, we show that the dynamics of two identical networks display near-instantaneous synchronization to a periodic state when forced by a common periodic Boolean signal. A theoretical analysis of the network reveals the conditions under which complex behavior is expected in an individual network and the occurrence of synchronization in the forced networks. This research will enable future experiments on autonomous time-delay networks using readily available electronic components with dynamics on a slow enough time-scale so that inexpensive data collection systems can faithfully record the dynamics.

  20. Synchronization in networks of spatially extended systems

    SciTech Connect

    Filatova, Anastasiya E.; Hramov, Alexander E.; Koronovskii, Alexey A.; Boccaletti, Stefano

    2008-06-15

    Synchronization processes in networks of spatially extended dynamical systems are analytically and numerically studied. We focus on the relevant case of networks whose elements (or nodes) are spatially extended dynamical systems, with the nodes being connected with each other by scalar signals. The stability of the synchronous spatio-temporal state for a generic network is analytically assessed by means of an extension of the master stability function approach. We find an excellent agreement between the theoretical predictions and the data obtained by means of numerical calculations. The efficiency and reliability of this method is illustrated numerically with networks of beam-plasma chaotic systems (Pierce diodes). We discuss also how the revealed regularities are expected to take place in other relevant physical and biological circumstances.

  1. Anticipated synchronization in neuronal network motifs

    NASA Astrophysics Data System (ADS)

    Matias, F. S.; Gollo, L. L.; Carelli, P. V.; Copelli, M.; Mirasso, C. R.

    2013-01-01

    Two identical dynamical systems coupled unidirectionally (in a so called master-slave configuration) exhibit anticipated synchronization (AS) if the one which receives the coupling (the slave) also receives a negative delayed self-feedback. In oscillatory neuronal systems AS is characterized by a phase-locking with negative time delay τ between the spikes of the master and of the slave (slave fires before the master), while in the usual delayed synchronization (DS) regime τ is positive (slave fires after the master). A 3-neuron motif in which the slave self-feedback is replaced by a feedback loop mediated by an interneuron can exhibits both AS and DS regimes. Here we show that AS is robust in the presence of noise in a 3 Hodgkin-Huxley type neuronal motif. We also show that AS is stable for large values of τ in a chain of connected slaves-interneurons.

  2. [Synchronous tumors of the gastrointestinal tract].

    PubMed

    Pătraşcu, Tr; Doran, H; Catrina, E; Mihalache, O; Degeratu, D; Predescu, G

    2010-01-01

    The term "synchronous tumors" is reserved for simultaneous evolution of two or more tumors with distinct sites, in which the possibility that one tumor is a metastasis of the other has been excluded. In medical practice, the involvement of two different cavitary organs of the gastrointestinal tract is very rare. We present two clinical cases of synchronous tumors: one of a malignant degeneration of a colonic polyp, associated to a jejunal tumor; the other of a patient with a gastric adenocarcinoma, who also had a bulky rectal villous tumor. We tried to find out the etiology of the tumors and the frequency of these associations, mentioned in medical literature. Immunohistochemistry investigations, genetic analysis and familial screening must complete an individualized medical approach in which the surgical technique must be adequate for each case. PMID:20405687

  3. Another look at synchronized neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Akhmedov, Evgeny; Mirizzi, Alessandro

    2016-07-01

    In dense neutrino backgrounds present in supernovae and in the early Universe neutrino oscillations may exhibit complex collective phenomena, such as synchronized oscillations, bipolar oscillations and spectral splits and swaps. We consider in detail possible decoherence effects on the simplest of these phenomena - synchronized neutrino oscillations that can occur in a uniform and isotropic neutrino gas. We develop an exact formalism of spectral moments of the flavour spin vectors describing such a system and then apply it to find analytical approaches that allow one to study decoherence effects on its late-time evolution. This turns out to be possible in part due to the existence of the (previously unknown) exact conservation law satisfied by the quantities describing the considered neutrino system. Interpretation of the decoherence effects in terms of neutrino wave packet separation is also given, both in the adiabatic and non-adiabatic regimes of neutrino flavour evolution.

  4. Synchronous and Cogged Fan Belt Performance Assessment

    SciTech Connect

    Cutler, D.; Dean, J.; Acosta, J.

    2014-02-01

    The GSA Regional GPG Team commissioned the National Renewable Energy Laboratory (NREL) to perform monitoring of cogged V-belts and synchronous belts on both a constant volume and a variable air volume fan at the Byron G. Rodgers Federal Building and U.S. Courthouse in Denver, Colorado. These motor/fan combinations were tested with their original, standard V-belts (appropriately tensioned by an operation and maintenance professional) to obtain a baseline for standard operation. They were then switched to the cogged V-belts, and finally to synchronous belts. The power consumption by the motor was normalized for both fan speed and air density changes. This was necessary to ensure that the power readings were not influenced by a change in rotational fan speed or by the power required to push denser air. Finally, energy savings and operation and maintenance savings were compiled into an economic life-cycle cost analysis of the different belt options.

  5. Electro-hydrodynamic synchronization of piezoelectric flags

    NASA Astrophysics Data System (ADS)

    Xia, Yifan; Doaré, Olivier; Michelin, Sébastien

    2016-08-01

    Hydrodynamic coupling of flexible flags in axial flows may profoundly influence their flapping dynamics, in particular driving their synchronization. This work investigates the effect of such coupling on the harvesting efficiency of coupled piezoelectric flags, that convert their periodic deformation into an electrical current. Considering two flags connected to a single output circuit, we investigate using numerical simulations the relative importance of hydrodynamic coupling to electrodynamic coupling of the flags through the output circuit due to the inverse piezoelectric effect. It is shown that electrodynamic coupling is dominant beyond a critical distance, and induces a synchronization of the flags' motion resulting in enhanced energy harvesting performance. We further show that this electrodynamic coupling can be strengthened using resonant harvesting circuits.

  6. Phase synchronization of instrumental music signals

    NASA Astrophysics Data System (ADS)

    Mukherjee, Sayan; Palit, Sanjay Kumar; Banerjee, Santo; Ariffin, M. R. K.; Bhattacharya, D. K.

    2014-06-01

    Signal analysis is one of the finest scientific techniques in communication theory. Some quantitative and qualitative measures describe the pattern of a music signal, vary from one to another. Same musical recital, when played by different instrumentalists, generates different types of music patterns. The reason behind various patterns is the psycho-acoustic measures - Dynamics, Timber, Tonality and Rhythm, varies in each time. However, the psycho-acoustic study of the music signals does not reveal any idea about the similarity between the signals. For such cases, study of synchronization of long-term nonlinear dynamics may provide effective results. In this context, phase synchronization (PS) is one of the measures to show synchronization between two non-identical signals. In fact, it is very critical to investigate any other kind of synchronization for experimental condition, because those are completely non identical signals. Also, there exists equivalence between the phases and the distances of the diagonal line in Recurrence plot (RP) of the signals, which is quantifiable by the recurrence quantification measure τ-recurrence rate. This paper considers two nonlinear music signals based on same raga played by two eminent sitar instrumentalists as two non-identical sources. The psycho-acoustic study shows how the Dynamics, Timber, Tonality and Rhythm vary for the two music signals. Then, long term analysis in the form of phase space reconstruction is performed, which reveals the chaotic phase spaces for both the signals. From the RP of both the phase spaces, τ-recurrence rate is calculated. Finally by the correlation of normalized tau-recurrence rate of their 3D phase spaces and the PS of the two music signals has been established. The numerical results well support the analysis.

