Direct Laboratory Observations Research Articles

Analisis Implementasi Peningkatan Kualitas Pendidikan Melalui Standarisasi Laboratorium di SMAN 5 Jember

This study was conducted with the aim of analyzing the implementation of Physics Laboratory Standards at SMA Negeri 5 Jember. The research method used in this research is descriptive method with qualitative approach. Data collection was done through questionnaires and interviews with the head of the laboratory and also with physics teachers. In addition, data collection is also through direct laboratory observation, interviews through the head of the laboratory assistant, and document analysis such as guidebooks and the use of tools and materials in the laboratory. In this study, the results showed that the infrastructure facilities in the laboratory showed an average percentage of 90% with a very good classification. The results of standardization for tools and materials got an average of 68% with a good classification. Furthermore, the standardization of laboratory personnel with a very good classification on average 90%. In the standardization of security, maintenance and supervision of the laboratory gets an average percentage of 91% with a very good classification. The last is the standardization of services gets an average percentage of 100% with a very good classification. Overall, the laboratory at Jember 5 Public School has good standardization, but there is a need to improve the quality of these laboratory facilities so that they can support the learning process better.

The 2020 release of the ExoMol database: Molecular line lists for exoplanet and other hot atmospheres

The ExoMol database (www.exomol.com) provides molecular data for spectroscopic studies of hot atmospheres. While the data are intended for studies of exoplanets and other astronomical bodies, the dataset is widely applicable. The basic form of the database is extensive line lists; these are supplemented with partition functions, state lifetimes, cooling functions, Landé g-factors, temperature-dependent cross sections, opacities, pressure broadening parameters, k-coefficients and dipoles. This paper presents the latest release of the database which has been expanded to consider 80 molecules and 190 isotopologues totaling over 700 billion transitions. While the spectroscopic data are concentrated at infrared and visible wavelengths, ultraviolet transitions are being increasingly considered in response to requests from observers. The core of the database comes from the ExoMol project which primarily uses theoretical methods, albeit usually fine-tuned to reproduce laboratory spectra, to generate very extensive line lists for studies of hot bodies. The data have recently been supplemented by line lists derived from direct laboratory observations, albeit usually with the use of ab initiotransition intensities. A major push in the new release is towards accurate characterisation of transition frequencies for use in high resolution studies of exoplanets and other bodies.

Intrinsic mirror noise in Fabry\u2013Perot based polarimeters: the case for the measurement of vacuum magnetic birefringence

Although experimental efforts have been active for about 30 years, a direct laboratory observation of vacuum magnetic birefringence, due to vacuum fluctuations, still needs confirmation: the predicted birefringence of vacuum is Delta n = 4.0times 10^{-24} @ 1 T. Key ingredients of a polarimeter for detecting such a small birefringence are a long optical path within the magnetic field and a time dependent effect. To lengthen the optical path a Fabry–Perot is generally used with a finesse ranging from {{mathscr {F}}} approx 10^4 to {{mathscr {F}}} approx 7times 10^5. Interestingly, there is a difficulty in reaching the predicted shot noise limit of such polarimeters. We have measured the ellipticity and rotation noises along with Cotton-Mouton and Faraday effects as a function of the finesse of the cavity of the PVLAS polarimeter. The observations are consistent with the idea that the cavity mirrors generate a birefringence-dominated noise whose ellipticity is amplified by the cavity itself. The optical path difference sensitivity at 10;hbox {Hz} is S_{Delta {{mathscr {D}}}}=6times 10^{-19};hbox {m}/sqrt{mathrm{Hz}}, a value which we believe is consistent with an intrinsic thermal noise in the mirror coatings. Our findings prove that the continuous efforts to increase the finesse of the cavity to improve the sensitivity has reached a limit.

