We compare the expected effects of so-called gravitationally enhanced depolarization of ultracold neutrons to measurements carried out in a spin-precession chamber exposed to a variety of vertical ...magnetic-field gradients. In particular, we have investigated the dependence upon these field gradients of spin depolarization rates and also of shifts in the measured neutron Larmor precession frequency. We find excellent qualitative agreement, with gravitationally enhanced depolarization accounting for several previously unexplained features in the data.
The design of the n2EDM experiment Ayres, N. J.; Ban, G.; Bienstman, L. ...
The European physical journal. C, Particles and fields,
2021/6, Letnik:
81, Številka:
6
Journal Article
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We present the design of a next-generation experiment, n2EDM, currently under construction at the ultracold neutron source at the Paul Scherrer Institute (PSI) with the aim of carrying out a ...high-precision search for an electric dipole moment of the neutron. The project builds on experience gained with the previous apparatus operated at PSI until 2017, and is expected to deliver an order of magnitude better sensitivity with provision for further substantial improvements. An overview is of the experimental method and setup is given, the sensitivity requirements for the apparatus are derived, and its technical design is described.
Reduction of CT tube current is an effective strategy to minimize radiation load. However, tube current is also a major determinant of image quality. We investigated the impact of CTA tube current on ...spot sign detection and diagnostic performance for intracerebral hemorrhage expansion.
We retrospectively analyzed a prospectively collected cohort of consecutive patients with primary intracerebral hemorrhage from January 2001 to April 2015 who underwent CTA. The study population was divided into 2 groups according to the median CTA tube current level: low current (<350 mA) and high current (≥350 mA). CTA first-pass readings for spot sign presence were independently analyzed by 2 readers. Baseline and follow-up hematoma volumes were assessed by semiautomated computer-assisted volumetric analysis. Sensitivity, specificity, positive and negative predictive values, and accuracy of spot sign in predicting hematoma expansion were calculated.
This study included 709 patients (288 and 421 in the low- and high-current groups, respectively). A higher proportion of low-current scans identified at least 1 spot sign (20.8% versus 14.7%,
= .034), but hematoma expansion frequency was similar in the 2 groups (18.4% versus 16.2%,
= .434). Sensitivity and positive and negative predictive values were not significantly different between the 2 groups. Conversely, high-current scans showed superior specificity (91% versus 84%,
= .015) and overall accuracy (84% versus 77%,
= .038).
CTA obtained at high levels of tube current showed better diagnostic accuracy for prediction of hematoma expansion by using spot sign. These findings may have implications for future studies using the CTA spot sign to predict hematoma expansion for clinical trials.
The objectives were to evaluate changes in endometrial thickness (ET) near the time of a synchronized ovulation and to assess the relationship of ET and fertility in lactating Holstein cows, with or ...without estrogen supplementation near timed ovulation. In Experiment 1, eight cows were examined with transrectal ultrasonography, once daily for 5 d, starting concurrent with PGF2α (PGF) treatment during an Ovsynch protocol (GnRH - 7d - PGF - 72h - GnRH). The ET increased rapidly after PGF (from ∼7 to ∼9.5 mm), remained > 9 mm for the next 2 d, then decreased to ∼8 and 7.4 mm, 1 and 2 d, respectively, after the second GnRH. In Experiment 2,642 cows (total of 758 breedings) were subjected to an Ovsynch protocol (GnRH - 7d - PGF - 56h - GnRH - 16h - timed AI); cows received either no further treatment (Ovsynch) or 1 mg of estradiol-17β im 8 h before the second GnRH (Ovsynch + E2). For both uterine horns, ET was measured (∼2 cm from the internal uterine body bifurcation) before E2 treatment (48 h after PGF). In cows with ET ≤ 8 mm vs > 8 mm, rates of ovulation were 86.0% (n = 136) vs 98.1% (n = 472; P < 0.01), respectively, and percentage pregnant per AI (P/AI) were 26.7% (n = 146) vs 42.7% (n = 524; P < 0.01). Treatment with E2 increased P/AI in cows with lower ET (Ovsynch + E2 = 37.0% vs Ovsynch = 23.3%; P = 0.07), but did not significantly improve P/AI in cows with ET > 8 mm (Ovsynch + E2 = 43.4% vs Ovsynch = 42.1%). In conclusion, a single ultrasonographic evaluation of ET in Holstein cows 48 h after PGF treatment in an Ovsynch program was a good predictor of ovulation failure and pregnancy success. Perhaps poor fertility in cows with reduced ET was low peripheral E2 concentrations near AI, poor P4 priming, or luteolysis failure during timed AI procedures.