  7. Bilateral synchronous plasmacytoma of the testis.

    PubMed

    Narayanan, Geetha; Joseph, Rona; Soman, Lali V

    2016-04-01

    Extramedullary plasmacytoma (EMP) is usually seen in the head and neck regions and in the upper respiratory, gastrointestinal, and central nervous systems. Testis is a rare site for EMP, and bilateral synchronous testicular plasmacytoma occurring as an isolated event at initial presentation has been reported only once previously. We present herein the second such report in a 70-year-old man who underwent bilateral orchidectomy. PMID:27034568

  8. Bilateral synchronous plasmacytoma of the testis

    PubMed Central

    Joseph, Rona; Soman, Lali V.

    2016-01-01

    Extramedullary plasmacytoma (EMP) is usually seen in the head and neck regions and in the upper respiratory, gastrointestinal, and central nervous systems. Testis is a rare site for EMP, and bilateral synchronous testicular plasmacytoma occurring as an isolated event at initial presentation has been reported only once previously. We present herein the second such report in a 70-year-old man who underwent bilateral orchidectomy. PMID:27034568

  9. Synchronization of motion sequences from different sources

    NASA Astrophysics Data System (ADS)

    Skurowski, Przemysław; Pruszowski, Przemysław; Peszor, Damian

    2016-06-01

    The paper describes an algorithm for the synchronization of motion sequences derived with different motion capture (mocap) systems. The algorithm is invented for the temporal matching of the motion represented as angular orientation timeseries obtained with different mocap systems. We employed the PCA to reduce problem to a single dimension, then the algorithm comprises twofold exhaustive search allowing for the precise matching of sequences. The method was verified with both - semi synthetic and real sequences.

  10. System for synchronizing synthesizers of communication systems

    NASA Technical Reports Server (NTRS)

    Enriquez, E. A. (Inventor); Gookin, R. E.

    1979-01-01

    Frequency synthesizers at first and second stations that communicate with each other via a transmission link having a constant propagation delay time are started and synchronized by transmitting a tone from the first station to the second station via the link. The frequencies derived from the synthesizer at the second station are received at the first station and are combined with the frequencies derived from the synthesizer at the first station to derive a constant beat frequency as the two synthesizers are stepped.

  11. Synchronization Dynamics of Coupled Chemical Oscillators

    NASA Astrophysics Data System (ADS)

    Tompkins, Nathan

    The synchronization dynamics of complex networks have been extensively studied over the past few decades due to their ubiquity in the natural world. Prominent examples include cardiac rhythms, circadian rhythms, the flashing of fireflies, predator/prey population dynamics, mammalian gait, human applause, pendulum clocks, the electrical grid, and of the course the brain. Detailed experiments have been done to map the topology of many of these systems and significant advances have been made to describe the mathematics of these networks. Compared to these bodies of work relatively little has been done to directly test the role of topology in the synchronization dynamics of coupled oscillators. This Dissertation develops technology to examine the dynamics due to topology within networks of discrete oscillatory components. The oscillatory system used here consists of the photo-inhibitable Belousov-Zhabotinsky (BZ) reaction water-in-oil emulsion where the oscillatory drops are diffusively coupled to one another and the topology is defined by the geometry of the diffusive connections. Ring networks are created from a close-packed 2D array of drops using the Programmable Illumination Microscope (PIM) in order to test Turing's theory of morphogenesis directly. Further technology is developed to create custom planar networks of BZ drops in more complicated topologies which can be individually perturbed using illumination from the PIM. The work presented here establishes the validity of using the BZ emulsion system with a PIM to study the topology induced effects on the synchronization dynamics of coupled chemical oscillators, tests the successes and limitations of Turing's theory of morphogenesis, and develops new technology to further probe the effects of network topology on a system of coupled oscillators. Finally, this Dissertation concludes by describing ongoing experiments which utilize this new technology to examine topology induced transitions of synchronization

  12. Reed-solomon Code Synchronization Revisited

    NASA Technical Reports Server (NTRS)

    Deutsch, L. J.

    1985-01-01

    A concatenated coding consisting of an inner (7, 1/2) convolutional code and an outer (255, 223) Reed-Solomon code was recommended by the Consultative Committee for Space Data Systems for cross-supported space missions. The Reed-Solomon code that was chosen makes use of the Berlekamp encoding algorithm. Some peculiarities of this code that could give rise to synchronization problems are examined. Suggestions are given to alleviate these problems.

  13. Traveling-wave synchronous coil gun

    NASA Technical Reports Server (NTRS)

    Elliott, David G.

    1991-01-01

    An outline is presented of the coilgun concept, excitation, switching, brush commutation, power supply, and performance. It is shown that a traveling-wave synchronous coilgun permits independent adjustment of the magnetic field and armature current for high velocity at low armature mass fraction. Magnetic field energy is transferred from the rear of the wave to the front without passing through the power supply. Elaborate switching is required.

  14. Pulse Ejection Presentation System Synchronized with Breathing

    NASA Astrophysics Data System (ADS)

    Kadowaki, Ami; Sato, Junta; Ohtsu, Kaori; Bannai, Yuichi; Okada, Kenichi

    Trials on transmission of olfactory information together with audio/visual information are currently being conducted in the field of multimedia. However, continuous emission of scents in high concentration creates problems of human adaptation and remnant odors in air. To overcome such problems we developed an olfactory display in conjunction with Canon Inc. This display has high emission control in the ink-jet so that it can provide stable pulse emission of scents. Humans catch a scent when they breathe in and inhale smell molecules in air. Therefore, it is important that the timing of scent presentation is synchronized with human breathing. We also developed a breath sensor which detects human inspiration. In this study, we combined the olfactory display with the breath sensor to make a pulse ejection presentation system synchronized the breath. The experimental evaluation showed that the system had more than 90 percent of detection rate. Another evaluation was held at KEIO TECHNO-MALL 2007. From questionnaire results of the participants, we found that the system made the user feel continuous sense of smell avoiding adaptation. It is expected that our system enables olfactory information to be synchronized with audio/visual information in arbitrary duration at any time.

  15. Driven synchronization in random networks of oscillators.

    PubMed

    Hindes, Jason; Myers, Christopher R

    2015-07-01

    Synchronization is a universal phenomenon found in many non-equilibrium systems. Much recent interest in this area has overlapped with the study of complex networks, where a major focus is determining how a system's connectivity patterns affect the types of behavior that it can produce. Thus far, modeling efforts have focused on the tendency of networks of oscillators to mutually synchronize themselves, with less emphasis on the effects of external driving. In this work, we discuss the interplay between mutual and driven synchronization in networks of phase oscillators of the Kuramoto type, and explore how the structure and emergence of such states depend on the underlying network topology for simple random networks with a given degree distribution. We find a variety of interesting dynamical behaviors, including bifurcations and bistability patterns that are qualitatively different for heterogeneous and homogeneous networks, and which are separated by a Takens-Bogdanov-Cusp singularity in the parameter region where the coupling strength between oscillators is weak. Our analysis is connected to the underlying dynamics of oscillator clusters for important states and transitions. PMID:26232970

  16. Inter-Brain Synchronization during Social Interaction

    PubMed Central

    Dumas, Guillaume; Nadel, Jacqueline; Soussignan, Robert; Martinerie, Jacques

    2010-01-01

    During social interaction, both participants are continuously active, each modifying their own actions in response to the continuously changing actions of the partner. This continuous mutual adaptation results in interactional synchrony to which both members contribute. Freely exchanging the role of imitator and model is a well-framed example of interactional synchrony resulting from a mutual behavioral negotiation. How the participants' brain activity underlies this process is currently a question that hyperscanning recordings allow us to explore. In particular, it remains largely unknown to what extent oscillatory synchronization could emerge between two brains during social interaction. To explore this issue, 18 participants paired as 9 dyads were recorded with dual-video and dual-EEG setups while they were engaged in spontaneous imitation of hand movements. We measured interactional synchrony and the turn-taking between model and imitator. We discovered by the use of nonlinear techniques that states of interactional synchrony correlate with the emergence of an interbrain synchronizing network in the alpha-mu band between the right centroparietal regions. These regions have been suggested to play a pivotal role in social interaction. Here, they acted symmetrically as key functional hubs in the interindividual brainweb. Additionally, neural synchronization became asymmetrical in the higher frequency bands possibly reflecting a top-down modulation of the roles of model and imitator in the ongoing interaction. PMID:20808907

