scholarly journals First Observations of the McMurdo-South Pole Ionospheric HF Channel

2020 ◽  
Author(s):  
Alex Timothy Chartier ◽  
Juha Vierinen ◽  
Geonhwa Jee
Keyword(s):  
Low Cost ◽  
Ionospheric Parameter ◽  
True Positive ◽  
South Pole ◽  
True Negative ◽  
Pilot Experiment ◽  
Mcmurdo Station ◽  
Spread F ◽  
The Antarctic ◽  
Hf Channel

Abstract. We present the first observations from a new low-cost oblique ionosonde located in Antarctica. The transmitter is located at McMurdo Station, Ross Island and the receiver at Amundsen-Scott Station, South Pole. The system was demonstrated successfully in March 2019, with the experiment yielding over 30 000 ionospheric echoes over a two-week period. These data indicate the presence of a stable E-layer and a sporadic and variable F-layer with dramatic spread-F of sometimes more than 500 km (in units of virtual height). The most important ionospheric parameter, NmF2, validates well against the Jang Bogo VIPIR ionosonde (observing more than 1000 km away). GPS-derived TEC data from the MIDAS algorithm can be considered necessary but insufficient to predict 7.2 MHz propagation between McMurdo and South Pole, yielding a true positive in 40 % of cases and a true negative in 73 % of cases. The success of this pilot experiment at a total grant cost of $116k and an equipment cost of ~$15k indicates that a large multi-static network could be built to provide unprecedented observational coverage of the Antarctic ionosphere.

scholarly journals First observations of the McMurdo–South Pole oblique ionospheric HF channel

2020 ◽  
Vol 13 (6) ◽  
pp. 3023-3031
Author(s):  
Alex T. Chartier ◽  
Juha Vierinen ◽  
Geonhwa Jee
Keyword(s):  
Low Cost ◽  
Ionospheric Parameter ◽  
True Positive ◽  
South Pole ◽  
Analysis Software ◽  
True Negative ◽  
Mcmurdo Station ◽  
Spread F ◽  
The Antarctic ◽  
Hf Channel

Abstract. We present the first observations from a new low-cost oblique ionosonde located in Antarctica. The transmitter is located at McMurdo Station, Ross Island, and the receiver at Amundsen–Scott Station, South Pole. The system was demonstrated successfully in March 2019, with the experiment yielding over 30 000 ionospheric echoes over a 2-week period. These data indicate the presence of a stable E layer and a sporadic and variable F layer with dramatic spread F of sometimes more than 500 km (in units of virtual height). The most important ionospheric parameter, NmF2, validates well against the Jang Bogo Vertical Incidence Pulsed Ionospheric (VIPIR) ionosonde (observing more than 1000 km away). GPS-derived TEC data from the Multi-Instrument Data Analysis Software (MIDAS) algorithm can be considered necessary but insufficient to predict 7.2 MHz propagation between McMurdo and the South Pole, yielding a true positive in 40 % of cases and a true negative in 73 % of cases. The success of this pilot experiment at a total grant cost of USD 116 000 and an equipment cost of ∼ USD 15 000 indicates that a large multi-static network could be built to provide unprecedented observational coverage of the Antarctic ionosphere.

scholarly journals Fully Automatic Fall Risk Assessment Based on a Fast Mobility Test

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1338
Author(s):  
Wojciech Tylman ◽  
Rafał Kotas ◽  
Marek Kamiński ◽  
Paweł Marciniak ◽  
Sebastian Woźniak ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Fall Risk ◽  
Low Cost ◽  
Body Movement ◽  
Sole Source ◽  
Timed Up And Go ◽  
True Negative ◽  
Fall Risk Assessment ◽  
Positive Ratio ◽  
Mobility Test

This paper presents a fall risk assessment approach based on a fast mobility test, automatically evaluated using a low-cost, scalable system for the recording and analysis of body movement. This mobility test has never before been investigated as a sole source of data for fall risk assessment. It can be performed in a very limited space and needs only minimal additional equipment, yet provides large amounts of information, as the presented system can obtain much more data than traditional observation by capturing minute details regarding body movement. The readings are provided wirelessly by one to seven low-cost micro-electro-mechanical inertial measurement units attached to the subject’s body segments. Combined with a body model, these allow segment rotations and translations to be computed and for body movements to be recreated in software. The subject can then be automatically classified by an artificial neural network based on selected values in the test, and those with an elevated risk of falls can be identified. Results obtained from a group of 40 subjects of various ages, both healthy volunteers and patients with vestibular system impairment, are presented to demonstrate the combined capabilities of the test and system. Labelling of subjects as fallers and non-fallers was performed using an objective and precise sensory organization test; it is an important novelty as this approach to subject labelling has never before been used in the design and evaluation of fall risk assessment systems. The findings show a true-positive ratio of 85% and true-negative ratio of 63% for classifying subjects as fallers or non-fallers using the introduced fast mobility test, which are noticeably better than those obtained for the long-established Timed Up and Go test.

