scholarly journals Calculation of the Specific Attenuation in Satellite Bands Due to the Rain in the City of Cartagena and its Importance in the Naval Field

2020 ◽  
Vol 14 (27) ◽  
pp. 39-53
Author(s):  
Lorenzo Cardona ◽  
William Cuadrado

This work studies the attenuation by rain that occurs in the Caribbean region, specifically, in high frequency bands, considering that modern communication systems make greater use of satellite bands. In this sense, the methodology of the recommendation ITU 838 was used to calculate the radio attenuation by rain in the city of Cartagena (Colombia), for the range of 1-100 GHz, and the data provided by the Center of Oceanographic and Hydrographic Research - CIOH were used as atmospheric information sources. As a result, the attenuation for the first quarter of the analyzed years was observed to be low (2.0x10-2 dB/km), growing in the following months until October (1.0x10-1 dB/km), when it decreases again. This information is particularly useful in the naval field, especially, in relation to the use of these frequencies for information exchange.

2020 ◽  
Vol 4 (1) ◽  
pp. 21-34
Author(s):  
Leonel Hernandez ◽  
Piedad Marchena ◽  
Aji Prasetya Wibawa

By 1997, Cisco Systems, a company already consolidated in the technology and communications market, saw the need to train personnel who had the skills to configure, manage, install and support all its products in general at all levels, from design to the implementation of solutions. In Colombia, more precisely in the city of Barranquilla, the ITSA University Institution in the early 2000s saw an excellent opportunity to ally with the University created by Cisco, called Cisco Networking Academy, to train professionals in the Caribbean region capable of face the new challenges that technology in networks is generating day by day, becoming in the first Institution of higher education in the region to provide this type of training with international certification and endorsement. From then on, the local Cisco academy has strengthened and significantly impacted local society, generating valued and skilled labor in the labor market of the city and the region. The purpose of this work is to measure this impact, focused on the Cisco, CCNA, and CCNP flagship courses between 2015 and 2019, verifying how ITSA, through the Cisco Academy, has transformed lives. The research methodology is descriptive, exploratory, and documentary


2014 ◽  
Vol 77 (12) ◽  
pp. 2153-2160 ◽  
Author(s):  
ABIODUN ADESIYUN ◽  
LLOYD WEBB ◽  
LISA MUSAI ◽  
BOWEN LOUISON ◽  
GEORGE JOSEPH ◽  
...  

This investigation determined the frequency of resistance of 84 isolates of Salmonella comprising 14 serotypes recovered from layer farms in three Caribbean countries (Trinidad and Tobago, Grenada, and St. Lucia) to eight antimicrobial agents, using the disc diffusion method. Resistance among isolates of Salmonella was related to the country of recovery, type of sample, size of layer farms, and isolate serotype. Overall, all (100.0%) of the isolates exhibited resistance to one or more of seven antimicrobial agents tested, and all were susceptible to chloramphenicol. The resistance detected ranged from 11.9% to sulphamethoxazole-trimethoprim (SXT) to 100.0% to erythromycin. The difference was, however, not statistically significant (P = 0.23). Across countries, for types of samples that yielded Salmonella, significant differences in frequency of resistance were detected only to SXT (P = 0.002) in Trinidad and Tobago and to gentamycin (P = 0.027) in St. Lucia. For the three countries, the frequency of resistance to antimicrobial agents was significantly different for ampicillin (P = 0.001) and SXT (P = 0.032). A total of 83 (98.8%) of the 84 isolates exhibited 39 multidrug resistance patterns. Farm size significantly (P = 0.032) affected the frequency of resistance to kanamycin across the countries. Overall, among the 14 serotypes of Salmonella tested, significant (P < 0.05) differences in frequency of resistance were detected to kanamycin, ampicillin, and SXT. Results suggest that the relatively high frequency of resistance to six of the antimicrobial agents (erythromycin, streptomycin, gentamycin, kanamycin, ampicillin, and tetracycline) tested and the multidrug resistance detected may pose prophylactic and therapeutic concerns for chicken layer farms in the three countries studied.


