A model for vortex formation in magnetic nanodots

We use Monte Carlo simulation to study the vortex nucleation on magnetic nanodots at low temperature. In our simulations, we have considered a simple microscopic two-dimensional anisotropic Heisenberg model with term to describe the anisotropy due to the presence of the nanodot edge. We have considered the thickness of the edge, which was not considered in previous works, introducing a term that controls the energy associated to the edge. Our results clearly show that the thickness of the edge has a considerable influence in the vortex nucleation on magnetic nanodots. We have obtained the hysteresis curve for several values of the surface anisotropy and skin depth parameter ($\xi$). The results are in excellent agreement with experimental data

Biophysical probing of Spartina maritima photo-system II changes during prolonged tidal submersion periods

Submergence is one of the major constrains affecting wetland plants, with inevitable impacts on their physiology and productivity. Global warming as a driving force of sea level rise, tend to increase the submersion periods duration. Photosynthesis biophysical probing arise as an important tool to understand the energetics underlying plant feedback to these constrains. As in previous studies with Spartina maritima, there was no inhibition of photosynthetic activity in submerged individuals. Comparing both donor and acceptor sides of the PSII, the first was more severely affected during submersion, driven by the inactivation of the OEC with consequent impairment of the ETC. Although this apparent damage in the PSII donor side, the electron transport per active reaction centre was not substantially affected, indicating that this reduction in the electron flow is accompanied by a proportional increase in the number of active reaction centres. These conditions lead to the accumulation of excessive reducing power, source of damaging ROS, counteracted by efficient energy dissipation processes and anti-oxidant enzymatic defences. This way, S. maritima appears as a well-adapted species with an evident photochemical plasticity towards submersion, allowing it to maintain its photosynthetic activity even during prolonged submersion periods.The authors would like to thank to the “ Fundação para a Ciência e Tecnologia (FCT)” for funding the research in the Centre of Oceanography (CO) throughout the project PEst-OE/MAR/UI0199/ 2011, the Institute of Marine Research (IMAR) throughout the project PEst-C/MAR/UI0284/2011 and this specific work throughout the ECOSAM project (PTDC/AAC-CLI/104085/2008). B. Duarte investigationwas supported by FCT throughout a PhD grant (SFRH/BD/75951/2011)

Development and validation of a multiplex-PCR assay for X-linked intellectual disability

BACKGROUND: X-linked intellectual disability is a common cause of inherited cognitive deficit affecting mostly males. There are several genetic causes implicated in this condition, which has hampered the establishment of an accurate diagnosis. We developed a multiplex-PCR assay for the mutational hotspot regions of the FMR1, AFF2 and ARX genes. METHODS: The multiplex-PCR was validated in a cohort of 100 males selected to include known alleles for the FMR1 repetitive region: five full mutations (250-650 CGGs), ten premutations (70-165 CGGs) and eighty-five in the normal range (19-42 CGGs). Sequencing or Southern blotting was used to confirm the results, depending on the allele class. In this cohort, with the exception of one sample showing an AFF2 intermediate-sized allele, all other samples were normal (8-34 CCGs). No ARX variant was found besides the c.429_452dup. The validated assay was applied to 5000 samples (64.4% males and 35.6% females). RESULTS: The normal-allelic range of both FMR1 and AFF2 genes as well as the nature of ARX variants identified was similar in both genders. The rate of homozygosity observed in female samples, 27.5% for FMR1 and 17.8% for AFF2 alleles, is comparable to that published by others. Two FMR1 premutations were identified, in a male (58 CGGs) and a female case [(CGG)(47)/(CGG)(61)], as well as several FMR1 or AFF2 intermediate-sized alleles. One AFF2 premutation (68 CCGs) and two putative full expansions were picked up in male subjects, which seems relevant considering the rarity of reported AFF2 mutations found in the absence of a family history. CONCLUSIONS: We developed a robust multiplex-PCR that can be used to screen the mutational hotspot regions of FMR1, AFF2 and ARX genes. Moreover, this strategy led to the identification of variants in all three genes, representing not only an improvement in allele-sizing but also in achieving a differential diagnosis. Although the distinction between females who are truly homozygous and those with a second pre- or full mutation sized allele, as well as a definitive diagnosis, requires a specific downstream technique, the use of this multiplex-PCR for initial screening is a cost-effective approach which widens the scope of detection

Chemical changes of heat treated pine and eucalypt wood monitored by FTIR

A hardwood, Eucalyptus globulus Labill., and a softwood Pinus pinaster Aiton., were heat treated at temperatures between 170 and 210ºC in an oven and in an autoclave. The samples were pre-extracted with dichloromethane, ethanol and water and ground prior to Fourier Transform Infrared (FTIR) spectroscopic analysis. The heat treatment caused significant changes in the chemical composition and structure of wood, in lignin and polysaccharides. Hemicelluloses were the first to degrade as proved by the initial decrease of the 1730 cm-1 peak due to the breaking of acetyl groups in xylan. Hardwood lignin changed more than softwood lignin, with a shift of maximum absorption from 1505 cm-1 to approximately 1512 cm-1 due to decrease of methoxyl groups, loss of syringyl units or breaking of aliphatic side-chains. The macromolecular structure becomes more condensed and there is a clear increase of non-conjugated (1740 cm-1) in relation to conjugated groups (1650 cm-1). However, the changes induced by the thermal treatment are difficult to monitor by FTIR spectroscopy due to the different chemical reactions occurring simultaneously.info:eu-repo/semantics/publishedVersio

