Jordan Forms of Real and Complex Matrices Under Rank One Perturbations

New perturbation results for the behavior of eigenvalues and Jordan forms of real and complex matrices under generic rank one perturbations are discussed. Several results that are available in the complex case are proved as well for the real case and the assumptions on the genericity are weakened. Rank one perturbations that lead to maximal algebraic multiplicities of the new eigenvalues are also discussed

Multiple Captures of White-footed Mice (Peromyscus leucopus): Evidence for Social Structure?

Multiple captures (34 double, 6 triple) in standard Sherman live traps accounted for 6.3% of 1355 captures of Peromyscus leucopus (white-footed mice) in forested habitat in southern Illinois, from Oct. 2004 through Oct. 2005. There was a significant positive relationship between both the number and the proportion of multiple captures and estimated monthly population size. Multiple captures were all intraspecific and occurred significantly more often from Nov. through Mar. when animals were not reproductively active, but this was confounded by seasonal changes in abundance. Age/gender distribution of animals in double captures did not differ from that expected from random pairing. We suggest that sociality and synchronous entry of two white-footed mice into traps were the primary determinants of double captures; sensitivity of traps may have been the primary factor in triple capture

Geographic variation in dispersal distance facilitates range expansion of a lake shore plant in response to climate change

AimGeographic variation in dispersal abilities is widespread and likely to affect species’ range dynamics in response to climate change. However, distribution models that predict climate‐induced range shifts do not account for spatial variation in dispersal. We developed an eco‐genetic model to investigate how variation in dispersal distances across a species’ range could interact with climate‐induced selection and alter predicted range dynamics in a species with documented variation in dispersal traits.LocationWe investigated the range of an annual plant, Cakile edentula var. lacustris, which occupies beaches spanning a 555 km latitudinal gradient along the Laurentian Great Lakes.MethodsWe built a hybrid model that combines climatic niche modelling, based on decadal climate projections, with an individual‐based model that allows for evolutionary processes to act upon a heritable dispersal kernel. We evaluated how spatial variation in dispersal distance and dispersal evolution influenced range dynamics, spatial and temporal variation in dispersal, and the distribution of neutral genetic variation. The model was parametrized with data on C. edentula’s distribution, life history and dispersal characteristics.ResultsGeographic variation in dispersal distance, adaptive dispersal evolution and dispersal distance increased the potential for local populations of C. edentula to keep pace with changing climatic conditions through range shifts. Dispersal distances always increased at the expanding and contracting range edges when dispersal was allowed to evolve. Furthermore, scenarios where dispersal distances were initially lower at the range edges resulted in the largest evolutionary changes over 105 years (>1.5 km increase in mean distance at northern edge). Adaptive dispersal evolution always reduced neutral genetic diversity across the species’ range.Main conclusionsVariation in dispersal abilities across C. edentula’s range and adaptive evolution led to different predicted outcomes in range dynamics during climate change illustrating the importance of including spatial variation in dispersal into species distribution models.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151269/1/ddi12951.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151269/2/ddi12951_am.pd

Biobehavioral effects of Tai Chi Qigong in men with prostate cancer: Study design of a three-arm randomized clinical trial.

