Le rôle de la relation conjugale dans l’abus et la négligence d’enfants : vers une étude écologique

Le phénomène de Tabus et de la négligence d'enfants a toujours été répandu dans la société occidentale. Or, ce n'est que récemment que cliniciens et chercheurs se sont sérieusement penchés sur ces problèmes. Cet intérêt, sans cesse grandissant, a été suscité non seulement par le nombre impressionnant de cas signalés chaque année, mais encore par l'ampleur et la gravité des conséquences observables chez les enfants. Plusieurs professionnels intéresses par cette question ont proposé une multitude de facteurs étiologiques pour expliquer les abus et la négligence au sein d'une famille. Cependant, lorsque nous évaluons les modèles théoriques offerts (psychiatrique/psychologique, sociologique, systémique), il ressort que certains facteurs simples peuvent jouer un rôle important, comme par exemple l'histoire du développement des parents, la qualité de la relation conjugale, la relation parents-enfant, le stress et l'étendue du réseau social, mais aucun d'entre eux ne différencie parfaitement les familles abusives des familles non abusives. Il semble toutefois que ces différents facteurs explicatifs présenteraient une grande valeur s ' ils étaient considérés en interaction plutôt qu'individuellement. S'inspirant du cadre écologique de Bronfenbrenner (1977, 1979), Belsky (1980, 1984) ainsi que Cicchetti et Rizley (1981) ont d'ailleurs élaboré un modèle qui tient compte simultanément de tous ces facteurs et de leur interaction.The phenomenon of child abuse and neglect has always existed in Western society. Yet, it is only recently that clinicians and researchers have taken a serious look at these problems. This ever growing interest has come about from not only the stunning number of cases identified each year, but also by the extent and gravity of consequences observed among children. Several professionals interested by the issue have put forward a great number of etiological factors to try to explain abuse and neglect within the family unit. However, when assessing the proposed theoretical models (psychiatric/psychological, sociological, systemic), it appears that certain simple factors can play a large role, for instance the history behind parental development, the quality of marital relations, the child-parent relation, the stress and the extent of the social network, but none of these can clearly differentiate abusive families from non abusive families. It seems however that these different explicative factors would be even more valuable if they were considered in interaction rather than taken individually. Inspired by the ecological framework proposed by Bronfenbrenner (1977, 1979), Belsky (1980, 1984) as well as Cicchetti and Rizley (1981) have also developed a model that simultaneously takes into account all of these factors and their interaction

Reactivity ratio estimation for co- and terpolymerization of n-butyl acrylate, methyl methacrylate and 2-ethylhexyl acrylate

N-butyl acrylate (BA), 2-ethylhexyl acrylate (EHA) and methyl methacrylate (MMA) are commonly used as monomers in coatings, adhesives and many other applications. Our current interest is in BA/MMA/EHA terpolymer formulations for the production of pressure sensitive adhesives. For the purposes of controlling polymer adhesive performance, kinetic parameters such as the reactivity ratios, are required. Reactivity ratios for BA/MMA are available in the literature1, while that for BA/EHA and MMA/EHA are not. The bulk copolymerization reactivity ratios for BA/EHA and MMA/EHA were determined at 60 C using statistically designed free-radical polymerizations at low-conversion (\u3c10%). The estimates were then validated using high-conversion copolymerizations. These reactivity ratio estimates were used, along with the literature values for the BA/MMA system, for the prediction of BA/MMA/EHA composition in a series of high conversion bulk terpolymerizations. Please click Additional Files below to see the full abstract

The effect of cellulose nanocrystals on latex and adhesive properties in emulsion- based polymer nanocomposites

Pressure sensitive adhesives (PSAs) adhere quickly and firmly to surfaces with the application of light pressure, and can be removed without leaving a residue. Their mechanical performance is measured by tack, peel strength and shear strength. A balanced combination between the three mechanical performance measurements depends on the specific end-use application and is challenging to achieve. This is particularly so when replacing solvent-based technologies with more sustainable, water-based (i.e., emulsion polymerization) technologies. PSAs synthesized using emulsion polymerization tend to have a lower shear strength due to poor gel network formation. As a result, conventional emulsion-based PSAs suffer from the inability to increase certain adhesive properties (e.g., tack and peel strength) while simultaneously increasing shear strength. Nanomaterials are often used in polymer composites to improve polymer properties (e.g., tensile strength). They are particularly effective in low quantities (e.g., \u3c2 \u3ewt.%) because of their high surface area. Cellulose nanocrystals (CNCs) are a “green alternative” to common nanomaterials and are isolated from natural cellulose. CNCs have been used more commonly, in the past, as rheological modifiers and interface stabilizers.[1] Because CNCs form colloidally stable dispersions in water, they can be incorporated/processed in water-based systems, eliminating the need for organic solvents.[2] The most common method to produce CNCs is through acid hydrolysis with sulfuric acid; this process preferentially degrades the disordered cellulose regions and leaves behind the crystalline CNCs with grafted anionic sulfate half ester groups.[1] The resulting nanoparticles are whisker-shaped and have a high aspect ratio.[3] CNCs provide composite material reinforcement in the range of other nanomaterials. In the past, CNCs have been blended with polymers and significant strength improvements were noted.[4] Our studies demonstrate how to incorporate CNCs in a nanocomposite using an in situ semi-batch emulsion polymerization protocol.[5] PSA nanocomposite films were generated for a broad variety of copolymer systems including monomers such as iso-butyl acrylate, n-butyl acrylate, 2-ethyl hexyl acrylate, methyl methacrylate, styrene and vinyl acetate. In all cases, the monomer composition of the reaction formulations was manipulated to achieve a suitable range of polymer glass transition temperatures. CNC loadings were varied from 0 to 0.5 to 1 wt.% (based on monomer weight). The addition of CNC was shown to significantly and simultaneously increase tack, peel strength, and shear strength.[6] References [1] Dufresne, A., Nanocellulose, De Gruyter, Saint Martin D’Heres Cedex, France 2012. [2] Flauzino Neto, W. P., Mariano, M., da Silva, I. S. V., Silvério, H. A., Putaux, J.-L., Otaguro, H., Pasquini, D., Dufresne, A., Carbohydr. Polym. 2016, 153, 143. [3] Moon, R. J., Martini, A., Nairn, J., Simonsen, J., Youngblood, J., Chem. Soc. Rev., 2011, 40, 3941. [4] Rajisha, K. R., Maria, H. J., Pothan, L. A., Ahmad, Z., Thomas, S., Int. J. Biol. Macromol., 2014, 67, 147. [5] Dastjerdi, Z., Cranston, E. D., Dubé, M. A., Macromol. React. Eng., 2018, in press. [6] Dastjerdi, Z., Cranston, E. D., Dubé, M. A., Int. J. Adh. Adh. 2018, 81, 36-42