  17. Inter-brain synchronization during social interaction.

    PubMed

    Dumas, Guillaume; Nadel, Jacqueline; Soussignan, Robert; Martinerie, Jacques; Garnero, Line

    2010-01-01

    During social interaction, both participants are continuously active, each modifying their own actions in response to the continuously changing actions of the partner. This continuous mutual adaptation results in interactional synchrony to which both members contribute. Freely exchanging the role of imitator and model is a well-framed example of interactional synchrony resulting from a mutual behavioral negotiation. How the participants' brain activity underlies this process is currently a question that hyperscanning recordings allow us to explore. In particular, it remains largely unknown to what extent oscillatory synchronization could emerge between two brains during social interaction. To explore this issue, 18 participants paired as 9 dyads were recorded with dual-video and dual-EEG setups while they were engaged in spontaneous imitation of hand movements. We measured interactional synchrony and the turn-taking between model and imitator. We discovered by the use of nonlinear techniques that states of interactional synchrony correlate with the emergence of an interbrain synchronizing network in the alpha-mu band between the right centroparietal regions. These regions have been suggested to play a pivotal role in social interaction. Here, they acted symmetrically as key functional hubs in the interindividual brainweb. Additionally, neural synchronization became asymmetrical in the higher frequency bands possibly reflecting a top-down modulation of the roles of model and imitator in the ongoing interaction. PMID:20808907

  18. The synchronous active neutron detection assay system

    SciTech Connect

    Pickrell, M.M.; Kendall, P.K.

    1994-08-01

    We have begun to develop a novel technique for active neutron assay of fissile material in spent nuclear fuel. This approach will exploit a 14-MeV neutron generator developed by Schlumberger. The technique, termed synchronous active neutron detection (SAND), follows a method used routinely in other branches of physics to detect very small signals in presence of large backgrounds. Synchronous detection instruments are widely available commercially and are termed ``lock-in`` amplifiers. We have implemented a digital lock-in amplifier in conjunction with the Schlumberger neutron generator to explore the possibility of synchronous detection with active neutrons. The Schlumberger system can operate at up to a 50% duty factor, in effect, a square wave of neutron yield. Results are preliminary but promising. The system is capable of resolving the fissile material contained in a small fraction of the fuel rods in a cold fuel assembly; it also appears resilient to background neutron interference. The interrogating neutrons appear to be non-thermal and penetrating. Work remains to fully explore relevant physics and optimize instrument design.

  19. The synchronous active neutron detection assay system

    SciTech Connect

    Pickrell, M.M.; Kendall, P.K.

    1994-09-01

    The authors have begun to develop a novel technique for active neutron assay of fissile material in spent nuclear fuel. They are using a Schlumberger neutron generator for the direct measurement of the fissile material content in spent fuel, in place of the indirect measures used at present. The technique they are investigating is termed synchronous active neutron detection (SAND). It closely follows a method that has been used routinely in other branches of physics for the detection of very small signals in the presence of large backgrounds. Synchronous detection instruments are widely available commercially and are termed ``lock-in`` amplifiers. They have implemented a digital lock-in amplifier in conjunction with the Schlumberger neutron generator to explore the possibility of synchronous detection with active neutrons. The results to data are preliminary but quite promising. The system is capable of resolving the fissile material contained in a small fraction of the fuel rods in a cold fuel assembly. It also appears to be quite resilient to background neutron interference.

  20. Synchronous behavior of two coupled electronic neurons

    SciTech Connect

    Pinto, R. D.; Varona, P.; Volkovskii, A. R.; Szuecs, A.; Abarbanel, Henry D. I.; Rabinovich, M. I.

    2000-08-01

    We report on experimental studies of synchronization phenomena in a pair of analog electronic neurons (ENs). The ENs were designed to reproduce the observed membrane voltage oscillations of isolated biological neurons from the stomatogastric ganglion of the California spiny lobster Panulirus interruptus. The ENs are simple analog circuits which integrate four-dimensional differential equations representing fast and slow subcellular mechanisms that produce the characteristic regular/chaotic spiking-bursting behavior of these cells. In this paper we study their dynamical behavior as we couple them in the same configurations as we have done for their counterpart biological neurons. The interconnections we use for these neural oscillators are both direct electrical connections and excitatory and inhibitory chemical connections: each realized by analog circuitry and suggested by biological examples. We provide here quantitative evidence that the ENs and the biological neurons behave similarly when coupled in the same manner. They each display well defined bifurcations in their mutual synchronization and regularization. We report briefly on an experiment on coupled biological neurons and four-dimensional ENs, which provides further ground for testing the validity of our numerical and electronic models of individual neural behavior. Our experiments as a whole present interesting new examples of regularization and synchronization in coupled nonlinear oscillators. (c) 2000 The American Physical Society.

  1. Synchronous particle and non-adiabatic capture

    SciTech Connect

    Kats, J.M.

    1988-01-01

    In the theory of particle longitudinal motion, a classical definition of synchronous particle (synchronous energy, phase, and orbit) assumes that there is a one-to-one correspondence between the guiding magnetic field and the frequency of the accelerating electrical field. In practice, that correspondence may not be sustained because of errors in the magnetic field, in the frequency, or because sometimes one does not want to keep that relationship for some reason. In this paper, a definition of synchronous particle is introduced when the magnetic field and the frequency are independent functions of time. The result is that the size and shape of the bucket (separatrix) depends not only on the field rate of change but also on the frequency rate of change. This means, for example, that one can have a stationary bucket even with a rising field. Having the frequency, in addition to the field and voltage, as parameters controlling the shape and the size of the bucket, it is shown how to decrease particle losses during injection and capture. 2 refs., 2 figs.

  2. Synchronous behavior of two coupled electronic neurons

    NASA Astrophysics Data System (ADS)

    Pinto, R. D.; Varona, P.; Volkovskii, A. R.; Szücs, A.; Abarbanel, Henry D. I.; Rabinovich, M. I.

    2000-08-01

    We report on experimental studies of synchronization phenomena in a pair of analog electronic neurons (ENs). The ENs were designed to reproduce the observed membrane voltage oscillations of isolated biological neurons from the stomatogastric ganglion of the California spiny lobster Panulirus interruptus. The ENs are simple analog circuits which integrate four-dimensional differential equations representing fast and slow subcellular mechanisms that produce the characteristic regular/chaotic spiking-bursting behavior of these cells. In this paper we study their dynamical behavior as we couple them in the same configurations as we have done for their counterpart biological neurons. The interconnections we use for these neural oscillators are both direct electrical connections and excitatory and inhibitory chemical connections: each realized by analog circuitry and suggested by biological examples. We provide here quantitative evidence that the ENs and the biological neurons behave similarly when coupled in the same manner. They each display well defined bifurcations in their mutual synchronization and regularization. We report briefly on an experiment on coupled biological neurons and four-dimensional ENs, which provides further ground for testing the validity of our numerical and electronic models of individual neural behavior. Our experiments as a whole present interesting new examples of regularization and synchronization in coupled nonlinear oscillators.