Quantitative experimental monitoring of molecular diffusion in clay with positron emission tomography

Abstract. Clay plays a prominent role as barrier material in the geosphere. The small particle sizes cause extremely small pore sizes and induce low permeability and high sorption capacity. Transport of dissolved species by molecular diffusion, driven only by a concentration gradient, is less sensitive to the pore size. Heterogeneous structures on the centimetre scale could cause heterogeneous effects, like preferential transport zones, which are difficult to assess. Laboratory measurements with diffusion cells yield limited information on heterogeneity, and pore space imaging methods have to consider scale effects. We established positron emission tomography (PET), applying a high-resolution PET scanner as a spatially resolved quantitative method for direct laboratory observation of the molecular diffusion process of a PET tracer on the prominent scale of 1–100 mm. Although PET is rather insensitive to bulk effects, quantification required significant improvements of the image reconstruction procedure with respect to Compton scatter and attenuation. The experiments were conducted with 22Na and 124I over periods of 100 and 25 days, respectively. From the images we derived trustable anisotropic diffusion coefficients and, in addition, we identified indications of preferential transport zones. We thus demonstrated the unique potential of the PET imaging modality for geoscientific process monitoring under conditions where other methods fail, taking advantage of the extremely high detection sensitivity that is typical of radiotracer applications.

A chamber study of the influence of boreal BVOC emissions and sulfuric acid on nanoparticle formation rates at ambient concentrations

Abstract. Aerosol formation from biogenic and anthropogenic precursor trace gases in continental background areas affects climate via altering the amount of available cloud condensation nuclei. Significant uncertainty still exists regarding the agents controlling the formation of aerosol nanoparticles. We have performed experiments in the Jülich plant–atmosphere simulation chamber with instrumentation for the detection of sulfuric acid and nanoparticles, and present the first simultaneous chamber observations of nanoparticles, sulfuric acid, and realistic levels and mixtures of biogenic volatile compounds (BVOCs). We present direct laboratory observations of nanoparticle formation from sulfuric acid and realistic BVOC precursor vapour mixtures performed at atmospherically relevant concentration levels. We directly measured particle formation rates separately from particle growth rates. From this, we established that in our experiments, the formation rate was proportional to the product of sulfuric acid and biogenic VOC emission strength. The formation rates were consistent with a mechanism in which nucleating BVOC oxidation products are rapidly formed and activate with sulfuric acid. The growth rate of nanoparticles immediately after birth was best correlated with estimated products resulting from BVOC ozonolysis.

Dispersal and Movement Mechanisms of Phytophthora capsici Sporangia

Understanding the mechanisms of Phytophthora capsici sporangial dissemination is paramount to understanding epidemic initiation and development. Direct laboratory observations showed P. capsici sporangial dispersal occurred in water with capillary force, but did not occur in response to wind or a reduction in relative humidity. Atmospheric sporangial concentrations were monitored under field conditions using a volumetric spore sampler in a commercial cucurbit field and in an experimental setting where copious sporangia were continuously available in close proximity to the spore trap. Dispersal was infrequent (0.7% of total hours monitored) during sampling in a commercial field; 14 sporangia were detected during a 7.5-week sampling period. In the experimental field situation, dispersal occurred in 4.6% of the hours sampled and 438 sporangia were impacted onto tapes during a 7-week sampling period. Airborne sporangial concentrations were positively associated with rainfall at both sites, but not vapor pressure deficit. Furthermore, in the experimental field situation, wind speed was not significant in regression analysis. Wind speed was not measured in the commercial field. Hence, both direct laboratory observations and volumetric spore sampling indicate that dispersal of sporangia via wind currents is infrequent, and sporangia are unlikely to be naturally dispersed among fields by wind alone.

Velocity-saturation relation transition during rocks saturation: direct laboratory observation by computer tomography and ultrasonic technique

Maximising the recovery of known hydrocarbon reserves is one of the biggest challenges facing the petroleum industry today. Optimal production strategies require accurate monitoring of production-induced changes of reservoir saturation and pressure over the life of the field. Time-lapse seismic technology is increasingly used to map these changes in space and time. However until now, interpretation of time-lapse seismic data has been mostly qualitative. In order to allow accurate estimation of the saturation, it is necessary to know the quantitative relationship between fluid saturation and seismic characteristics (elastic moduli, velocity dispersion and attenuation). The problem of calculating acoustic properties of rocks saturated with a mixture of two fluids has attracted considerable interest (Gist, 1994; Mavko and Nolen-Hoeksema, 1994; Knight et al. 1998); for a comprehensive review of theoretical and experimental studies of the patchy saturation problem see Toms et al. (2006).

