Relativistic Spacecraft Propelled by Directed Energy

Achieving relativistic flight to enable extrasolar exploration is one of the dreams of humanity and the long term goal of our NASA Starlight program. We derive a fully relativistic solution for the motion of a spacecraft propelled by radiation pressure from a directed energy system. Depending on the system parameters, low mass spacecraft can achieve relativistic speeds; thereby enabling interstellar exploration. The diffraction of the directed energy system plays an important role and limits the maximum speed of the spacecraft. We consider 'photon recycling' as a possible method to achieving higher speeds. We also discuss recent claims that our previous work on this topic is incorrect and show that these claims arise from an improper treatment of causality

Learning To Play The Trading Game

Can we train a stock trading bot that can take decisions in high-entropy envi- ronments like stock markets to generate profits based on some optimal policy? Can we further extend this learning for any general trading problem? Quantitative Al- gorithms are responsible for more than 75% of the stock trading around the world. Creating a stock market prediction model is comparatively easy. But creating a prof- itable prediction model is still considered as a challenging task in the field of machine learning and deep learning due to the unpredictability of the financial markets. Us- ing biologically inspired computing techniques of reinforcement learning (RL) and artificial neural networks(ANN), this project attempts to train an agent who takes decisions based on the optimal decision policies learned. Different existing RL tech- niques and their slightly modified variants will be used to train the agent, and the trained model is then tested against different stock prices and also stock portfolio settings to see if the agent has learned the rules of the game and can it act optimally irrespective of the testing data provided. This work aims to provide general users with simple recommendations about the possible investment decisions of selected stocks in the portfolio. Results of the implemented approaches do seem to work somewhat well on specific periods of stock market time series, but they are observed to be fragile. Selected strategies do not guarantee similar results on all historical time-periods, nor they are guaranteed to provide exceptional performance on unpredictable future stock market time-series data

Misoprostol with Foleys Versus Misoprostol Alone For Induction of Labour in Term Primigravidas: A Prospective Randomized Control Trial