Sfida all’ultimo parallelo: la conquista del Polo Sud cento anni dopo

2012 ◽  
pp. 17-28
Author(s):  
Paolo Bernat
Keyword(s):  
Nineteenth Century ◽  
Scientific Research ◽  
South Pole ◽  
The South ◽  
The Antarctic

100 years ago, Antarctica was still mostly unknown and unexplored. The first landings on the Antarctic coast took place in the early decades of the nineteenth century and were made by whalers and sealers. In the following years the first scientific expeditions began and European and US expeditions started the geographical discovery and the mapping of the Antarctic coasts. But it was only in the years 1911-1912 that two expeditions, very different but equally well prepared, arrived almost simultaneously at the South Pole. The events that happened in the Antarctic together with the different nature of the two leaders Roald Amundsen and Robert Scott determined the outcome of these expeditions and the fate of their teams. The centenary of the conquest of the South Pole (December 14, 1911) is an opportunity to remember the passion for science, the spirit of adventure and the fierce perseverance that characterized those extraordinary men and that even now form the basis of scientific research and of human progress, not only in Antarctica but in all areas of knowledge and life.

scholarly journals Coupling Uncertainties with Accuracy Assessment in Object-based Slum Detections, Case Study: Jakarta, Indonesia

2017 ◽  
Author(s):  
Jati Pratomo ◽  
Monika Kuffer ◽  
Javier Martinez ◽  
Divyani Kohli
Keyword(s):  
Land Tenure ◽  
Classification Accuracy ◽  
Accuracy Assessment ◽  
False Negative ◽  
National Policy ◽  
True Positive ◽  
True Negative ◽  
Object Based ◽  
The Impact

Object-Based Image Analysis (OBIA) has been successfully used to map slums. In general, the occurrence of uncertainties in producing geographic data is inevitable. However, most studies concentrated solely on assessing the classification accuracy and neglecting the inherent uncertainties. Our research analyses the impact of uncertainties in measuring the accuracy of OBIA-based slum detection. We selected Jakarta as our case study area, because of a national policy of slum eradication, which is causing rapid changes in slum areas. Our research comprises of four parts: slum conceptualization, ruleset development, implementation, and accuracy and uncertainty measurements. Existential and extensional uncertainty arise when producing reference data. The comparison of a manual expert delineations of slums with OBIA slum classification results into four combinations: True Positive, False Positive, True Negative and False Negative. However, the higher the True Positive (which lead to a better accuracy), the lower the certainty of the results. This demonstrates the impact of extensional uncertainties. Our study also demonstrates the role of non-observable indicators (i.e., land tenure), to assist slum detection, particularly in areas where uncertainties exist. In conclusion, uncertainties are increasing when aiming to achieve a higher classification accuracy by matching manual delineation and OBIA classification.

scholarly journals Comparison Study Between Local TSH IRMA Kit (CRRT) and Imported TSH IRMA Kit (Riakey, Korea)

2019 ◽  
Vol 4 (2) ◽  
pp. 77
Author(s):  
Gina Mondrida ◽  
Triningsih Triningsih ◽  
Kristina Dwi Purwanti ◽  
Sutari Sutari ◽  
Sri Setyowati ◽  
...  
Keyword(s):  
False Negative ◽  
Thyroid Stimulating Hormone ◽  
The Body ◽  
True Positive ◽  
Comparison Study ◽  
Complex Matrix ◽  
Normal Range ◽  
True Negative ◽  
Immunoassay Technique ◽  
Tsh Levels

<p><em>Thyroid Stimulating Hormone</em> (TSH) is one of hormones that our body need for growth of brains, bones and other tissues and regulate the metabolism in the body. Normal range of TSH for adult is from 0.3 to 5.5 µIU/ml, whereas for baby ranged from 3 to 18 µIU/ml. An Immunoradiometricassay (IRMA) is one of immunoassay technique using radionuclide as the tracer to detect low quantity of analyte. This technique is suitable for determine TSH levels in human blood serum which has complex matrix and various concentration. The Center for Radioisotope and Radiopharmaceutical Technology (CRRT)-BATAN has developed a reagent of TSH IRMA kit. The aim of this research is to compare between local TSH IRMA kit (CRRT-BATAN) and imported TSH IRMA kit (Riakey, Korea) toward 110 adult samples obtained from PTKMR - BATAN. The results showed 97 samples as true negative, 5 samples as true positive, 1 sample as false negative and 7 samples false positive. The comparison study gave diagnostic sensitivity as much as 83.33 %, diagnostic spesificity as much as 93.27 % and accuracy as much as 92.72 %.</p>

