David J. Castro DSc - Academia.edu (original) (raw)

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Papers by David J. Castro DSc

European Journal of Alternative Education Studies, 2020

This article presents a study of the use of experiences from the natural and biological sciences ... more This article presents a study of the use of experiences from the natural and biological sciences in the classroom. The questioning of classical and traditional methods of teaching science, at the same time with the development of modern research in the psychology of learning and education, have led to revisions of the role of students and educators. The student is now seen as an active shaper of his own approach to knowledge and to the transformation of his daily experience into learning the physical and biological sciences. The teacher is treated as the critical intermediary between knowledge and the child and thus his role in the management of scientific experience is decisive but not transmissive. These issues are approached from different angles.

Foundations of Computational Mathematics, 2002

Oncotarget, 2016

Cancers are heterogeneous by nature. While traditional oncology screens commonly use a single end... more Cancers are heterogeneous by nature. While traditional oncology screens commonly use a single endpoint of cell viability, altering the phenotype of tumorinitiating cells may reveal alternative targets that regulate cellular growth by processes other than apoptosis or cell division. We evaluated the impact of knocking down expression of 420 kinases in bi-lineage triple-negative breast cancer (TNBC) cells that express characteristics of both myoepithelial and luminal cells. Knockdown of ERN1 or ALPK1 induces bi-lineage MDA-MB-468 cells to lose the myoepithelial marker keratin 5 but not the luminal markers keratin 8 and GATA3. In addition, these cells exhibit increased β-casein production. These changes are associated with decreased proliferation and clonogenicity in spheroid cultures and anchorage-independent growth assays. Confirmation of these assays was completed in vivo, where ERN1or ALPK1-deficient TNBC cells are less tumorigenic. Finally, treatment with K252a, a kinase inhibitor active on ERN1, similarly impairs anchorage-independent growth of multiple breast cancer cell lines. This study supports the strategy to identify new molecular targets for types of cancer driven by cells that retain some capacity for normal differentiation to a non-tumorigenic phenotype. ERN1 and ALPK1 are potential targets for therapeutic development.

2010 Design, Automation & Test in Europe Conference & Exhibition (DATE 2010), 2010

The design and first measuring results of an ultra-low power 12bit Successive-Approximation ADC f... more The design and first measuring results of an ultra-low power 12bit Successive-Approximation ADC for autonomous multi-sensor systems are presented. The comparator and the DAC are optmised for the lowest power consumption. The proposed design has a power consumption of 0.52µW at a bitclock of 50-kHz and of 0.85µW at 100-kHz with a 1.2-V supply. As far as we know, the Figure-of-Merit of 66 fJ/convertion-step is the best reported so far. The ADC was realised in the NXP CMOS 0.14µm technology with an area of 0.35 mm 2. Only four metal layers were used in order to allow 3D integration of the sensors.

JOURNAL OF ADVANCES IN HUMANITIES

This research examines children's (ages 12-13) ideas of changes in the state of matter of sal... more This research examines children's (ages 12-13) ideas of changes in the state of matter of salt. Children construct ideas of physical phenomena and these ideas are serious to education. The change of state of matter is a transformation of substance due to the transfer of energy as heat. In several studies focused on children's ideas we find that these representations are often incompatible with the scientific model. In this research, where we studied the ideas of the melting and coagulation of the salt attended 104 children aged 12 to 13 years. The results of an interview show that these children use different types of ideas, the majority dominated by the nature of the substance under study.

JOURNAL OF ADVANCES IN NATURAL SCIENCES

In several researches focused on representations of light that are children from 5 to 15 years fo... more In several researches focused on representations of light that are children from 5 to 15 years found that these representations are often incompatible with the scientific model. 110 children participated in this research where we studied representations of children 8-9 years on the light. As a technique of research we chose the directive individual interview. The results of the research show that children of 8-9 years use different categories of representations for the light and they rarely recognize the light as a separate entity in the area, independent sources that produce it and the effects it causes during its spread.

Foods

The presence of emerging contaminants in food and the sources of the contamination are relevant i... more The presence of emerging contaminants in food and the sources of the contamination are relevant issues in food safety. The impact of climate change on these contaminations is a topic widely debated; however, the consequences of climate change for the food system is not as deeply studied as other human and animal health and welfare issues. Projections of climate change in Europe have been evaluated through the EU Commission, and the impact on the marine environment is considered a priority issue. Marine biotoxins are produced by toxic microalgae and are natural contaminants of the marine environment. They are considered to be an important contaminant that needs to be evaluated. Their source is affected by oceanographic and environmental conditions; water temperature, sunlight, salinity, competing microorganisms, nutrients, and wind and current directions affect the growth and proliferation of microalgae. Although climate change should not be the only reason for this increase and othe...

Journal of Social Sciences Research, 2013

The light is a separate entity in the area, independent sources that produce it and the effects i... more The light is a separate entity in the area, independent sources that produce it and the effects it causes during its spread. In several research focused on representations of light that are children from 5 to 15 years found that these representations are often incompatible with the scientific model. 112 (60 boys and 62 girls) participated in this research where we studied representations of children 11-12 years on the light. As a technique of research we chose the directive individual interview. The results of the research show that children of 11-12 years, use different categories of representations for the light.

Microelectronics Journal, Nov 1, 2010

The design and first measuring results of an ultra-low power 12 bit successive-approximation ADC ... more The design and first measuring results of an ultra-low power 12 bit successive-approximation ADC for autonomous multi-sensor systems are presented. The comparator and the DAC are optmised for low power consumption. The power consumption is 0.52μW from a 1.2V supply with a sample clock of 3.125kHz and 0.85μW at 6.25kHz. This gives 136pJ per conversion or 66fJ per conversion step.

2011 12th International Radar Symposium, Sep 1, 2011

Abstract The problem of high-resolution array radar/SAR imaging is stated and treated as a nonlin... more Abstract The problem of high-resolution array radar/SAR imaging is stated and treated as a nonlinear ill-posed inverse problem of nonparametric estimation of the power spatial spectrum pattern (SSP) of the wavefield scattered from the remotely sensed scene ...