Carlos Perez

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Partidos políticos y medios de comunicación como agentes movilizadores del voto

A pesar de que el desencanto de la ciudadania con quienes representan la politica es una norma se... more A pesar de que el desencanto de la ciudadania con quienes representan la politica es una norma segun muestran sondeos de opinion, las elites de la misma tienen capacidad de movilizar nichos de poblacion cuando se inmiscuyen en explicar los beneficios del ejercicio del voto (Rosenstone y Hansen 1993). Tanto estas elites politicas como otros legitimadores de los medios de comunicacion y dirigentes civicos que hagan parte de campanas de invitacion a ser activos en las jornadas democraticas, han demostrado su efectividad. En este sentido, uno de los protagonistas de todo proceso electoral, los partidos politicos, lograron establecer una masa critica de seguidores anclados a lo que representaban esas colectividades, sin embargo con el pasar de los anos y al devenir el desencanto que llego hacia ellos, los partidos han dado paso a rupturas ( cleavages ) que transformaron tanto la esencia de ellos mismos, como su relacion con la ciudadania (Dix, 1989).

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Climate Change in the High Andes

The International Journal of Environmental, Cultural, Economic, and Social Sustainability: Annual Review, 2010

Global climate change represents a major threat to sustainable farming in the Andes. Farmers have... more Global climate change represents a major threat to sustainable farming in the Andes. Farmers have used local ecological knowledge and intricate production systems to cope, adapt and reorganize to meet climate uncertainty and risk, which have always been a fact of life. Those traditional systems are generally highly resilient, but the predicted effects, rates and variability of climate change may push them beyond their range of adaptability. This article examines the extent of actual and potential impacts of climate variability and change on small-scale farmers in the highland Andes of Bolivia, Ecuador and Peru. It describes how climate change impacts agriculture through deglaciation, changes in hydrology, soil and pest and disease populations. The article highlights some promising adaptive strategies currently in use by or possible for producers, rural communities and local institutions to mitigate climate change effects while preserving the livelihoods and environmental and social sustainability of the region.

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The first gold coins struck in Brazil: myth or reality?

ArchéoSciences, 2009

Besieged in Pernambuco by the Portuguese, the Dutch issued in 1645 and 1646, to pay their soldier... more Besieged in Pernambuco by the Portuguese, the Dutch issued in 1645 and 1646, to pay their soldiers, the irst coin inscribed "BRASIL". Named obsidional, it is said to have been fabricated by melting either African gold or gold tableware. It is only in 1694 that the Brazilian itinerant mint was created in Bahia, and successively closed and transferred to Rio de Janeiro in 1698, to Pernambuco in 1700, and back to Rio de Janeiro in 1702. his itinerary is related to the exhaustion of the local metal supplies, until the discovery of gold in Brazil in the late 1600s. SR-XRF analyses of a small set of coins issued by the Dutch West Indies Company and the irst Rio de Janeiro mint show the use of diferent gold alloys and the ratios of trace elements allow advancing several assumptions on the provenance of the gold. Résumé : Ain de payer la solde de leurs soldats assiégés par les Portugais à Pernambuco, les Hollandais frappèrent, en 1645 et 1646, les premières monnaies portant l'inscription « BRASIL », dites obsidionales, à partir de la fonte d'or africain ou de vaisselle d'or. Ce n'est qu'en 1694 que le premier atelier itinérant brésilien fut créé à Bahia; il fut ensuite fermé et transféré à Rio de Janeiro en 1698, puis à Pernambuco en 1700 avant de s'installer de nouveau à Rio de Janeiro en 1702. Ces délocalisations successives apparaissent liées à l'épuisement des stocks de métal jusqu'aux découvertes de gisements d'or au Brésil à la in du XVI e siècle. L'analyse par SR-XRF de quelques monnaies émises par la Compagnie Hollandaise des Indes Occidentales et d'autres frappées par le premier atelier de Rio de Janeiro indique que l'utilisation de diférents alliages d'or et les teneurs en certains éléments traces apportent quelques indices quant à la provenance de l'or.

