Grouper culture in floating net cages

The manual describes the culture of groupers (Epinephelus) in floating cages, providing a farming option for grouper growers and also a production alternative to the farmed species being done today, such as shrimp, milkfish and tilapia. The following aspects are covered: species identification for commercially cultured groupers; source of stock; net cage specifications; anchor; hides and shelters; nursery net cage operation; production cages; harvesting; post-harvest; profitability analysis of grouper cage culture; and, cost and return of growing grouper in cages

Numerical modelling of waves in the solar atmosphere

The Sun is the closest star to Earth and the bringer of life for all of us. Remove the Sun and Earth is rendered a lifeless, icy rock floating in outer space. It stands to reason that a thorough understanding of the workings of the Sun would be high priority in the scientific world, and beyond. The outer-most layer of the interior of the Sun comprises of what is known as the convection zone. This chaotic zone produces innumerable pressure waves, which propagate through the Sun. These waves carry the energy of the Sun to its atmosphere and beyond, and are thought to be responsible for the infamous ‘coronal heating problem’. The magnetic nature of the Sun allows both acoustic and magnetic waves, or various combinations of the two, to exist. This is where the complexity lies, with so many different types of waves being produced and exchanging energy between themselves, it is extremely difficult to pinpoint which waves are responsible for the observations we make. Observations and mathematical/physical theories of ever improving quality are used to understand the details of waves in the Sun, however they often lack a bridge to connect them, which is where numerical simulations come in. The work presented here provides a combination of 1.5, 2.5 and 3 dimensional simulations looking to explain how a variety of waves propagate and carry energy through the internal and external layers of the Sun. When a wave reaches a layer in the Sun’s atmosphere where the sound and Alfvén speeds coincide, it splits into two ‘modes’, a fast and slow mode. Recent mathematical findings suggested an incoming shock wave would not only split into its fast and slow components, but that both wave modes would be smoothed as they exit this area. Numerical simulations herein show that only the slow wave is smoothed, with the fast wave propagating unhindered. Within the Sun’s atmosphere, various steep gradients of its physical components are found. These gradients have been proposed to act as barriers to incoming waves, which can be partially reflected off them. Multiple reflection sites suggests cavities can be created that acoustic waves can resonate within. Numerical simulations herein show a stark increase in the velocity of frequencies proposed to be characteristic of a cavity within the chromosphere. This suggests cavities can exist within the Sun’s atmosphere and the amplitude of velocity observations from within these areas must be partially attributed to the resonant effects of the cavities themselves. Following the onset of some solar flares, ripples are observed on the Solar surface emanating from the flare site. These ripples show strong anisotropies in their appearance, a characteristic not well studied. Numerical simulations herein show that these anisotropies can be attributed to both the strength and inclination of the magnetic field but even more so by the nature of the impacting source. A source with motion perpendicular to the solar surface causes constructive interference and higher amplitude ripples are created along the axis of motion

Effet magnéto-optique et optique des couches minces à base de ferrite de cobalt

Cette étude a pour but la mesure des effets magnéto-optiques (rotation Faraday) en fonction du champ magnétique appliqué et en fonction de la longueur d’onde, ainsi que la mesure de la transmittance (effet optique) des couches minces à base de ferrite de cobalt. Les résultats montrent une forte rotation Faraday spécifique avec des cycles d'hystérésis et des spectres de transmittance d'une bonne transparence dans la gamme Télécom (≈1550 nm).Mots-clés: ferrite de cobalt, sol-gel, couches minces, rotation Faraday, transmittance. Magneto-optical effect and optical thin films cobalt ferriteThis study was designed to measure the magneto-optical effect (Faraday rotation) according to the applied magnetic field and a function of the wavelength and the transmittance measurement (optical effect) thin film based on cobalt ferrite. The results show a high specific Faraday rotation with hysteresis cycles and transmittance spectra of a good transparency in the range Telecom (≈1550 nm).Keywords: cobalt ferrite, sol-gel thin films, Faraday rotation, transmittance

Etude des propriétés magnéto-optiques des couches minces à base de ferrite de cobalt obtenues par voie sol-gel