Pressure sensitive adhesives produced by in-situ emulsion polymerization of cellulose nanocrystal-poly(nBA-VAc)

Pressure sensitive adhesives (PSAs) are conventionally produced using a variety of polymerization methods such as emulsion, solution, or radiation curing. Environmental concerns favor the development of emulsion polymerization based PSAs.[1] However, maintaining and controlling the PSA properties achievable from solution polymerization in PSAs produced by emulsion polymerization remains challenging. Depending on the particular adhesive application, PSA properties are largely guided by the polymer glass transition temperature and the polymer microstructure. The latter is controlled in a variety of ways but typically via the addition of chain transfer agents and crosslinkers.[2] During the last decades, efforts in PSA property manipulation have included the preparation of nanocomposite latexes by introducing nanomaterials such as titanium dioxide, silica, and carbon nanotubes into the formulations.[3] On the other hand, utilizing cellulose nanocrystals (CNCs) as a sustainable source of reinforcement in polymers is emerging rapidly.[4] CNCs are the product of controlled hydrolysis of plant based tissues, through which crystalline domains of cellulose are isolated from the disordered parts of the raw material. High aspect ratio, surface activity and modulus, as well as non-toxic nature of CNCs make them ideal candidates for use in nanocomposite formulations. More recently, our group have prepared CNC nanocomposite PSAs which were revealed to significantly and simultaneously improve tack, peel strength and shear strength in the PSA films.[5] The ability to improve tack and peel strength without decreasing shear strength overcomes a major challenge in PSA formulation. We will present results from emulsion polymerization of n-butyl acrylate/vinyl acetate/CNC nanocomposite PSAs. We will identify the location of the CNCs relative to the latex particles and show their effect on latex viscosity, gel content, and PSA properties. The goal of these new results is to show how the manipulation of the reaction formulation (e.g., monomer feed ratio, surfactant type) will affect the distribution and relative location of the CNCs in the polymer latex and ultimately the PSA properties. [1] Jovanović, R., Dubé, M. A., J. Macromol. Sci., Part C, 44:1, 1-51, 2004. [2] Qie, L., Dubé, M. A., 46, 1225–1236, 2010. [3] Dastjerdi, Z., Cranston, E. D., Berry, R. Fraschini, C., Dubé, M. A., J. Matls. Sci., submitted January 2018. [4] Lee, K-Y., Aitomäki, Y., Berglund, L. A., Oksman, K., Bismarck, A., Compos. Sci. Technol. 105, 15–27, 2014. [5] Dastjerdi, Z., Cranston, E. D., Dubé, M. A., Macromol. React. Eng., 11, 1700013, 2017. [6] Dastjerdi, Z., Cranston, E. D., Dubé, M. A., Int. J. Adh. Adh., 81, 36-42, 201

A new cavity ring-down instrument for airborne monitoring of N2O5, NO3, NO2 and O3 in the upper troposphere lower stratosphere

A new airborne instrument based on pulsed cavity ring-down spectroscopy for simultaneous detection of N2O5, NO3, NO2 and O3 in the upper troposphere lower stratosphere is being developed for global atmospheric monitoring. OCIS codes: 010.0010, 120.0120, 140.0140, 280.0280, 300.0300, 300.6260, 300.6360

Paternal age explains a major portion of de novo germline mutation rate variability in healthy individuals

De novo mutations (DNM) are an important source of rare variants and are increasingly being linked to the development of many diseases. Recently, the paternal age effect has been the focus of a number of studies that attempt to explain the observation that increasing paternal age increases the risk for a number of diseases. Using disease-free familial quartets we show that there is a strong positive correlation between paternal age and germline DNM in healthy subjects. We also observed that germline CNVs do not follow the same trend, suggesting a different mechanism. Finally, we observed that DNM were not evenly distributed across the genome, which adds support to the existence of DNM hotspots

Le Forum, Vol. 44 #4

https://digitalcommons.library.umaine.edu/francoamericain_forum/1106/thumbnail.jp

F.A.R.O.G. FORUM, Vol. 6 No. 4

https://digitalcommons.library.umaine.edu/francoamericain_forum/1065/thumbnail.jp

Sexual attraction, sexual identity, and psychosocial well-being in a national sample of young women during emerging adulthood.

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106627/1/Sexual attraction, sexual identity, and psychosocial well-being in a national sample of young women during emerging adulthood.pd