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Malignant tumors of the tonsil. Analysis of failures and factors affecting prognosis

The American journal of roentgenology, radium therapy, and nuclear medicine, 1972

... I MALIGNANT TUMORS OF THE TONSIL* ANALYSIS OF FAILURES AND FACTORS AFFECTING PROGNOSIS By CAR... more

Esthesioneuroblastomas

Encyclopedia of Radiation Oncology, 2013

Physics of Radiotherapy Planning and Delivery

Medical Radiology, 2011

A solid foundation in the physics concepts used in the planning and delivery of the cancer patien... more A solid foundation in the physics concepts used in the planning and delivery of the cancer patient’s radiation therapy is one of the fundamental cornerstones for the practice of radiation therapy. The essential concepts are discussed in this chapter, including a brief review of modern treatment machines, basic dosimetry parameters used in treatment planning, monitor unit and dose calculation methods, dose calculation algorithms and correction factors for the effects of patient topography and internal heterogeneities, isodose distributions for various combined fields, peripheral dose, field junctions, field shaping and special considerations including patients with cardiac pacemakers, fetal dose and gonadal dose. These topics are presented in detail suitable for practicing radiation oncologists and physician residents.

New records of octocorals (Cnidaria: Anthozoa) from the Brazilian coast

Aquatic Biology, 2011

The Oceanography Department of the Federal University of Pernambuco (DOCEAN-UFPE) possesses a lar... more

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Synthesis of Ta2O5 Nanorods in the Presence of Poly L - Lysine by a Sol-Gel Process

Annali di Chimica, 2005

... Humberto MONREAL ROMERO(°) 1 , Alberto MARTINEZ VILLAFAÑE 1 , José CHACON NAVA 1 , Perla GARC... more

Three-Dimensional Conformal Therapy Versus Standard Radiation Therapy in Localized Carcinoma of Prostate: An Update

Clinical Prostate Cancer, 2002

This study updates technical principles and results of 3-dimensional conformal radiation therapy ... more This study updates technical principles and results of 3-dimensional conformal radiation therapy (3D-CRT) in localized carcinoma of the prostate. Between January 1992 and December 1999, 312 patients were treated with 3D-CRT and 135 patients were treated with bilateral arcs standard radiation therapy (SRT) alone for clinical stage T1b-c or T2 histologically confirmed prostate cancer. None of these patients received hormonal therapy. Mean follow-up for patients in the 3D-CRT group was 3.2 years (range, 2-5.9 years) and for SRT patients, 4.7 years (range, 4-7 years). For 3D-CRT, 7 intersecting fields were used (cerrobend blocking or multileaf collimation) to deliver 68-74 Gy to the prostate. Standard radiation therapy consisted of bilateral 120°rotational arcs, with portals using 2-cm margins around the prostate to deliver 68-70 Gy to the prostate. The criterion for chemical disease-free survival was a postirradiation prostate-specific antigen (PSA) value following the American Society for Therapeutic Radiology and Oncology guidelines. Symptoms during treatment were quantitated weekly, and late effects were assessed every 4-6 months. Dosevolume histograms showed a two-thirds reduction with 3D-CRT in normal bladder or rectum receiving ≥ 70 Gy with 3D-CRT. Higher 5-year chemical disease-free survival was observed with 3D-CRT (75% for T1b-c and 79% for T2 tumors) compared with SRT (61% and 65%, P = 0.01 and P = 0.12, respectively). There was no statistically significant difference in chemical disease-free survival in patients with Gleason score of ≤ 4 (P = 0.85), but, with Gleason score of 5-7, the 5year survival rates were 83% with 3D-CRT and 59% with SRT (P ≤ 0.01). In 245 patients with pretreatment PSA of ≤ 10 ng/mL treated with 3D-CRT, the chemical disease-free rate was 80% versus 72% in 98 patients treated with SRT (P = 0.21). In patients with PSA of 10.1-20 ng/mL, the chemical disease-free survival rate for 50 patients treated with 3D-CRT was 71% compared with 43% for 20 patients treated with SRT (P = 0.02). The corresponding values were 59% and 16%, respectively, for patients with PSA levels > 20 ng/mL (P = 0.09). On multivariate analysis, the most important prognostic factors for chemical failure were pretreatment PSA (P = 0.004), nadir PSA (P = 0.001), and 3D-CRT technique (P = 0.012). Moderate dysuria was reported by 2%-5% of patients treated with 3D-CRT in contrast to 6%-9% of patients treated with SRT. The incidence of moderate loose stools or diarrhea, usually after the fourth week of treatment, was 3%-5% in the 3D-CRT patients and 8%-19% in the SRT group. Late intestinal grade 2 morbidity (proctitis or rectal bleeding) was 1% in the 3D-CRT group in contrast to 7% in SRT patients. The 3D-CRT spares more normal tissues, yields higher chemical disease-free survival, and results in less treatment morbidity than SRT in treatment of stage T1-T2 prostate cancer. Follow-up at ≥ 10 years is needed to confirm these observations.

