2,065 research outputs found
Control mechanisms and perceived organizational support: exploring the relationship between new and traditional forms of control
Purpose: Taking into account the need to make a clearer distinction between traditional and new organizational controls, this paper aims to investigate similarities and differences between those two forms and explore the extent to which new forms of control can be operationalized from a quantitative point of view. Design/methodology/approach: Suggesting that new organizational controls can be understood also in light of quantitative paradigms, we develop and test a scale to measure the existence of these types of controls, examine its construct validity and evaluate its convergent validity. Findings: The theoretical dimensions of new controls have empirical correspondence. Input and behaviour controls are strongly associated with the promotion of values and beliefs in organizations. New controls become responsible for employees’ acceptance of companies’ management, an aspect measured by Perceived-Organizational-Support (POS)
Increased levels of RNA oxidation enhance the reversion frequency in aging pro-apoptotic yeast mutants
Despite recent advances in understanding the complexity of RNA processes, regulation of the metabolism of oxidized cellular RNAs and the mechanisms through which oxidized ribonucleotides affect mRNA translation, and consequently cell viability, are not well characterized. We show here that the level of oxidized RNAs is markedly increased in a yeast decapping Kllsm4Δ1 mutant, which accumulates mRNAs, ages much faster that the wild type strain and undergoes regulated-cell-death. We also found that in Kllsm4Δ1 cells the mutation rate increases during chronological life span indicating that the capacity to han- dle oxidized RNAs in yeast declines with aging. Lowering intracellular ROS levels by antioxidants recovers the wild- type phenotype of mutant cells, including reduced amount of oxidized RNAs and lower mutation rate. Since mRNA oxidation was reported to occur in different neurodegen- erative diseases, decapping-deficient cells may represent a useful tool for deciphering molecular mechanisms of cell response to such conditions, providing new insights into RNA modification-based pathogenesis
Energy dissipation over large-scale roughness for both transition and uniform flow conditions
Rock chutes are natural river training structures and are efficient energy dissipaters too. From the hydraulic and environmental point of view, rock chutes have become important structures in the natural river morphology. A physical study was conducted and flow properties were measured over rough bed materials of a rock chute, which was assembled at the PITLAB center of the University of Pisa, Italy. Experiments were performed for slopes varying between 0.18≤ S ≤0.38, 0.03 < dc/H < 0.54 and for ramp lengths Lr between 1.17 m ≤Lr≤3.6 m. This paper presents the energy dissipation characteristics of the two-phase flows in the presence of two different base materials. In addition, the dissipative process was also analyzed in the presence of reinforcing boulders located on the base material. The findings showed that energy dissipation rate slightly increases with the boulder concentrations for the tested slopes and materials. The experiments were conducted for different rock chute lengths in order to understand its effect on the energy dissipation. An empirical expression is developed for determining the energy dissipation characteristics over different base materials in different ramp length conditions in twophase flows. Results have been compared with the results obtained for stepped chutes and found a similar decreasing trend of dissipation rate for dc/Lr ≤0.1
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Spontaneous Embedding of DNA Mismatches Within the RNA:DNA Hybrid of CRISPR-Cas9.
CRISPR-Cas9 is the forefront technology for editing the genome. In this system, the Cas9 protein is programmed with guide RNAs to process DNA sequences that match the guide RNA forming an RNA:DNA hybrid structure. However, the binding of DNA sequences that do not fully match the guide RNA can limit the applicability of CRISPR-Cas9 for genome editing, resulting in the so-called off-target effects. Here, molecular dynamics is used to probe the effect of DNA base pair mismatches within the RNA:DNA hybrid in CRISPR-Cas9. Molecular simulations revealed that the presence of mismatched pairs in the DNA at distal sites with respect to the Protospacer Adjacent Motif (PAM) recognition sequence induces an extended opening of the RNA:DNA hybrid, leading to novel interactions established by the unwound nucleic acids and the protein counterpart. On the contrary, mismatched pairs upstream of the RNA:DNA hybrid are rapidly incorporated within the heteroduplex, with minor effect on the protein-nucleic acid interactions. As a result, mismatched pairs at PAM distal ends interfere with the activation of the catalytic HNH domain, while mismatches fully embedded in the RNA:DNA do not affect the HNH dynamics and enable its activation to cleave the DNA. These findings provide a mechanistic understanding to the intriguing experimental evidence that PAM distal mismatches hamper a proper function of HNH, explaining also why mismatches within the heteroduplex are much more tolerated. This constitutes a step forward in understanding off-target effects in CRISPR-Cas9, which encourages novel structure-based engineering efforts aimed at preventing the onset of off-target effects
Transition from a simple yield stress fluid to a thixotropic material
From MRI rheometry we show that a pure emulsion can be turned from a simple
yield stress fluid to a thixotropic material by adding a small fraction of
colloidal particles. The two fluids have the same behavior in the liquid regime
but the loaded emulsion exhibits a critical shear rate below which no steady
flows can be observed. For a stress below the yield stress, the pure emulsion
abruptly stops flowing, whereas the viscosity of the loaded emulsion
continuously increases in time, which leads to an apparent flow stoppage. This
phenomenon can be very well represented by a model assuming a progressive
increase of the number of droplet links via colloidal particles.Comment: Published in Physical Review E.