OBJECTIVE : To determine whether use of Foleys in combination with Misoprostol, as opposed to Misoprostol alone, for induction of labour will lead to i. Decreased induction to delivery interval, ii. Higher probability of achieving vaginal delivery, iii. Lower incidence of Caesarean section, iv. Affect the rates of meconium stained liquor, v. Lower rates of hyperstimulation, vi. Affect incidence of chorioamnionitis/ endomyometritis, vii. Lower rates of atonic post partum haemorrhage, viii. Affect neonatal morbidity. Methods: This is a prospective, randomised control trial to study the efficacy of Foleys and Misoprostol versus Misoprostol alone for induction of labour. The trial was presented before the Institutional Review Board in Christian Medical College, and protocol was approved prior to start of recruitment. All Primigravida, low risk, term patients coming to CMC labor room & Obstetrics wards for routine induction of labor were screened for the trial. All primigrravidas with singleton pregnancies in longitudinal lie and cephalic presentation at 37 +0 to 40+6 weeks of gestation, with a medical indication for induction, intact membranes and a Bishops score of <6 were counselled for participation in this trial. High risk pregnancies, multigravidas, non vertex pregnancies, those with fever/ sepsis, those undergoing reinduction or those with a known allergy to Misoprostol/ Latex were excluded. Eligible women who agreed to be part of the trial, were given an information sheet and explained about details of the trial. If they agreed, they were asked to sign a consent form. Patients were recruited from July 2015 to August 2016 in Christian Medical College, a 2450 bed, tertiary care, teaching hospital. Consenting women were then subjected to a pre induction Non Stress Test, which was carried out for a minimum of 20 minutes. If this was reactive, the Principal Investigator was called in to randomize the patient. Patients were randomly allotted to two groups – those for induction with Misoprostol plus Foleys catheter and those for induction with only Misoprotol – using computer generated randomization codes in a 1:1 ratio using Block randomisation. Sealed, opaque envelopes were used, and the Principle Investigator was not aware of the randomisation sequence prior to actual randomisation. However, due to the nature of treatment, after randomization, the patient, principal investigator & caregiver were aware of the arm into which the patient was allocated. Patients in the combination arm were induced with a 16 Fr Foleys catheter inserted by registrars into the cervix and inflated with 30ml of distilled water. Simultaneously, 25 mcgm of Misoprostol was inserted into the posterior fornix of vagina, which was repeated 4 hourly for a total of 3 doses with Foleys in situ. Foleys was removed after 12 hrs of insertion, unless there was an indication to do so earlier. Patients were monitored with continuous CTG. Subsequent doses of Misoprostol were withheld if patient developed contractions, ruptured of membranes or fetal heart became non reassuring. Patients in the Misoprostol Only arm were induced with Misoprostol alone, 25 mcgm Q4th hourly for a total of 3 doses in the posterior fornix of vagina by registrars. Continuous CTG monitoring was done. Indications for abandoning subsequent doses were similar as in the combined treatment arm. RESULTS : This study recruited 300 patients over the period of 1 year from July 2015 to August 2016. Of these patients, 151 were recruited to the Misoprostol arm and 149 patients to the Misoprostol and Foleys Arm. Only Primigravidas with low risk pregnancies were eligible for this trial. The baseline characteristics of our two groups were similar with regard to age, BMI and risk factors such as anemia and advanced maternal age. There were more patients with primary infertility in the Misoprostol only arm, however this is unlikely to have bearing on the results. Majority of our patients were from Vellore. Majority of our patients were in the BMI range of 19.5 to 24.9 kg/m2: 72 patients (47.7%) in the Misoprostol only arm and 88 patients (59.1%) in the Misoprostol and Foleys arm. There were 61 patients (40.4%) in the Misoprostol arm and 45 patients (30.2%) in the Misoprostol and Foleys arm in the BMI range of 25 – 29.9. 20.3% of patients had a BMI of 30kg/m2. We hypothesized that combining Misoprostol and Foleys catheter for induction of labour, through their synergistic effect, would shorten induction to delivery interval and the overall duration of labour. Our findings are contrary to this hypothesis. There was a shorter induction to delivery interval in the Misoprostol only arm by 1 hour 18 minutes compared to the Misoprostol and Foleys arm. This difference was statistically significant (p value 0.017). The latent phase of labour was found to be shorter by 1 hour and 16 minutes in the Misprostol only group (p value 0.001). The active phase of labour was also shorter in the Misoprostol only group by 44 minutes. Though this was not statistically significant (p value – 0.38), this is of clinical importance. Shortened active phase of labour may help reduce infectious morbidity, the strain on the mother and the baby, as well as allow greater turnover in institutes where patient load is greater and doctors are hard pressed for empty beds. There were more patients with a Bishops score of 2 or 3 randomised to the Misoprostol and Foleys arm compared to the Misoprostol only arm (118 versus 85). Those with a higher Bishops score (4,5 or 6) were randomised in larger numbers to the Misoprostol only arm (66 versus 31 patients). Gestational age wise, for patients from 37+0/7 to 38+6/7 weeks, there were 5 patients each with a Bishops score of 2/3 and 4/5/6. Of the Bishops score of 2 or 3, two patients were in the Misoprostol arm and 3 patients were in the Misoprostol and Foleys arm. Of a Bishops score of 4,5 or 6; there was one patient in the Misoprsotol arm and 4 patients in the Misoprostol and Foleys arm. Above 39 weeks to 41+0/7 weeks, there were 198 patients (68.3%) with Bishops score of 2 and 3 compared to 92 patients (31.7%) with a Bishops score score Inspite of randomisation of the sample, only 85 patients (55.6%) with a Bishops score of 2 and 3 were in the Misoprostol arm. In contrast, there were 118 patients (79.2%) with a Bishops Score of 2 and 3 in the Misoprostol and Foleys arm. Despite this uneven distribution, it was found that those patients with a lower Bishops score in the Misoprostol only arm had a significantly shorter latent phase of labour (30 minutes, p value 0.35). There were more patients with meconium stained liquor in the Misoprostol only arm (40 patients, 26.5%) compared to the Misoprostol and Foleys arm (15 patients, 9.4%). These findings were statitistically significant (p value 0.001). More patients with meconium stained liquor ultimately underwent Caesarean sections/ Instrumental deliveries. Of the 40 patients in the Misoprostol arm with meconium staining, 21.2% underwent normal vaginal delivery, whereas 62.5% had either Instrumental/ Caesarean delivery. These findings were statistically significant, with a p value of 0.157. Of the 15 patients with meconium stained liquor in the Misoprostol and Foleys arm, only one patient had a normal vaginal delivery whereas 14 patients underwent either Instrumental or LSCS deliveries. These findings were also statistically significant (p value 0.034). Other studies (Lanka et al, Rust et al, Chen et al) did not find a statistically significant difference in the rates of Vaginal/ Instrumental/ Caesarean deliveries in the two groups. 21 patients (13.9%) in the Misoprostol arm required Inj. Terbutaline for hyperstimulation as compared to 15 patients (10.1%) in the Misoprostol and Foleys arm. However, this difference was not found to be statistically significant (p value 0.3). Cheng et al analysed 5 trials that studied this outcome and found the the combination group had a significantly decreased incidence of tachysystole. Women in the BMI range of 25 to 29.9 kg/m2 had a statistically significant reduction in both the latent and the active phase of labour, both being significantly shorter in the Misoprostol only arm. The latent phase was shorter by 1 hour 51 minutes (p value 0.001) and the active phase by 35 minutes (p value 0.002). The total duration of labour was thus reduced by 2 hours 39 minutes in the Misoprostol only group. Although labour was shorter in BMI of 30 kg/m2 for the Misoprostol only arm, this was not statistically significant. The incidence of chorioamnionitis was nearly equal in both arms contrary to the findings in Chen et al meta analysis where combination arm had higher incidence of chorioamnionitis. Post partum haemorrhage was slightly higher in the Misoprostol only group, but this was not statistically significant. Endomyometritis seemed to be more frequent in the Misoprostol Only arm, and wound infections more common in the Misoprostol and Foleys arms. Neither of these findings reached statistical significance. More babies in the Misoprostol group (27 babies, 17.9%) were diagnosed with neonatal sepsis compared to the Misoprostol and Foleys arm (20 babies, 13.4%), however this was not statistically significant. When using Misoprostol alone, there is a higher risk for meconium staining of liquor, hyperstimulation and ultimately Caesarean section/ Instrumental deliveries. CONCLUSION : Misoprostol alone seems to have the following advantages as compared to misoprostol with Foleys together : 1. Shorter induction to delivery interval. 2. Shorter overall duration of labour. 3. Useful in unfavourable cervix ( bishop score < 4). 4. After subgroup analysis, in overweight women (BMI 25 to 29.9 kg/m2), it shortened duration of labour( statistically significant). • Even though these findings are statistically significant in our study, our numbers are underpowered to advocate Misoprostol as the best agent for induction of labour. • Use of Misoprostol alone results in higher rates of Meconium stained liquor, hyperstimulation requiring Terbutaline and subsequently a higher Caesarean rates/ Instrumental deliveries in these patients. • There is no statistical difference in infectious and neonatal morbidity in the two groups