2015 ◽  
Vol 20 (3) ◽  
pp. 225-228 ◽  
Author(s):  
Luis Gregorio ESTRADA ◽  
Odethe Alejandra APONTE ◽  
Eduar Elias BEJARANO

<p>El estudio de los insectos asociados a la epidemiología de la leishmaniasis, en la Costa Caribe colombiana, se ha concentrado en los departamentos de Sucre y Córdoba, por consiguiente existe un escaso conocimiento de la fauna de flebotomíneos del resto de la región. En la presente nota se presentan cuatro nuevos registros de <em>Lutzomyia</em> spp., para el departamento de Cesar. Los insectos fueron colectados con dos trampas de luz tipo CDC, equipadas con LED de color azul, en el Balneario Hurtado de la ciudad de Valledupar, Cesar. Se recolectaron en total 50 flebotomíneos, los cuales estuvieron representados por las especies <em>Lutzomyia cayennensis</em> <em>cayennensis</em> (38 %), <em>L. evansi</em> (28 %), <em>L. trinidadensis</em> (14 %), <em>L. venezuelensis</em> (10 %), <em>L. micropyga</em> (6 %) y <em>L. rangeliana</em> (2 %). Como primeros registros para el departamento sobresalen <em>L. evansi</em>, <em>L. venezuelensis</em>, <em>L. micropyga</em> y <em>L. </em><em>rangeliana</em>, con lo que se eleva a ocho el número de especies reportadas hasta la fecha en el Cesar. Entre los nuevos registros se destaca el hallazgo de <em>L. evansi</em>, reconocido vector de <em>Leishmania</em> spp. en la Costa Caribe de Colombia. </p><p><strong>New Records of Species of <em>Lutzomyia</em> (Diptera: Psychodidae) From the Department of Cesar, Colombia</strong></p><p>Studies of the insects associated with the epidemiological cycle of leishmaniasis on the Caribbean coast of Colombia have been focused on the departments of Sucre and Córdoba. The phlebotomine sand fly fauna of the rest of the Caribbean region remains little known. In the present study four species of the genus <em>Lutzomyia</em> are reported from the department of Cesar for the first time. Sand flies were sampled using two CDC light traps with blue color LEDs at Balneario Hurtado, a tourist area in the city of Valledupar. A total of 50 phlebotomine sand flies were collected, of which the species <em>Lutzomyia cayennensis cayennensis</em> (38 % of the sample) and <em>L. trinidadensis</em> (14 %) were already known from the departament. Specimens of <em>L. evansi</em> (28 %), <em>L. venezuelensis</em> (10 %), <em>L. micropyga</em> (6 %) and <em>L. rangeliana</em> (2 %) represent the first records of these species for Cesar, raising the number of known occurrences from the department to eight species. Noteworthy among the new records is the sandfly <em>L. evansi</em>, recognized vector de <em>Leishmania</em> spp. in the Colombian Caribbean coast.</p><p><strong> </strong></p>


Author(s):  
Lisa Williams

Scotland is gradually coming to terms with its involvement in slavery and colonialism as part of the British Empire. This article places the spotlight on the lives of African Caribbean people who were residents of Edinburgh during the eighteenth and nineteenth centuries. I discuss their varied experiences and contributions: from runaways and men fighting for their freedom in the Scottish courts to women working as servants in city households or marrying into Edinburgh high society. The nineteenth century saw activism among political radicals from abolitionists to anticolonialists; some of these figures studied and taught at Edinburgh University. Their stories reflect the Scottish capital’s many direct connections with the Caribbean region.


2015 ◽  
Vol E98.B (5) ◽  
pp. 773-782 ◽  
Author(s):  
Ngochao TRAN ◽  
Tetsuro IMAI ◽  
Yukihiko OKUMURA

2020 ◽  
Vol 10 (4) ◽  
pp. 501-506
Author(s):  
Monisha Ghosh ◽  
Arindam Biswas ◽  
Aritra Acharyya

Aims:: The potentiality of Multiple Quantum Well (MQW) Impacts Avalanche Transit Time (IMPATT) diodes based on Si~3C-SiC heterostructures as possible terahertz radiators have been explored in this paper. Objective:: The static, high frequency and noise performance of MQW devices operating at 94, 140, and 220 GHz atmospheric window frequencies, as well as 0.30 and 0.50 THz frequency bands, have been studied in this paper. Methods: The simulation methods based on a Self-Consistent Quantum Drift-Diffusion (SCQDD) model developed by the authors have been used for the above-mentioned studies. Results: Thus the noise performance of MQW DDRs will be obviously better as compared to the flat Si DDRs operating at different mm-wave and THz frequencies. Conclusion:: Simulation results show that Si~3C-SiC MQW IMPATT sources are capable of providing considerably higher RF power output with the significantly lower noise level at both millimeter-wave (mm-wave) and terahertz (THz) frequency bands as compared to conventional flat Si IMPATT sources.