Ce travail est consacré à l'étude des propriétés magnéto-optiques (rotation Faraday) de couches minces à base de ferrite de cobalt obtenues par voie sol-gel. La contribution de la méthode sol-gel utilisée est très importante et cela permet d’obtenir des couches minces ayant une bonne qualité optique. Cette démarche nécessite juste l’utilisation de liquides magnétiques ou ferro fluides, de précurseurs de silice (pas cher) et d’un substrat de verre. Le but est d’obtenir des couches minces et étudier leurs propriétés magnéto-optiques. Les courbes obtenues à la longueur d’onde de 820 nm présentent des cycles d’hystérésis avec des rotations rémanentes de 40, 60 et 81°/cm. Ces résultats présentent une excellente rotation Faraday de 212, 318 et 340°/cm à la longueur d’onde de 820 nm. Ceci montre la forte potentialité de la matrice sol-gel dopée.Mots-clés: nanoparticules magnétiques, ferrite de cobalt, sol-gel, couches minces, rotation Faraday. Study of themagneto-optical properties of thin films cobalt ferrite obtainedby the sol-gel This work is devoted to the study of magneto-optical (Faraday rotation) of thin cobalt ferrite layers obtained by sol-gel. The contribution of the sol-gel method is very important and it allows obtaining thin film shaving a good optical quality. This requires only the use of magnetic fluids or ferro fluids, silica precursors (cheap) and a glass substrate. The goal is to obtain thin layers and study their magneto-optical properties. The curves obtained for the wave length of 820 nm have hysteresis loops with retentive rotations of 40, 60 and 81°/ cm. These results show excellentFaradayrotation 212, 318 and 340°/cm ata wave length of 820 nm. This shows the high potential of the doped sol-gel matrix.Keywords: agnetic nanoparticles, cobalt ferrite, sol-gel, thin films, Faraday rotation

Northern Hemisphere atmospheric stilling accelerates lake thermal responses to a warming world

Climate change, in particular the increase in air temperature, has been shown to influence lake thermal dynamics, with climatic warming resulting in higher surface temperatures, stronger stratification, and altered mixing regimes. Less-studied is the influence on lake thermal dynamics of atmospheric stilling, the decrease in near-surface wind speed observed in recent decades. Here we use a lake model to assess the influence of atmospheric stilling, on lake thermal dynamics across the Northern Hemisphere. From 1980-2016, lake thermal responses to warming have accelerated as a result of atmospheric stilling. Lake surface temperatures and thermal stability have changed at respective rates of 0.33 and 0.38°C decade-1, with atmospheric stilling contributing 15 and 27% of the calculated changes, respectively. Atmospheric stilling also resulted in a lengthening of stratification, contributing 23% of the calculated changes. Our results demonstrate that atmospheric stilling has influenced lake thermal responses to warming

Net cage culture of tilapia in dams and small farm reservoirs

A 14-page manual that details net cage design and cage management after tilapia has been stocked. Some data on operating costs included.The manual describes the net cage of tilapia in dams and small farm reservoirs, which has been found to be a low-cost yet high-income earning farm activity and offers an excellent option as an alternative livelihood for poor inland fisherfolks. The following aspects are covered: 1) Characteristics of a suitable site; 2) Design of the net cages - the floating cage, the stationary/fixed cage; 3) Stocking the net cages - source of juveniles, stocking rate, stocking time, acclimation; 4) Management of the cages - feeds and feeding, monitoring activities; 5) Harvesting - partial harvest, total harvest; and, 6) Profitability analysis

‘Nowhere and no one is safe’: spatial analysis of damage to critical civilian infrastructure in the Gaza Strip during the first phase of the Israeli military campaign, 7 October to 22 November 2023

Background Since the Hamas attacks in Israel on 7 October 2023, the Israeli military has launched an assault in the Gaza Strip, which included over 12,000 targets struck and over 25,000 tons of incendiary munitions used by 2 November 2023. The objectives of this study include: (1) the descriptive and inferential spatial analysis of damage to critical civilian infrastructure (health, education, and water facilities) across the Gaza Strip during the first phase of the military campaign, defined as 7 October to 22 November 2023 and (2) the analysis of damage clustering around critical civilian infrastructure to explore broader questions about Israel’s adherence to International Humanitarian Law (IHL). Methods We applied multi-temporal coherent change detection on Copernicus Sentinel 1-A Synthetic Aperture Radar (SAR) imagery to detect signals indicative of damage to the built environment through 22 November 2023. Specific locations of health, education, and water facilities were delineated using open-source building footprint and cross-checked with geocoded data from OCHA, OpenStreetMap, and Humanitarian OpenStreetMap Team. We then assessed the retrieval of damage at and with close proximity to sites of health, education, and water infrastructure in addition to designated evacuation corridors and civilian protection zones. The Global Moran’s I autocorrelation inference statistic was used to determine whether health, education, and water facility infrastructure damage was spatially random or clustered. Results During the period under investigation, in the entire Gaza Strip, 60.8% (n = 59) of health, 68.2% (n = 324) of education, and 42.1% (n = 64) of water facilities sustained infrastructure damage. Furthermore, 35.1% (n = 34) of health, 40.2% (n = 191) of education, and 36.8% (n = 56) of water facilities were functionally destroyed. Applying the Global Moran’s I spatial inference statistic to facilities demonstrated a high degree of damage clustering for all three types of critical civilian infrastructure, with Z-scores indicating < 1% likelihood of cluster damage occurring by random chance. Conclusion Spatial statistical analysis suggests widespread damage to critical civilian infrastructure that should have been provided protection under IHL. These findings raise serious allegations about the violation of IHL, especially in light of Israeli officials’ statements explicitly inciting violence and displacement and multiple widely reported acts of collective punishment

