Review and Perspectives of the Use of Alginate as a Polymer Matrix for Microorganisms Applied in Agro-Industry.

Alginate is a polysaccharide with the property of forming hydrogels, which is economic production, zero toxicity, and biocompatibility. In the agro-industry, alginate is used as a super absorbent polymer, coating seeds, fruits, and vegetables and as a carrier of bacteria and fungi as plant-growth promoters and biocontrol. The latter has a high impact on agriculture since the implementation of microorganisms in a polymer matrix improves soil quality; plant nutrition, and is functional as a preventive measure for the appearance of phytopathogenic. Additionally, it minimizes losses of foods due to wrong post-harvest handling. In this review, we provide an overview of physicochemical properties of alginate, some methods for preparation and modification of capsules and coatings, to finally describe its application in agro-industry as a matrix of plant-growth-promoting microorganisms, its effectiveness in cultivation and post-harvest, and its effect on the environment, as well as the prospects for future agro-industrial applications.

Optical Methods Based on Ultraviolet, Visible, and Near-Infrared Spectra to Estimate Fat and Protein in Raw Milk: A Review.

The present manuscript focuses on reviewing the optical techniques proposed to monitor milk quality in dairy farms to increase productivity and reduce costs. As is well known, the quality is linked to the fat and protein concentration; in addition, this issue is crucial to maintaining a healthy herd and preventing illnesses such as mastitis and ketosis. Usually, the quality of the milk is carried out with invasive methods employing chemical reagents that increase the time analysis. As a solution, several spectroscopy optical methods have been proposed, here, the benefits such as non-invasive measurement, online implementation, rapid estimation, and cost-effective execution. The most attractive optical methods to estimate fat and protein in cow's milk are compared and discussed considering their performance. The analysis is divided considering the wavelength operation (ultraviolet, visible, and infrared). Moreover, the weaknesses and strengths of the methods are fully analyzed. Finally, we provide the trends and a recent technique based on spectroscopy in the visible wavelength.

Applications of solar and wind renewable energy in agriculture: A review.

The growing demand for food and the unstable price of fossil fuels has led to the search for environmentally friendly sources of energy. Energy is one of the largest overhead costs in the production of greenhouse crops for favorable climate control. The use of wind-solar renewable energy system for the control of greenhouse environments reduces fuel consumption and so enhances the sustainability of greenhouse production. This review describes the impact of solar-wind renewable energy systems in agricultural greenhouses.

A New Method for Total Fat Detection in Raw Milk Based on Dual Low-Coherence Interferometer.

The present work experimentally demonstrates a multimode fiber optic sensing setup for total fat detection in raw milk samples. The optical fiber arrangement incorporates a low-coherence Fabry-Perot cavity operating in dual response. The system provides a phase modulation for a total fat range from 0.97% to 4.36%. Here, the protein remains constant at 3%. The data indicate that maximum sensitivity close to 616 pm/%fat could be achieved at optimal wavelength operation (500 nm). In addition, the system presented a minimal repeatability error measurement of 0.08%, cross-sensitivity between protein and fat of 0.134, and a regression coefficient of r2=0.9763. A thermal analysis was also performed, which indicate the temperature immunity of the system. The proposed method represents a low-cost alternative to detect minimal fat variations in raw cow milk.

Dual-Phase Lock-In Amplifier Based on FPGA for Low-Frequencies Experiments.

Photothermal techniques allow the detection of characteristics of material without invading it. Researchers have developed hardware for some specific Phase and Amplitude detection (Lock-In Function) applications, eliminating space and unnecessary electronic functions, among others. This work shows the development of a Digital Lock-In Amplifier based on a Field Programmable Gate Array (FPGA) for low-frequency applications. This system allows selecting and generating the appropriated frequency depending on the kind of experiment or material studied. The results show good frequency stability in the order of 1.0 × 10(-9) Hz, which is considered good linearity and repeatability response for the most common Laboratory Amplitude and Phase Shift detection devices, with a low error and standard deviation.