A total of 177 Nelore heifers were examined by ultrasonography to determine the presence or absence of a corpus luteum (CL) and received a 3
mg norgestomet ear implant plus 2
mg of estradiol benzoate ...i.m. On Day 8, implants were removed and 150
μg of
d-cloprostenol i.m. was administered. At the time of norgestomet implant removal, heifers with or without CL at the time of initiating treatment were assigned equally and by replicate to be treated with 0
IU (
n
=
87) or 400
IU (
n
=
90) eCG i.m. All heifers received 1
mg of EB i.m. on Day 9 and were submitted to fixed-time artificial insemination (FTAI) 30–34
h later. The addition of eCG increased the diameter of the largest follicle (LF) at FTAI (10.6
±
0.2
mm vs. 9.5
±
0.2
mm;
P
=
0.003; mean
±
SEM), the final growth rate of the LF (1.14
±
0.1
mm/day vs. 0.64
±
0.1
mm/day;
P
=
0.0009), ovulation rate 94.4% (85/90) vs. 73.6% (64/87);
P
=
0.0006, the diameter of the CL at Day 15 (15.5
±
0.3
mm vs. 13.8
±
0.3
mm;
P
=
0.0002), serum concentrations of progesterone 5 days after FTAI (6.6
±
1.0
ng/ml vs. 3.6
±
0.7
ng/ml;
P
=
0.0009), and pregnancy per AI P/AI; 50.0% (45/90) vs. 36.8% (32/87);
P
=
0.04. The absence of a CL at the beginning of the treatment negatively influenced the P/AI 30.2% (16/53) vs. 49.2% (61/124);
P
=
0.01. Therefore, the presence of a CL (and/or onset of puberty) must be considered in setting up FTAI programs in heifers. In addition, eCG may be an important tool for the enhancement of follicular growth, ovulation, size and function of the subsequent CL, and pregnancy rates in progestin-based FTAI protocols in
Bos indicus heifers.
Despite major improvements in air quality resulting from increasingly stringent legislation, there remains a strong association between daily mortality and current levels of air pollution. Growing ...epidemiological evidence suggests that many, perhaps the majority, of these deaths are caused by cardiovascular disease.
The abilities of two different estradiol esters to induce ovulation in a timed AI (TAI) synchronization protocol in suckled Bos indicus cows were evaluated. In Experiment 1 (synchrony of ovulation), ...31 cows were submitted to an estradiol/progestin-based synchronization protocol (Day 0) and randomly assigned to one of three treatments at the time of progestin removal on Day 8: 0.5 or 1.0mg of estradiol cypionate (EC) at that time or 1.0mg of estradiol benzoate (EB) 24h later (Day 9). To determine the timing of ovulation, ultrasound examinations were performed every 12h from ear implant removal to 96h after the removal. Orthogonal comparisons were performed to determine the effects of estradiol ester and the effects of the dose of EC on reproductive parameters. Although neither the E2 ester (P=0.83) nor the dose of EC (P=0.55) affected the ovulation rate, the interval from progestin removal to ovulation was longer (P=0.04) in EC-treated cows (1.0mg EC=71.1±3.6 and 0.5mg EC=78.0±3.5) than EB-treated cows (EB=66.0±2.3) was detected. Ovulation in 0.5-mg-EC-treated cows was less synchronous than that in 1.0-mg-EC-treated cows (distribution curves compared using kurtosis). In Experiment 2 (pregnancy per AI; P/AI), 660 cows at two different locations received the same synchronization protocol (n=361 at Farm A and n=299 at Farm B) and were treated with estradiol esters as in Experiment 1 0.5mg EC (n=220) or 1.0mg EC (n=219) at the time of progestin removal or 1.0mg EB (n=221) 24h later. The cows were inseminated 54 to 56h after progestin removal. As applied in the Experiment 1, orthogonal comparisons were performed to evaluate the effect of estradiol ester and the dose of EC on P/AI. Although the type of estradiol ester used did not affect the P/AI (P=0.57; EB – 43.0% vs. EC – 44.6%), the P/AI was higher (P=0.03) in cows treated with 1.0mg EC (55.7%) than in those treated with 0.5mg EC (38.6%). In summary, the administration of 0.5mg EC at the time of progestin removal altered the distribution of ovulation and resulted in a lower P/AI when compared with the use of 1.0mg EC in suckled B. indicus cows. However, the P/AI following the administration of 1.0mg EC at the time of progestin removal did not differ from that after the administration of 1.0mg EB 24h later.
We present the new spectrometer for the neutron electric dipole moment (nEDM) search at the Paul Scherrer Institute (PSI), called n2EDM. The setup is at room temperature in vacuum using ultracold ...neutrons. n2EDM features a large UCN double storage chamber design with neutron transport adapted to the PSI UCN source. The design builds on experience gained from the previous apparatus operated at PSI until 2017. An order of magnitude increase in sensitivity is calculated for the new baseline setup based on scalable results from the previous apparatus, and the UCN source performance achieved in 2016.
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