Solubility Enhancement of Water Insoluble Drug for Ophthalmic Formulation

Product development of ophthalmic preparations has received considerable attention in the last few years. With the increasing emphasis on their sterility, some of the differences between them and parenteral preparations are becoming less evident. Both classes of preparations employ similar added substances and manufacturing procedures. The successful formulation of poorly water-soluble drugs is one of the major problems in pharmaceutical manufacturing. Poorly water-soluble drugs, such as indomethacin, may show low and erratic oral bioavailability due to poor dissolution of the drug in the fluids of the gastrointestinal tract. Indomethacin is a water insoluble drug, so problems of formulating an aqueous eye-drop are well known. Moreover, unstability of Indomethacin aqueous preparations is also a great challenge. In this research work, considering pharmacological importance of drug Indomethacin, we tried to overcome the problem of poor water solubility by making a salt of it and thus formulating an aqueous ophthalmic preparation.Keywords: ophthalmic preparation, indomethacin salt, aqueous eye drops, poor water soluble drugs

Anisotropic magnetic and superconducting properties of pure and Co-doped CaFe2_2As2_2 single crystals

We report anisotropic dc magnetic susceptibility $\chi(T)$, electrical resistivity $\rho(T)$, and heat capacity $C(T)$ measurements on the single crystals of CaFe$_{2-x}$Co$_x$As$_2$ for $x$ = 0 and 0.06. Large sized single crystals were grown by the high temperature solution method with Sn as the solvent. For the pure compound with $x$ = 0, a high temperature transition at 170 K is observed which is attributed to a combined spin density wave (SDW) ordering and a structural phase transition. On the other hand, for the Co-doped samples for $x$ = 0.06, the SDW transition is suppressed while superconductivity is observed at $\simeq$17 K. The superconducting transition has been confirmed from the magnetization and electrical resistivity studies. The $^{57}$Fe M\"ossbauer spectrum in CaFe$_2$As$_2$ indicates that the SDW ordering is incommensurate. In the Co-doped sample, a prominent paramagnetic line at 4.2 K is observed indicating a weakening of the SDW state.Comment: 4 pages 5 figures. Submitted to Phys. Rev.