  3. Explosive synchronization with asymmetric frequency distribution

    NASA Astrophysics Data System (ADS)

    Zhou, Wenchang; Chen, Lumin; Bi, Hongjie; Hu, Xin; Liu, Zonghua; Guan, Shuguang

    2015-07-01

    In this work, we study the synchronization in a generalized Kuramoto model with frequency-weighted coupling. In particular, we focus on the situations in which the frequency distributions of oscillators are asymmetric. For typical unimodal frequency distributions, such as Lorentzian, Gaussian, triangle, and even special Rayleigh, we find that the synchronization transition in the model generally converts from the first order to the second order as the central frequency shifts toward positive direction. We characterize two interesting coherent states in the system: In the former, two phase-locking clusters are formed, rotating with the same frequency. They correspond to those oscillators with relatively high frequencies while the oscillators with relatively small frequencies are not entrained. In the latter, two phase-locking clusters rotate with different frequencies, leading to the oscillation of the order parameter. We further conduct theoretical analysis to reveal the relation between the asymmetric frequency distribution and the conversion of synchronization type, and justify the coherent states observed in the system.

  4. Synchronization and Propagation of Global Sleep Spindles

    PubMed Central

    de Souza, Rafael Toledo Fernandes; Gerhardt, Günther Johannes Lewczuk; Schönwald, Suzana Veiga; Rybarczyk-Filho, José Luiz; Lemke, Ney

    2016-01-01

    Sleep spindles occur thousands of times during normal sleep and can be easily detected by visual inspection of EEG signals. These characteristics make spindles one of the most studied EEG structures in mammalian sleep. In this work we considered global spindles, which are spindles that are observed simultaneously in all EEG channels. We propose a methodology that investigates both the signal envelope and phase/frequency of each global spindle. By analysing the global spindle phase we showed that 90% of spindles synchronize with an average latency time of 0.1 s. We also measured the frequency modulation (chirp) of global spindles and found that global spindle chirp and synchronization are not correlated. By investigating the signal envelopes and implementing a homogeneous and isotropic propagation model, we could estimate both the signal origin and velocity in global spindles. Our results indicate that this simple and non-invasive approach could determine with reasonable precision the spindle origin, and allowed us to estimate a signal speed of 0.12 m/s. Finally, we consider whether synchronization might be useful as a non-invasive diagnostic tool. PMID:26963102

  5. Synchronized slice viewing of similar image series

    NASA Astrophysics Data System (ADS)

    Ali, Sharib; Foncubierta, Antonio; Depeursinge, Adrien; Meriaudeau, Fabrice; Ratib, Osman; Müller, Henning

    2012-02-01

    Comparing several series of images is not always easy as the corresponding slices often need to be selected manually. In times where series contain an ever-increasing number of slices this can mean manual work when moving several series to the corresponding slice. Particularly two situations were identified in this context: (1) patients with a large number of image series over time (such as patients with cancers that are monitored) frequently need to compare the series, for example to compare tumor growth over time. Manually adapting two series is possible but with four or more series this can mean loosing time. Having automatically the closest slice by comparing visual similarity also in older series with differing slice thickness and inter slice distance can save time and synchronize the viewing instantly. (2) analyzing visually similar image series of several patients can profit from being viewed in a synchronized way to compare the cases, so when sliding through the slices in one volume, the corresponding slices in the other volumes are shown. This application could be employed after content-based 3D image retrieval has found similar series, for example. Synchronized viewing can help finding or confirming the most relevant cases quickly. To allow for synchronized viewing of several image volumes, the test image series are first registered applying affine transformation for the global registration of images followed by diffeomorphic image registration. Then corresponding slices in the two volumes are estimated based on a visual similarity. Once the registration is finished, the user can subsequently move inside the slices of one volume (reference volume) and can view the corresponding slices in the other volumes. These corresponding slices are obtained after a correspondence match in the registration procedure. These volumes are synchronized in that the slice closest to the original reference volume is shown even when the slice thicknesses or inter slice

  6. Rupture Synchronicity in Complex Fault Systems

    NASA Astrophysics Data System (ADS)

    Milner, K. R.; Jordan, T. H.

    2013-12-01

    While most investigators would agree that the timing of large earthquakes within a fault system depends on stress-mediated interactions among its elements, much of the debate relevant to time-dependent forecasting has been centered on single-fault concepts, such as characteristic earthquake behavior. We propose to broaden this discussion by quantifying the multi-fault concept of rupture synchronicity. We consider a finite set of small, fault-spanning volumes {Vk} within a fault system of arbitrary (fractal) complexity. We let Ck be the catalog of length tmax comprising Nk discrete times {ti(k)} that mark when the kth volume participates in a rupture of magnitude > M. The main object of our analysis is the complete set of event time differences {τij(kk') = ti(k) - tj(k')}, which we take to be a random process with an expected density function ρkk'(t). When k = k', we call this function the auto-catalog density function (ACDF); when k ≠ k', we call it the cross-catalog density function (CCDF). The roles of the ACDF and CCDF in synchronicity theory are similar to those of autocorrelation and cross-correlation functions in time-series analysis. For a renewal process, the ACDF can be written in terms of convolutions of the interevent-time distribution, and many of its properties (e.g., large-t asymptote) can be derived analytically. The interesting information in the CCDF, like that in the ACDF, is concentrated near t = 0. If two catalogs are completely asynchronous, the CCDF collapses to an asymptote given by the harmonic mean of the ACDF asymptotes. Synchronicity can therefore be characterized by the variability of the CCDF about this asymptote. The brevity of instrumental catalogs makes the identification of synchronicity at large M difficult, but we will illustrate potentially interesting behaviors through the analysis of a million-year California catalog generated by the earthquake simulator, RSQSim (Deiterich & Richards-Dinger, 2010), which we sampled at a

  7. A Spatiotemporal-Chaos-Based Cryptosystem Taking Advantage of Both Synchronous and Self-Synchronizing Schemes

    NASA Astrophysics Data System (ADS)

    Lü, Hua-Ping; Wang, Shi-Hong; Li, Xiao-Wen; Tang, Guo-Ning; Kuang, Jin-Yu; Ye, Wei-Ping; Hu, Gang

    2004-06-01

    Two-dimensional one-way coupled map lattices are used for cryptography where multiple space units produce chaotic outputs in parallel. One of the outputs plays the role of driving for synchronization of the decryption system while the others perform the function of information encoding. With this separation of functions the receiver can establish a self-checking and self-correction mechanism, and enjoys the advantages of both synchronous and self-synchronizing schemes. A comparison between the present system with the system of advanced encryption standard (AES) is presented in the aspect of channel noise influence. Numerical investigations show that our system is much stronger than AES against channel noise perturbations, and thus can be better used for secure communications with large channel noise.

