Intensity statistics in the presence of translational noncrystallographic symmetry.

In the case of translational noncrystallographic symmetry (tNCS), two or more copies of a component in the asymmetric unit of the crystal are present in a similar orientation. This causes systematic modulations of the reflection intensities in the diffraction pattern, leading to problems with structure determination and refinement methods that assume, either implicitly or explicitly, that the distribution of intensities is a function only of resolution. To characterize the statistical effects of tNCS accurately, it is necessary to determine the translation relating the copies, any small rotational differences in their orientations, and the size of random coordinate differences caused by conformational differences. An algorithm to estimate these parameters and refine their values against a likelihood function is presented, and it is shown that by accounting for the statistical effects of tNCS it is possible to unmask the competing statistical effects of twinning and tNCS and to more robustly assess the crystal for the presence of twinning

Incorporating Chokeberry (Aronia) into a Home Landscape

Chokeberry (Aronia) is an ornamental plant that has found use in the home landscape, providing colorful displays and annually producing berries for the enjoyment of the homeowner and wildlife alike. With careful placement, this durable plant needs minimal care and has few pest problems. It is gaining attention for its timeless beauty

Book reviews

Reviews of the following items: Excellence in coaching: the industry guide. Edited by Jonathan Passmore. London: Kogan Page, 2010. ISBN 978-0-7494-5667-2. Doing your PGCE at M-level: a guide for students. Edited by Keira Sewell. London: Sage, 2012. ISBN 978-1-4462-0830-4. Contemporary issues in learning and teaching. Edited by Margery McMahon, Christine Forde and Margaret Martin. London: Sage, 2011. ISBN 978-1-84920-128-5. Using museums as an educational resource: an introductory handbook for students and teachers. Graeme Talboys. Aldershot: Ashgate Publishing, 2010. ISBN: 978-1-4094-0145-2

Injury prevention in male youth soccer: Current practices and perceptions of practitioners working at elite English academies

Forty-one practitioners inclusive of physiotherapists, sports scientists and strength and conditioning coaches from the academies of elite soccer clubs in the United Kingdom completed an on-line questionnaire which examined their: (1) background information; (2) perceptions of injury occurrence and risk factors; (3) screening and return to play; and (4) approach to designing and delivering injury prevention programmes with a response rate of 55% (41/75). Contact injuries were the most common mechanism reported and players between 13-16 years of age were perceived to be at the greatest risk. Pertinent risk factors included: reduced lower limb and eccentric hamstring strength, proprioception, muscle imbalances, and under developed foundational movement skills. Joint range of motion, jump tests, the functional movement screen, overhead and single leg squats were the most utilised screening methods. Training modalities rated in order of importance included: resistance training, flexibility development, agility, plyometrics and balance training. Training frequency was most commonly once or twice per week, during warm-ups, independent sessions or a combination of both. Injury prevention strategies in this cohort appear to be logical; however, the classification of injury occurrence and application of screening tools to identify 'at risk' players do not align with existing research. The frequency and type of training used may also be insufficient to elicit an appropriate stimulus to address pertinent risk factors based on current recommendations

Using VLBI to Probe the Orion-KL Outflow on AU Scales

We present the first contemporaneous 43GHz and 86GHz VLBI images of the v=1 J=2-1 and J=1-0 SiO masers in the Orion-KL nebula. Both maser species exhibit the same general morphology of earlier J=1-0 maser images which appear to trace the edges of a bi-polar conical outflow. Surprisingly, the J=2-1 masers form further from the central protostar than the J=1-0 masers, a fact not readily explained by current SiO maser pumping models. The average magnitude of offsets between corresponding regions of the two masing transitions is approximately 14% of the total radial extent of the SiO maser emission. This offset indicates that each transition must trace different physical conditions.Comment: 20 pages, 4 figure

Lower extremity stiffness: considerations for testing, performance enhancement and injury risk

