Algivory in food webs of three temperate Andean rivers

Food web analyses have been fundamental in understanding community organization and ecosystem functioning. To date, a number of studies demonstrate that stream food webs depend to a large extent on allochthonous detritus, but there are more recent studies that show a high degree of autochthony. Our food-web study was carried out in three Andean rivers (Coilaco, Guampoe and Trancura) within the catchment area of Toltén River in southern Chile. Based on the analyses of 4251 invertebrate gut contents, we found that these Andean stream food webs are dominated by herbivores (range: 50-73% of all species) supported by a species-rich algal (basal) component, and characterized by a low proportion of omnivores (range: 8-27% of all species) and predatory species (range: 10-24%). Significant differences in the number of feeding links of the herbivores Meridialis diguillina and Antarctoperla michaelseni and the omnivore Smicridea chilensis were found between seasons. The spring herbivore Aubertoperla sp. showed significant differences between rivers. S.chilensis fed on 50 different prey items as compared with the herbivores whose maximum number of links ranged between 37 and 40. Web sizes ranged between 93 and 131 species and the proportion of top species was distinctly lower than those of basal (up to 0.651 in Coilaco River) and intermediate species. Direct connectance (links per species2) values were low and similar among rivers (range: 0.051-0.074), whereas mean food chain length ranged between 2.23 and 2.90. The distributions of web property values from the Andean rivers differed from those previously published. In contrast to previous predictions, mean food chain length in these Andean streams displayed a scale-invariant pattern across different web sizes, but it was significantly related to the proportion of intermediate species. © 2011 The Authors. Journal compilation © 2011 Ecological Society of Australia

Integrating process design and control: An application of optimal control to chemical processes

In this paper, the optimal design of process systems generically used in chemical industries is studied. The closely coupled nature of optimal design specification of the equipment, the determination of the optimal process parameters in steady-state, moreover, some issues of the application of optimal control is shown. The solution of the overall optimization problem including (i) optimal design of the equipment and (ii) specification of its optimal control strategy can be found relying on two different design concepts, namely, on the conventionally used sequential or, on the newly emerged simultaneous design approaches. This paper gives the theoretical background of the ideas and presents a comparative summary of the approaches. The two approaches are contrasted to each other in which the effects of the interaction of optimal process design and optimal control is highlighted. A new simultaneous optimization procedure providing economic and operability benefits over the traditional stand-alone approach is proposed. The applicability of the idea is demonstrated by means of a design study carried out for optimal design of a coaxial heat exchanger and a reactive distillation column for the synthesis of ethyl tert butyl ether (ETBE), relying on the benefits of the utilization of optimal control

Faith seeking understanding

The debate between faith and science is an ongoing and dynamic conversation marked by the need to consistently factor in new data generated by the sciences, and new perspectives developed in theology. In this book, a group of theologians and ethicists provide insights into the debate from a faith perspective. The basic thesis permeating the discussions is that faith and science are capable of enriching and complementing each other, albeit in their own unique way. What unifies faith and science is the search for truth. What differentiates them is the unique lenses they employ to find the truth. In the end, both scientists and theologians must take into account all the pathways and lenses that lead us to a better understanding of reality. This study presents concrete examples of how theological knowledge and scientific data can be fruitfully used and integrated to develop new horizons of understanding. The general aim of this contribution was to narrow in on some of the burning themes that are driving the faith or science scholarly debate. Each contributor highlights a different aspect of the debate. The topics addressed include theoretical perspectives on the science-faith relation, the ancient scientific worldview of the creation narratives in Genesis, evolution and human origins, science and African Pentecostalism, faith and the Fourth Industrial Revolution, science and transhumanism, science and traditional medicine, and the role that faith and science can play in the human quest for meaning. Most of the contributors approach the topic from a post-foundationalist and postpositivist epistemological point of view. A wide range of hermeneutical methods is employed, ranging from systematic biblical-theological perspectives to literary and source criticism. Analytical, normative and existential philosophical arguments are also utilised throughout the course of the book. The most important contribution of the book lies in the transdisciplinary perspectives that emanate from the discussion. The ways in which the authors go about integrating theological and scientific perspectives to address ultimate questions about meaning and to inform moral discourse show that religion still has an important role to play in a world increasingly shaped by technological rationality. At the same time, it indicates that religion and science do not have to stand in conflict with each other. If the two lenses on reality engage in mature dialogue, they can enrich, inform and, on some occasions, even correct each other. The target audience of this book includes theological scholars, natural scientists and science philosophers. This book contains no plagiarism, and none of the work has been published elsewhere