  8. Robust finite-time chaos synchronization of uncertain permanent magnet synchronous motors.

    PubMed

    Chen, Qiang; Ren, Xuemei; Na, Jing

    2015-09-01

    In this paper, a robust finite-time chaos synchronization scheme is proposed for two uncertain third-order permanent magnet synchronous motors (PMSMs). The whole synchronization error system is divided into two cascaded subsystems: a first-order subsystem and a second-order subsystem. For the first subsystem, we design a finite-time controller based on the finite-time Lyapunov stability theory. Then, according to the backstepping idea and the adding a power integrator technique, a second finite-time controller is constructed recursively for the second subsystem. No exogenous forces are required in the controllers design but only the direct-axis (d-axis) and the quadrature-axis (q-axis) stator voltages are used as manipulated variables. Comparative simulations are provided to show the effectiveness and superior performance of the proposed method. PMID:26250587

  9. Synchronization Analysis of Master-Slave Probabilistic Boolean Networks.

    PubMed

    Lu, Jianquan; Zhong, Jie; Li, Lulu; Ho, Daniel W C; Cao, Jinde

    2015-01-01

    In this paper, we analyze the synchronization problem of master-slave probabilistic Boolean networks (PBNs). The master Boolean network (BN) is a deterministic BN, while the slave BN is determined by a series of possible logical functions with certain probability at each discrete time point. In this paper, we firstly define the synchronization of master-slave PBNs with probability one, and then we investigate synchronization with probability one. By resorting to new approach called semi-tensor product (STP), the master-slave PBNs are expressed in equivalent algebraic forms. Based on the algebraic form, some necessary and sufficient criteria are derived to guarantee synchronization with probability one. Further, we study the synchronization of master-slave PBNs in probability. Synchronization in probability implies that for any initial states, the master BN can be synchronized by the slave BN with certain probability, while synchronization with probability one implies that master BN can be synchronized by the slave BN with probability one. Based on the equivalent algebraic form, some efficient conditions are derived to guarantee synchronization in probability. Finally, several numerical examples are presented to show the effectiveness of the main results. PMID:26315380

  10. Synchronization Analysis of Master-Slave Probabilistic Boolean Networks

    NASA Astrophysics Data System (ADS)

    Lu, Jianquan; Zhong, Jie; Li, Lulu; Ho, Daniel W. C.; Cao, Jinde

    2015-08-01

    In this paper, we analyze the synchronization problem of master-slave probabilistic Boolean networks (PBNs). The master Boolean network (BN) is a deterministic BN, while the slave BN is determined by a series of possible logical functions with certain probability at each discrete time point. In this paper, we firstly define the synchronization of master-slave PBNs with probability one, and then we investigate synchronization with probability one. By resorting to new approach called semi-tensor product (STP), the master-slave PBNs are expressed in equivalent algebraic forms. Based on the algebraic form, some necessary and sufficient criteria are derived to guarantee synchronization with probability one. Further, we study the synchronization of master-slave PBNs in probability. Synchronization in probability implies that for any initial states, the master BN can be synchronized by the slave BN with certain probability, while synchronization with probability one implies that master BN can be synchronized by the slave BN with probability one. Based on the equivalent algebraic form, some efficient conditions are derived to guarantee synchronization in probability. Finally, several numerical examples are presented to show the effectiveness of the main results.

  11. System and method to allow a synchronous motor to successfully synchronize with loads that have high inertia and/or high torque

    SciTech Connect

    Melfi, Michael J.

    2015-10-20

    A mechanical soft-start type coupling is used as an interface between a line start, synchronous motor and a heavy load to enable the synchronous motor to bring the heavy load up to or near synchronous speed. The soft-start coupling effectively isolates the synchronous motor from the load for enough time to enable the synchronous motor to come up to full speed. The soft-start coupling then brings the load up to or near synchronous speed.

  12. Delivering non-hormonal contraceptives to men: advances and obstacles

    PubMed Central

    Mruk, Dolores D.; Cheng, C. Yan

    2014-01-01

    There have been major advances in male contraceptive research during the past two decades. However, for a contraceptive to be used by men, its safety requires more stringent scrutiny than therapeutic compounds for treatment of illnesses because the contraceptives will be used by healthy individuals for an extended period of time, perhaps decades. A wide margin is therefore required between the effective dose range and doses that cause toxicity. It might be preferable that a male contraceptive, in particular a non-hormone-based compound, is delivered specifically and/or directly to the testis and has a rapid metabolic clearance rate, reducing the length of exposure in the liver and kidney. In this article, we highlight the latest developments regarding contraceptive delivery to men and with the aim of providing useful information for investigators in future studies. PMID:18191256

  13. Clinical Inquiry: Which nonhormonal treatments are effective for hot flashes?

    PubMed

    Kelsberg, Gary; Maragh, Leticia; Safranek, Sarah

    2016-05-01

    Selective serotonin reuptake inhibitors (SSRIs [fluoxetine, sertraline, paroxetine]) and the selective norepinephrine reuptake inhibitor (SNRI) venlafaxine, as well as clonidine and gabapentin, reduce hot flashes by about 25% (approximately one per day) in women with and without a history of breast cancer. No studies compare medications against each other to determine a single best option. PMID:27275942

  14. Delays, Connection Topology, and Synchronization of Coupled Chaotic Maps

    NASA Astrophysics Data System (ADS)

    Atay, Fatihcan M.; Jost, Jürgen; Wende, Andreas

    2004-04-01

    We consider networks of coupled maps where the connections between units involve time delays. We show that, similar to the undelayed case, the synchronization of the network depends on the connection topology, characterized by the spectrum of the graph Laplacian. Consequently, scale-free and random networks are capable of synchronizing despite the delayed flow of information, whereas regular networks with nearest-neighbor connections and their small-world variants generally exhibit poor synchronization. On the other hand, connection delays can actually be conducive to synchronization, so that it is possible for the delayed system to synchronize where the undelayed system does not. Furthermore, the delays determine the synchronized dynamics, leading to the emergence of a wide range of new collective behavior which the individual units are incapable of producing in isolation.

  15. Network structure, topology, and dynamics in generalized models of synchronization

    NASA Astrophysics Data System (ADS)

    Lerman, Kristina; Ghosh, Rumi

    2012-08-01

    Network structure is a product of both its topology and interactions between its nodes. We explore this claim using the paradigm of distributed synchronization in a network of coupled oscillators. As the network evolves to a global steady state, nodes synchronize in stages, revealing the network's underlying community structure. Traditional models of synchronization assume that interactions between nodes are mediated by a conservative process similar to diffusion. However, social and biological processes are often nonconservative. We propose a model of synchronization in a network of oscillators coupled via nonconservative processes. We study the dynamics of synchronization of a synthetic and real-world networks and show that the traditional and nonconservative models of synchronization reveal different structures within the same network.

  16. A three-sphere swimmer for flagellar synchronization

    NASA Astrophysics Data System (ADS)

    Polotzek, Katja; Friedrich, Benjamin M.

    2013-04-01

    In a recent letter (Friedrich et al 2012 Phys. Rev. Lett. 109 138102), a minimal model swimmer has been proposed that propels itself at low Reynolds numbers by the revolving motion of a pair of spheres. The motion of the two spheres can synchronize by virtue of a hydrodynamic coupling that depends on the motion of the swimmer, but is rather independent of direct hydrodynamic interactions. This novel synchronization mechanism could account for the synchronization of a pair of flagella, e.g. in the green algae Chlamydomonas. In this paper, we discuss in detail how swimming and synchronization depend on the geometry of the model swimmer and compute the swimmer design for optimal synchronization. Our analysis highlights the role of broken symmetries in swimming and synchronization.

  17. Modulation and synchronization technique for MF-TDMA system

    NASA Technical Reports Server (NTRS)

    Faris, Faris; Inukai, Thomas; Sayegh, Soheil

    1994-01-01

    This report addresses modulation and synchronization techniques for a multi-frequency time division multiple access (MF-TDMA) system with onboard baseband processing. The types of synchronization techniques analyzed are asynchronous (conventional) TDMA, preambleless asynchronous TDMA, bit synchronous timing with a preamble, and preambleless bit synchronous timing. Among these alternatives, preambleless bit synchronous timing simplifies onboard multicarrier demultiplexer/demodulator designs (about 2:1 reduction in mass and power), requires smaller onboard buffers (10:1 to approximately 3:1 reduction in size), and provides better frame efficiency as well as lower onboard processing delay. Analysis and computer simulation illustrate that this technique can support a bit rate of up to 10 Mbit/s (or higher) with proper selection of design parameters. High bit rate transmission may require Doppler compensation and multiple phase error measurements. The recommended modulation technique for bit synchronous timing is coherent QPSK with differential encoding for the uplink and coherent QPSK for the downlink.

