Spreading Patterns of the Influenza A (H1N1) Pandemic

We investigate the dynamics of the 2009 influenza A (H1N1/S-OIV) pandemic by analyzing data obtained from World Health Organization containing the total number of laboratory-confirmed cases of infections - by country - in a period of 69 days, from 26 April to 3 July, 2009. Specifically, we find evidence of exponential growth in the total number of confirmed cases and linear growth in the number of countries with confirmed cases. We also find that, i) at early stages, the cumulative distribution of cases among countries exhibits linear behavior on log-log scale, being well approximated by a power law decay; ii) for larger times, the cumulative distribution presents a systematic curvature on log-log scale, indicating a gradual change to lognormal behavior. Finally, we compare these empirical findings with the predictions of a simple stochastic model. Our results could help to select more realistic models of the dynamics of influenza-type pandemics

Liver trauma: WSES 2020 guidelines

Abstract: Liver injuries represent one of the most frequent life-threatening injuries in trauma patients. In determining the optimal management strategy, the anatomic injury, the hemodynamic status, and the associated injuries should be taken into consideration. Liver trauma approach may require non-operative or operative management with the intent to restore the homeostasis and the normal physiology. The management of liver trauma should be multidisciplinary including trauma surgeons, interventional radiologists, and emergency and ICU physicians. The aim of this paper is to present the World Society of Emergency Surgery (WSES) liver trauma management guidelines

Applying the angular spectrum representation to calculate the optical force density generated in dielectrics by tightly focused laser beams

The Angular Spectrum Representation (ASR) is applied to describe semi-analytically the optical force densities acting on linear dielectric media when a quasi-monochromatic tightly focused Gaussian beam is applied. This method is seen to be inherently faster than conventional finite-difference schemes. Numerical simulations of the optical force densities were also performed and found to be in agreement with the literature, providing a complementary tool for the study of opto-mechanical effects in matter

On the formulations of the electromagnetic stress–energy tensor

In this work, we review the main existing theories for the electromagnetic stress-energy tensor in dielectric media - a problem directly related to the century-long debate regarding the correct momentum of light in dielectric media, known as Abraham-Minkowski controversy. The theoretical validity of the main existing formulations is analyzed in terms of symmetry and invariance requirements for the tensors. We also present position- and time-dependent numerical simulations of the related electromagnetic forces for a lossless nondispersive medium, highlighting the different expected spatial force distributions. The force densities of different formulations drive forward different momentum and atomic number density distributions of the medium contributing to the total momentum and energy densities associated with the coupled field-medium state of light.Peer reviewe

Lasersko povzročen termoelastični pomik površine v trdnih snoveh zaznan hkrati s fototermalnim zrcalom in interferometrijo

We propose a combined pump-probe optical method to investigate heat diffusion properties of solids. We demonstrate single-shot simultaneous laser-induced thermoelastic surface displacement of metals detected by concurrent measurements using photothermal mirror and interferometry. Both methods probe the surface displacement by analyzing the wavefront distortions of the probe beams reflected from the surface of the sample. Thermoelastic properties are retrieved by transient analysis in combination with numerical description of the thermoelastic displacement and temperature rise in the sample and in the surrounding air. This technique presents a capability for material characterization that can be extended to experiments for quantitative surface mapping.Predlagamo združitev dveh optičnih metod za raziskavo toplotnih difuzijskih lastnosti trdnih snovi. Z uporabo fototermalnega zrcala in interferometrije lahko istočasno zaznamo lasersko induciran termoelastični pomik površine kovin. Obe metodi merita pomik površine preko analize spremembe valovne fronte sondirnega svetlobnega žarka odbitega s površine vzorca. Termoelastične lastnosti dobimo s primerjavo med meritvami in numeričnim opisom termoelastičnega pomika ter dviga temperature v vzorcu in v okoliškem zraku. To tehniko lahko uporabimo za karakterizacijo materialov in jo lahko nadgradimo za kvantitativno določanje reliefa površin

Spectroscopic investigation and heat generation of Yb3+/Ho3+ codoped aluminosilicate glasses looking for the emission at 2 μm

