We updated the agent based Monte Carlo code HERITAGE that simulates human evolution within restrictive environments such as interstellar, sub-light speed spacecraft in order to include the effects of ...population genetics. We incorporated a simplified -- yet representative -- model of the whole human genome with 46 chromosomes (23 pairs), containing 2110 building blocks that simulate genetic elements (loci). Each individual is endowed with his/her own diploid genome. Each locus can take 10 different allelic (mutated) forms that can be investigated. To mimic gamete production (sperm and eggs) in human individuals, we simulate the meiosis process including crossing-over and unilateral conversions of chromosomal sequences. Mutation of the genetic information from cosmic ray bombardments is also included. In this first paper of a series of two, we use the neutral hypothesis: mutations (genetic changes) have only neutral phenotypic effects (physical manifestations), implying no natural selection on variations. We will relax this assumption in the second paper. Under such hypothesis, we demonstrate how the genetic patrimony of multi-generational crews can be affected by genetic drift and mutations. It appears that centuries-long deep space travels have small but unavoidable effects on the genetic composition/diversity of the traveling populations that herald substantial genetic differentiation on longer time-scales if the annual equivalent dose of cosmic ray radiation is similar to the Earth radioactivity background at sea level. For larger doses, genomes in the final populations can deviate more strongly with significant genetic differentiation that arises within centuries.
The CMS detector's core is composed of the largest silicon detector ever built. This tracker consists of a hybrid pixel detector with 66 million channels and a 200 m silicon strip detector with 10 ...million read out channels. Thanks to its fine granularity, it can perform excellent tracks and vertices reconstruction, essential objects in physics analyses. However, the next LHC upgrades will expose CMS to a higher number of simultaneous inelastic collisions per crossing (pile-up events). In order to maintain such performances, the pixel detector will be upgraded. In this contribution, we describe the current tracker performances, driven by the resolution and efficiency of the tracks and vertices reconstruction. We will then highlight the significant role of secondary vertices in physics analyses, especially for the identification of jets coming from the hadronization of a b quark, fundamental in new particles and new physics searches. Finally, we will describe the foreseen upgrades of the tracker and emphasis the expected performance improvements in a high luminosity and high pile-up environment.
The architecture of a large interstellar spaceship, which is capable of serving as a living environment for a population over many generations, is mainly dictated by the needs of said population in ...terms of food, water and breathable gases. These resources cannot be stored for the entire duration of a journey that goes on for several centuries, so they must be produced in situ. In order to determine the quantities necessary for the survival of the population, it is imperative to precisely estimate their needs. In this article, we focus on accurate simulations of the water and air (oxygen) requirements for any type of population in order to be able to provide precise constraints on the overall architecture of an interstellar ark (the requirements in terms of food having already been studied in a previous publication). We upgrade our agent-based, numerical, Monte Carlo code HERITAGE to include human physiological needs. Our simulations show that, for a crew of about 1100 crew members (each characterized with individual anthropometric and biological data), 1.8 \(\times\) 10\(^8\) litres of oxygen are annually required, together with 1.1 \(\times\) 10\(^6\) litres of water. Those results do not account for oxygen and water used in growing plants, but they give us an insight of how much resources are needed in the spaceship. We also review the best methods for generating water from waste gases (namely carbon dioxide and dihydrogen) and how such system could complement the oxygen-supplying biospheres inside multi-generational spaceship to form a closed and controlled environment.
The survival of a genetically healthy multi-generational crew is of a prime concern when dealing with space travel. It has been shown that determining a realistic population size is tricky as many ...parameters (such as infertility, inbreeding, sudden deaths, accidents or random events) come into play. To evaluate the impact of those parameters, Monte Carlo simulations are among the best methods since they allow testing of all possible scenarios and determine, by numerous iterations, which are the most likely. This is why we use the Monte Carlo code HERITAGE to estimate the minimal crew for a multi-generational space travel towards Proxima Centauri b. By allowing the crew to evolve under a list of adaptive social engineering principles (namely yearly evaluations of the vessel population, offspring restrictions and breeding constraints), we show in this paper that it is possible to create and maintain a healthy population virtually indefinitely. A initial amount of 25 breeding pairs of settlers drives the mission towards extinction in 50 +/- 15% of cases if we completely forbid inbreeding. Under the set of parameters described in this publication, we find that a minimum crew of 98 people is necessary ensure a 100% success rate for a 6300-year space travel towards the closest telluric exoplanet known so far.
In the first papers of our series on interstellar generation ships we have demonstrated that the numerical code HERITAGE is able to calculate the success rate of multi-generational space missions. ...Thanks to the social and breeding constraints we examined, a multi-generational crew can safely reach an exoplanet after centuries of deep space travel without risks of consanguinity or genetic disorders. We now turn to addressing an equally important question : how to feed the crew? Dried food stocks are not a viable option due to the deterioration of vitamins with time and the tremendous quantities that would be required for long-term storage. The best option relies on farming aboard the spaceship. Using an updated version of HERITAGE that now accounts for age-dependent biological characteristics such as height and weight, and features related to the varying number of colonists, such as infertility, pregnancy and miscarriage rates, we can estimate the annual caloric requirements aboard using the Harris-Benedict principle. By comparing those numbers with conventional and modern farming techniques we are able to predict the size of artificial land to be allocated in the vessel for agricultural purposes. We find that, for an heterogeneous crew of 500 people living on an omnivorous, balanced diet, 0.45 km2 of artificial land would suffice in order to grow all the necessary food using a combination of aeroponics (for fruits, vegetables, starch, sugar, and oil) and conventional farming (for meat, fish, dairy, and honey).
Spine fusion is a surgical procedure characterized by a significant perioperative bleeding, which often requires red blood cell (RBC) transfusion.