Synthesis, magnetic and optical properties of core/shell Co1-xZnxFe2O4/SiO2 nanoparticles

The optical properties of multi-functionalized cobalt ferrite (CoFe2O4), cobalt zinc ferrite (Co0.5Zn0.5Fe2O4), and zinc ferrite (ZnFe2O4) nanoparticles have been enhanced by coating them with silica shell using a modified Stöber method. The ferrites nanoparticles were prepared by a modified citrate gel technique. These core/shell ferrites nanoparticles have been fired at temperatures: 400°C, 600°C and 800°C, respectively, for 2 h. The composition, phase, and morphology of the prepared core/shell ferrites nanoparticles were determined by X-ray diffraction and transmission electron microscopy, respectively. The diffuse reflectance and magnetic properties of the core/shell ferrites nanoparticles at room temperature were investigated using UV/VIS double-beam spectrophotometer and vibrating sample magnetometer, respectively. It was found that, by increasing the firing temperature from 400°C to 800°C, the average crystallite size of the core/shell ferrites nanoparticles increases. The cobalt ferrite nanoparticles fired at temperature 800°C; show the highest saturation magnetization while the zinc ferrite nanoparticles coated with silica shell shows the highest diffuse reflectance. On the other hand, core/shell zinc ferrite/silica nanoparticles fired at 400°C show a ferromagnetic behavior and high diffuse reflectance when compared with all the uncoated or coated ferrites nanoparticles. These characteristics of core/shell zinc ferrite/silica nanostructures make them promising candidates for magneto-optical nanodevice applications

Morphological, physiological and behavioural evaluation of a ‘Mice in Space’ housing system

Environmental conditions likely affect physiology and behaviour of mice used for life sciences research on Earth or in Space. Here, we analysed the effects of cage confinement on the weightbearing musculoskeletal system, behaviour and stress of wild-type mice (C57BL/6JRj, 30 g b.wt., total n = 24) housed for 25 days in a prototypical ground-based and fully automated life support habitat device called “Mice in Space” (MIS). Compared with control housing (individually ventilated cages) the MIS mice revealed no significant changes in soleus muscle size and myofiber distribution (type I vs. II) and quality of bone (3-D microarchitecture and mineralisation of calvaria, spine and femur) determined by confocal and micro-computed tomography. Corticosterone metabolism measured non-invasively (faeces) monitored elevated adrenocortical activity at only start of the MIS cage confinement (day 1). Behavioural tests (i.e., grip strength, rotarod, L/D box, elevated plus-maze, open field, aggressiveness) performed subsequently revealed only minor changes in motor performance (MIS vs. controls). The MIS habitat will not, on its own, produce major effects that could confound interpretation of data induced by microgravity exposure during spaceflight. Our results may be even more helpful in developing multidisciplinary protocols with adequate scenarios addressing molecular to systems levels using mice of various genetic phenotypes in many laboratories

Spatial representation for navigation in animats

This article considers the problem of spatial representation for animat navigation systems. It is proposed that the global navigation task, or "wayfinding, " is best supported by multiple interacting subsystems, each of which builds its own partial representation of relevant world knowledge. Evidence from the study of animal navigation is reviewed to demonstrate that similar principles underlie the wayfinding behavior of animals, including humans. A simulated wayfinding system is described that embodies and illustrates several of the themes identified with animat navigation. This system constructs a network of partial models of the quantitative spatial relations between groups of salient landmarks. Navigation tasks are solved by propagating egocentric view information through this network, using a simple but effective heuristic to arbitrate between multiple solutions