Energy transfer (ET) and heat generation processes in Yb3+/Ho3+-codoped low-silica calcium aluminosilicate glasses were investigated using thermal lens (TL) and photoluminescence measurements looking for the emission around 2.0 μm. Stepwise ET processes from Yb3+ to Ho3+, upon excitation at 0.976 μm, produced highly efficient emission in the mid-infrared range at around 2.0 μm, with high fluorescence quantum efficiency (η1 ∼ 0.85 and independent of Ho3+ concentration) and relatively very low thermal loading (<0.4) for concentration up to 1.5% of Ho2O3. An equation was deduced for the description of the TL results that provided the absolute value of η1 and the number of emitted photons at 2.0 μm per absorbed pump photon by the Yb3+ ions, the latter reaching 60% for the highest Ho3+ concentration. These results suggest that the studied codoped system would be a promising candidate for the construction of photonic devices, especially for medical applications.PRONEX/FAPEAL (2009-09-006)FINEPCNPqInstituto Nacional de Ciência e Tecnologia de NanoBioEstruturas & Simulação NanoBioMolecular (INCT NANO(BIO)SIMES)CAPES (02727/09-9)Fundação AraucáriaCAPES / COFECU

Vloga elektrostrikcije pri tvorbi akustičnih valov z optičnimi silami v vodi

We present semi-analytical solutions describing the spatiotemporal distributions of temperature and pressure inside low-absorbing dielectrics excited by tightly focused laser beams. These solutions are compared to measurements in water associated with variations of the local refractive index due to acoustic waves generated by electrostriction, heat deposition, and the Kerr effect at different temperatures. The experimental results exhibited an excellent agreement with the modeling predictions, with electrostriction being the dominant transient effect in the acoustic wave generation. Measurements at show that the thermoelastic contribution to the optical signal is significantly reduced due to the low thermal expansion coefficient of water at this temperature.Predstavljamo pol-analitične rešitve, ki opisujejo prostorsko-časovne porazdelitve temperature in tlaka znotraj dielektrikov z nizko absorpcijo, ki jih vzbujamo s tesno fokusirani laserski žarki. Te rešitve primerjamo pri različnih temperaturah z meritvami v vodi, ki so povezane s spremembami lokalnega lomnega količnika kot posledica preleta akustičnih valov, ki nastanejo z elektrostrikcijo in z odlaganjem toplote ter s Kerrovim učinkom. Eksperimentalni rezultati so pokazali odlično skladnost z napovedmi modeliranja, pri čemer je bila elektrostrikcija prevladujoč prehodni učinek pri ustvarjanju akustičnih valov. Meritve pri 4,0 °C kažejo, da je termoelastični prispevek k optičnemu signalu znatno oslabljen zaradi nizkega toplotnega razteznega koeficienta vode pri tej temperaturi

Photo-Phytotherapeutic Gel Composed of Copaifera reticulata, Chlorophylls, and k-Carrageenan: A New Perspective for Topical Healing

Chronic wound healing represents an impactful financial burden on healthcare systems. In this context, the use of natural products as an alternative therapy reduces costs and maintains effectiveness. Phytotherapeutic gels applied in photodynamic therapy (PDT) have been developed to act as topical healing medicines and antibiotics. The bioactive system is composed of Spirulina sp. (source of chlorophylls) and Copaifera reticulata oil microdroplets, both incorporated into a polymeric blend constituted by kappa-carrageenan (k-car) and F127 copolymer, constituting a system in which all components are bioactive agents. The flow behavior and viscoelasticity of the formulations were investigated. The photodynamic activity was accessed from studies of the inactivation of Staphylococcus aureus bacteria, the main pathogen of hospital relevance. Furthermore, in vivo studies were conducted using eighteen rabbits with dermatitis (grade III and IV) in both paws. The gels showed significant antibiotic potential in vitro, eliminating up to 100% of S. aureus colonies in the presence or absence of light. The k-car reduced 41% of the viable cells; however, its benefits were enhanced by adding chlorophyll and copaiba oil. The animals treated with the phytotherapeutic medicine showed a reduction in lesion size, with healing and re-epithelialization verified in the histological analyses. The animals submitted to PDT displayed noticeable improvement, indicating this therapy&rsquo;s viability for ulcerative and infected wounds. This behavior was not observed in the iodine control treatment, which worsened the animals&rsquo; condition. Therefore, gel formulations were a viable alternative for future pharmaceutical applications, aiming at topical healing