Breeding Biology and Longevity of Russet-Crowned Motmots in Central Mexico

Motmots, with their distinctive racketed-tails, represent one of the most easily recognized tropical birds, yet little is known about the basic natural history of most species in the family Momotidae. We report basic breeding biology and longevity of Russet-crowned Motmots (Momotus mexicanus), a medium-sized Neotropical bird that ranges from northwest Mexico to central Guatemala. We monitored nest success of eight pairs from 1 May to 17 July 1998 in tropical deciduous forests in central Mexico. Motmots laid an average of 4.1 eggs and incubated for approximately 20 d. Four of eight nests fledged young. Of these four nests, average hatching success was 69% and average fledgling success was 56%. The mean duration of the nestling period at three nests was 33.7 d. Based on the recapture of one individual bird in April 2008, we provide a longevity estimate that Russet-crowned Motmots can survive at least 11 yr in the wild. These data on nesting success and longevity add to our limited knowledge of the natural history of this understudied species

Primary molt in Gruiforms and simpler molt summary tables

Molt summary tables reveal the sequence and mode of flight-feather replacement and how these feathers are divided into independent replacement series. Tables for summarizing molt are relatively new, and the rules for generating them were first formally illustrated using data from a temperate passerine. However, this first illustration failed to address (i) species with primaries divided into more than one replacement series, (ii) species with stepwise primary replacement, which almost always involves incomplete annual replacement of the primaries, and (iii) species with incomplete annual replacement within molt series characterized by single-wave replacement. Here, we review complications that arise in developing molt summary tables for such cases and we offer solutions that remove ambiguity about the direction that molt proceeds within a replacement series and about the recognition of nodal and terminal feathers that mark the beginning and end of molt series. We use these modified molt summary tables to describe the sequence of primary replacement in four groups of Gruiform birds, a group for which primary replacement has been reported to proceed from the outermost primary toward the body, unlike most other birds. Eighty molting Grey-winged Trumpeters, Psophia crepitans, and 124 molting Limpkins, Aramus guarauna, show the sequence of primary replacement is proximal in both groups; furthermore, the primaries of trumpeters are divided into two replacement series, one beginning at the outermost primary P10, and the other beginning at P3. To further evaluate the extent of this highly unusual direction of replacement in Gruiforms, we cast the data (Stresemann & Stresemann, 1966) on primary replacement in upland rails (Rallidae) and flufftails (Sarothruridae) into molt summary tables; both also replace their primaries proximally, from outermost to innermost, suggesting that this mode of primary replacement may be characteristic of Gruiformes

Least squares support vector machines for direction of arrival estimation

Machine learning research has largely been devoted to binary and multiclass problems relating to data mining, text categorization, and pattern/facial recognition. Recently, popular machine learning algorithms, including support vector machines (SVM), have successfully been applied to wireless communication problems. The paper presents a multiclass least squares SVM (LS-SVM) architecture for direction of arrival (DOA) estimation as applied to a CDMA cellular system. Simulation results show a high degree of accuracy, as related to the DOA classes, and prove that the LS-SVM DDAG (decision directed acyclic graph) system has a wide range of performance capabilities. The multilabel capability for multiple DOAs is discussed. Multilabel classification is possible with the LS-SVM DDAG algorithm presented

Least squares support vector machines for direction of arrival estimation with error control and validation

The paper presents a multiclass, multilabel implementation of least squares support vector machines (LS-SVM) for direction of arrival (DOA) estimation in a CDMA system. For any estimation or classification system, the algorithm\u27s capabilities and performance must be evaluated. Specifically, for classification algorithms, a high confidence level must exist along with a technique to tag misclassifications automatically. The presented learning algorithm includes error control and validation steps for generating statistics on the multiclass evaluation path and the signal subspace dimension. The error statistics provide a confidence level for the classification accuracy

Machine learning based CDMA power control

This paper presents binary and multiclass machine learning techniques for CDMA power control. The power control commands are based on estimates of the signal and noise subspace eigenvalues and the signal subspace dimension. Results of two different sets of machine learning algorithms are presented. Binary machine learning algorithms generate fixed-step power control (FSPC) commands based on estimated eigenvalues and SIRs. A fixed-set of power control commands are generated with multiclass machine learning algorithms. The results show the limitations of a fixed-set power control system, but also show that a fixed-set system achieves comparable performance to high complexity closed-loop power control systems

Least squares support vector machines for fixed-step and fixed-set CDMA power control

This paper presents two machine learning based algorithms for CDMA power control. The least squares support vector machine (LS-SVM) algorithms classify eigenvalues estimates into sets of power control commands. A binary LS-SVM algorithm generates fixed step power control (FSPC) commands, while the one vs. one multiclass LS-SVM algorithm generates estimates for fixed set power control

Harmonic oscillator in a background magnetic field in noncommutative quantum phase-space

We solve explicitly the two-dimensional harmonic oscillator and the harmonic oscillator in a background magnetic field in noncommutative phase-space without making use of any type of representation. A key observation that we make is that for a specific choice of the noncommutative parameters, the time reversal symmetry of the systems get restored since the energy spectrum becomes degenerate. This is in contrast to the noncommutative configuration space where the time reversal symmetry of the harmonic oscillator is always broken.Comment: 7 pages Late

Feather growth rate and mass in nearctic passerines with variablemigratory behavior and molt pattern

Bird species vary greatly in the duration of their annual complete feather molt. However, such variation is not well documented in birds from many biogeographic areas, which restricts our understanding of the diversification of molt strategies. Recent research has revealed that molt duration can be estimated in passerines from ptilochronology-based measurements of the growth rate of their tail feathers. We used this approach to explore how molt duration varied in 98 Nearctic species that have different migratory strategies and molt patterns. As previously documented for Palearctic species, migration was associated with a shortening of molt duration among species that molted during summer on their breeding range. However, molts of winter-molting migratory species were as long as those of summer-molting sedentary species, which suggests that winter molt also allows Nearctic migrants to avoid the temporal constraints experienced during summer. Our results also suggest that migratory species that undergo a stopover molt within the Mexican monsoon region have the shortest molt duration among all Nearctic passerines. Interestingly, and contrary to expectations from a potential tradeoff between molt duration and feather quality, observed variation in feather growth rate was positively correlated with differences in tail feather mass, which may be caused by differences among groups in the availability of resources for molting. We encourage the use of similar approaches to study the variation in molt duration in other geographic areas where knowledge of the evolution of molt is limited.

Noncommutative quantum mechanics -- a perspective on structure and spatial extent

We explore the notion of spatial extent and structure, already alluded to in earlier literature, within the formulation of quantum mechanics on the noncommutative plane. Introducing the notion of average position and its measurement, we find two equivalent pictures: a constrained local description in position containing additional degrees of freedom, and an unconstrained nonlocal description in terms of the position without any other degrees of freedom. Both these descriptions have a corresponding classical theory which shows that the concept of extended, structured objects emerges quite naturally and unavoidably there. It is explicitly demonstrated that the conserved energy and angular momentum contain corrections to those of a point particle. We argue that these notions also extend naturally to the quantum level. The local description is found to be the most convenient as it manifestly displays additional information about structure of quantum states that is more subtly encoded in the nonlocal, unconstrained description. Subsequently we use this picture to discuss the free particle and harmonic oscillator as examples.Comment: 25 pages, no figure