Author(s):  
Samuel Andrés Gil Ruiz ◽  
Julio Eduardo Cañón Barriga ◽  
J. Alejandro Martínez

2010 ◽  
Vol 5 (1) ◽  
pp. 135
Author(s):  
Kate Kelly

A Review of: Veinot, T., Harris, R., Bella, L., Rootman, I., & Krajnak, J. (2006). HIV/AIDS Information exchange in rural communities: Preliminary findings from a three-province study. Canadian Journal of Information and Library Science, 30(3/4), 271-290. Objective –To explore and analyze, against three theoretical frameworks of information behaviours, how people with HIV/AIDS, their friends, and their family living in rural communities find information on HIV/AIDS. Design – Qualitative, individual, in-depth, semi-structured interviews. Setting – Two rural regions in Ontario, Canada. Subjects – Sixteen participants; 10 people with HIV/AIDS (PHAs) and 6 family members or friends. Methods – Participants were recruited through health care providers, social service agencies and through snowball sampling. Semi-structure interviews were conducted focusing on participants’ experience with HIV/AIDS, how they find and use information on HIV/AIDS, networks for information exchange and the effect of technology on information exchange. Interviews were taped, transcribed, analyzed qualitatively using NVivo software. Results were compared to three theoretical frameworks for information behaviour: 1. purposeful information seeking (i.e., the idea that people purposefully seek information to bridge perceived knowledge gaps); 2. non-purposeful or incidental information acquisition (i.e., the idea that people absorb information from going about daily activities); and 3. information gate keeping (i.e., the concept of private individuals who act as community links and filters for information gathering and dissemination). Main Results – Consistent with the theories: • PHAs prefer to receive information from people they have a personal relationship with, particularly their physician and especially other PHAs. • PHAs’ friends and families rely on their friends and family for information, and are particularly reliant upon the PHA in their lives. • Fear of stigma and discrimination cause some to avoid seeking information or to prefer certain sources of information, such as healthcare providers, who are bound by codes of professional conduct. • Emotional support is important in information provision and its presence supersedes the professional role of the provider (social workers and counsellors were identified as key information sources over medical professionals in this instance). Participants responded negatively to the perceived lack of support from providers including doubting the information provided. • PHAs monitor their worlds and keep up to date about HIV/AIDS. Inconsistent with theories: • Reliance on caregivers for information is not solely explained by fear of stigma or exposure. Rather, it is the specialized knowledge and immersion in HIV/AIDS which is valued. • The distinction between peer or kin sources of information and institutional information sources is less clear and relationships with professionals can turn personal over time. • Inter-personal connections include organisations, not just individuals, particularly AIDS Service Organizations and HIV specialist clinics. • Relatively few incidents of finding useful information about HIV/AIDS incidentally were described. The concept of information just being “out there” was not really applicable to rural settings, likely due to the lack of discussion within participant communities and local media. When it was discussed, participants reported being more likely to gain misinformation through their personal networks. • Incidental information acquisition originates mostly from professional and organisational sources. Participants identified posters, leaflets, and, for those who interacted with organisations, information via mail as contributing to current awareness. • The gate keeping concept does not capture all the information sharing activities undertaken by “gate keepers” in rural areas, and neither does it include formal providers of information, yet all PHAs interviewed identified formal providers as key sources. Conclusion – The findings reinforce some of the existing analytical framework theories, particularly the importance of affective components (i.e. emotional supports) of information seeking, the presence of monitoring behaviours, and of interpersonal sources of information. However, alternate theories may need to be explored as the role of institutional information sources in the lives of PHAs doesn’t match the theoretical predication and the “gate keeper” concept doesn’t capture a significant portion of that role in rural HIV/AIDS information exchange.


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