Yarkovsky Drift Detections for 247 Near-Earth Asteroids

The Yarkovsky effect is a thermal process acting upon the orbits of small celestial bodies, which can cause these orbits to slowly expand or contract with time. The effect is subtle (da/dt ~ 10^-4 au/My for a 1 km diameter object) and is thus generally difficult to measure. We analyzed both optical and radar astrometry for 600 near-Earth asteroids (NEAs) for the purpose of detecting and quantifying the Yarkovsky effect. We present 247 NEAs with measured drift rates, which is the largest published set of Yarkovsky detections. This large sample size provides an opportunity to examine the Yarkovsky effect in a statistical manner. In particular, we describe two independent population-based tests that verify the measurement of Yarkovsky orbital drift. First, we provide observational confirmation for the Yarkovsky effect's theoretical size dependence of 1/D, where D is diameter. Second, we find that the observed ratio of negative to positive drift rates in our sample is 2.34, which, accounting for bias and sampling uncertainty, implies an actual ratio of $2.7^{+0.3}_{-0.7}$. This ratio has a vanishingly small probability of occurring due to chance or statistical noise. The observed ratio of retrograde to prograde rotators is two times lower than the ratio expected from numerical predictions from NEA population studies and traditional assumptions about the sense of rotation of NEAs originating from various main belt escape routes. We also examine the efficiency with which solar energy is converted into orbital energy and find a median efficiency in our sample of 12%. We interpret this efficiency in terms of NEA spin and thermal properties.Comment: 27 pages, 9 figures, published in the Astronomical Journal, 159, 92, 202

Pressure induced electride phase formation in calcium: A key to its strange high-pressure behavior

Elemental calcium (Ca), a simple metal at ambient conditions, has attracted huge interest because of its unusual high-pressure behavior in structural, electrical, and melting properties whose origin remain unsolved. Here, using a theoretical framework appropriate for describing electride phase formation, i.e., the presence of anionic electrons, we establish electride formation in Ca at a pressure as low as 8 GPa. Our analysis shows that under pressure the valence electrons of Ca localize at octahedral holes and exhibit anionic character which is responsible for its strange pressure behavior. Our calculated enthalpy and electrical resistance indicate that Ca will directly transform from an FCC-electride phase to an SC-electride phase near 30 GPa thereby avoiding the intermediate BCC phase. These findings are not limited to Ca but might hold a key to the understanding of host-guest type structures which occur in other elemental solids though at much higher pressures.Comment: 6 pages, 5 figure

Kitozan male molekulske mase kao nosač hidrodinamički uravnoteženog sustava za usporenu isporuku ciprofloksacin hidroklorida

Chitosan has become a focus of major interest in recent years due to its excellent biocompatibility, biodegradability and non-toxicity. Although this material has already been extensively investigated in the design of different types of drug delivery systems, it is still little explored for stomach specific drug delivery systems. The objective of the present investigation was to explore the potential of low molecular mass chitosan (LMCH) as carrier for a hydrodynamically balanced system (HBS) for sustained delivery of water soluble drug ciprofloxacin hydrochloride (CP). Various formulations were prepared by physical blending of drug and polymer(s) in varying ratios followed by encapsulation into hard gelatin capsules. All the formulations remained buoyant in 0.1mol L1 HCl (pH 1.2) throughout the experiment. Effect of addition of xanthan gum (XG) or ethyl cellulose (EC) on drug release was also investigated. Zero order drug release was obtained from the formulations containing LMCH alone or in combination with XG, and in one instance also with EC. Our results suggest that LMCH alone or in combination with XG is an excellent material for stomach specific sustained delivery of CP from hydrodynamically balanced single unit capsules.Zbog svoje biokompatibilnosti, biorazgradljivosti i netoksičnosti kitozan je vrlo interesantan istraživačima u području farmaceutske tehnologije. Najviše se upotrebljavao u dizajniranju različitih sustava za isporuku lijekova ali vrlo malo za sustave za specifičnu isporuku u želucu. Cilj ovog rada bio je ispitati mogućnost upotrebe kitozana male molekulske mase (LMCH) kao nosača u hidrodinamički balansiranom sustavu (HBS) za usporenu isporuku vodotopljivog lijeka ciprofloksacin hidroklorida (CP). Pripravljene su različite formulacije stvaranjem fizičke smjese lijeka i polimera u različitim omjerima, koje su potom kapsulirane u želatinske kapsule. Svi su pripravci za vrijeme cijelog eksperimenta ostali plutati u 0,01mol L1 HCl (pH 1,2). Ispitivan je i učinak ksantan gume (XG) ili etilceluloze (EC) na oslobađanje lijeka. Oslobađanje lijeka nultog reda postignuto je iz formulacija koje sadrže samo LMCH ili LMCH u kombinaciji sa XG i u jednom slučaju s EC. Dobiveni rezultati pokazuju da je LMCH, sam ili u kombinaciji sa XG, izvrstan materijal za sustave za specifičnu isporuku CP iz hidrodinamički balansiranih kapsula

COVID-19 Pandemic: New Challenges for Environmental Sustainability in Developing Countries