Faith seeking understanding

The debate between faith and science is an ongoing and dynamic conversation marked by the need to consistently factor in new data generated by the sciences, and new perspectives developed in theology. In this book, a group of theologians and ethicists provide insights into the debate from a faith perspective. The basic thesis permeating the discussions is that faith and science are capable of enriching and complementing each other, albeit in their own unique way. What unifies faith and science is the search for truth. What differentiates them is the unique lenses they employ to find the truth. In the end, both scientists and theologians must take into account all the pathways and lenses that lead us to a better understanding of reality. This study presents concrete examples of how theological knowledge and scientific data can be fruitfully used and integrated to develop new horizons of understanding. The general aim of this contribution was to narrow in on some of the burning themes that are driving the faith or science scholarly debate. Each contributor highlights a different aspect of the debate. The topics addressed include theoretical perspectives on the science-faith relation, the ancient scientific worldview of the creation narratives in Genesis, evolution and human origins, science and African Pentecostalism, faith and the Fourth Industrial Revolution, science and transhumanism, science and traditional medicine, and the role that faith and science can play in the human quest for meaning. Most of the contributors approach the topic from a post-foundationalist and postpositivist epistemological point of view. A wide range of hermeneutical methods is employed, ranging from systematic biblical-theological perspectives to literary and source criticism. Analytical, normative and existential philosophical arguments are also utilised throughout the course of the book. The most important contribution of the book lies in the transdisciplinary perspectives that emanate from the discussion. The ways in which the authors go about integrating theological and scientific perspectives to address ultimate questions about meaning and to inform moral discourse show that religion still has an important role to play in a world increasingly shaped by technological rationality. At the same time, it indicates that religion and science do not have to stand in conflict with each other. If the two lenses on reality engage in mature dialogue, they can enrich, inform and, on some occasions, even correct each other. The target audience of this book includes theological scholars, natural scientists and science philosophers. This book contains no plagiarism, and none of the work has been published elsewhere

Examination of the importance of age of onset, callous-unemotional traits and anger dysregulation in youths with antisocial behaviors.

Age of onset, callous-unemotional (CU) traits and anger dysregulation have separately been proposed as relevant factors in explaining the heterogeneity of antisocial behaviour (ASB). Taking a dimensional perspective, this study examined the specific contributions and the mutual influences (i.e., interactions) of these three characteristics on specific dimensions of ASB (i.e., criminal behaviours and externalizing symptoms). Assessments were conducted on 536 youths from institutions with the youth psychopathic traits inventory (CU traits), the Massachusetts youth screening instrument-second version (anger dysregulation), the criminology questionnaire (criminal behaviours) and the child behavior checklist (externalizing symptoms), rated by both the youths and their carers. Using Bayes as estimators, the results revealed that the number and frequency of crimes (and, more specifically, damage to property, property offenses and media crimes) were explained by a specific contribution of each factor (age of onset, CU traits and anger dysregulation). Additionally, the interactions between age of onset and CU traits or anger dysregulation were relevant predictors of some types of crimes (i.e., damage to property, property offences and media crimes). Furthermore, when rated by youths, externalizing symptoms were explained by CU traits and anger dysregulation. However, when rated by the carer, anger dysregulation was more important in explaining externalizing symptoms. This study highlights the importance of considering these factors altogether and the value of using a dimensional perspective when examining the structure of ASB in youths. Consequently, future classifications should take into account the mutual account of these characteristics, which were previously studied separately

