1,824 research outputs found
Scaling theory of DNA confined in nanochannels and nanoslits
A scaling analysis is presented of the statistics of long DNA confined in
nanochannels and nanoslits. It is argued that there are several regimes in
between the de Gennes and Odijk limits introduced long ago. The DNA chain folds
back on itself giving rise to a global persistence length which may be very
large owing to entropic deflection. Moreover, there is an orientational
excluded-volume effect between the DNA segments imposed solely by the
nanoconfinement. These two effects cause the chain statistics to be intricate
leading to nontrivial power laws for the chain extension in the intermediate
regimes. It is stressed that DNA confinement within nanochannels differs from
that in nanoslits because the respective orientational excluded-volume effects
are not the same.Comment: 5 pages, 1 figure Several corrections, some minor changes in the text
and replacement of one referenc
The Role of Common Agricultural Policy in the Landscape Evolution: the Case Study of Val d'Orcia (Siena, Italy)
In the last years there is growing debate between agricultural economists on the role of agriculture to product positive ad negative externalities. The externalities are defined as pubblic goods or no-commodity outputs (Marangon, 2006; Daugstad et al., 2006; OECD, 2001; Brunori et al., 2006) and they need of specific regulation. In rural areas landscape is a typical example of externality because it is the result of agricultural activity and it changes with the agricultural change. At same time, landscape in specific territorial contexts can assume historic, cultural, social and economic value, so that it could become a strategic resource for local development politics (Brunori et al, 2006).
The decupling and cross-compliance introduced by the new Common Agricultural Policy (CAP) and the increasing demand of environmental goods by citizen/consumers are elements of novelty that will modify farms in next years. In particular, CAP reform could lead to farm externalisation of activity or suspension of business in many rural areas with important socio-economic and environmental impacts as, for example, on landscape.
In Val dâOrcia, as in other Tuscany rural areas, landscape assumes the role of economic resource because it attracts tourists and is utilised to promote the territory (landscape as a âbusiness cardâ). This is in connection with the rural configuration of the landscape and the high concentration of architectonic and artistic goods. To remember, for example, the UNESCO recognition in 2004 as âVal dâOrcia cultural landscapeâ. At same time, if this landscape is an important points of strength of the local economy, it shows also environmental fragility (biodiversity reduction, soli erosion, etc.) that they need specific actions.
In agreement with art.1 of European Landscape Convention (European Council, 2000) where is affirmed that âLandscape means an area, as perceived by people, whose character is the result of the action and interaction of natural and/or human factorsâ, this work shows the results of a survey developed in Val dâOrcia with this objectives:
âą to identify the driving forces that have leaded to the current landscape in Val dâOrcia to start to 1970th;
âą to try to define the possible landscape evolution in relationship with the novelty introduced by the CAP reform;
âą to suggest specific actions to drive the landscape evolution in the direction of a âsustainable rural landscapeâ where landscape is an element to strengthen the identity of local rural community, to promote local sustainable development and to safeguard environmental resources in their complex (European Council, 2000)
Rapid review on covid-19, work-related aspects, and age differences
The COVID-19 pandemic significantly impacted the labor market and multiple aspects of work and workersâ life. The present rapid review analyzes this impact considering the effects that COVID-19 pandemic had on employment and work-related aspects across different age groups. A comprehensive literature search was performed on scientific contributions published between 2019 and March 2021, resulting in 36 papers pertinent to the scope of this review. Findings were grouped according to different topics, all linked to age: occupational risk, implications on the labor market (i.e., job loss and reemployment, job insecurity, turnover intentions and retirement, and healthcare workersâ return-to-work phase), remote work, and key individual and organizational resources and strategies. Overall, the review revealed variability across age groups in the impact this pandemic had on employment and several work-related aspects (i.e., occupational risk, remote work). Findings supported an age-differential effect of normative history-graded events such as the current pandemic, highlighting different responses and consequences depending on workersâ age
Changes in insulin sensitivity in response to different modalities of exercise: a review of the evidence
Summary: Type 2 diabetes is an increasingly prevalent condition with complications including blindness and kidney failure. Evidence suggests that type 2 diabetes is associated with a sedentary lifestyle, with physical activity demonstrated to increase glucose uptake and improve glycaemic control. Proposed mechanisms for these effects include the maintenance and improvement of insulin sensitivity via increased glucose transporter type four production. The optimal mode, frequency, intensity and duration of exercise for the improvement of insulin sensitivity are however yet to be identified. We review the evidence from 34 published studies addressing the effects on glycaemic control and insulin sensitivity of aerobic exercise, resistance training and both combined. Effect sizes and confidence intervals are reported for each intervention and meta-analysis presented. The quality of the evidence is tentatively graded, and recommendations for best practice proposed
James Lind Alliance research priorities:Should diet and exercise be used as an alternative to drugs for the management of Type 2 diabetes or alongside them?