  18. Synchronization transition in gap-junction-coupled leech neurons

    NASA Astrophysics Data System (ADS)

    Wang, Qingyun; Duan, Zhisheng; Feng, Zhaosheng; Chen, Guanrong; Lu, Qishao

    2008-07-01

    Real neurons can exhibit various types of firings including tonic spiking, bursting as well as silent state, which are frequently observed in neuronal electrophysiological experiments. More interestingly, it is found that neurons can demonstrate the co-existing mode of stable tonic spiking and bursting, which depends on initial conditions. In this paper, synchronization in gap-junction-coupled neurons with co-existing attractors of spiking and bursting firings is investigated as the coupling strength gets increased. Synchronization transitions can be identified by means of the bifurcation diagram and the correlation coefficient. It is illustrated that the coupled neurons can exhibit different types of synchronization transitions between spiking and bursting when the coupling strength increases. In the course of synchronization transitions, an intermittent synchronization can be observed. These results may be instructive to understand synchronization transitions in neuronal systems.

  19. Generalized chaotic synchronization in coupled Ginzburg-Landau equations

    SciTech Connect

    Koronovskii, A. A. Popov, P. V. Hramov, A. E.

    2006-10-15

    Generalized synchronization is analyzed in unidirectionally coupled oscillatory systems exhibiting spatiotemporal chaotic behavior described by Ginzburg-Landau equations. Several types of coupling between the systems are analyzed. The largest spatial Lyapunov exponent is proposed as a new characteristic of the state of a distributed system, and its calculation is described for a distributed oscillatory system. Partial generalized synchronization is introduced as a new type of chaotic synchronization in spatially nonuniform distributed systems. The physical mechanisms responsible for the onset of generalized chaotic synchronization in spatially distributed oscillatory systems are elucidated. It is shown that the onset of generalized chaotic synchronization is described by a modified Ginzburg-Landau equation with additional dissipation irrespective of the type of coupling. The effect of noise on the onset of a generalized synchronization regime in coupled distributed systems is analyzed.

  20. Synchronization, quantum correlations and entanglement in oscillator networks

    PubMed Central

    Manzano, Gonzalo; Galve, Fernando; Giorgi, Gian Luca; Hernández-García, Emilio; Zambrini, Roberta

    2013-01-01

    Synchronization is one of the paradigmatic phenomena in the study of complex systems. It has been explored theoretically and experimentally mostly to understand natural phenomena, but also in view of technological applications. Although several mechanisms and conditions for synchronous behavior in spatially extended systems and networks have been identified, the emergence of this phenomenon has been largely unexplored in quantum systems until very recently. Here we discuss synchronization in quantum networks of different harmonic oscillators relaxing towards a stationary state, being essential the form of dissipation. By local tuning of one of the oscillators, we establish the conditions for synchronous dynamics, in the whole network or in a motif. Beyond the classical regime we show that synchronization between (even unlinked) nodes witnesses the presence of quantum correlations and entanglement. Furthermore, synchronization and entanglement can be induced between two different oscillators if properly linked to a random network. PMID:23486526

  1. Optomechanical synchronization phenomena in the presence of (quantum) noise

    NASA Astrophysics Data System (ADS)

    Weiss, Talitha; Kronwald, Andreas; Walter, Stefan; Marquardt, Florian

    Synchronization is a phenomenon that appears in various natural and man-made systems. Optomechanical limit-cycle oscillators can synchronize when they are coupled to each other or to an external periodic force. Classically, in the absence of noise, different synchronization regimes can be identified. Notably, optomechanical systems tend to synchronize either in-phase or anti-phase. We investigate how the synchronization behaviour is affected in the presence of the fundamental quantum noise (arXiv:1507.06190). We find a regime where fluctuations drive transitions between the classical synchronization states and explore the quantum-to-classical crossover. Finally, we compare the effects of quantum noise to the effects of thermal noise.

  2. Research on synchronization technique of the DRM system

    NASA Astrophysics Data System (ADS)

    Guo, Wen-fei; Zheng, Jian-sheng; Cheng, Wen; Su, Fan

    2011-10-01

    To deal with the degradation of the synchronization performance in low SNR condition, a novel DRM (Digital Radio Mondiale) synchronization algorithm is proposed. The proposed algorithm employs cyclic prefix for timing synchronization and fractional frequency offset estimation like conventional methods, but accomplishes frame synchronization and integer frequency offset estimation using time pilot cells and differential coding technologies, which are designed specially for the DRM system. After channel estimation and equalization, frequency pilot cells are used to estimate residue fractional frequency offset and subsequent sample offset as well as fixed phase offset to achieve complete synchronization. Simulation results show that the proposed algorithm can possesses better time and frequency synchronization performance than the conventional method in the multi-path fading channel with low SNR condition.

  3. Optimal information transfer in the cortex through synchronization.

    PubMed

    Buehlmann, Andres; Deco, Gustavo

    2010-01-01

    In recent experimental work it has been shown that neuronal interactions are modulated by neuronal synchronization and that this modulation depends on phase shifts in neuronal oscillations. This result suggests that connections in a network can be shaped through synchronization. Here, we test and expand this hypothesis using a model network. We use transfer entropy, an information theoretical measure, to quantify the exchanged information. We show that transferred information depends on the phase relation of the signal, that the amount of exchanged information increases as a function of oscillations in the signal and that the speed of the information transfer increases as a function of synchronization. This implies that synchronization makes information transport more efficient. In summary, our results reinforce the hypothesis that synchronization modulates neuronal interactions and provide further evidence that gamma band synchronization has behavioral relevance. PMID:20862355

  4. Synchronous thymoma and oligodendroglioma: A rare association

    PubMed Central

    Vaziri, Mohammad; Rad, Kamelia

    2016-01-01

    Introduction Patients with thymoma are found to have another systemic illness and a broadly increased risk for secondary malignancies. We present the case of a 53-year-old female patient who harbored two synchronous primary malignant neoplasms—an anaplastic oligodendroglioma of the right frontal lobe and an anterior mediastinal thymoma. Presentation of case A 53-year-old female patient presented in her first hospital admission with nausea, chest pain and non-pulsatile bitemporal headache. Continued headache and nausea along with negative cardiac findings prompted radiological evaluation including chest CT scan and brain CT scan which revealed simultaneous anterior mediastinal mass and frontal lobe calcification respectively. The patient underwent craniotomy and the pathological diagnosis was anaplastic oligodendriglioma. The anterior mediastinal tumor resection was performed three months later, while the patient had no newly onset of any symptoms necessitating more investigation. Discussion Multiple primary malignancies have been diagnosed by the following criteria: each tumor must have an obvious picture of malignancy, each must be separate and discrete and the probability that one was a metastatic lesion from the other must be excluded. Treatment strategies in cases of double malignancy involve treating the malignancy that is more advanced first. In our case we concluded that synchronous double malignancy can be treated successfully according to the above mentioned criteria. Conclusion Clinicians should be aware of the possibility of synchronous malignancies in order to use screening procedures in patients with reported increased risk of double malignancy. Such clinical alertness may lead to a better outcome for double primary tumor cases. PMID:26957188

  5. Leader emergence through interpersonal neural synchronization.

    PubMed

    Jiang, Jing; Chen, Chuansheng; Dai, Bohan; Shi, Guang; Ding, Guosheng; Liu, Li; Lu, Chunming