Abstract P387: Race and Sex Differences Exist in the Volumes of Visceral Adipose Tissue Associated With Prevalent Hypertension in Middle Age Adults

Circulation ◽  
2014 ◽  
Vol 129 (suppl_1) ◽  
Author(s):  
Christina M Shay ◽  
Prasenjeet N Motghare ◽  
David R Jacobs ◽  
Cora E Lewis ◽  
J. Greg Terry ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Adipose Tissue ◽  
Black Women ◽  
White Women ◽  
Middle Age ◽  
White Men ◽  
True Positive ◽  
True Negative ◽  
Cut Points ◽  
Visceral Adipose

Background: Higher visceral adipose tissue (VAT) volume is associated with greater risk for hypertension (HTN). Although VAT volume and prevalence of HTN vary by sex and race, the differences in VAT volumes associated with identification of individuals with prevalent HTN across these groups is unclear. Objective: To determine VAT volume cut points that maximize true positive, true negative and optimal identification of prevalent HTN and to compare the cut points across sex and race groups. Methods: Data were examined from the Coronary Artery Risk Development in Young Adults (CARDIA) study, a multi-center longitudinal study of the development of cardiovascular risk in black and white men and women ages 18-30 years at baseline. In 2010-11, the Year 25 exam was performed (43-55 years) and VAT volume (cm3) was quantified by computed tomography based on two 5 mm contiguous slices at the level of the 4th-5th lumbar vertebra (n=3,153). HTN was defined as systolic blood pressure ≥140 mmHg, diastolic blood pressure ≥90 mmHg and/or anti-hypertension medication use. Receiver operating characteristic (ROC) curve analysis was used to identify VAT volume cut points associated with true positive, true negative and optimal identification of prevalent HTN. Results: Year 25 prevalence of HTN ranged from 18.2% (white women) to 49.4% (black women); mean VAT volume ranged from 113.5 cm3 (white women) to 172.1 cm3 (white men). White males exhibited the highest VAT volumes (22-36% higher) and black women exhibited the lowest VAT volumes (3-50% lower) associated with true positive, true negative and optimal identification of HTN compared to other race/sex groups (Table 1). VAT volumes associated with HTN among black participants were generally lower than those exhibited for whites. Conclusions: Although the utility of VAT alone to identify HTN cases is modest - likely a result of unaccounted HTN confounders - these findings display the distinct race- and sex-specific differences in VAT volumes associated with prevalent HTN in middle age adults.

L’Antartide è veramente un "awful place"? I caratteri ambientali del continente più freddo della Terra

2012 ◽  
pp. 29-46
Author(s):  
Claudio Smiraglia
Keyword(s):  
Indigenous Population ◽  
Terrestrial Ecosystems ◽  
South Pole ◽  
The Past ◽  
Unique Information ◽  
The World ◽  
Antarctic Continent ◽  
Harsh Climate ◽  
The Many ◽  
The Antarctic

The Antarctic continent is certainly made an "awful" place by its harsh climate: in the past, explorers and researchers endured terrible hardships and the climate remains a challenge today, in spite of the many improvements in knowledge and technology. The Antarctic may be termed "the continent of the extremes", as it occupies an area unlike any other on earth. It is the farthest and most inaccessible and isolated continent; the most regular because of its rounded shape, with the South Pole at the centre; the coldest continent, with temperatures falling to -90°C; the driest (with an average of 130 mm of precipitation); the windiest, the highest, the most glacialized (it contains 91% of the volume of the earth’s ice). It also displays the most monotonous landscapes and presents the greatest contrast between marine and terrestrial ecosystems. But the Antarctic is also "extreme" because it is the least populated continent, with no indigenous population at all, while its few settlements (consisting in scientific bases) are concentrated on the coast; it is the only place that does not belong to one nation, but to all the world; it is the place where unique information on the past, present and future of humankind is revealed.

