5,003 research outputs found
Wess-Zumino term in the N=4 SYM effective action revisited
The low-energy effective action for the N=4 super Yang-Mills on the Coulomb
branch is known to include an SO(6)-invariant Wess-Zumino (WZ) term for the six
scalar fields. For each maximal, non-anomalous subgroup of the SU(4)
R-symmetry, we find a four-dimensional form of the WZ term with this subgroup
being manifest. We then show that a recently proposed expression for the
four-derivative part of the effective action in N=4 USp(4) harmonic superspace
yields the WZ term with manifest SO(5) R-symmetry subgroup. The N=2 SU(2)
harmonic superspace form of the effective action produces the WZ term with
manifest SO(4) x SO(2). We argue that there is no four-dimensional form of the
WZ term with manifest SU(3) R-symmetry, which is relevant for N=1 and N=3
superspace formulations of the effective action.Comment: 26 pages; minor corrections and improvement
Regge asymptotics and color suppressed heavy meson decays
We discuss a possible generation of color suppressed B-decays amplitudes
through a soft final state interaction. As a typical example, we consider in
detail the decay (and also ). We show that in the approximation of the
two particle unitarity and at zero order in this process can be
related to the weak decay followed by
the strong charge exchange scattering in the Regge kinematics. We estimate the
amplitude of this process using the light cone QCD sum rule technique and find
that it is supppressed as a power of in comparison to the amplitude
generated by the effective non-leptonic Hamiltonian, but remains important for
the physical value of .Comment: 14 pages,Latex,no figure
A high throughput screening system of coils for ELF magnetic fields experiments: Proof of concept on the proliferation of cancer cell lines
Background: It has been demonstrated that relatively small variations of the parameters of exposure to extremely low frequency magnetic fields (ELF-MF) can change significantly the outcome of experiments. Hence, either in trying to elucidate if these fields are carcinogenic, or in exploring their possible therapeutic use, it is desirable to screen through as many different exposures as possible. The purpose of this work is to provide a proof of concept of how a recently reported system of coils allows testing different field exposures, in a single experiment. Methods: Using a novel exposure system, we subjected a glioblastoma cancer cell line (U251) to three different time modulations of an ELF-MF at 60 different combinations of the alternated current (AC) and direct current (DC) components of the field. One of those three time modulations was also tested on another cell line, MDA-MB-231 (breast cancer). After exposure, proliferation was assessed by colorimetric assays. Results: For the U251 cells, a total of 180 different exposures were tested in three different experiments. Depending on exposure modulation and AC field intensity (but, remarkably, not on DC intensity), we found the three possible outcomes: increase (14.3% above control, p < 0.01), decrease (16.6% below control, p < 0.001), and also no-effect on proliferation with respect to control. Only the time modulation that inhibited proliferation of U251 was also tested on MDA-MB-231 cells which, in contrast, showed no alteration of their proliferation on any of the 60 AC/DC field combinations tested. Conclusions: We demonstrated, for the first time, the use of a novel system of coils for magnetobiology research, which allowed us to find that differences of only a few μT resulted in statistically different results. Not only does our study demonstrate the relevance of the time modulation and the importance of finely sweeping through the AC and DC amplitudes, but also, and most importantly, provides a proof of concept of a system that sensibly reduces the time and costs of screening.Fil: Makinistian, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentina. Slovak Academy of Sciences. Biomedical Center. Cancer Research Institute. Department of Radiobiology; EslovaquiaFil: Marková, Eva. Slovak Academy of Sciences. Biomedical Center. Cancer Research Institute. Department of Radiobiology; EslovaquiaFil: Belyaev, Igor. Slovak Academy of Sciences. Biomedical Center. Cancer Research Institute. Department of Radiobiology; Eslovaqui
No repulsion between critical points for planar Gaussian random fields
We study the behaviour of the point process of critical points of isotropic stationary Gaussian fields. We compute the main term in the asymptotic expansion of the two-point correlation function near the diagonal. Our main result implies that for a ‘generic’ field the critical points neither repel nor attract each other. Our analysis also allows to study how the short-range behaviour of critical points depends on their index
Microwaves from Mobile Phones Inhibit 53BP1 Focus Formation in Human Stem Cells More Strongly Than in Differentiated Cells: Possible Mechanistic Link to Cancer Risk
BACKGROUND: It is widely accepted that DNA double-strand breaks (DSBs) and their misrepair in stem cells are critical events in the multistage origination-of various leukemias and tumors, including gliomas. OBJECTIVES: We studied whether microwaves from mobile telephones of the Global System for Mobile Communication (GSM) and the Universal Global Telecommunications System (UMTS) induce DSBs or affect DSB repair in stem cells. METHODS: We analyzed tumor suppressor TP53 binding protein 1 (53BP1) foci that are typically formed at the sites of DSB location (referred to as DNA repair foci) by laser confocal microscopy. RESULTS: Microwaves from mobile phones inhibited formation of 53BP1 foci in human primary fibroblasts and mesenchymal stem cells. These data parallel our previous findings for human lymphocytes. Importantly, the same GSM carrier frequency (915 MHz) and UMTS frequency band (1947.4 MHz) were effective for all cell types. Exposure at 905 MHz did not inhibit 53BP1 foci in differentiated cells, either fibroblasts or lymphocytes, whereas some effects were seen in stem cells at 905 MHz. Contrary to fibroblasts, stem cells did not adapt to chronic exposure during 2 weeks. CONCLUSIONS: The strongest microwave effects were always observed in stem cells. This result may suggest both significant misbalance in DSB repair and severe stress response. Our findings that stem cells are most sensitive to microwave exposure and react to more frequencies than do differentiated cells may be important for cancer risk assessment and indicate that stem cells are the most relevant cellular model for validating safe mobile communication signals