    2015-04-01

    The neural mechanism of leader emergence is not well understood. This study investigated (i) whether interpersonal neural synchronization (INS) plays an important role in leader emergence, and (ii) whether INS and leader emergence are associated with the frequency or the quality of communications. Eleven three-member groups were asked to perform a leaderless group discussion (LGD) task, and their brain activities were recorded via functional near infrared spectroscopy (fNIRS)-based hyperscanning. Video recordings of the discussions were coded for leadership and communication. Results showed that the INS for the leader-follower (LF) pairs was higher than that for the follower-follower (FF) pairs in the left temporo-parietal junction (TPJ), an area important for social mentalizing. Although communication frequency was higher for the LF pairs than for the FF pairs, the frequency of leader-initiated and follower-initiated communication did not differ significantly. Moreover, INS for the LF pairs was significantly higher during leader-initiated communication than during follower-initiated communications. In addition, INS for the LF pairs during leader-initiated communication was significantly correlated with the leaders' communication skills and competence, but not their communication frequency. Finally, leadership could be successfully predicted based on INS as well as communication frequency early during the LGD (before half a minute into the task). In sum, this study found that leader emergence was characterized by high-level neural synchronization between the leader and followers and that the quality, rather than the frequency, of communications was associated with synchronization. These results suggest that leaders emerge because they are able to say the right things at the right time. PMID:25831535

  6. Leader emergence through interpersonal neural synchronization

    PubMed Central

    Jiang, Jing; Chen, Chuansheng; Dai, Bohan; Shi, Guang; Ding, Guosheng; Liu, Li; Lu, Chunming

    2015-01-01

    The neural mechanism of leader emergence is not well understood. This study investigated (i) whether interpersonal neural synchronization (INS) plays an important role in leader emergence, and (ii) whether INS and leader emergence are associated with the frequency or the quality of communications. Eleven three-member groups were asked to perform a leaderless group discussion (LGD) task, and their brain activities were recorded via functional near infrared spectroscopy (fNIRS)-based hyperscanning. Video recordings of the discussions were coded for leadership and communication. Results showed that the INS for the leader–follower (LF) pairs was higher than that for the follower–follower (FF) pairs in the left temporo-parietal junction (TPJ), an area important for social mentalizing. Although communication frequency was higher for the LF pairs than for the FF pairs, the frequency of leader-initiated and follower-initiated communication did not differ significantly. Moreover, INS for the LF pairs was significantly higher during leader-initiated communication than during follower-initiated communications. In addition, INS for the LF pairs during leader-initiated communication was significantly correlated with the leaders’ communication skills and competence, but not their communication frequency. Finally, leadership could be successfully predicted based on INS as well as communication frequency early during the LGD (before half a minute into the task). In sum, this study found that leader emergence was characterized by high-level neural synchronization between the leader and followers and that the quality, rather than the frequency, of communications was associated with synchronization. These results suggest that leaders emerge because they are able to say the right things at the right time. PMID:25831535

  7. Modulation and Synchronization for Aeronautical Telemetry

    NASA Astrophysics Data System (ADS)

    Shaw, Christopher G.

    Aeronautical telemetry systems have historically been implemented with constant envelope modulations like CPM. Shifts in system constraints including reduced available bandwidth and increased throughput demands have caused many in the field to reevaluate traditional methods and design practices. This work examines the costs and benefits of using APSK for aeronautical telemetry instead of CPM. Variable rate turbo codes are used to improve the power efficiency of 16- and 32-APSK. Spectral regrowth in nonlinear power amplifiers when driven by non-constant envelope modulation is also considered. Simulation results show the improved spectral efficiency of this modulation scheme over those currently defined in telemetry standards. Additionally, the impact of transitioning from continuous transmission to burst-mode is considered. Synchronization loops are ineffective in burst-mode communication. Data-aided feedforward algorithms can be used to estimate offsets in carrier phase, frequency, and symbol timing between the transmitter and the receiver. If a data-aided algorithm is used, a portion of the transmitted signal is devoted to a known sequence of pilot symbols. Optimum pilot sequences for the three synchronization parameters are obtained analytically and numerically for different system constraints. The alternating sequence is shown to be optimal given a peak power constraint. Alternatively, synchronization can be accomplished using blind algorithms that do not rely on a priori knowledge of a pilot sequence. If blind algorithms are used, the observation interval can be longer than for data-aided algorithms. There are combinations of pilot sequence length and packet length where data-aided algorithms perform better than blind algorithms and vice versa. The conclusion is that a sequential arrangement of blind algorithms operating over an entire burst performs better than a CRB-achieving data-aided algorithm operating over a short pilot sequence.

  8. Synchronous monitoring of muscle dynamics and electromyogram

    NASA Astrophysics Data System (ADS)

    Zakir Hossain, M.; Grill, Wolfgang

    2011-04-01

    A non-intrusive novel detection scheme has been implemented to detect the lateral muscle extension, force of the skeletal muscle and the motor action potential (EMG) synchronously. This allows the comparison of muscle dynamics and EMG signals as a basis for modeling and further studies to determine which architectural parameters are most sensitive to changes in muscle activity. For this purpose the transmission time for ultrasonic chirp signal in the frequency range of 100 kHz to 2.5 MHz passing through the muscle under observation and respective motor action potentials are recorded synchronously to monitor and quantify biomechanical parameters related to muscle performance. Additionally an ultrasonic force sensor has been employed for monitoring. Ultrasonic traducers are placed on the skin to monitor muscle expansion. Surface electrodes are placed suitably to pick up the potential for activation of the monitored muscle. Isometric contraction of the monitored muscle is ensured by restricting the joint motion with the ultrasonic force sensor. Synchronous monitoring was initiated by a software activated audio beep starting at zero time of the subsequent data acquisition interval. Computer controlled electronics are used to generate and detect the ultrasonic signals and monitor the EMG signals. Custom developed software and data analysis is employed to analyze and quantify the monitored data. Reaction time, nerve conduction speed, latent period between the on-set of EMG signals and muscle response, degree of muscle activation and muscle fatigue development, rate of energy expenditure and motor neuron recruitment rate in isometric contraction, and other relevant parameters relating to muscle performance have been quantified with high spatial and temporal resolution.

  9. A Diode Laser System for Synchronous Photoinjection

    SciTech Connect

    Poelker, M., Hansknecht, J.

    1997-12-31

    A laser system, which is composed of a gain switched diode seed laser and a single-pass diode optical amplifier, is used to drive the polarized electron source at Jefferson Lab. The system emits pulsed laser light synchronized to the accelerating cavity radio frequency (rf) at 1497 MHz or the third subharmonic, 499 MHz. The maximum average output power from the laser system is 500 mW and the optical pulse width is 60 to 80 ps. The laser system is compact and very reliable operating remotely for many days without attention.

  10. Laser Mégajoule synchronization system

    NASA Astrophysics Data System (ADS)

    Luttmann, Michel; Pastor, Jean François; Drouet, Vincent; Prat, Michel; Raimbourg, Jo"l.; Adolf, Alain

    2011-03-01

    This paper describes the synchronisation system under development on the Laser Mégajoule (LMJ) in order to synchronize the laser quads on the target to better than 40ps rms. Our architecture is based on a Timing System (TS) which delivers trigger signals with jitter down to 15ps rms coupled with an ultra precision timing system with 5ps rms jitter. In addition to TS, a sensor placed at the target chamber center measures the arrival times of the 3ω nano joule laser pulses generated by front end shots.

  11. Synchronized manufacture of composites knowledge study (SMACKS)

    NASA Astrophysics Data System (ADS)

    Strickland, B.; Oliver, M.

    1990-06-01

    The need for a competitive manufacturing knowledge base for the composites industry, encompasses a change from a 'functionally' organized factory to a product-based organization, and has led to major reductions in inventories, manufacturing costs and cycle times. The net effect was that products became more price- and delivery-competitive. It is believed that composite manufacturers have an equal need to improve their competitive edge, particularly as the demand for composite products grows and more manufacturers enter the marketplace. 'SMACKS' has begun to establish these needs and market trends, with a view to establishing the advantages offered to composite manufacturers by synchronized manufacturing methods.