Direct laboratory observation of patchy saturation and its effects on ultrasonic velocities

Maximizing the recovery of known hydrocarbon reserves is one of the biggest challenges facing the petroleum industry today. Optimal production strategies require accurate monitoring of production-induced changes of reservoir saturation and pressure over the life of the field. Time-lapse seismic technology is increasingly used to map these changes in space and time. However, until now, interpretation of time-lapse seismic data has been mostly qualitative. In order to allow accurate estimation of the saturation, it is necessary to know the quantitative relationship between fluid saturation and seismic characteristics (elastic moduli, velocity dispersion, and attenuation). The problem of calculating acoustic properties of rocks saturated with a mixture of two fluids has attracted considerable interest (Gist, 1994; Mavko and Nolen-Hoeksema, 1994; Knight et al., 1998. For a comprehensive review of theoretical and experimental studies of the patchy saturation problem see Toms et al., 2006).

Atlas of Human Anatomy and Surgery: The Complete Coloured Plates of 1831–1854

This book is essentially a tribute to Jean Babtiste Marc Bougery (1797–1849) who together with Nicolas Henri Jacob (1782–1871), a student of the French painter Jacques Louis David, wrote and illustrated an eight-volume treatise Atlas of Anatomy over two decades, commencing in 1831, the final one of which was not published until five years after Bougery’s death. This reprint, reproduced from an original copy in the possession of Simon Finch, includes the complete set of 726 colour plates. It is beautifully produced in large folio format on high-quality paper and delivered in an outer protective cardboard carrying case. The press release by no means exaggerates the fact that ‘Jacob’s spectacular hand-coloured, life-size lithographs are remarkable for their clarity, colour and aesthetic appeal, reflecting a combination of direct laboratory observation and illustrative research’. Indeed, few would argue that ‘the images are to this day unsurpassed in anatomical illustration’. Their accuracy, even taking into consideration an element of artistic and presentational licence, is most impressive. I guess they would even be valued by the modern medical student and basic surgical trainee, perhaps now less privileged than earlier generations who had the opportunity to study anatomy in greater depth. The text is written in English, French and German and, although not repeated for each, is relatively simplistic and even easy to follow for the non-linguist. It is divided into eight ‘tomes’, each representing a summary of a volume of the full Atlas. The earlier sections include a technical description of the way that the lithographs were produced and the Atlas developed. The chapters then progress topographically through osteology; muscles, tendons and fasciae; the nervous system; angiology and the heart; and the thoracic and abdominal regions. However, I found the later equally impressively illustrated sections even more enticing with descriptions of surgical instruments and techniques, including methods of holding a scalpel, before progressing through operative procedures of the day. These ranged from control of haemorrhage, for example by external compression apparatus; insertion of drains; phlebotomy and the extraction of teeth through removal of sequestra; amputations; surgery of the ear, nose and throat including cleft lip and palate; tracheostomy; management of herniae; procedures on the urethra and prostate; hysterectomy and Caesarean section. Finally, there are sections on comparative anatomy, embryology and histology, including microscopy of the blood. The book is aimed not only at those in the medical field but also artists, students and those interested in the study of the human body. Clearly, it would be a most desirable acquisition, especially as for the medical historian it provides a glimpse as the publishers state of ‘a monumental work of the 19th century’. At £100, it represents extremely good value and is most attractive.

Role of substrate on larval development of the freshwater teleost Pelvicachromis pulcher.