Ecophysiological responses to the effect of annual management on an endemic viviparous fish in central plateau of México

Studies on the biological aspects of fish typically focus on species that currently have commercial value, causing species that lack such market value to be ignored. This is the case of several freshwater fish, specifically of several members of the Goodeidae family. In the State of Querétaro there are several species of this family characterized for being viviparous and having distinctive sexual dimorphism that may have commercial potential. The subject of this study is Girardinichthys multiradiatus, a viviparous fish endemic to the upper-half of the Lerma River basin. The lack of knowledge regarding its biology and ecology has prevented the development of guidelines to manage its habitat and to preserve its population. The objective was to determine the ecophysiological responses of G. multiradiatus to its environmental management. From the sampling (24 hours every two months) population structure and dynamics were analyzed throughout a hydrological cycle using meristic data (standard length). Trophic and ecophysiological responses to fluctuations in environmental factors were also identified. Although the mexcalpique is a polytrophic species, results show that it prefers feeding on Diptera or Cladocera, while detritus is the third substance frequently found in their stomachs. Environmentally, the water regime is responsible for fluctuations in the population dynamics of the species, while temperature changes are the most influence its energy balance. These results can guide efforts to conserve this species and its habitat.

Los estudios sobre aspectos biológicos de los peces se centran, generalmente, en especies que actualmente tienen interés comercial, lo que ocasiona que las especies que carecen de tal valor en el mercado estén prácticamente olvidadas; tal es el caso de varios peces de agua dulce y más específicamente de algunos integrantes de la familia Godeidae. En el estado de Querétaro se encuentran varias especies pertenecientes a esta familia que se caracterizan por ser vivíparas y presentar un marcado dimorfismo sexual, aspectos que pudieran definir un potencial comercial. El pez objeto de este estudio es Girardinichthys multiradiatus, especie endémica de la parte alta-media de la cuenca del río Lerma; los lugares donde habita presentan procesos de degradación, fragmentación del hábitat y extracción de agua, que ponen en riesgo su existencia. Además, la falta de conocimiento sobre su biología y ecología, no permiten que se elaboren pautas de gestión de sus poblaciones o hábitats con fines de conservación y preservación de la especie o de los procesos ecológicos que mantienen la estabilidad del ecosistema que ocupa. En el presente trabajo se estudió la población de G. multiradiatus localizada en el bordo de San Martín, Amealco. El objetivo del presente trabajo fue determinar las respuestas ecofisológicas de G. multiradiatus debido al manejo de su ambiente. Se hicieron ciclos de 24 horas en muestreos bimensuales a lo largo de un ciclo hidrológico en el que se analizaron la estructura y dinámica de la población; asimismo, se determinaron las respuestas tróficas y ecofisiológicas de la población ante las fluctuaciones de los factores ambientales de su entorno. Los resultados muestran que aunque el mexcalpique es polítrofo, prefiere dípteros, cladóceros y detritus, habiendo diferencias alimentarias entre las clases de edades. G. multiradiatus presenta 12 clases de talla que van de 8 a 48 mm de longitud patrón. En el medio ambiente, el régimen de agua es responsable de las fluctuaciones en la dinámica poblacional de las especies, mientras que el cambio de temperatura es el factor de mayor influencia sobre su balance energético. Estos resultados pueden guiar los esfuerzos para conservar esta especie y su hábitat.

Long-range wireless mesh network for weather monitoring in unfriendly geographic conditions.

In this paper a long-range wireless mesh network system is presented. It consists of three main parts: Remote Terminal Units (RTUs), Base Terminal Units (BTUs) and a Central Server (CS). The RTUs share a wireless network transmitting in the industrial, scientific and medical applications ISM band, which reaches up to 64 Km in a single point-to-point communication. A BTU controls the traffic within the network and has as its main task interconnecting it to a Ku-band satellite link using an embedded microcontroller-based gateway. Collected data is stored in a CS and presented to the final user in a numerical and a graphical form in a web portal.