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The Simulation Process in the Determination and Definition of the Treatment Volume and Treatment Planning

Medical Radiology

Three-Dimensional Treatment Planning and Conformal Therapy

Medical Radiology

Preliminary clinical results are presented for 209 patients with cancer who had treatment planned... more Preliminary clinical results are presented for 209 patients with cancer who had treatment planned on our three-dimensional radiation treatment planning (3-D RTP) system and were treated with external beam conformal radiation therapy. Average times (min) for CT volumetric simulation were: 74 without or 84 with contrast material; 36 for contouring of tumor/target volume and 44 for normal anatomy; 78 for treatment planning; 53 for plan evaluation/optimization; and 58 for verification simulation. Average time of daily treatment sessions with 3-D conformal therapy or standard techniques was comparable for brain, head and neck, thoracic, and hepatobiliary tumors (11.8-14 min and 11.5-12.1, respectively). For prostate cancer patients treated with 3-D conformal technique and Cerrobend blocks, mean treatment time was 19 min; with multileaf collimation it was 14 min and with bilateral arc rotation, 9.8 min. Acute toxicity was comparable to or lower than with standard techniques. Sophisticated 3-D RTP and conformal irradiation can be performed in a significant number of patients at a reasonable cost. Further efforts, including dose-escalation studies, are necessary to develop more versatile and efficient 3-D RTP systems and to enhance the cost benefit of this technology in treatment of patients with cancer.

Glomus Tumors

Encyclopedia of Radiation Oncology, 2013

Radiation Therapy for Increasing Prostate-Specific Antigen Levels After Radical Prostatectomy

Clinical Prostate Cancer, 2003

Herein we present data on outcomes in patients with increasing prostate-specific antigen (PSA) le... more Herein we present data on outcomes in patients with increasing prostate-specific antigen (PSA) levels treated with irradiation to the pelvis and/or prostatic bed after radical prostatectomy. Between 1988 and 1998, 92 patients who presented with increasing PSA levels after radical prostatectomy were treated with irradiation, 29 to the pelvis and prostatic bed and 63 to the prostatic bed only. The mean follow-up was 4 years for the 3D-CRT group and 6.5 years for the standard radiation therapy group. Criterion for biochemical failure was an increase in post irradiation PSA level on ≥ 1 consecutive measurement. Patients were classified into 3 risk groups based on prognostic factors: pathologic tumor extent and stage, Gleason score, and PSA levels before irradiation. Acute and late morbidity was quantitatively evaluated in all patients. There was a close correlation between the preirradiation PSA level and the probability of 4-year biochemical failure-free survival (75% with PSA levels ≤ 1 ng/mL, 30% with PSA levels of 1.1-2 ng/mL, and 20% with PSA levels > 2 ng/mL; P = 0.05). The 4-year chemical failure rate was 20% in the low/intermediate-risk group and 65% in the high-risk group (P = 0.36). In 20 patients in the low-PSA group (≤ 1 ng/mL) receiving doses > 62 Gy, no biochemical failures have been detected in comparison to a 70% failure rate at 4 years in patients treated with lower doses (P = 0.15). In the higher-PSA groups, no impact of irradiation dose on outcome was noted (40%-60% incidence of failure at 3 years). Pelvic irradiation was associated with a trend toward decreased biochemical failure rate in the low-PSA group (70% vs. 0% at 4 years; P = 0.35), but not in the high-PSA group. Only 1 patient (1.5%) experienced clinical local recurrence in the prostatic bed and 2 patients (1.8%) had distant metastases. Treatment has been very well tolerated, with only 3 patients in the arc-rotation group experiencing grade 2 treatment toxicity. Prostate bed irradiation is an effective treatment in a significant proportion of patients who present with a biochemical failure after radical prostatectomy.

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Implementing biologic target volumes in radiation treatment planning for non-small cell lung cancer

Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2004

18F-FDG PET offers the radiation oncology community the ability to incorporate biologic informati... more 18F-FDG PET offers the radiation oncology community the ability to incorporate biologic information into radiation therapy targets. To date, most of the work in this arena has involved patients with non-small cell lung cancer (NSCLC). The literature suggests that biologic targeting with PET alters the radiation treatment volume significantly in 30%-60% of NSCLC patients for whom definitive therapy is planned. This is mostly the result of the incorporation of regional nodes with 18F-FDG avidity that were previously judged to be uninvolved by CT criteria. The development of the integrated PET/CT scanner is a valuable tool that improves diagnostic accuracy for staging this disease and will increase the accessibility of PET for radiation treatment planning. Its implementation into radiation treatment planning requires strong collaboration between radiation oncologists and nuclear physicians. In this report, we will review the literature on PET-based radiation treatment planning, its pot...

