8,011 research outputs found
The labial gene is required to terminate proliferation of identified neuroblasts in postembryonic development of the Drosophila brain
The developing brain of Drosophila has become a useful model for studying the molecular genetic mechanisms that give rise to the complex neuronal arrays that characterize higher brains in other animals including mammals. Brain development in Drosophila begins during embryogenesis and continues during a subsequent postembryonic phase. During embryogenesis, the Hox gene labial is expressed in the developing tritocerebrum, and labial loss-of-function has been shown to be associated with a loss of regional neuronal identity and severe patterning defects in this part of the brain. However nothing is known about the expression and function of labial, or any other Hox gene, during the postembryonic phase of brain development, when the majority of the neurons in the adult brain are generated. Here we report the first analysis of Hox gene action during postembryonic brain development in Drosophila. We show that labial is initially expressed in six larval brain neuroblasts, of which only four give rise to the labial expressing neuroblast lineages present in the late larval brain. Although MARCM-based clonal mutation of labial in these four neuroblast lineages does not result in an obvious phenotype, a striking and unexpected effect of clonal labial loss-of-function does occur during postembryonic brain development, namely the formation of two ectopic neuroblast lineages that are not present in wild-type brains. The same two ectopic neuroblast lineages are also observed following cell death blockage and, significantly, in this case the resulting ectopic lineages are Labial-positive. These findings imply that labial is required in two specific neuroblast lineages of the wildtype brain for the appropriate termination of proliferation through programmed cell death. Our analysis of labial function reveals a novel cell autonomous role of this Hox gene in shaping the lineage architecture of the brain during postembryonic development
Command system study for the operation and control of unmanned scientific satellites, task III - Command system interference Third quarterly progress report, 1 Jan. - 31 Mar. 1965
Effects of CW and modulated interference on baseband of AM and FM demodulators used for control of unmanned scientific satellite
NOViSE: a virtual natural orifice transluminal endoscopic surgery simulator
Purpose: Natural Orifice Transluminal Endoscopic Surgery (NOTES) is a novel technique in minimally invasive surgery whereby a flexible endoscope is inserted via a natural orifice to gain access to the abdominal cavity, leaving no external scars. This innovative use of flexible endoscopy creates many new challenges and is associated with a steep learning curve for clinicians. Methods: We developed NOViSE - the first force-feedback enabled virtual reality simulator for NOTES training supporting a flexible endoscope. The haptic device is custom built and the behaviour of the virtual flexible endoscope is based on an established theoretical framework – the Cosserat Theory of Elastic Rods. Results: We present the application of NOViSE to the simulation of a hybrid trans-gastric cholecystectomy procedure. Preliminary results of face, content and construct validation have previously shown that NOViSE delivers the required level of realism for training of endoscopic manipulation skills specific to NOTES Conclusions: VR simulation of NOTES procedures can contribute to surgical training and improve the educational experience without putting patients at risk, raising ethical issues or requiring expensive animal or cadaver facilities. In the context of an experimental technique, NOViSE could potentially facilitate NOTES development and contribute to its wider use by keeping practitioners up to date with this novel surgical technique. NOViSE is a first prototype and the initial results indicate that it provides promising foundations for further development
Strong and Δ
Let K be a nonempty closed and convex subset of a complete
CAT(0) space. Let Ti:K→CBK,i=1,2,…,m, be a family of multivalued demicontractive mappings such that F:=⋂i=1mF(Ti)≠∅. A Krasnoselskii-type iterative sequence is shown to Δ-converge to a common fixed point of
the family Ti,i=1,2,…,m. Strong convergence theorems are also proved
under some additional conditions. Our theorems complement and extend several recent important results on approximation of fixed points of certain nonlinear mappings in CAT(0) spaces. Furthermore, our method of the proof is of
special interest
Protandric hermaphroditism in the bivalve Arca noae (Mollusca: Arcidae)
Following the histological analysis of Arca noae samples from the south-western Adriatic Sea, five hermaphroditic specimens were found out of 168 sexed individuals (3.0%). The hermaphrodite gonads showed the co-occurrence of male and female germ cells within the same acini, i.e. both spermatozoa in the lumen and oogonia lining its wall. Oogonia increased in size through winter, thus suggesting that the direction of sex change is from male to female. Both the biometrical analyses and theoretical considerations strongly suggest that A. noae is an obligate protandric species
Protandric hermaphroditism in the bivalve Arca noae (Mollusca: Arcidae)
Following the histological analysis of Arca noae samples from the south-western Adriatic Sea, five hermaphroditic specimens were found out of 168 sexed individuals (3.0%). The hermaphrodite gonads showed the co-occurrence of male and female germ cells within the same acini, i.e. both spermatozoa in the lumen and oogonia lining its wall. Oogonia increased in size through winter, thus suggesting that the direction of sex change is from male to female. Both the biometrical analyses and theoretical considerations strongly suggest that A. noae is an obligate protandric species
Synchronizing Sequencing Software to a Live Drummer
Copyright 2013 Massachusetts Institute of Technology. MIT allows authors to archive published versions of their articles after an embargo period. The article is available at
Challenges of Utilizing Agricultural Information Sources by Small Scale Farmers in Nasarawa State, Nigeria
This paper discusses the challenges of utilizing agricultural sources by small-scale farmers in Nasarawa State of Central Nigeria. Poorly trained extension workers contribute significantly to inadequacy of interpersonal communication strategy which lent cognizance to the use of mass media support in conducting information dissemination to farmers in the area. It was discovered that mass media strategy in the absence of education, material resources, appropriate infrastructure and technical skills was unlikely to eradicate inaccessibility and ineffective information utilization among rural farming community. There is need for extension managers to improve both the quality and quantity of their extension personnel through continued staff recruitment and training. Keywords: Inter-personal channels; mass media, dissemination of information, persuasion, Johari windows, process of communication
Congenital Malformations of the Female Genital Tract: a Review of Available Classification Systems
Congenital malformations of the female genital tract are being diagnosed more frequently due to advances in imaging techniques. A broad international consensus on their classification is still lacking. This paper aimed to comparatively summarize the most frequently and widely used, as well as the most recently developed classification systems of congenital female genital malformations. A non-systematic review was done through a search on major databases with the medical subject heading (MeSH) term ‘‘congenital abnormalities” in combination with ‘‘classification” and ‘‘female genitalia”. All available systems, including, among others, the
American Fertility Society Classification (1988), the Acien and Acien classification (1992, 2004), the VCUAM system (2005), the European Society for Human Reproduction and Embryology - European Society for Gynecological Endoscopy classification (2013), the Congenital Uterine Malformation Experts (CUME) group recommendations, and the American Society for Reproductive Medicine Classification (2021) possess the advantages and disadvantages listed in this article. Regarding the most common situations, the criteria for differentiating physiologic arcuate and discrete partial septate uteri vary widely between classifications, while difficulties also persist with the rarer complex abnormalities that cannot be easily classified, contributing to
a gap in clinical and research protocols. The main factor compromising any attempt to reach an ideal classification system is the lack of evidence-based data, justifying the need for comparative multicenter international randomized control trials in this field. Pending new research data and a broad international consensus, it seems essential for adequate patient orientation to describe each detected malformation in detail and to correlate it with the clinical presentation, regardless the type of classification used.info:eu-repo/semantics/publishedVersio
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