Fatigue is often one of the most commonly reported symptoms in prostate cancer survivors, but it is also one of the least understood cancer-related symptoms. Fatigue is associated with psychological distress, disruptions in sleep quality, and impairments in health-related quality of life. Moreover, inflammatory processes and changes related to the hypothalamic-pituitary-adrenal (HPA) axis and/or autonomic nervous system may also play a role in cancer-related fatigue. Thus, effective treatments for fatigue in prostate cancer survivors represent a current unmet need. Prior research has shown that Tai Chi Qigong, a mind-body exercise intervention, can improve physical and emotional health. Herein, we describe the protocol of the ongoing 3-arm randomized controlled Health Empowerment & Recovery Outcomes (HERO) clincal trial. One hundred sixty-six prostate cancer survivors with fatigue are randomized to a modified Tai Chi Qigong intervention (TCQ), intensity-matched body training intervention (BT), or usual care (UC) condition. Guided by biopsychosocial and psychoneuroimmunology models, we propose that TCQ, as compared to BT or UC will: i) reduce fatigue (primary outcome) in prostate cancer survivors; ii) reduce inflammation; and iii) regulate the expression of genes from two major functional clusters: a) inflammation, vasodilation and metabolite sensing and b) energy and adrenergic activation. Assessments are conducted at baseline, the 6-week midpoint of the intervention, and 1 week, 3 months, and 12 months post-intervention. If our findings show that TCQ promotes recovery from prostate cancer and its treatment, this type of intervention can be integrated into survivorship care plans as the standard of care. The study's findings will also provide novel information about underlying biobehavioral mechanisms of cancer-related fatigue. Trial registration number:NCT03326713; clinicaltrials.gov

Eigenvalue perturbation theory of structured real matrices and their sign characteristics under generic structured rank-one perturbations

An eigenvalue perturbation theory under rank-one perturbations is developed for classes of real matrices that are symmetric with respect to a non-degenerate bilinear form, or Hamiltonian with respect to a non-degenerate skew-symmetric form. In contrast to the case of complex matrices, the sign characteristic is a crucial feature of matrices in these classes. The behavior of the sign characteristic under generic rank-one perturbations is analyzed in each of these two classes of matrices. Partial results are presented, but some questions remain open. Applications include boundedness and robust boundedness for solutions of structured systems of linear differential equations with respect to general perturbations as well as with respect to structured rank perturbations of the coefficients

Extraction of uranium from seawater: evaluation of uranium resources and plant siting

This report deals with the evaluation of U.S. coastal waters as a uranium resource and with the selection of a suitable site for construction of a large-scale plant for uranium extraction. Evaluation of the resource revealed that although the concentration of uranium is quite low, about 3.3 ppB in seawater of average oceanic salinity, the amount present in the total volume of the oceans is very great, some 4.5 billion metric tons. Of this, perhaps only that uranium contained in the upper 100 meters or so of the surface well-mixed layer should be considered accessible for recovery, some 160 million tonnes. The study indicated that open ocean seawater acquired for the purpose of uranium extraction would be a more favorable resource than rivers entering the sea, cooling water of power plants, or the feed or effluent streams of existing plants producing other products such as magnesium, bromine, or potable and/or agricultural water from seawater. Various considerations led to the selection of a site for a pumped seawater coastal plant at a coastal location. Puerto Yabucoa, Puerto Rico was selected. Recommendations are given for further studies. 21 figures, 8 tables

Stability of polar decompositions

Certain continuity properties of the factors in generalized polar decompositions of real and complex matrices are studied. A complete characterization is given of those generalized polar decompositions that persist under small perturbations in the matrix and in the scalar product. Connections are made with quadratic matrix equations, and with stability properties of certain invariant subspaces

Negotiating daughterhood and strangerhood: retrospective accounts of serial migration

Most considerations of daughtering and mothering take for granted that the subjectivities of mothers and daughters are negotiated in contexts of physical proximity throughout daughters’ childhoods. Yet many mothers and daughters spend periods separated from each other, sometimes across national borders. Globally, an increasing number of children experience life in transnational families. This paper examines the retrospective narratives of four women who were serial migrants as children (whose parents migrated before they did) . It focuses on their accounts of the reunion with their mothers and how these fit with the ways in which they construct their mother-daughter relationships. We take a psychosocial approach by using a psychoanalytically-informed reading of these narratives to acknowledge the complexities of the attachments produced in the context of migration and to attend to the multi-layered psychodynamics of the resulting relationships. The paper argues that serial migration positioned many of the daughters in a conflictual emotional landscape from which they had to negotiate ‘strangerhood’ in the context of sadness at leaving people to whom they were attached in order to join their mothers (or parents). As a result, many were resistant to being positioned as daughters, doing daughtering and being mothered in their new homes

