Is it possible to Measure the Weak Phase of a Penguin Diagram?

The $b\to d$ penguin amplitude receives contributions from internal $u$, $c$ and $t$-quarks. We show that it is impossible to measure the weak phase of any of these penguin contributions without theoretical input. However, a single assumption involving the hadronic parameters makes it possible to obtain the weak phase and test for the presence of new physics in the $b\to d$ flavour-changing neutral current.Comment: 4 pages, latex, no figures, talk given by R. Sinha at the 3rd International Conference on B Physics and CP Violation, Taipei, Taiwan, December 3-7, 1999, to appear in the Proceeding

Probing New Physics via an Angular Analysis of B --> V1 V2 decays

We show that an angular analysis of B --> V1 V2 decays yields numerous tests for new physics in the decay amplitudes. Unlike direct CP asymmetries, many of these new-physics observables are nonzero even if the strong phase differences vanish. For certain observables, neither time-dependent measurements nor tagging is necessary. Should a signal for new physics be found, one can place a lower limit on the size of the new-physics parameters, as well as on their effect on the measurement of the phase of B0--Bbar0 mixing.Comment: 9 pages, plain latex, no figures. Title modified slightly. Paragraph added about viability of method. Conclusions unchanged. To be published in Europhysics Letter

Obtaining the Full Unitarity Triangle from B -> pi K Decays

We present a method of obtaining the entire unitarity triangle from measurements of B -> pi K decay rates alone. Electroweak penguin amplitudes are included, and are related to tree operators. Discrete ambiguities are removed by comparing solutions with independent experimental data. The theoretical uncertainty in this method is rather small, in the range 5--10%.Comment: 4 pages, RevTeX, no figures. Clarifying remarks and references adde

Mission Capabilities of Ion Engines. Phase II

Payloads and mission times were calculated for space vehicles propelled by ion rockets using nuclear power supplies having specific weights from 10 t o 50 lb/kw. Included in the study were five missions: low-altitude lunar satellite, low-altitude Venus satellite, solar probe, Saturn probe, and a Jupiter satellite with a circular orbit at the altitude of Jupiter's fourth moon. The variation of payload with the ration of power supply weight to gross weight was studied and the optimum power levels thereby determined. The ion rocket payload capabilities were compared with those of high-thrust vehicles using hydrogen-oxygen rockets and tungsten-core nuclear rockets; in addition the performance of high- and low-thrust systems staged in combination has been investigated. Launch vehicles considered in this study were the Atlas-Centaur, the Saturn C-1, and the Saturn C-5

Safety and pain in electrodiagnostic studies

Discomfort is an unavoidable part of electrodiagnostic (EDX) studies. The most readily modifiable mediator of electromyography (EMG)‐associated pain is muscle selection. Interventions that may reduce pain include vapocoolant spray, ibuprofen, and techniques such as slapping or stretching the skin. Needlestick injuries to health care workers carry the risk of transmitting bloodborne illnesses, but other infectious complications of EDX studies are very rare. EMG probably contributes to asymptomatic hemorrhage in approximately 1% of patients, but clinically significant bleeding has only been reported a few times. Therapeutic anticoagulation does not significantly increase this risk. With standard procedures, there have been no reports of patients developing cardiac arrhythmia from nerve conduction studies. No special precautions are necessary in patients with implantable cardiac devices or intravenous lines. There is a small risk of pneumothorax associated with EMG of the diaphragm and chest wall muscles. Several techniques have been suggested to improve the safety of diaphragm EMG. Muscle Nerve 55: 149–159, 2017Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/136014/1/mus25421_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/136014/2/mus25421.pd

Reducing Penguin Pollution

The most common decay used for measuring 2beta_s, the phase of Bs-Bsbar mixing, is Bs -> J/psi phi. This decay is dominated by the colour-suppressed tree diagram, but there are other contributions due to gluonic and electroweak penguin diagrams. These are often referred to as "penguin pollution" (PP) because their inclusion in the amplitude leads to a theoretical error in the extraction of 2beta_s from the data. In the standard model (SM), it is estimated that the PP is negligible, but there is some uncertainty as to its exact size. Now, phi_s^{c\bar{c}s} (the measured value of 2beta_s) is small, in agreement with the SM, but still has significant experimental errors. When these are reduced, if one hopes to be able to see clear evidence of new physics (NP), it is crucial to have the theoretical error under control. In this paper, we show that, using a modification of the angular analysis currently used to measure phi_s^{c\bar{c}s} in Bs -> J/psi phi, one can reduce the theoretical error due to PP. Theoretical input is still required, but it is much more modest than entirely neglecting the PP. If phi_s^{c\bar{c}s} differs from the SM prediction, this points to NP in the mixing. There is also enough information to test for NP in the decay. This method can be applied to all Bs/Bsbar -> V1 V2 decays.Comment: 17 pages, latex, extensive discussion of theoretical error added, reference added. Further revision: even more detailed discussion of theoretical error added, as well as an explanation of why the NP strong phase is negligibl

Factors associated with contraceptive use in a rural area in Western Cape Province

Background. Safe and effective contraceptive use can substantially improve women’s reproductive health. Although the contraceptive prevalence rate (CPR) in South Africa is comparable to rates globally, inequalities in CPR affect poor and rural women. This study aimed to determine the CPR and factors associated with contraceptive use in a rural district of Western Cape Province. Method. Cross-sectional survey data based on 412 face-to-face interviews with female participants between 18 and 44 years of age were collected in 2006 for a primary fetal alcohol syndrome prevention study in a rural district in Western Cape Province. The study used effective contraception (ECC) as the outcome variable. ECC included use of oral contraceptives, condoms, injectables or sterilisation. Independent variables included socio-demographic factors, substance use, psychosocial factors, community factors, childbearing characteristics and partner characteristics. Results. Women were more likely to use ECC if they reported high self-esteem (compared with low or moderate self-esteem (prevalence risk ratio (PRR)=1.23; 95% confidence interval (CI) 0.99 - 1.53); if they strongly or moderately agreed that their culture entitled men to make decisions regarding child-bearing compared with those who disagreed (PRR=1.28; 95% CI 0.96 - 1.71); and if they had one child or more compared with no children (PRR=1.62; 95% CI 1.24 - 2.11). Conclusion. The CPR for sexually active women in this study was low at 39.3%. To promote contraceptive use in similar rural populations, family planning programmes should focus on increasing men’s approval of contraception, improving partner communication around family planning and bolstering women’s confidence in their reproductive decision-making, and particularly their self-esteem. There should be greater focus on nulliparous women