6,429 research outputs found
Analysis of Self-Organized Criticality in the Olami-Feder-Christensen model and in real earthquakes
We perform a new analysis on the dissipative Olami-Feder-Christensen model on
a small world topology considering avalanche size differences. We show that
when criticality appears the Probability Density Functions (PDFs) for the
avalanche size differences at different times have fat tails with a q-Gaussian
shape. This behaviour does not depend on the time interval adopted and is found
also when considering energy differences between real earthquakes. Such a
result can be analytically understood if the sizes (released energies) of the
avalanches (earthquakes) have no correlations. Our findings support the
hypothesis that a self-organized criticality mechanism with long-range
interactions is at the origin of seismic events and indicate that it is not
possible to predict the magnitude of the next earthquake knowing those of the
previous ones.Comment: 5 pages, 3 figures. New version accepted for publication on PRE Rapid
Communication
The Star Formation History of NGC 1705: a Post-Starburst Galaxy on the Verge of Activity
We infer the star formation history in different regions of the blue compact
dwarf NGC 1705 by comparing synthetic color-magnitude diagrams with HST optical
and near-infrared photometry. We find that NGC 1705 is not a young galaxy
because its star formation commenced at least 5 Gyr ago. On the other hand, we
confirm the existence of a recent burst of star formation between 15 and 10 Myr
ago. We also find evidence for new strong activity, which started 3 Myr ago and
is still continuing. The old population is spread across the entire galaxy,
while the young and intermediate stars are more concentrated in the central
regions. We derive an almost continuous star formation with variable rate, and
exclude the presence of long quiescent phases between the episodes during the
last ~1 Gyr. The central regions experienced an episode of star formation of
\~0.07 Msun/yr (for a Salpeter initial mass function [IMF]) 15 to 10 Myr ago.
This coincides with the strong activity in the central super star cluster. We
find a rate of ~0.3 Msun/yr for the youngest ongoing burst which started ~3 Myr
ago. This is higher than in other dwarfs and comparable to the rate of NGC
1569. The star formation rate of earlier episodes is not especially high and
falls in the range 10^{-3}-10^{-1} Msun/yr. The IMF is close to the Salpeter
value or slightly steeper.Comment: 34 pages, including 6 tables and 14 .ps figures (9 in colour), AJ in
pres
LAPORAN KASUS PENYAKIT COLIBASILLOSIS PADA ANAK BABI
Pengelolaan peternakan babi tidak lepas dari berbagai kendala yang dapat menghambat produktivitas suatu peternakan, salah satunya adalah infeksi penyakit pada ternakbaik itu anak babi maupun babi dewasa. Penyakit yang sering dijumpai pada anak babi yang baru lahir sampai masa sapihanbiasanya ditandai dengan mencret warna putih. Penyakit ini dikenal dengan nama “kolibasilosis” yang disebabkan oleh infeksi bakteri E.coli (Jorgensen et al., 2007).Kolibasilosis yang menyerang anak babi dapat mengakibatkan penurunan berat badan, pertumbuhan terhambat dan jika tidak segera ditangani akan menimbulkan kematian (Hartaningsih dan Hasan, 1985). Tujuan kali ini adalah untuk mengetahui kejadian penyakit yang terjadi pada ternak, mengidentifikasi penyebab penyakit dan menanggulangi penyakit yang terjadi pada ternak. Berdasarkan hasil pengamatan yang dilakukan, terlihat anak babi mencret warna putih dengan konsistensi sangat encer dan dari hasil anamnesa bahwa hal ini sudah berlangsung selama 3 hari, Oleh karena itu anak babi terlihat lemah. Menurut Jorgensen et al. 2007 bahwa penyakit yang sering terjadi pada anak babi baru lahir sampai disapih adalah penyakit kolibasilosis yang disebabkan oleh bakteri E. coli, gejala khasnya ditandai dengan feses yang cair dan berwarna putih. menangani infeksi kolibasilosis. Contohnya menggunkan antibiotik golongan penisilin (Sornplang et al., 2010). Pada kasus kali ini, pengobatan dilakukan menggunakan antibiotik gologongan penisilin yakni Oxytetracycline. Hari ke-4 pasca pemberian antibiotik, anak babi bebas dari mencret putih
Exchange-correlation potential for Current Density Functional Theory of frequency dependent linear response
The dynamical, long-wavelength longitudinal and transverse
exchange-correlation potentials for a homogeneous electron gas are evaluated in
a microscopic model based on an approximate decoupling of the equation of
motion for the current-current response function. The transverse spectrum turns
out to be very similar to the longitudinal one. We obtain evidence for a strong
spectral structure near twice the plasma frequency due to a two-plasmon
threshold for two-pair excitations, which may be observable in inelastic
scattering experiments. Our results give the entire input needed to implement
the Time-Dependent Current Density Functional Theory scheme recently developed
by G. Vignale and W. Kohn [Phys. Rev. Lett. 77, 2037 (1996)] and are fitted to
analytic functions to facilitate such applications.Comment: 6 pages, 3 figure
The MHC-II transactivator CIITA, a viral restriction factor inhibiting the replication of Human T cell Lymphotropic virus type 1.
