On fixed points of self maps of the free ball

In this paper, we study the structure of the fixed point sets of noncommutative self maps of the free ball. We show that for such a map that fixes the origin the fixed point set on every level is the intersection of the ball with a linear subspace. We provide an application for the completely isometric isomorphism problem of multiplier algebras of noncommutative complete Pick spaces

Hubble space telescope: Pointing error effects on nonlinear ball joints

The Hubble Space Telescope pointing error produced by optical benches mounted on free ball joints is examined. Spacecraft cable connections are assumed to produce translational and rotational damping and restoring forces which act through the optical bench center of mass. The nonlinear dynamics are modeled and then implemented using an existing computer program for simulating the vehicle dynamics and pointing control system algorithm. Results are presented for the test case which indicate acceptable performance

Alternative conditions for the synthesis of novel spiro[1,3-N,N-heterocyclic-adamantanes]

A series of new spiro[N-heterocyclic-adamantanes] was synthesized through the reaction of 2-adamantanone with beta-amino carboxamides. Depending on the chemical and physical characteristics of the starting compounds, the cyclocondensations proceeded under simple and mild (aqueous, solvent-free, ball-milling or/and microwave-assisted) conditions with no necessity for chromatographic purification of the products. The reaction was extended to leucinamide and salicylamide

Employing Halogen Bonding Interactions in Chemiresistive Gas Sensors

This paper reports the use of halogen bonding interactions for gas-phase detection of pyridine in SWCNT-based chemiresistive sensors with sub-ppm theoretical detection limits. The chemiresistors are prepared by solvent-free ball-milling of single-walled carbon nanotubes (SWCNTs) and aryl halide-based selectors, compression into a pellet, and subsequent mechanical abrasion between gold electrodes on paper. The sensing responses reflect halogen bonding trends, with few exceptions. The predominant signal transduction mechanism is likely attributed to swelling of the insulating haloarene matrix.National Institutes of Health (U.S.) (National Cancer Institute (U.S.). Ruth L. Kirschstein National Research Service Award F32CA157197

Analytic mappings between noncommutative pencil balls

In this paper, we analyze problems involving matrix variables for which we use a noncommutative algebra setting. To be more specific, we use a class of functions (called NC analytic functions) defined by power series in noncommuting variables and evaluate these functions on sets of matrices of all dimensions; we call such situations dimension-free. In an earlier paper we characterized NC analytic maps that send dimension-free matrix balls to dimension-free matrix balls and carry the boundary to the boundary; such maps we call "NC ball maps". In this paper we turn to a more general dimension-free ball B_L, called a "pencil ball", associated with a homogeneous linear pencil L(x):= A_1 x_1 + ... + A_m x_m, where A_j are complex matrices. For an m-tuple X of square matrices of the same size, define L(X):=\sum A_j \otimes X_j and let B_L denote the set of all such tuples X satisfying ||L(X)||<1. We study the generalization of NC ball maps to these pencil balls B_L, and call them "pencil ball maps". We show that every B_L has a minimal dimensional (in a certain sense) defining pencil L'. Up to normalization, a pencil ball map is the direct sum of L' with an NC analytic map of the pencil ball into the ball. That is, pencil ball maps are simple, in contrast to the classical result of D'Angelo on such analytic maps in C^m. To prove our main theorem, this paper uses the results of our previous paper mentioned above plus entirely different techniques, namely, those of completely contractive maps.Comment: 30 pages, final version. To appear in the Journal of Mathematical Analysis and Application

The Effect of self-controlled practice on forearm passing, motivation, and affect in women’s volleyball players

Motor learning research has suggested that self-controlled practice (or “autonomy”) leads to more effective learning of motor tasks. Debate continues, however, as to why. Most motor behaviorists maintain the better learning is due to cognitive and information-processing factors. Recently, others have proposed the learning enhancement is due to such psychological factors as motivation and affect. The present study sought to measure motor skill learning, intrinsic motivation, and affect in self-controlled versus externally-controlled (yoked) practice conditions. Participants, 16 collegiate women’s volleyball student-athletes from two National Collegiate Athletic Association Division I programs, were paired by forearm passing skill level, and one of each pair was randomly placed in either the self-control or yoked group. The self-control participants were asked to design their own forearm passing drill during the practice phase of the experiment. The yoked participants followed the design established by the self-control participant to whom they were yoked. Each of the participants’ forearm passing accuracy was measured in a free ball passing drill consisting of a pre-test and practice phase on Day 1, and a post-test on Day 2. Their intrinsic motivation was measured using the Intrinsic Motivation Inventory (IMI), and their positive and negative affect was measured using the Positive and Negative Affect Scale – Expanded Edition (PANAS-X). The IMI and PANAS-X were administered in a baseline condition (after a team practice one week prior to participation in the study) at the end of Day 1, and the end of Day 2. Analysis of the data revealed no statistically significant differences between groups in either forearm passing, intrinsic motivation, or affect. Further research is needed to determine if intrinsic motivation and affect are partially responsible for the learning benefits of self-controlled practice

Sustainable protocol for the reduction of nitroarenes by heterogeneous Au@SBA‐15 using NaBH4 under flow conditions

Gold‐incorporated SBA‐15 catalyst was prepared by a solvent‐free ball milling approach. The catalyst showed high reactivity and selectivity in the reduction of a variety of nitroarenes to anilines operating in absolute EtOH using NaBH4 as reducing agent. The catalyst was reused in batch conditions over 5 consecutive runs without detecting any losses of activity and selectivity. Considering the high chemical stability and reusability of the catalytic system, a continuous flow protocol was also investigated and defined in order to minimize the production of waste associated to the process and optimize the continuous reuse of the catalyst. Benefits of flow conditions were proven by TON values that increased from 47.5 to 1902 and also by the minimization of both leaching (9.5 vs 1 ppm) and E‐factor values (8 vs 23 in batch)