A retrospective study on maternal and perinatal outcome in pregnancy requiring DJ stent and PCN during pregnancy

Background: Gestational hydronephrosis (GH) is result of dilatation effect of the progesterone and mechanical compression of the gravid uterus. Management during pregnancy is challenging as routine radiological investigations and surgical treatments cannot be applied due to the potential harm to the fetus. Intervention is indicated in women who fail to respond to conservative management. Acute hydronephrosis and renal colic are common etiologies for loin pain, and can lead to severe form of urinary tract infection affecting perinatal outcome. Ureteric stenting and percutaneous nephrostomy (PCN) during pregnancy are safe, requiring no intra-operative imaging, and inserted under local anaesthesia. It provides good symptom relief, low complication rate, efficient and safe modality for women with refractory symptoms.Methods: A retrospective study of pregnant women admitted under obstetric units with acute hydronephrosis requiring DJ stenting and/or PCN. Aim was to evaluate the course and pregnancy outcomes in a tertiary center of Southern India over a period of five years.Results: Descriptive statistical analysis was done in 12 women with acute hydronephrosis in pregnancy. 66.7% were nulliparous and mean gestational age at admission was 31 weeks. Diagnosis was done by USG. One-fourth had pyelonephritis and calculus being the main pathology (n=9;75%).Women requiring DJ stent and PCN were 41.6% and 58.4% respectively. 41.7% had preterm labour. 66.7% delivered vaginally, birth weight was more than 2.5kg in 50%.Conclusions: Maternal and neonatal outcome mainly depends on the early diagnosis. In this study we emphasize on the importance of multidisciplinary team approach in the management of women with acute hydronephrosis. DJ stent and PCN are efficient and safe modalities in women with refractory symptoms

Damped Ly-alpha Absorbers in Star-forming Galaxies at z < 0.15 Detected with the Hubble Space Telescope and Implications for Galaxy Evolution

We report {\it HST} COS spectroscopy of 10 quasars with foreground star-forming galaxies at 0.02$<$$z$$<$ 0.14 within impact parameters of $\sim$1-7 kpc. We detect damped/sub-damped Ly$\alpha$ absorption in 100$\%$ of cases where no higher-redshift Lyman-limit systems extinguish the flux at the expected wavelength of Ly$\alpha$ absorption, obtaining the largest targeted sample of DLA/sub-DLAs in low-redshift galaxies. We present absorption measurements of neutral hydrogen and metals. Additionally, we present GBT 21-cm emission measurements for 5 of the galaxies (including 2 detections). Combining our sample with the literature, we construct a sample of 115 galaxies associated with DLA/sub-DLAs spanning 0$<$$z$$<$4.4, and examine trends between gas and stellar properties, and with redshift. The H~I column density is anti-correlated with impact parameter and stellar mass. More massive galaxies appear to have gas-rich regions out to larger distances. The specific SFR (sSFR) of absorbing galaxies increases with redshift and decreases with $M^{\ast}$, consistent with evolution of the star-formation main sequence (SFMS). However, $\sim$20$\%$ of absorbing galaxies lie below the SFMS, indicating that some DLA/sub-DLAs trace galaxies with longer-than-typical gas-depletion time-scales. Most DLA/sub-DLA galaxies with 21-cm emission have higher H I masses than typical galaxies with comparable $M^{\ast}$. High $M_{\rm H I}/M^{\ast}$ ratios and high sSFRs in DLA/sub-DLA galaxies with $M^{\ast}$$<$$10^{9}$$M_{\odot}$ suggest these galaxies may be gas-rich because of recent gas accretion rather than inefficient star formation. Our study demonstrates the power of absorption and emission studies of DLA/sub-DLA galaxies for extending galaxy-evolution studies to previously under-explored regimes of low $M^{\ast}$ and low SFR.Comment: 51 pages, 12 figures. Submitted to the Astrophysical Journa