Force-deformation characteristics of the lower limb have been associated with athletic performance and may modulate the risk of injury. In-spite of these known associations, measurements of lower extremity stiffness are not commonly administered by strength and conditioning coaches. This review provides an overview of the available literature pertaining to the effects of lower extremity stiffness on physical performance and injury risk. Practical methods of monitoring and training stiffness are also discussed. The cumulative body of evidence indicates that increases in lower extremity stiffness are associated with heightened performance in athletic tasks such as hopping, jumping, throwing, endurance running, sprinting and changing direction. Relationships with injury are less conclusive as both excessive and insufficient limb stiffness have been postulated to increase risk. Thus, the ‘optimal’ level of stiffness appears to be dependent on the anthropometry, and physical capabilities of the athlete, in addition to sport-specific activity demands. Training interventions can positively enhance lower extremity stiffness, including isometric, eccentric and isotonic strength training and plyometrics. Complex training also appears to provide a potent stimulus and may be more effective than the use of singular training modes. For plyometric activities, it is recommended that coaches use a developmental sequence of exercises with increasing eccentric demand to provide an appropriate stimulus based on the training age and technical competency of the athlete

Shared Decision-Making: Some cautionary observations in the context of elite sport

The concept of shared decision-making (SDM) has emerged as a key component in the return to play interface as a hallmark of good practice that is athlete focused and allows greater engagement from the athlete. SDM is an appealing, well-intentioned framework that would seemingly lend itself to effectively being implemented. However, in this editorial, we have identified concerns surrounding the social complexities of elite sports and the difficulties of truly applying this concept in practice. In what follows, we explain the dynamics associated, discuss the importance of context when considering the efficacy of this practice and lastly offer what we see as certain key issues that might impede effective SDM

Improvement of cryo-EM maps by density modification.

A density-modification procedure for improving maps from single-particle electron cryogenic microscopy (cryo-EM) is presented. The theoretical basis of the method is identical to that of maximum-likelihood density modification, previously used to improve maps from macromolecular X-ray crystallography. Key differences from applications in crystallography are that the errors in Fourier coefficients are largely in the phases in crystallography but in both phases and amplitudes in cryo-EM, and that half-maps with independent errors are available in cryo-EM. These differences lead to a distinct approach for combination of information from starting maps with information obtained in the density-modification process. The density-modification procedure was applied to a set of 104 datasets and improved map-model correlation and increased the visibility of details in many of the maps. The procedure requires two unmasked half-maps and a sequence file or other source of information on the volume of the macromolecule that has been imaged

Phases of the Traditional 505 Test: Between Session and Direction Reliability

Change of direction (COD) testing has commonly reported a single total time to quantify performance despite that tests are made up of a number of different phases. No investigation into these phases has been completed, therefore the aim of this study was to examine the reliability between sessions and directions of the different phases of a 505 test. Twenty-one male youth athletes performed the 505 test in both directions on three occasions. Differences between directions and sessions were determined via a T-test and Two-way ANOVA respectively and a significance threshold was set at P ≤ 0.05. All strategy variables show acceptable relative and absolute reliability in both directions between sessions (ICC = 0.73-0.94; CV = 2.3-6.3%) apart from ground contact time (GCT) (ICC = 0.57-0.68, CV = 14.8–22.4%). Significant differences were identified between session one and three for entry time. Significant differences between directions for exit time on day two and for full approach, entry and GCT on day three. The non-dominant turning direction showed lower relative and absolute reliability between session for entry time (ICC = 0.73 vs 0.89; CV = 6.3% vs 3.7%) and GCT (ICC = 0.57 vs 0.68; CV = 14.8% vs 22.4%). Results indicate the phases of a 505 COD test have high relative and absolute reliability between sessions, although turning directions should be considered independently

(Disulfur dinitrido)triphenyl­anti­mony(V)

The title compound, [Sb(C6H5)3(N2S2)], contains a molecular entity that is very similar to that of the known polymorph of Sb(S2N2)Ph3 [Kunkel et al. (1997 ▶). Z. Naturforsch. Teil B, 52, 193–198], differing only in the orientation of the phenyl rings. The bond order in the SNSN unit is S—N=S=N, consisting of one long S—N bond, an inter­mediate length N=S bond and a short S=N bond