Information flow and Laplacian dynamics on local optima networks

We propose a new way of looking at local optima networks (LONs). LONs represent fitness landscapes; the nodes are local optima, and the edges are search transitions between them. Many metrics computed on LONs have been proposed and shown to be linked to metaheuristic search difficulty. These have typically considered LONs as describing static structures. In contrast to this, Laplacian dynamics (LD) is an approach to consider the information flow across a network as a dynamical process. We adapt and apply LD to the context of LONs. As a testbed, we consider instances from the quadratic assignment problem (QAP) library. Metrics related to LD are proposed and these are compared with existing LON metrics. The results show that certain LD metrics are strong predictors of metaheuristic performance for iterated local search and tabu search

Functional analysis of the magnetosome island in Magnetospirillum gryphiswaldense: the mamAB operon is sufficient for magnetite biomineralization

Bacterial magnetosomes are membrane-enveloped, nanometer-sized crystals of magnetite, which serve for magnetotactic navigation. All genes implicated in the synthesis of these organelles are located in a conserved genomic magnetosome island (MAI). We performed a comprehensive bioinformatic, proteomic and genetic analysis of the MAI in Magnetospirillum gryphiswaldense. By the construction of large deletion mutants we demonstrate that the entire region is dispensable for growth, and the majority of MAI genes have no detectable function in magnetosome formation and could be eliminated without any effect. Only <25% of the region comprising four major operons could be associated with magnetite biomineralization, which correlated with high expression of these genes and their conservation among magnetotactic bacteria. Whereas only deletion of the mamAB operon resulted in the complete loss of magnetic particles, deletion of the conserved mms6, mamGFDC, and mamXY operons led to severe defects in morphology, size and organization of magnetite crystals. However, strains in which these operons were eliminated together retained the ability to synthesize small irregular crystallites, and weakly aligned in magnetic fields. This demonstrates that whereas the mamGFDC, mms6 and mamXY operons have crucial and partially overlapping functions for the formation of functional magnetosomes, the mamAB operon is the only region of the MAI, which is necessary and sufficient for magnetite biomineralization. Our data further reduce the known minimal gene set required for magnetosome formation and will be useful for future genome engineering approaches

A COMPARISON BETWEEN THE MODERN AND THE LOWER BODY GOLF SWING TECHNIQUES– PILOT STUDY WITH IMPLICATIONS FOR LOWER BACK INJURY RISK

The purpose of this study was to compare the biomechanical characteristics of the lower body swing to modern swing techniques, with a focus on lower back injury risk. Fifteen male individuals free from lower back injury participated in this study. Nine participants utilized the modern swing (age = 48.0 ± 13.6 years; height = 176.8 ± 4.4 cm; mass = 82.1 ± 5.3 kg) while six utilized the lower body swing (age = 53.9 ±12.1 years; height = 182.9 ± 6.1 cm; mass = 92.5 ± 14.8 kg). Whole body kinematics were recorded with a ten-camera motion analysis system while individuals performed 5 shots with a driver for maximum distance. Continuous waveform and discrete point analysis was used to explore the differences between these two techniques. The lower body swing demonstrated favourable kinematics in the majority of variables related to lower back pain and lumbar load

The molecular pathology of pathogenic mitochondrial tRNA variants

Mitochondrial diseases are clinically and genetically heterogeneous disorders, caused by pathogenic variants in either the nuclear or mitochondrial genome. This heterogeneity is particularly striking for disease caused by variants in mitochondrial DNA-encoded tRNA (mt-tRNA) genes, posing challenges for both the treatment of patients and understanding the molecular pathology. In this review, we consider disease caused by the two most common pathogenic mt-tRNA variants: m.3243A>G (within MT-TL1, encoding mt-tRNA(Leu(UUR))) and m.8344A>G (within MT-TK, encoding mt-tRNA(Lys)), which together account for the vast majority of all mt-tRNA-related disease. We compare and contrast the clinical disease they are associated with, as well as their molecular pathologies, and consider what is known about the likely molecular mechanisms of disease. Finally, we discuss the role of mitochondrial-nuclear crosstalk in the manifestation of mt-tRNA-associated disease and how research in this area not only has the potential to uncover molecular mechanisms responsible for the vast clinical heterogeneity associated with these variants but also pave the way to develop treatment options for these devastating diseases.Peer reviewe

The joy of gratifications: Promotion as a short-term boost or long-term success – The same for women and men?

Job satisfaction helps create a committed workforce with many positive effects, such as increased organisational citizenship behaviour and reduced absenteeism. In turn, job satisfaction can be increased through gratifications, such as wage increases and promotions. But human satisfaction is prone to being governed by the homeostatic principle and will eventually return to the individual's base level. Thus, we longitudinally examined the effects of promotions to managerial positions and pay raises on job satisfaction across a period of 27 years. Our analyses were based on a large-scale representative German panel (N = 5978 observations) that allowed us to separate the effect of a promotion from the effect of the corresponding wage increase. We found that promotions positively affected job satisfaction in the short term but diminished after 1 year. Furthermore, the influence of a promotion on job satisfaction was more pronounced for men than for women

Phenotypic plasticity facilitates resistance to climate change in a highly variable environment

Increased summer drought will exacerbate the regeneration of many tree species at their lower latitudinal and altitudinal distribution limits. In vulnerable habitats, introduction of more drought-tolerant provenances or species is currently considered to accelerate tree species migration and facilitate forest persistence. Trade-offs between drought adaptation and growth plasticity might, however, limit the effectiveness of assisted migration, especially if introductions focus on provenances or species from different climatic regions. We tested in a common garden experiment the performance of Pinus sylvestris seedlings from the continental Central Alps under increased temperatures and extended spring and/or summer drought, and compared seedling emergence, survival and biomass allocation to that of P. sylvestris and closely related Pinus nigra from a Mediterranean seed source. Soil heating had only minor effects on seedling performance but high spring precipitation doubled the number of continental P. sylvestris seedlings present after the summer drought. At the same time, twice as many seedlings of the Mediterranean than the continental P. sylvestris provenance were present, which was due to both higher emergence and lower mortality under dry conditions. Both P. sylvestris provenances allocated similar amounts of biomass to roots when grown under low summer precipitation. Mediterranean seedlings, however, revealed lower phenotypic plasticity than continental seedlings under high precipitation, which might limit their competitive ability in continental Alpine forests in non-drought years. By contrast, high variability in the response of individual seedlings to summer drought indicates the potential of continental P. sylvestris provenances to adapt to changing environmental condition

The Ursinus Weekly, April 21, 1952

Juniors schedule prom, show for this weekend • Operetta Sari judged to be great success • Chem group plans April 28 program • Lit. readings held • Juniors, sophomores plan activities for May 2, 3 • Loyalty forms needed for civil service jobs • Meeker awarded fellowship • Spirit group meets to plan for next year • Speaker tells of life in Africa and Pakistan • Annual campus elections to take place tomorrow • Member of Board of Directors dies • Intersorority Council plans freshmen party • French Club to give movie • Herber awarded fellowship • Group Four to give play on April 22 • Frat president elected • Editorials: Get out and vote; A question; Presidential race changing • Letters to the editor • Request made to form Eisenhower Club • Lampeter hurls eight hit victory over Temple, 6-3 • Mermaids choose future captains • Track team drops first dual meet to Haverford • Netmen lose in first outing • Engagements • Diocese president electedhttps://digitalcommons.ursinus.edu/weekly/1541/thumbnail.jp