http://pre.aps.org/abstract/PRE/v76/i5/e05140
Seismic-proof buildings in developing countries
The use of \u201cductile seismic frames,\u201d whose proper seismic behavior largely depends upon construction details and specific design rules, may do not always lead to effective seismic resistant structures, as dramatically denounced by the famous Chinese artist Ai Weiwei in his artwork Straight. The artwork (96 t of undulating metal bars that were salvaged from schools destroyed by the 2008 Sichuan, China earthquake, where over 5,000 students were killed) is a clear denounce against the corruption yielding to shoddy construction methods. The issue of safe constructions against natural hazards appears even more important in developing countries where, in most cases, building structures are realized by non-expert workers, or even by simple \u201cpeople from the street,\u201d who does not have any technical knowledge on construction techniques and seismic engineering. In this paper, a brief history from the first frame structures to the more efficient wall-based structures is provided within Earthquake Engineering perspectives. The superior structural properties of box-type wall structures with respect to conventional frame structures envisage a change of paradigm from actual \u201cductility-based\u201d Earthquake Engineering (centered on frame structures) toward 100% safe buildings through a \u201cstrength-based\u201d design exploiting the use of box-type wall-based structures
Cluster of legionnaires’ disease in an Italian prison
Background: Legionella pneumophila (Lp) is the most common etiologic agent causing Legionnaires’ Disease (LD). Water systems offer the best growth conditions for Lp and support its spread by producing aerosols. From 2015 to 2017, the Regional Reference Laboratory of Clinical and Environmental Surveillance of Legionellosis of Palermo monitored the presence of Lp in nine prisons in Western Sicily. During this investigation, we compared Lp isolates from environmental samples in a prison located in Palermo with isolates from two prisoners in the same prison. Methods: We collected 93 water samples from nine Sicilian prisons and the bronchoalveolar lavages (BALs) of two prisoners considered cases of LD. These samples were processed following the procedures described in the Italian Guidelines for the Prevention and Control of Legionellosis of 2015. Then, genotyping was performed on 19 Lp colonies (17 from water samples and 2 from clinical samples) using the Sequence-Based Typing (SBT) method, according to European Study Group for Legionella Infections (ESGLI) protocols. Results: Lp serogroup (sg) 6 was the most prevalent serogroup isolated from the prisons analyzed (40%), followed by Lp sg 1 (16%). Most of all, in four penitentiary institutions, we detected a high concentration of Lp >104 Colony Forming Unit/Liter (CFU/L). The environmental molecular investigation found the following Sequence Types (STs) in Lp sg 6: ST 93, ST 292, ST 461, ST 728, ST 1317 and ST 1362, while most of the isolates in sg 1 belonged to ST 1. We also found a new ST that has since been assigned the number 2451 in the ESGLI-SBT database. From the several Lp sg 1 colonies isolated from the two BALs, we identified ST 2451. Conclusions: In this article, we described the results obtained from environmental and epidemiological investigations of Lp isolated from prisons in Western Sicily. Furthermore, we reported the first cluster of Legionnaires’ in an Italian prison and the molecular typing of Lp sg 1 from one prison’s water system and two BALs, identified the source of the contamination, and discovered a new ST
LE REGIONI D'EUROPA TRA IDENTITĂ€ LOCALI, NUOVE COMUNITĂ€ E DISPARITĂ€ TERRITORIALI
L’Europa è oggi attraversata da una forte domanda di autonomia da parte dei territori: da un lato, a tutela dell’identità delle comunità locali e, dall’altro, per la crescente rivendicazione di una più ampia rappresentanza delle cittadinanze. Queste istanze possono, però, mettere a rischio gli obiettivi di equilibrio e di coesione economica, sociale e territoriale, da sempre al centro della riflessione e delle proposte sviluppate dagli studiosi delle scienze regionali. La recente crisi ha acuito l’instabilità e allargato i complessivi divari tra le regioni, anche nella loro dinamica interna di evoluzione. Alla resilienza economica non sempre è corrisposto, nell’attuale transizione verso un nuovo paradigma, il mantenimento di solidi livelli di coesione sociale e di integrazione tra aree e comunità .