  12. Synchronized Ion Acceleration by Ultraintense Slow Light.

    PubMed

    Brantov, A V; Govras, E A; Kovalev, V F; Bychenkov, V Yu

    2016-02-26

    An effective scheme of synchronized laser-triggered ion acceleration and the corresponding theoretical model are proposed for a slow light pulse of relativistic intensity, which penetrates into a near-critical-density plasma, strongly slows, and then increases its group velocity during propagation within a target. The 3D particle-in-cell simulations confirm this concept for proton acceleration by a femtosecond petawatt-class laser pulse experiencing relativistic self-focusing, quantify the characteristics of the generated protons, and demonstrate a significant increase of their energy compared with the proton energy generated from optimized ultrathin solid dense foils. PMID:26967421

  13. Improved Gene Targeting through Cell Cycle Synchronization

    PubMed Central

    Tsakraklides, Vasiliki; Brevnova, Elena; Stephanopoulos, Gregory; Shaw, A. Joe

    2015-01-01

    Gene targeting is a challenge in organisms where non-homologous end-joining is the predominant form of recombination. We show that cell division cycle synchronization can be applied to significantly increase the rate of homologous recombination during transformation. Using hydroxyurea-mediated cell cycle arrest, we obtained improved gene targeting rates in Yarrowia lipolytica, Arxula adeninivorans, Saccharomyces cerevisiae, Kluyveromyces lactis and Pichia pastoris demonstrating the broad applicability of the method. Hydroxyurea treatment enriches for S-phase cells that are active in homologous recombination and enables previously unattainable genomic modifications. PMID:26192309

  14. Subordination to periodic processes and synchronization

    NASA Astrophysics Data System (ADS)

    Ascolani, Gianluca; Bologna, Mauro; Grigolini, Paolo

    2009-07-01

    We study the subordination to a process that is periodic in the natural time scale, and equivalent to a clock with N states. The rationale for this investigation is given by a set of many interacting clocks with N states. The natural time scale representation corresponds to the dynamics of an individual clock with no interaction with the other clocks of this set. We argue that the cooperation among the clocks of this set has the effect of generating a global clock, whose times of sojourn in each of its N states are described by a distribution density with an inverse power law form and power index μ<2. This is equivalent to extending the widely used subordination method from fluctuation-dissipation processes to periodic processes, thereby raising the question of whether special conditions exist of perfect synchronization, signaled by regular oscillations, and especially by oscillations with no damping. We study first the case of a Poisson subordination function. We show that in spite of the random nature of the subordination method the procedure has the effect of creating damped oscillations, whose damping vanishes in the limiting case of N≫1, thereby suggesting a condition of perfect synchronization in this limit. The Bateman’s mathematical arguments [H. Bateman, Higher Transcendental Functions, vol. III, Robert K Krieger, Publishing Company, Inc. Krim.Fr. Drive Malabar, FL; Copyright 1953 by McGraw-Hill Book Company Inc.] indicate that the condition of perfect synchronization is possible also in the non-Poisson case, with μ<2, although it may lie beyond the range of computer simulation. To make the theoretical predictions accessible to numerical simulation, we use a subordination function whose survival probability is a Mittag-Leffler exponential function. This method prevents us from directly establishing the macroscopic coherence emerging from μ=2, which generates a perfect form of 1/f noise. However, it affords indirect evidence that perfect

  15. Magnetic switch coupling to synchronize magnetic modulators

    DOEpatents

    Reed, K.W.; Kiekel, P.

    1999-04-27

    Apparatus for synchronizing the output pulses from a pair of magnetic switches is disclosed. An electrically conductive loop is provided between the pair of switches with the loop having windings about the core of each of the magnetic switches. The magnetic coupling created by the loop removes voltage and timing variations between the outputs of the two magnetic switches caused by any of a variety of factors. The only remaining variation is a very small fixed timing offset caused by the geometry and length of the loop itself. 13 figs.

  16. Magnetic switch coupling to synchronize magnetic modulators

    DOEpatents

    Reed, Kim W.; Kiekel, Paul

    1999-01-01

    Apparatus for synchronizing the output pulses from a pair of magnetic switches. An electrically conductive loop is provided between the pair of switches with the loop having windlings about the core of each of the magnetic switches. The magnetic coupling created by the loop removes voltage and timing variations between the outputs of the two magnetic switches caused by any of a variety of factors. The only remaining variation is a very small fixed timing offset caused by the geometry and length of the loop itself.

  17. Synchronized Ion Acceleration by Ultraintense Slow Light

    NASA Astrophysics Data System (ADS)

    Brantov, A. V.; Govras, E. A.; Kovalev, V. F.; Bychenkov, V. Yu.

    2016-02-01

    An effective scheme of synchronized laser-triggered ion acceleration and the corresponding theoretical model are proposed for a slow light pulse of relativistic intensity, which penetrates into a near-critical-density plasma, strongly slows, and then increases its group velocity during propagation within a target. The 3D particle-in-cell simulations confirm this concept for proton acceleration by a femtosecond petawatt-class laser pulse experiencing relativistic self-focusing, quantify the characteristics of the generated protons, and demonstrate a significant increase of their energy compared with the proton energy generated from optimized ultrathin solid dense foils.

  18. Automatic Mode Switch (AMS) Causes Less Synchronization

    PubMed Central

    Jorat, Mohammadvahid; Nikoo, Mohammadhossein

    2016-01-01

    Introduction: Cardiac resynchronization devices are part of modern heart failure management. After implantation, we analyze and program devices in an attempt to ensure their success. Biventricular pacing should be 98% or more for the lowest mortality and best symptom improvement. Case Presentation: In this case series, we present a combination of far field sensing and automatic mode switching (AMS) in six patients. It is found that this combination causes ventricular sensing (VS) episodes with wide QRS and no synchronization. We turn off the AMS and alleviate the problem. Conclusions: Switching AMS off may increase biventricular pacing in some patients. PMID:26949695

  19. Synchronous Fibrolamellar Hepatocellular Carcinoma and Auricular Myxoma

    PubMed Central

    González-Cantú, Yessica M.; Rodriguez-Padilla, Cristina; Tena-Suck, Martha Lilia; García de la Fuente, Alberto; Mejía-Bañuelos, Rosa María; Díaz Mendoza, Raymundo; Quintanilla-Garza, Samuel; Batisda-Acuña, Yolaester

    2015-01-01

    Synchronic occurrence of benign and malignant tumors is extremely rare. Fibrolamellar hepatocellular carcinoma represents 1% to 2% of all hepatocarcinomas, while myxomas represent about half of all the cases of primary tumors of the heart. We present the case of a 53-year-old woman with a left atrial myxoma that was surgically removed. Several weeks later, the patient returned to the hospital with abdominal pain. CT scan showed a mass in the left lobe of the liver that was resected and diagnosed as fibrolamellar hepatocellular carcinoma. As of this writing, the patient is healthy. PMID:26509093

  20. Bioreactor and methods for producing synchronous cells

    NASA Technical Reports Server (NTRS)

    Helmstetter, Charles E. (Inventor); Thornton, Maureen (Inventor); Gonda, Steve (Inventor)

    2005-01-01

    Apparatus and methods are directed to a perfusion culture system in which a rotating bioreactor is used to grow cells in a liquid culture medium, while these cells are attached to an adhesive-treated porous surface. As a result of this arrangement and its rotation, the attached cells divide, with one cell remaining attached to the substrate, while the other cell, a newborn cell is released. These newborn cells are of approximately the same age, that are collected upon leaving the bioreactor. The populations of newborn cells collected are of synchronous and are minimally, if at all, disturbed metabolically.