Coronavirus disease-19 (COVID-19), produced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global pandemic, giving rise to a serious health threat globally. The global Covid-19 pandemic is a setback for sustainable development and compromise the world commitment to the 2030 Agenda for Sustainable Development. The measures taken to control the spread of the virus and the slowdown of economic activities during lockdown have significant effects on the environment. Therefore, this review discuss the indirect positive and negative impacts of Covid-19 pandemic towards sustainable environment. This study indicates that, the pandemic situation significantly improves air quality in different cities across the world, reduces the emission of greenhouse gases, and decreases water and noise pollution, which may help in the restoration of the ecosystem. In addition, there are also some negative impact of Covid-19, such as increase of medical waste, haphazard use and disposal of disinfectants, mask, and gloves; and burden of untreated wastes continuously endangering the environment. It points to the fact that the net effect has been positive; in terms of reduction in greenhouse emissions, oil exploration activities, and pollution. It is expected that the proper implementation of the proposed suggestion might be helpful for the global environmental sustainability

COVID-19 Pandemic: New Challenges for Environmental Sustainability in Developing Countries

Coronavirus disease-19 (COVID-19), produced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global pandemic, giving rise to a serious health threat globally. The global Covid-19 pandemic is a setback for sustainable development and compromise the world commitment to the 2030 Agenda for Sustainable Development. The measures taken to control the spread of the virus and the slowdown of economic activities during lockdown have significant effects on the environment. Therefore, this review discuss the indirect positive and negative impacts of Covid-19 pandemic towards sustainable environment. This study indicates that, the pandemic situation significantly improves air quality in different cities across the world, reduces the emission of greenhouse gases, and decreases water and noise pollution, which may help in the restoration of the ecosystem. In addition, there are also some negative impact of Covid-19, such as increase of medical waste, haphazard use and disposal of disinfectants, mask, and gloves; and burden of untreated wastes continuously endangering the environment. It points to the fact that the net effect has been positive; in terms of reduction in greenhouse emissions, oil exploration activities, and pollution. It is expected that the proper implementation of the proposed suggestion might be helpful for the global environmental sustainability

Dodatak supranutritivnih doza cinkova sulfata i bakterija Bacillus firmus ubijenih toplinom u obrok rano odbijenih svinja: utjecaj na rast, funkciju neutrofila i upalne citokine

The objective of the study was to investigate the effect of supplementation of a supranutritional dose of zinc sulfate (ZnSO4) and Bacillus firmus derived bio-response modifier (BRM) on growth, blood neutrophil functions, pro-inflammatory and anti-inflammatory cytokine responses in early weanling piglets. In total, 45 piglets (age of 19.25 ± 0.84 days) were randomly divided into five groups: I (basal diet only), II (basal diet supplemented with ZnSO4), III (basal diet supplemented with BRM), IV (basal diet supplemented with ZnSO4 plus BRM) and V (basal diet without weaning from dam). The production of myeloperoxidase (MPO) and superoxide anion (O2-), and the concentration of transforming growth factor-β1 (TGF-β1) were markedly reduced, whereas the concentrations of intercellular adhesion molecule 1 (ICAM1), and monocyte chemoattractant protein 1 (MCP1) were significantly (P0.05) but a marked increase (P0,05), ali kod prasadi iz skupine II. i III. je 14. i 7. dana opaženo znakovito povišenje (P<0,05) ICAM1, MCP1, te sniženje koncentracije TGF-β1. U prasadi iz skupine IV dodavanje BRM i ZnSO4 u osnovnom obroku poboljšalo je MPO (2. dan) i O2- (7. dan), bez znakovitih promjena u rastu i koncentraciji citokina. Na kraju, zaključeno je da dodavanje kombinacije BRM i ZnSO4 u obroku potiče urođenu imunost prasadi što nije slučaj kada se ZnSO4 ili BRM dodaju zasebno. Rezultati ovog istraživanja pomoći će u formuliranju učinkovitog upravljanja hranidbom kod rano odbijene prasadi u krdu svinja

Control of Ralstonia Solanacearum Infection in Tomato, Brinjal and Capsicum by Antibiotic Sensitivity Test

Ralstonia solanacearum is one of the important dreaded soil's borne bacterial phytopathogen which causes enormous losses in the crop plants in tropical, subtropical and temperate region of the world. In India, the disease is highly prevalent and active throughout the year where the soil is acidic in the Eastern Plateau and Hill Region. Once the disease is established in the field, it cannot be controlled by chemical means. Keeping these in view, screening of potential antibiotics for the management of R. solanacearum was done. In the present study, three strains of R. solanacearum were isolated from Brinjal, Tomato and Capsicum. Against these three strains of R. solanacearum, four antibiotics were screened through food poison techniques viz. Kasugamycin, Streptomycin, Ceftriaxone and Gentamicin. The different strains of R. solanacearum and antibiotic sensitivity showed varied response. Among the screened antibiotics, Gentamicin showed strong antibacterial efficacy which inhibited 100% Colony-forming Unit (cfu) at very low concentration (1 ppm) followed by Ceftriaxone which inhibited &gt;50% cfu at 1 ppm against all three strains. However, Streptomycin also showed antibacterial efficacy and inhibited &gt;50% cfu at 3 ppm, but Kasugamycin was found less antibacterial as compared to other tested antibiotics and inhibited &gt;50% cfu at 4 ppm