Future Dominance by Quaking Aspen Expected Following Short-Interval, Compounded Disturbance Interaction

The spatial overlap of multiple ecological disturbances in close succession has the capacity to alter trajectories of ecosystem recovery. Widespread bark beetle outbreaks and wildfire have affected many forests in western North America in the past two decades in areas of important habitat for native ungulates. Bark beetle outbreaks prior to fire may deplete seed supply of the host species, and differences in fire‐related regeneration strategies among species may shift the species composition and structure of the initial forest trajectory. Subsequent browsing of postfire tree regeneration by large ungulates, such as elk (Cervus canadensis), may limit the capacity for regeneration to grow above the browse zone to form the next forest canopy. Five stand‐replacing wildfires burned ~60,000 ha of subalpine forest that had previously been affected by severe ( \u3e90% mortality) outbreaks of spruce beetle (SB, Dendroctonus rufipennis) in Engelmann spruce (Picea engelmannii) in 2012–2013 in southwestern Colorado. Here we examine the drivers of variability in abundance of newly established conifer tree seedlings [spruce and subalpine fir (Abies lasiocarpa)] and resprouts of quaking aspen (Populus tremuloides) following the short‐interval sequence of SB outbreaks and wildfire (2–8 yr between SB outbreak and fire) at sites where we previously reconstructed severities of SB and fire. We then examine the implications of ungulate browsing for forest recovery. We found that abundances of postfire spruce seedling establishment decreased substantially in areas of severe SB outbreak. Prolific aspen resprouting in stands with live aspen prior to fire will favor an initial postfire forest trajectory dominated by aspen. However, preferential browsing of postfire aspen resprouts by ungulates will likely slow the rate of canopy recovery but browsing is unlikely to alter the species composition of the future forest canopy. Collectively, our results show that SB outbreak prior to fire increases the vulnerability of spruce–fir forests to shifts in forest type (conifer to aspen) and physiognomic community type (conifer forest to non‐forest). By identifying where compounded disturbance interactions are likely to limit recovery of forests or tree species, our findings are useful for developing adaptive management strategies in the context of warming climate and shifting disturbance regimes

Till death (or an intruder) do us part: intrasexual-competition in a monogamous Primate

Polygynous animals are often highly dimorphic, and show large sex-differences in the degree of intra-sexual competition and aggression, which is associated with biased operational sex ratios (OSR). For socially monogamous, sexually monomorphic species, this relationship is less clear. Among mammals, pair-living has sometimes been assumed to imply equal OSR and low frequency, low intensity intra-sexual competition; even when high rates of intra-sexual competition and selection, in both sexes, have been theoretically predicted and described for various taxa. Owl monkeys are one of a few socially monogamous primates. Using long-term demographic and morphological data from 18 groups, we show that male and female owl monkeys experience intense intra-sexual competition and aggression from solitary floaters. Pair-mates are regularly replaced by intruding floaters (27 female and 23 male replacements in 149 group-years), with negative effects on the reproductive success of both partners. Individuals with only one partner during their life produced 25% more offspring per decade of tenure than those with two or more partners. The termination of the pair-bond is initiated by the floater, and sometimes has fatal consequences for the expelled adult. The existence of floaters and the sporadic, but intense aggression between them and residents suggest that it can be misleading to assume an equal OSR in socially monogamous species based solely on group composition. Instead, we suggest that sexual selection models must assume not equal, but flexible, context-specific, OSR in monogamous species.Wenner-Gren Foundation, L.S.B. Leakey Foundation, the National Geographic Society, National Science Foundation (BCS- 0621020), the University of Pennsylvania Research Foundation and the Zoological Society of San Diego, German Science Foundation (HU 1746-2/1