2,515 research outputs found
Explaining discrepancies in the study of maternal effects:the role of context and embryo
Prenatal maternal effects are increasingly recognized as important mediators in the development of individual differences during early sensitive or even critical periods. Hormone-mediated maternal effects in egg-laying species are a frequently used model to study such effects, mostly to test whether these increase maternal fitness. However, experimental evidence is inconsistent. This has led researchers to divert to other topics. In this review, we argue that from a Darwinian perspective one should however expect strong interactions between effects of maternal hormones with contextual cues, including environmental factors, embryonic modulation of maternal signals, offspring age and sex, and fathers’ influence. Taking these into account may explain the inconsistencies and new experiments should reveal how the benefits and costs of maternal hormones and prenatal maternal effects in general play out in different contexts.</p
Extensive DRB region diversity in cynomolgus macaques: recombination as a driving force
The DR region of primate species is generally complex and displays diversity concerning the number and combination of distinct types of DRB genes present per region configuration. A highly variable short tandem repeat (STR) present in intron 2 of nearly all primate DRB genes can be utilized as a quick and accurate high through-put typing procedure. This approach resulted previously in the description of unique and haplotype-specific DRB-STR length patterns in humans, chimpanzees, and rhesus macaques. For the present study, a cohort of 230 cynomolgus monkeys, including self-sustaining breeding groups, has been examined. MtDNA analysis showed that most animals originated from the Indonesian islands, but some are derived from the mainland, south and north of the Isthmus of Kra. Haplotyping and subsequent sequencing resulted in the detection of 118 alleles, including 28 unreported ones. A total of 49 Mafa-DRB region configurations were detected, of which 28 have not yet been described. Humans and chimpanzees possess a low number of different DRB region configurations in concert with a high degree of allelic variation. In contrast, however, allelic heterogeneity within a given Mafa-DRB configuration is even less frequently observed than in rhesus macaques. Several of these region configurations appear to have been generated by recombination-like events, most probably propagated by a retroviral element mapping within DRB6 pseudogenes, which are present on the majority of haplotypes. This undocumented high level of DRB region configuration-associated diversity most likely represents a species-specific strategy to cope with various pathogens
Fitting Neutrino Physics with a U(1)_R Lepton Number
We study neutrino physics in the context of a supersymmetric model where a
continuous R-symmetry is identified with the total Lepton Number and one
sneutrino can thus play the role of the down type Higgs. We show that
R-breaking effects communicated to the visible sector by Anomaly Mediation can
reproduce neutrino masses and mixing solely via radiative contributions,
without requiring any additional degree of freedom. In particular, a relatively
large reactor angle (as recently observed by the Daya Bay collaboration) can be
accommodated in ample regions of the parameter space. On the contrary, if the
R-breaking is communicated to the visible sector by gravitational effects at
the Planck scale, additional particles are necessary to accommodate neutrino
data.Comment: 19 pages, 3 figures; v2: references added, constraints updated,
overall conclusions unchange
Bio-nanotechnology application in wastewater treatment
The nanoparticles have received high interest in the field of medicine and water purification, however, the nanomaterials produced by chemical and physical methods are considered hazardous, expensive, and leave behind harmful substances to the environment. This chapter aimed to focus on green-synthesized nanoparticles and their medical applications. Moreover, the chapter highlighted the applicability of the metallic nanoparticles (MNPs) in the inactivation of microbial cells due to their high surface and small particle size. Modifying nanomaterials produced by green-methods is safe, inexpensive, and easy. Therefore, the control and modification of nanoparticles and their properties were also discussed
Dynamical R-parity Breaking at the LHC
In a class of extensions of the minimal supersymmetric standard model with
(B-L)/left-right symmetry that explains the neutrino masses, breaking R-parity
symmetry is an essential and dynamical requirement for successful gauge
symmetry breaking. Two consequences of these models are: (i) a new kind of
R-parity breaking interaction that protects proton stability but adds new
contributions to neutrinoless double beta decay and (ii) an upper bound on the
extra gauge and parity symmetry breaking scale which is within the large hadron
collider (LHC) energy range. We point out that an important prediction of such
theories is a potentially large mixing between the right-handed charged lepton
() and the superpartner of the right-handed gauge boson (), which leads to a brand new class of R-parity violating interactions of
type and \widetilde{d^c}^\dagger\u^c
e^c. We analyze the relevant constraints on the sparticle mass spectrum and
the LHC signatures for the case with smuon/stau NLSP and gravitino LSP. We note
the "smoking gun" signals for such models to be lepton flavor/number violating
processes: (or ) and
(or ) without
significant missing energy. The predicted multi-lepton final states and the
flavor structure make the model be distinguishable even in the early running of
the LHC.Comment: 30 pages, 13 figures, 6 tables, reference adde
Risk factors for Brucella spp. and Coxiella burnetii infection among small ruminants in Eastern India
Small ruminants are the main reservoirs for brucellosis and coxiellosis, two zoonotic diseases affecting livestock production, and posing a public health threat in India. Understanding disease prevalence and risk factors associated with small ruminant infection can help mitigate disease transmission. We report a cross-sectional survey in the states of Assam and Odisha in Eastern India. We interviewed 244 farmers to assess knowledge, attitude and practices relevant to brucellosis and coxiellosis infection. Serum samples from 411 goats and 21 sheep were analysed using enzyme-linked immunosorbent assay and Rose-Bengal Brucella agglutination plate test. Higher Brucella and Coxiella burnetii seroprevalence were found in Odisha (22% and 11.5%, respectively) than Assam (9.8% and 1.6%, respectively), and certain districts in Odisha were at higher risk. No association was found between seropositive animals and clinical signs, a challenge when attempting to identify seropositive animals in the herd. None of the farmers interviewed were aware of brucellosis, its aetiology, clinical form, or zoonotic risk. This study acts as a first indication of the extent of these diseases among small ruminants in these Indian states, highlighting how farming practices are associated with increased risk of infection. More research is urgently needed to mitigate zoonoses transmission in this region
Estrogen receptor transcription and transactivation: Structure-function relationship in DNA- and ligand-binding domains of estrogen receptors
Estrogen receptors are members of the nuclear receptor steroid family that exhibit specific structural features, ligand-binding domain sequence identity and dimeric interactions, that single them out. The crystal structures of their DNA-binding domains give some insight into how nuclear receptors discriminate between DNA response elements. The various ligand-binding domain crystal structures of the two known estrogen receptor isotypes (α and β) allow one to interpret ligand specificity and reveal the interactions responsible for stabilizing the activation helix H12 in the agonist and antagonist positions
Hippocampal Volume Reduction in Congenital Central Hypoventilation Syndrome
Children with congenital central hypoventilation syndrome (CCHS), a genetic disorder characterized by diminished drive to breathe during sleep and impaired CO2 sensitivity, show brain structural and functional changes on magnetic resonance imaging (MRI) scans, with impaired responses in specific hippocampal regions, suggesting localized injury
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