Il volume raccoglie una selezione di contributi presentati alla XXXIX Conferenza Italiana di Scienze Regionali, svoltasi a Bolzano il 17, 18 e 19 settembre 2018. Nella sua articolazione, esso si sviluppa in tre parti. La prima analizza il tema della domanda di autonomia da parte dei territori all’interno dello sviluppo economico e sociale di regioni e paesi, e dell’attuale dibattito sul federalismo differenziato. Nella seconda le riflessioni si estendono alla crescente disparità tra aree centrali e aree periferiche, tra aree interne e aree esposte, tra Nord e Sud dei Paesi e dell’Europa, mentre nella terza parte, l’analisi guarda ai mutevoli equilibri tra territori e sistemi locali urbani e rurali, tra pianura e montagna e, all’interno delle aree montane, tra i fondivalle maggiormente urbanizzati e i territori di alta quota, zone spesso di confine tra province, regioni e stati.
La novità editoriale di quest’anno è rappresentata da uno spazio dedicato a brevi contributi a cura di giovani autori vincitori dei premi AISRe.Europe is today crossed by a strong demand for autonomy from the territories: to protect the identity of local communities and, also analyze the growing demand for a broader representation of citizens. However, these issues can jeopardize the objectives of balance and economic, social and territorial cohesion, which have always been at the center of the reflection and proposals developed by scholars of regional sciences. The recent crisis has worsened instability and widened the overall gaps between the regions, including in their internal dynamics of evolution. Economic resilience is not always matched, in the current transition towards a new paradigm, by maintaining solid levels of social cohesion and integration between areas and communities.
The volume collects a selection of contributions presented at the XXXIX Italian Conference of Regional Science, held in Bolzano on 17, 18 and 19 September 2018. The volume is divided into three parts. The first analyzes the issue of the demand for autonomy by the territories within the economic and social development of regions and countries, and the current debate on differentiated federalism. In the second, the reflections extend to the growing disparity between central and peripheral areas, between internal and exposed areas, between North and South of countries and Europe, while in the third part, the analysis looks at the changing balance between territories and systems. urban and rural areas, between plains and mountains and, within mountain areas, between the most urbanized valleys and high altitude territories, areas often bordering provinces, regions and states.
This year ia space is dedicated to short contributions by young authors who have won the AISRe Awards
LE REGIONI D’EUROPA TRA IDENTITÀ LOCALI, NUOVE COMUNITÀ E DISPARITÀ TERRITORIAL
Europe today is crossed by a strong demand for autonomy from the territories: on the one hand, to protect the identities of local communities and, on the other, for the growing demand for a wider representation of resident citizens. However, these requests can jeopardize the objectives of balance and integration between parts of the territory and between those who live in them, objectives that have always been at the center of reflection and proposals developed in the context of regional sciences. The recent crisis has heightened instability and widened economic and social gaps not only between regions, but also within the regions themselves. The North-South gaps in Italy have further increased and, in a post-crisis phase, this unstoppable process requires ever greater scientific and policy insights in terms of commitment and intervention capacity. If the economic growth of the past decade had found impetus in expanding the spaces of relationships and exchanges, the responses to the threats brought about by the crisis materialized in the closure of borders and in the defense of local levels of well-being. A particular specification of this theme also concerns the relationships between urban and rural territories and local systems, between plains and mountains as well as mountain areas, .
The preface is therefore an acute reflection on issues of urgent relevance for Italy and of great interest for the regional sciences, accepting important scientific and policy challenges
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