Superconductivity and antiferromagnetism in a hard-core boson spin-1 model in two dimensions

A model of hard-core bosons and spin-1 sites with single-ion anisotropy is proposed to approximately describe hole pairs moving in a background of singlets and triplets with the aim of exploring the relationship between superconductivity and antiferromagnetism. The properties of this model at zero temperature were investigated using quantum Monte Carlo techniques. The most important feature found is the suppression of superconductivity, as long range coherence of preformed pairs, due to the presence of both antiferromagnetism and $S^z=\pm 1$ excitations. Indications of charge ordered and other phases are also discussed.Comment: One figure, one reference, adde

Field-induced XY behavior in the S=1/2 antiferromagnet on the square lattice

Making use of the quantum Monte Carlo method based on the worm algorithm, we study the thermodynamic behavior of the S=1/2 isotropic Heisenberg antiferromagnet on the square lattice in a uniform magnetic field varying from very small values up to the saturation value. The field is found to induce a Berezinskii-Kosterlitz-Thouless transition at a finite temperature, above which a genuine XY behavior in an extended temperature range is observed. The phase diagram of the system is drawn, and the thermodynamic behavior of the specific heat and of the uniform and staggered magnetization is discussed in sight of an experimental investigation of the field-induced XY behavior.Comment: 4 pages, 4 figure

Influence of temperature gradients on tunnel junction thermometry below 1 K: cooling and electron-phonon coupling

We have studied thermal gradients in thin Cu and AlMn wires, both experimentally and theoretically. In the experiments, the wires were Joule heated non-uniformly at sub-Kelvin temperatures, and the resulting temperature gradients were measured using normal metal-insulator-superconducting tunnel junctions. The data clearly shows that even in reasonably well conducting thin wires with a short ($\sim 10 \mu$m) non-heated portion, significant temperature differences can form. In most cases, the measurements agree well with a model which includes electron-phonon interaction and electronic thermal conductivity by the Wiedemann-Franz law.Comment: J. Low Temp. Phys. in pres

PIF transcription factors link a neighbor threat cue to accelerated reproduction in Arabidopsis.

Changes in light quality indicative of competition for this essential resource influence plant growth and developmental transitions; however, little is known about neighbor proximity-induced acceleration of reproduction. Phytochrome B (phyB) senses light cues from plant competitors, ultimately leading to the expression of the floral inducers FLOWERING LOCUS T (FT) and TWIN SISTER of FT (TSF). Here we show that PHYTOCHROME INTERACTING FACTORs 4, 5 and 7 (PIF4, PIF5 and PIF7) mediate neighbor proximity-induced flowering, with PIF7 playing a prominent role. These transcriptional regulators act directly downstream of phyB to promote expression of FT and TSF. Neighbor proximity enhances PIF accumulation towards the end of the day, coinciding with enhanced floral inducer expression. We present evidence supporting direct PIF-regulated TSF expression. The relevance of our findings is illustrated by the prior identification of FT, TSF and PIF4 as loci underlying flowering time regulation in natural conditions

Pinning of stripes by local structural distortions in cuprate high-Tc superconductors

We study the spin-density wave (stripe) instability in lattices with mixed low-temperature orthorhombic (LTO) and low-temperature tetragonal (LTT) crystal symmetry. Within an explicit mean-field model it is shown how local LTT regions act as pinning centers for static stripe formation. We calculate the modulations in the local density of states near these local stripe regions and find that mainly the coherence peaks and the van Hove singularity (VHS) are spatially modulated. Lastly, we use the real-space approach to simulate recent tunneling data in the overdoped regime where the VHS has been detected by utilizing local normal state regions.Comment: Conference proceedings for Stripes1