Recommended from our members
Bottomonium Results By BaBar
Summary: Observation of {eta}{sub b}; Energy scan above {Upsilon}(4S); Search for {Upsilon} {r_arrow} {gamma}A{sup 0}, A{sup 0} {r_arrow} invisible; Hadronic transitions {Upsilon}(4S) {r_arrow} {Upsilon}(nS)
P-440 Impact of electrospun scaffold topology on the performance of in-vitro Folliculogenesis applied to preantral ovine follicles
Study question
How to improve in-vitro Folliculogenesis (ivF) protocols to address the enlarged demand of fertility preservation?
Summary answer
Tissue engineering-based approach opens new frontiers for ivF improving 3D-technologies addressed to support immature-ovarian-follicle-growth to obtain an increased number of competent oocytes enrolled in Assisted-Reproductive-Technology.
What is known already
ivF is a promising Assisted-Reproductive-Technology (ART) for preserving and restoring fertility. This technology potentially reproduces the early stages of folliculogenesis and oogenesis in-vitro allowing to move a large amount of oocyte on individual basis towards the validated protocol of in-vitro maturation/in-vitro fertilization (IVM/IVF).
The current availability of biocompatible-supporting materials offers the challenging opportunity to mimic the native organ stroma in order to better reproduce the 3D environmental conditions leading to synergic follicles-oocyte development in-vitro with the aim to improve the performance of ivF in translational large sized mammal models.
Study design, size, duration
The present research aimed to compare preantral (PA) follicles culture on two different typologies of scaffolds fabricated using PCL(poly(epsilon caprolactone)), respectively made with patterned and randomly aligned fibers (PCL-Patterned/PCL-Randomic) with a standardized-single-follicle scaffold-free-method (3D-oil), widely validated on ovine model (Cecconi et al., 2004). The culture outcomes are compared analyzing follicle/oocyte growth, percentage of antrum differentiation and the incidence of meiotic competence, by exposing ivF growing oocytes to IVM protocol.
Participants/materials, setting, methods
PA follicles (mean size diameter: 250±4μm), mechanically isolated from slaughterhoused lamb ovaries, were individually cultured on electrospun PCL scaffolds (patterned vs randomic) or using the 3D-oil method. ivF were cultured alphaMEM-Fetal Bovine Serum free medium (5% Knockout Serum Replacement) supplemented with 4 IU/mL of equine Chorionic Gonadotropin (Di Berardino et al., 2021). At the end of ivF (14-days) the fully-grown oocytes isolated from early-antral follicles were tested on IVM.
Main results and the role of chance
PCL-Patterned electrospun scaffolds were able to strongly support a synergic oocyte and follicular growth. The 3D culture on Patterned electrospun scaffold supported the highest viability of follicles (87.5% vs 63% under 3D-oil conditions). On the contrary, the highest incidence of degenerated follicles was observed in cultures performed using PCL-Randomic materials (55 vs 37% vs 12.5% for PCL-Randomic vs 3D-oil vs PCL-Patterned, respectively; p <0.0004). The greatest follicle diameter increment (74.7±1 vs 70±0.4 vs 60.9±2%, for PCL-Patterned vs 3D-oil vs PCL-Randomic, respectively p <0.0007) and rate of antrum differentiation (87.5% vs 45% and vs 63%, for PCL-Patterned vs 3D-oil vs PCL-Randomic, for both p <0.0001) were observed in PA ovine follicles cultured on PCL-Patterned scaffolds. Furthermore, PCL-Patterned electrospun scaffolds supported a complete functional development of the oocyte compartment. More in detail, the majority of fully grown oocytes isolated from early- antral follicles grown on PCL-Patterned materials reached the metaphase-II stage (MII 80%) at the end of IVM in comparison to the significant lower percentage in 3D-oil (MII 68%, p =0.04) and PCL-Randomic (MII 18%, p <0.0001) protocols, respectively.
Limitations, reasons for caution
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Wider implications of the findings
Tissue engineering scaffold-based approach represents a valid strategy generating a multi-organ in-vitro system, where different compartments may cooperate generating the complexity of paracrine-mechanism controlling early-follicles outcomes. Scaffold topology is essential to control early-follicles development. Indeed, exclusively PCL-Patterned can preserve long-term follicle 3D-microarchitecture supporting in-vitro oogenesis up to a complete meiotic-competence-acquisition.
Trial registration number
not applicabl
Aspergillus section fumigati pneumonia and oxalate nephrosis in a foal
Equine pulmonary aspergillosis is a rare deep mycosis often due to the hematogenous spread of hyphae after gastrointestinal tract disease. We describe herein the main clinic-pathological findings observed in a foal, which spontaneously died after showing diarrhea and respiratory distress. Necropsy and histopathological investigations allowed to diagnose pulmonary aspergillosis, which likely developed after necrotic typhlitis-colitis. Biomolecular studies identified Aspergillus section Fumigati strain as the causative agent. Notably, severe oxalate nephrosis was concurrently observed. Occasionally, oxalate nephropathy can be a sequela of pulmonary aspergillosis in humans. The present case report suggests that the renal precipitation of oxalates can occur also in horses affected by pulmonary aspergillosis and could likely contribute to the fatal outcome of the disease
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