It is known that, in an aquatic environment, the mineralogical composition of the substrate can affect the structure of settled communities. In marine environments, the presence of quartz negatively influences the formation of biofilm, as well as the selection and the colonization of the substrate by benthic organisms. Direct laboratory observation revealed that the freshwater teleost Pelivicachromis pulcher selects, when available, nonquartzitic brooding substrate. To monitor the effects of substrate on larvae development, ten lots of embryos were distributed in grid nurseries; carbonatic gravel was laid in five of the nurseries, while freshly fractured quartz gravel was used in the remaining ones. All the embryos laid in the two nurseries hatched, and 90% of the carbonate developing larvae reached adulthood, while 100% of those reared on quartz grain died 120 hr post hatching. Examination was made, both in larvae developed on carbonatic substrates and in those developed on quartz substrates, of the expression of the fetal growth factor, the insulin growth factor-II (IGF-II), of the molecular chaperone, the heat shock protein 70 (HSP70), which is involved in the folding of the nascent polypeptide chain, of the key enzyme of the glycolytic pathway, the glyceraldehyde-3-phosphate dehydrogenase (GADPH), and of the housekeeping gene, the beta-actin. All the data were normalized against 18S RNA expression. In larvae reared on quartz substrate, the genes IGF-II and the beta-actin showed a lower expression, while the GADPH was totally suppressed and the expression of HSP70 increased. In conclusion, the data presented in this article demonstrated, for the first time, that the presence of quarzitic substrates is sufficient to stop larvae development through the inhibition of gene transcription in this African cichlid, leading to its death.

Intersonic shear cracks and fault ruptures

Recent experimental observations of intersonic shear rupture events that occur in a variety of material systems have rekindled interest in the intersonic failure phenomenon. Since the early 1990s, engineers and scientists working in all length scales, from the atomistic, the structural, all the way up to the scale of the earth's deformation processes, have undertaken joint efforts to study this unexplored area of fracture mechanics. The analysis in the present article emphasizes the cooperative and complementary manner in which experimental observations and analytical and numerical developments have proceeded. The article first reviews early contributions to the theoretical literature of dynamic subsonic and intersonic fracture and highlights the significant differences between tensile and shear cracks. The article then uses direct laboratory observations as a framework for discussing the physics of intersonic shear rupture occurring in constitutively homogeneous (isotropic and anisotropic) as well as in inhomogeneous systems, all containing preferable crack paths or faults. Experiments, models, and field evidence at a variety of length scales (from the atomistic, the continuum, and up to the scale of geological ruptures) are used to discuss processes such as (1) shock wave formation, (2) large-scale frictional contact and sliding at the rupture faces, and (3) maximum attainable rupture speeds and rupture speed stability. Particular emphasis is given to geophysical field evidence and to the exploration of the possibility of intersonic fault rupture during shallow crustal earthquake events.

Cancer Virus Redux

W hen the U.S. government declared its war on in 1971, viruses were considered to be among the most likely cancer-causing agents. The National Cancer Institute (NCI) in Bethesda, Md., had special program to screen tumor cells for the presence of virus particles, but, says current NCI head Vincent T DeVita, wasn't to be that simple. Despite expense and effort, no one was able to isolate cancer virus from human tumor cells during that initial push; there arose a lot of skepticism about viruses as cause of DeVita says today. Some researchers dropped out of the field; others shifted their emphasis to basic virology research. Out of that [shift] emerged the basic ability to isolate viruses that we didn't have in the beginning, says DeVita. We're now back in the business of finding viruses [as a] cause of he said at the recent American Cancer Society's science writers' seminar in San Diego. Researchers there described virus-cancer connections ranging from epidemiological links coincident occurrences of virus and type of cancer in given population -to direct laboratory observations of virus transforming normal cells into cancerous ones. Viruses have been fingered in liver cancer, the most common cancer in the world; cervical cancer; Burkitt's lymphoma; nasopharyngeal carcinoma; and an adult T cell leukemia. But researchers are quick to caution that though these cancers are believed to be caused by they don't spread as easily as common viruses spread -for example, with sneeze. We have not found that kind of transmission of cancer viruses, says DeVita. You need very intimate contact to spread the viruses that we know can be spread. None of it seems to be easy, thank God. Virus-associated cancers are more common in less developed nations, DeVita notes. Differences in hygiene may be one reason, he suggests, with individuals exposed at an earlier age, giving cancer viruses longer time to act. The virus-associated cancers, which tend to occur earlier in life, also wind up representing greater proportion of total cancers in these countries, possibly because people in less developed countries are more likely to die before getting the old age cancers like cancer of the urinary tract, bladder and gut wall.