The flourishing forests of Antarctica

2007 ◽  
Author(s):  
David Beerling
Keyword(s):  
Sea Level ◽  
The Other ◽  
Cold Weather ◽  
South Pole ◽  
The South ◽  
Altitude Sickness ◽  
Antarctic Plateau ◽  
The Times ◽  
The Antarctic ◽  
As If

By arriving at the South Pole on 14 December 1911, the Norwegian explorer Roald Amundsen (1872–1928) reached his destination over a month ahead of the British effort led by Captain Robert Falcon Scott (1868–1912). As Scott’s party approached the South Pole on 17 January 1912, they were devastated to see from afar the Norwegian’s black flag. On arrival, they discovered the remains of his camp with ski and sledge tracks, and numerous dog footprints. Amundsen, it turned out, had used dogs and diversionary tactics to secure victory while the British team had man-hauled their sledges. These differences were not lost on The Times in London, which marked the achievement with muted praise, declaring it ‘not quite in accordance with the spirit of fair and open competition which hitherto marked Antarctic exploration’. Exhausted, Scott and his men spent time the following day making scientific observations around the Pole, erected ‘our poor slighted Union Jack’, and photographed themselves in front of it (Plate 11). Lieutenant Bowers took the picture by pulling a string to activate the shutter. It is perhaps the most well known, and at the same time the saddest picture, of the entire expedition—a poignant image of the doomed party, all of whom look utterly fed up as if somehow sensing the fate awaiting them. The cold weather, icy wind, and dismal circumstances led Scott to acerbically remark in his diary: ‘Great god! This is an awful place and terrible enough to have laboured to it without the reward of priority.’ By this time, the party had been hauling their sledges for weeks, and all the men were suffering from dehydration, owing to fatigue and altitude sickness from being on the Antarctic plateau that sits nearly 3000m above sea level. Three of them, Captain Oates, Seaman Evans, and Bowers, were badly afflicted with frostbitten noses and cheeks. Ahead lay the return leg, made all the more unbearable by the crippling psychological blow of knowing they had been second to the Pole. After a gruelling 21-day trek in bitterly cold summit winds, the team reached their first cache of food and fuel, covering the distance six days faster than it had taken them to do the leg in the other direction.

Performance of Fineneedle Aspiration Cytology of the Breast. Clinical Experience in Ravenna (Italy)

1993 ◽  
Vol 79 (6) ◽  
pp. 413-417
Author(s):  
Lauro Bucchi ◽  
Patrizia Schincaglia ◽  
Giangiuseppe Melandri ◽  
Nori Morini ◽  
Carlo Naldoni ◽  
...  
Keyword(s):  
Predictive Value ◽  
Breast Cancer Case ◽  
True Positive Rate ◽  
Cancer Case ◽  
Breast Lesions ◽  
Additional Contribution ◽  
True Positive ◽  
Aspiration Cytology ◽  
True Negative ◽  
Positive Rate

Aims and background Fineneedle aspiration cytology (FNAC) is a routine test in the evaluation of breast lesions. We assessed the diagnostic accuracy of mammography (MG), physical examination (PE), ultrasonography (US) and FNAC in 1064 histologically confirmed breast lesions (638 malignant, 426 benign) observed consecutively at the Cancer Prevention Center of Ravenna (Italy). Methods The performance of each test and the additional contribution of FNAC were determined. Results FNAC was done in 69.6 % of cancers and 39.7 % of benign lesions (P = 0.00000), the frequency of aspiration being significantly associated with severity at MG, PE, and US. For FNAC, the true positive rate was 95.1 % and the true negative rate 67.4 %. Only one breast cancer case was detected by FNAC alone (additional true positive rate 0.2 %). The positive predictive value of FNAC in the absence of other abnormalities was 5 %. The negative predictive value of a benign report at MG, PE, US and FNAC was 100 %. Conclusions All breast lesions should be evaluated by all available techniques, especially FNAC, and open biopsy should be avoided for those reported as benign at all tests.

Multiple- versus Single-Index Predictors of Dangerousness, Suicide, and other Rare Behaviors

1979 ◽  
Vol 45 (2) ◽  
pp. 343-349 ◽  
Author(s):  
James M. Vanderplas ◽  
Jean H. Vanderplas
Keyword(s):  
Boolean Function ◽  
Base Rate ◽  
True Positive ◽  
True Negative ◽  
Single Index

The principle that prediction of low base-rate events based on test signs may be grossly in error in the direction of overprediction is argued to be limited to situations where single-index predictors are used. An example is presented of a three-variable Boolean function which accurately distinguishes 70% of true positive instances and 100% of true negative instances in a situation where the base rate of the predicted event is 100 per 100,000.

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