The incidence and the cost of RBC transfusion were ...evaluated in all patients undergoing elective surgery for spine fusion in our Institution, a high-volume center for spine surgery, over a period of 3 years. The analysis specifically addressed the RBC transfusion need in all the different spine fusion procedures (atlanto-axial, cervical, dorsal, lumbar, revisions) with the different surgical approaches (anterior, posterior).
During the 3 years of observation, a total of 1.882 elective spine fusions were performed. More than half of the procedures (n = 964) were posterior lumbar fusions. Overall, 5% of the patients (n = 103) required RBC transfusion. The cervical fusions were the procedures with the lowest percentage of RBC need (0-5%), while the dorsal and the lumbar ones, with the anterior approach, represented the procedures with the highest rate of transfusion (29% and 25% respectively). More than 60 % of the RBC units were employed in the instance of posterior lumbar fusion, while a variable 1-10% of the units was used in each of the other procedures. The overall transfusion cost was of 46.000 euros, with a distribution of costs that paralleled the amount of units transfused for each procedure.
Several surgical and patient factors may contribute to the perioperative blood loss. An accurate patient blood management, may efficiently decrease transfusion requirements and ultimately healthcare costs.
(1) Background: This study evaluated the perioperative red blood cell (RBC) transfusion need and determined predictors for transfusion in patients undergoing elective primary lumbar posterior spine ...fusion in a high-volume center for spine surgery. (2) Methods: Data from all patients undergoing spine surgery between 1 January 2014 and 31 December 2016 were reviewed. Patients' demographics and comorbidities, perioperative laboratory results, and operative time were analyzed in relation to RBC transfusion. Multivariate logistic regression analysis was performed to identify the predictors of transfusion. (3) Results: A total of 874 elective surgeries for primary spine fusion were performed over the three years. Only 54 cases (6%) required RBC transfusion. Compared to the non-transfused patients, transfused patients were mainly female (
= 0.0008), significantly older, with a higher ASA grade (
= 0.0002), and with lower pre-surgery hemoglobin (HB) level and hematocrit (
< 0.0001). In the multivariate logistic regression, a lower pre-surgery HB (OR (95% CI) 2.84 (2.11-3.82)), a higher ASA class (1.77 (1.03-3.05)) and a longer operative time (1.02 (1.01-1.02)) were independently associated with RBC transfusion. (4) Conclusions: In the instance of elective surgery for primary posterior lumbar fusion in a high-volume center for spine surgery, the need for RBC transfusion is low. Factors anticipating transfusion should be taken into consideration in the patient's pre-surgery preparation.
Purpose
This study was done to assess the presence of both asymptomatic and symptomatic intervertebral disc calcifications in a large paediatric population.
Materials and methods
We retrospectively ...reviewed the radiographs taken during the past 26 years in children (age 0–18 years) undergoing imaging of the spine or of other body segments in which the spine was adequately depicted, to determine possible intervertebral disc calcifications. The following clinical evaluation was extrapolated from the patients’ charts: presence of spinal symptoms, history of trauma, suspected or clinically evident scoliosis, suspected or clinically evident syndromes, bone dysplasias, and preor postoperative chest or abdominal X-rays.
Results
We detected intervertebral disc calcifications in six patients only. Five calcifications were asymptomatic (one newborn baby with Patau syndrome; three patients studied to rule out scoliosis, hypochondroplasia and syndromic traits; one for dyspnoea due to sunflower seeds inhalation). Only one was symptomatic, with acute neck pain. Calcifications varied in number from one in one patient to two to five in the others.
Conclusions
Apart from the calcification in the patient with cervical pain, all calcifications were asymptomatic and constituted an incidental finding (particularly those detected at the thoracic level in the patient studied for sunflower-seed inhalation). Calcification shapes were either linear or round. Our series confirms that intervertebral disc calcifications are a rare finding in childhood and should not be a source of concern: symptomatic calcifications tend to regress spontaneously within a short time with or without therapy and immobilisation, whereas asymptomatic calcifications may last for years but disappear before the age of 20 years. Only very few cases, such as those of medullary compression or severe dysphagia due to anterior herniation of cervical discs, may require surgical procedures.
We report a child with a de novo interstitial deletion, 46,XY, int del(9)(9q22.31-q31.2). Cytogenetic and molecular analysis defined the boundaries of the lost region, of paternal origin, from ...D9S1796 to D9S938. The clinical picture included macrocephaly, frontal bossing, bilateral epicanthus, down-slanted palpebral fissures, low-set ears, hypoplastic nostrils, micrognathia, scoliosis, right single palmar crease, small nails, slender fingers, bilaterally flexed 5th finger, delayed bone age, abnormal metacarpophalangeal pattern (MCPP) profile and sole pits. No major malformation was recorded. The deleted region includes, among others, the PTCH and ROR2 genes. Mutations of the former cause the nevoid basal cell carcinoma syndrome (NBCCS) while mutations in the ROR2 gene have been found both in Robinow syndrome and in brachydactyly type 1B (BDB1). As the patient shows some clinical manifestation of both syndromes, we conclude that phenotypic changes related to haploinsufficiency of PTCH and ROR2 are recognisable in our patient even at a young age and in the presence of the more complex phenotype due to the deletion's large size. Thus the efforts to identify the genes included in a deletion are worthy as they may result in better care of the patient as, in this case, monitoring the possible development of tumours associated with NBCCS.
The following clinical evaluation was extrapolated from the patients' charts: presence of spinal symptoms, history of trauma, suspected or clinically evident scoliosis, suspected or clinically ...evident syndromes, bone dysplasias, and pre- or postoperative chest or abdominal X-rays.
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