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Uncertainties in radiation therapy: target definition in carcinoma of the uterine cervix

Rays

In treatment of patients with carcinoma of the cervix, as in any other malignant tumor, accurate ... more In treatment of patients with carcinoma of the cervix, as in any other malignant tumor, accurate identification of target volumes is critical to enhance precision of radiation therapy planning and delivery. These results in improved locoregional tumor control lead to lower incidence of distant metastases and improved survival. Also, radiation therapy morbidity is decreased, enhancing quality of life. Various imaging techniques are available to achieve better target delineation and this can be enhanced with image fusion. Available innovative treatment techniques to optimize the use of radiation therapy for these patients are illustrated.

Uncertainties in radiation therapy: target volume definition in prostate cancer

Rays

Accurate definition of target volumes and pelvic organs at risk is critical to improve the outcom... more Accurate definition of target volumes and pelvic organs at risk is critical to improve the outcome in patients treated with irradiation for localized carcinoma of the prostate. Precise delineation of these structures will assist in more rational therapeutic decisions and optimized radiation therapy treatment planning and delivery. Increased conformity in radiation dose distribution allows delivery of higher doses of irradiation and dose escalation studies and results in improved tumor control, lower incidence of distant metastasis, improved survival and better quality of life. Multiple imaging methods are available and significant advances have been made in image fusion to enhance target volume definition. An exhaustive review of the literature is presented.

Clinical assessment of outcome of prostate cancer (TCP, NTCP)

Rays

In the recent past there have been major advances in the management of patients with prostate can... more In the recent past there have been major advances in the management of patients with prostate cancer. New imaging procedures as 3-D CRT and IMRT have played a major role in the tretament of patients with localized prostate cancer. 3-D CRT allows higher doses to be delivered more precisely to the target volume with acceptable organs at risk morbidity. Improved tumor control results in lower incidence of distant metastases and better survival with an enhanced quality of life. This outcome yields a lower cost per treatment of patients over their life time.

Advances and future of Radiation Oncology

Reports of practical oncology and radiotherapy : journal of Greatpoland Cancer Center in Poznań and Polish Society of Radiation Oncology, Jan 8, 2013

Review of recent advances and vision for future developments in clinical practice of Radiation On... more Review of recent advances and vision for future developments in clinical practice of Radiation Oncology. There have been substantial research and technological developments in Radiation Oncology over the past 40 years. The relevant literature was reviewed and the authors offer their perspective on future opportunities for advancement in Radiation Oncology. Significant innovative technological developments have been introduced in the practice of Radiation Oncology, with more precise target delineation and tracking and three dimensional treatment planning, optimal delivery of radiation therapy to the target and lower doses to surrounding Organs at Risk. This dose optimization and adaptive therapy have enhanced the role of Radiation Therapy to more effectively treat patients with cancer. Further creativity and refinements will continue to advance the field into new applications of ionizing radiations in cancer therapy.

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Hemangiopericytomas

Encyclopedia of Radiation Oncology, 2013

Real-Time Drilling Engineering: Hydraulics and T&D Modeling for Predictive Interpretation While Drilling

SPE Intelligent Energy International, 2012

In the early stages of real-time data transmission from the rigsite, real-time monitoring enginee... more In the early stages of real-time data transmission from the rigsite, real-time monitoring engineers focused on viewing data as it was presented on the rigsite. While this setup was ideal for service quality and event mitigation, it fell short of providing predictions of wellbore condition. As remote real-time monitoring matures in its use of "while drilling" data, remote engineers need to identify issues before they affect drilling operations and are evident to rigsite personnel. Using a combination of data analysis, engineering models, algorithms for data reduction, historic behavior, and experience, a remote monitoring engineer is able to see the data in the context of the drilling environment and to identify developing incidents. However, as data volume increases, remote engineers must focus their analysis on the tools by which they can have the biggest impact and effectiveness. Real-time hydraulics and torque and drag (T&D) analysis are such tools, and by using enginee...

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