Regime processual e jurídico da atividade jurídica: Um estudo educacional
This article takes an educational look at controversial issues regarding the definition of the nature, essence (including the concept and signs) and the purpose of the procedural legal regime in the theory of procedural legal regulation. The procedural and legal regime, as an element of the procedural-legal form, unfortunately, has not received sufficient development in legal and educational science; a gap, in particular, remains the issues of establishing the characteristics of the category under consideration, without which it is impossible to establish the nature, essence and purpose of the procedural and legal regime. It is concluded that the procedural and legal regime is characterized by a special subjective composition and a specific goal - to ensure a special order (regulations, procedures) established by procedural norms.Este artículo realiza una mirada didáctica a cuestiones controvertidas en torno a la definición de la naturaleza, esencia (incluyendo el concepto y los signos) y la finalidad del régimen jurídico procesal en la teoría de la regulación jurídica procesal. El régimen procesal y jurídico, como elemento de la forma jurídico-procesal, lamentablemente, no ha recibido suficiente desarrollo en las ciencias jurídicas y de la educación; un vacío, en particular, subsisten las cuestiones de establecimiento de las características de la categoría en consideración, sin las cuales es imposible establecer la naturaleza, esencia y finalidad del régimen procesal y jurídico. Se concluye que el régimen procesal y legal se caracteriza por una composición subjetiva especial y un objetivo específico: garantizar un orden especial (reglamentos, procedimientos) establecido por las normas procesales.Este artigo lança um olhar educativo sobre questões controversas sobre a definição da natureza, essência (incluindo o conceito e os signos) e a finalidade do regime jurídico processual na teoria da regulação jurídica processual. O regime processual e jurídico, como elemento da forma processual-jurídica, infelizmente, não tem recebido suficiente desenvolvimento na ciência jurídica e educacional; uma lacuna, em particular, permanece a questão do estabelecimento das características da categoria em análise, sem a qual é impossível estabelecer a natureza, a essência e a finalidade do regime processual e jurídico. Conclui-se que o regime processual e jurídico se caracteriza por uma composição subjetiva especial e por um objetivo específico - assegurar uma ordem especial (regulamentos, procedimentos) estabelecida por normas processuais
Microwaves from GSM Mobile Telephones Affect 53BP1 and γ-H2AX Foci in Human Lymphocytes from Hypersensitive and Healthy Persons
The data on biologic effects of nonthermal microwaves (MWs) from mobile telephones are diverse, and these effects are presently ignored by safety standards of the International Commission for Non-Ionizing Radiation Protection (ICNIRP). In the present study, we investigated effects of MWs of Global System for Mobile Communication (GSM) at different carrier frequencies on human lymphocytes from healthy persons and from persons reporting hypersensitivity to electromagnetic fields (EMFs). We measured the changes in chromatin conformation, which are indicative of stress response and genotoxic effects, by the method of anomalous viscosity time dependence, and we analyzed tumor suppressor p53-binding protein 1 (53BP1) and phosphorylated histone H2AX (γ-H2AX), which have been shown to colocalize in distinct foci with DNA double-strand breaks (DSBs), using immunofluorescence confocal laser microscopy. We found that MWs from GSM mobile telephones affect chromatin conformation and 53BP1/γ-H2AX foci similar to heat shock. For the first time, we report here that effects of MWs from mobile telephones on human lymphocytes are dependent on carrier frequency. On average, the same response was observed in lymphocytes from hypersensitive and healthy subjects
Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon
The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe
Severe early onset preeclampsia: short and long term clinical, psychosocial and biochemical aspects
Preeclampsia is a pregnancy specific disorder commonly defined as de novo hypertension
and proteinuria after 20 weeks gestational age. It occurs in approximately 3-5% of pregnancies and it is still a major cause of both foetal and maternal morbidity and mortality worldwide1. As extensive research has not yet elucidated the aetiology of preeclampsia, there are no rational preventive or therapeutic interventions
available. The only rational treatment is delivery, which benefits the mother but is not in the interest of the foetus, if remote from term. Early onset preeclampsia (<32 weeks’ gestational age) occurs in less than 1% of pregnancies. It is, however often associated with maternal morbidity as the risk of progression
to severe maternal disease is inversely related with gestational age at onset2. Resulting prematurity is therefore the main cause of neonatal mortality and morbidity
in patients with severe preeclampsia3. Although the discussion is ongoing, perinatal survival is suggested to be increased in patients with preterm preeclampsia
by expectant, non-interventional management. This temporising treatment option to lengthen pregnancy includes the use of antihypertensive medication to control hypertension, magnesium sulphate to prevent eclampsia and corticosteroids
to enhance foetal lung maturity4. With optimal maternal haemodynamic status and reassuring foetal condition this results on average in an extension of 2 weeks. Prolongation of these pregnancies is a great challenge for clinicians to balance between potential maternal risks on one the eve hand and possible foetal benefits on the other. Clinical controversies regarding prolongation of preterm preeclamptic pregnancies still exist – also taking into account that preeclampsia is the leading cause of maternal mortality in the Netherlands5 - a debate which is even more pronounced in very preterm pregnancies with questionable foetal viability6-9. Do maternal risks of prolongation of these very early pregnancies outweigh
the chances of neonatal survival? Counselling of women with very early onset preeclampsia not only comprises of knowledge of the outcome of those particular pregnancies, but also knowledge of outcomes of future pregnancies of these women is of major clinical importance.
This thesis opens with a review of the literature on identifiable risk factors of preeclampsia
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