Experimental and Computational Study of the New Gaseous Molecules OMnF and OMnF[Sub 2]
The new gaseous species OMnF and OMnF2 were identified and studied by high-temperature Knudsen Cell Mass Spectrometry. Their thermochemical atomization energies were derived through the study of several all-gas equilibria in the temperature range 1735â1913 K. FTIR matrix isolation experiments together with ab initio and density functional calculations were performed to determine the molecular parameters, bond distances, and vibrational frequencies of OMnF(g) and OMnF2(g) . The results allowed us to evaluate a set of thermal functions for the new species that were used in the evaluation of the equilibrium data. The proposed atomization energies and enthalpies of formation are DaH0 + (OMnF,g)5(90365) kJ mol21, DfH298.15 + (OMnF,g)5(229765) kJ mol21, and DaH0 + (OMnF2 ,g)5(1470670) kJ mol21, DfH298.15 + (OMnF2 ,g)5(2789670) kJ mol21
Age Diversity Climate Affecting IndividualâLevel WorkâRelated Outcomes
The present study answers the call for more studies to investigate the age diversity climateâs effect on individualâlevel outcomes. Building on the social identity approach and social exchange theory, we surveyed 110 Italian employees aged between 18 and 61 years old (M = 46.10, SD = 10.02) and investigated the role of age diversity climate in predicting intentions to quit (H1), jobârelated wellbeing (H2), and work engagement (H3). Our findings confirmed the hypotheses (H1 and H2), showing the added effect of age diversity climate over and above age, job tenure, role clarity, job demands, job control, perceived support, and perceived job and organizational fit. In fact, age diversity climate accounted for a significant increase in the variance explained for two of the three hypothesized models (i.e., intentions to quit and jobârelated wellbeing, but not work engagement). To conclude, this study contributes to the existing literature by showing the age diversity climateâs predictive value for turnover intentions and jobârelated wellbeing, and corroborating the importance of supporting age diversity through a variety of Human Resources Management strategies
Emulsion polymerizations for a sustainable preparation of efficient TEMPOâbased electrodes
Organic polymerâbased batteries represent a promising alternative to presentâday metalâbased systems and a valuable step toward printable and customizable energy storage devices. However, most scientific work is focussed on the development of new redoxâactive organic materials, while straightforward manufacturing and sustainable materials and production will be a necessary key for the transformation to mass market applications. Here, a new synthetic approach for 2,2,6,6âtetramethylâ4âpiperinidylâ N âoxyl (TEMPO)âbased polymer particles by emulsion polymerization and their electrochemical investigation are reported. The developed emulsion polymerization protocol based on an aqueous reaction medium allowed the sustainable synthesis of a redoxâactive electrode material, combined with simple variation of the polymer particle size, which enabled the preparation of nanoparticles from 35 to 138â
nm. Their application in cell experiments revealed a significant effect of the size of the activeâpolymer particles on the performance of poly(2,2,6,6âtetramethylâ4âpiperinidylâ N âoxyl methacrylate) (PTMA)âbased electrodes. In particular rate capabilities were found to be reduced with larger diameters. Nevertheless, all cells based on the different particles revealed the ability to recover from temporary capacity loss due to application of very high charge/discharge rates.Sustainable and efficient organic electrode : A new synthetic approach for polymers for organic batteries includes an emulsion polymerization with adjustable particle sizes in aqueous dispersions and allows the sustainable manufacturing of active materials and composite electrodes. The electrochemical investigation shows that the influence of particle sizes and the resulting morphologies of composite films on the cell performance is as important as the active material itself
Impact of 3-Cyanopropionic Acid Methyl Ester on the Electrochemical Performance of ZnMnâOâ as Negative Electrode for Li-Ion Batteries
Due to their high theoretical capacity, transition metal oxide compounds are promising electrode materials for lithium-ion batteries. However, one drawback is associated with relevant capacity fluctuations during cycling, widely observed in the literature. Such strong capacity variation can result in practical problems when positive and negative electrode materials have to be matched in a full cell. Herein, the study of ZnMn2O4 (ZMO) in a nonconventional electrolyte based on 3-cyanopropionic acid methyl ester (CPAME) solvent and LiPF6 salt is reported for the first time. Although ZMO in LiPF6/CPAME electrolyte displays a dramatic capacity decay during the first cycles, it shows promising cycling ability and a suppressed capacity fluctuation when vinylene carbonate (VC) is used as an additive to the CPAME-based electrolyte. To understand the nature of the solid electrolyte interphase (SEI), the electrochemical study is correlated to ex situ X-ray photoelectron spectroscopy (XPS)
Clinical, magnetic resonance imaging, and histopathologic features of a hypoglossal malignant peripheral nerve sheath tumor in a maltese dog
Malignant tumours arising from peripheral nerves or displaying differentiation along the lines of the various elements of the nerve sheath are collectively referred to as MPNSTs. Histologically, in human MPNST, the malignant nature of these tumours is associated with an infiltrative and cellular proliferation of atypical, mitotically active spindle cells. Their predilection for sites varies with the species. In dogs the most common site for MPNST is the nerve roots or nerves of the brachial plexus, while the cranial nerve more frequently involved is the trigeminal nerve. In humans, hypoglossal peripheral nerve sheath tumours are rare, only few cases are described in literature; and the malignant forms are even exceptional. Fifty per cent of cases displayed both an intra- and extracrania component, and are referred as dumbbell-shaped tumours. To our knowledge this is the first case report an hypoglossal MPNST in a dog. In our case the tumour was dumbbell-shaped, with both intra-and extracranial components and associated with characteristic clinical signs of hypoglossal tumour. The malignant histological appearance of the lesion occurred without infiltrative growth
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