16 research outputs found

    Laterale bepantsering en groei bij <i>Gasterosteus aculeatus</i>. II

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    A positive correlation between number of lateral shields and total length is shown to exist in Gasterosteus aculeatus L. populations (gymnura-form), consisting of fishes of exactly the same age. These populations were reared in the laboratory from artificially fertilized eggs. The same correlation, found in natural populations, is thus caused by faster growth rates in more plated individuals. This possibility was considered previously . Also in artificial populations, the correlation is shown to decrease with increasing average length of the population, being + 0,64 (Table I), + 0,56 (Table II) and + 0,11 (Table III) for populations having reached respectively 21,81 ± 0, 90 mm, 32,39 ± 0,59 mm and 35,14 ± 0,608 mm average size. The rapid breaking down of the association between the two characters considered, was equally found to happen at exactly the same growth level in natural populations. It means evidently that after having reached the size of 33 to 35 mm, growth is slowing down first in more plated individuals, allowing the less plated ones to recover their initial lag

    Experimental studies on adaptive evolution in <i>Gasterosteus aculeatus</i> L.

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    Populations of the stickleback, Gasterosteus aculeatus L., vary greatly in morphological and physiological characters. The populations of Belgium and neighboring countries are differentiated into two sharply defined adaptive types. These types differ in morphological characters, especially in the mean plate numbers and in mean body size, and also in physiological traits, the most important of which concern the chlorine regulation of the blood. In Belgium one type occupies fresh water habitats and the other type salt water habitats. The gene exchange between these types is very limited because of the physiological properties of the hybrid eggs. Representatives of the same type coming from different countries are often distinct in the mean plate number. These geographical differences form north-south gradients. Indirect evidence is given, based on the study of the type, which in Belgium lives in fresh water, that the geographical distinctions are adaptive. The establishment of the geographical gradients was in all probability an adaptive process. An hypothesis is advanced, according to which the two types have arisen through a series of primary and secondary linkage rearrangements starting from an originally single polygenic complex. In this way, two physiologically distinct groups of populations might have been produced. Although these types intergrade morphologically, they are adapted to different combinations of temperature and salinity. The morphological intergrades are not physiologically intermediate between the two types; they belong physiologically, and therefore ecologically, to one or the other type. The physiological differentiation between and within the two types is large enough to explain the geographical and morphological divergence as well as the maintenance of the two types by natural selection. Natural selection is shown to act not only on the adult stage but even more sharply on the egg stage

    Hierarchical Estimation as Basis for Hierarchical Forecasting

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    In inventory management, hierarchical forecasting (HF) is a hot issue : families of items are formed for which total demand is forecasted; total forecast then is broken up to produce forecasts for the individual items.Since HF is a complicated procedure, analytical results are hard to obtain; consequently, most literature is based on simulations and case studies.This paper succeeds in following a more theoretical approach by simplifying the problem : we consider estimation instead of forecasting.So, from a random sample we estimate both total demand and the fraction of this total that individual items take; multiplying these two quantities gives a new estimate of individual demand.Then our research question is: can aggregation of items, followed by fractioning, lead to more accurate estimates of individual demand?Thirdly, a more practical situation is investigated by means of simulation.

    Evidence for the use of peri- and post-operative antibiotic prophylaxis in autologous breast reconstruction:A systematic review

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    Background: Autologous breast reconstruction has become standard of care, but there is no consensus on prophylactic antibiotic regimens for this surgical procedure. This review aims to present evidence on the best prophylactic antibiotic protocol to lower the risk of surgical site infections in autologous breast reconstructions. Methods: The search was performed in PubMed, EMBASE, Web of Science, and Cochrane Library on 25th of January 2022. Data on the number of surgical site infections, breast reconstruction type (pedicled or free flap) and reconstruction timing (immediate or delayed), as well as data on the type, dose, route of administration, timing, and duration of antibiotic treatment were extracted. All included articles were additionally assessed for potential risk of bias by using the revised RTI Item Bank tool. Results: 12 studies were included in this review. No evidence is found that giving post-operative antibiotics for a prolonged period longer than 24 h after surgery is useful in lowering infection rates. This review could not distinguish between the best choice of antimicrobial agent. Discussion: Although this is the first study that collected current evidence on this topic, the quality of evidence is limited due to a small number of available studies (N = 12) with small study populations. The included studies have high heterogeneity, no adjustment for confounding, and interchangeably used definitions. Future research is highly recommended with predefined definitions, and a sufficient number of included patients. Conclusion: Antibiotic prophylaxis up to a maximum of 24 h is useful in lowering infection rates in autologous breast reconstructions

    Simplified monopalmitoyl toll-like receptor 2 ligand mini-UPam for self-adjuvanting neoantigen-based synthetic cancer vaccines

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    Synthetic vaccines, based on antigenic peptides that comprise MHC−I and MHC‐II T‐cell epitopes expressed by tumors, show great promise for the immunotherapy of cancer. For optimal immunogenicity, the synthetic peptides (SPs) should be adjuvanted with suitable immunostimulatory additives. Previously, we have shown that improved immunogenicity in vivo is obtained with vaccine modalities in which an SP is covalently connected to an adjuvanting moiety, typically a ligand to Toll‐like receptor 2 (TLR2). SPs were covalently attached to UPam, which is a derivative of the classic TLR2 ligand Pam3CysSK4. A disadvantage of the triply palmitoylated UPam is its high lipophilicity, which precludes universal adoption of this adjuvant for covalent modification of various antigenic peptides as it renders the synthetic vaccine insoluble in several cases. Here, we report a novel conjugatable TLR2 ligand, mini‐UPam, which contains only one palmitoyl chain, rather than three, and therefore has less impact on the solubility and other physicochemical properties of a synthetic peptide. In this study, we used SPs that contain the clinically relevant neoepitopes identified in a melanoma patient who completely recovered after T‐cell therapy. Homogeneous mini‐UPam‐SP conjugates have been prepared in good yields by stepwise solid‐phase synthesis that employed a mini‐UPam building block pre‐prepared in solution and the standard set of Fmoc‐amino acids. The immunogenicity of the novel mini‐UPam‐SP conjugates was demonstrated by using the cancer patient's T‐cells.Bio-organic Synthesi
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