Food Insecurity Levels among University Students: A Cross-Sectional Study

Background: University students may be vulnerable to food insecurity (FI) due to limited financial resources, lower purchasing power, and increasing housing and food costs. This study aimed to assess the prevalence and severity of FI and its associated factors among university students attending a public Portuguese university. Methods: A cross-sectional survey was designed, and data were collected using a self-reported online questionnaire validated for the Portuguese population. The study population included students from all levels of study and the assessments were conducted during the winter semester (December 2021 to February 2022). Chi-square tests were used to determine the associations between FI and sociodemographic variables. Bivariate logistic regression was further used to assess factors associated with FI. Results: From the 284 participants, 17.3% of students were classified as food insecure, consisting of 14.1% with mild FI, 2.1% with moderate FI, and 1.1% with severe FI. FI was significantly associated with nationality (p = 0.028) and the number of unemployed household members (p = 0.001). In comparison to Portuguese students, students of other nationalities were 4.1 times more likely to be food insecure (OR = 4.089, 95% CI:1.057–15.821, p = 0.041). Students in households with a higher number of members (OR = 2.537, 95% CI:1.231–5.230, p = 0.012) and a higher number of unemployed members (OR = 3.192, 95% CI:1.681–6.059, p < 0.001) were also 2.5 and 3.1 times more likely, respectively, to be food insecure. Conclusions: This study provides an insight into the FI levels of university students in a Portuguese university. Further future studies are needed to use objective measures of food insecurity (availability, access, and utilization of food) and explore interventions addressing food insecurity in this population. © 2022 by the authors.The CECAV is supported by FCT/UIDB/CVT/00772/2020. The CITAB is supported by FCT/UIDB/04033/2020

Manejo de sistemas de produção de centeio visando a produção de forragem e de sementes para a agricultura familiar.

bitstream/item/78978/1/documento-319.pd

Phase transition of a two dimensional binary spreading model

We investigated the phase transition behavior of a binary spreading process in two dimensions for different particle diffusion strengths ($D$). We found that $N>2$ cluster mean-field approximations must be considered to get consistent singular behavior. The $N=3,4$ approximations result in a continuous phase transition belonging to a single universality class along the $D\in (0,1)$ phase transition line. Large scale simulations of the particle density confirmed mean-field scaling behavior with logarithmic corrections. This is interpreted as numerical evidence supporting that the upper critical dimension in this model is $d_c=2$.The pair density scales in a similar way but with an additional logarithmic factor to the order parameter. At the D=0 endpoint of the transition line we found DP criticality.Comment: 8 pages, 10 figure

The first Frontier Fields cluster: 4.5{\mu}m excess in a z~8 galaxy candidate in Abell 2744

We present in this letter the first analysis of a z~8 galaxy candidate found in the Hubble and Spitzer imaging data of Abell 2744, as part of the Hubble Frontier Fields legacy program. We applied the most commonly-used methods to select exceptionally high-z galaxies by combining non-detection and color-criteria using seven HST bands. We used GALFIT on IRAC images for fitting and subtracting contamination of bright nearby sources. The physical properties have been inferred from SED-fitting using templates with and without nebular emission. This letter is focussed on the brightest candidate we found (m$_{F160W}$=26.2) over the 4.9 arcmin$^2$ field of view covered by the WFC3. It shows a non-detection in the ACS bands and at 3.6{\mu}m whereas it is clearly detected at 4.5{\mu}m with rather similar depths. This break in the IRAC data could be explained by strong [OIII]+H{\beta} lines at z~8 which contribute to the 4.5{\mu}m photometry. The best photo-z is found at z~8.0$^{+0.2}_{-0.5}$, although solutions at low-redshift (z~1.9) cannot be completely excluded, but they are strongly disfavoured by the SED-fitting work. The amplification factor is relatively small at {\mu}=1.49$\pm$0.02. The Star Formation Rate in this object is ranging from 8 to 60 Mo/yr, the stellar mass is in the order of M$_{\star}$=(2.5-10) x 10$^{9}$Mo and the size is r~0.35$\pm$0.15 kpc. This object is one of the first z~8 LBG candidates showing a clear break between 3.6{\mu}m and 4.5{\mu}m which is consistent with the IRAC properties of the first spectroscopically confirmed galaxy at a similar redshift. Due to its brightness, the redshift of this object could potentially be confirmed by near infrared spectroscopy with current 8-10m telescopes. The nature of this candidate will be revealed in the coming months with the arrival of new ACS and Spitzer data, increasing the depth at optical and near-IR wavelengths.Comment: 4 pages, 2 figures, Accepted for publication in Astronomy and Astrophysics Letter