142 research outputs found
Vicious or Virtuous Cycle? The Privacy Implications of Active Assisted Living Technologies for Older People
A variety of technologies are being developed to help older people live healthier, more independent, and safer lives, for longer. While many of these technologies are positively impacting the lives of older adults, they also have the potential to dictate specific behaviours or restrict their autonomy rather than empower them. The vulnerability theory of privacy proposes that vulnerable populations are not only more likely to be susceptible to privacy violations, but are also disproportionately affected by said violations. In this position paper, we adapt the vulnerability theory of privacy to the older adult population, and identify a further potential exacerbatory cycle. The risk of a 'slippery slope' of privacy violation occurs when AAL technologies enable an elevated and quantified visibility of (mis)behaviour and irregular activity that could seem to justify the deployment of further AAL technology. We present ĝ€?FOR VERIFICATION>ratchet-wise rehabilitation' as an alternative vision to the ĝ€?FOR VERIFICATION>slippery slope' and identify research and design challenges throughout the paper
Serum prostate-specific antigen as surrogate for the Histological diagnosis of Prostate cancer
Introduction. To determine whether there is a cut-off value of serum prostate-specific antigen (PSA) which can be used confidently to make the diagnosis of prostate cancer, thereby obviating the need for biopsy.Patients and methods. During the period October 1991 to March 1998 the Department of Chemical Pathology at Tygerberg Hospital performed a total of 6 733 serum PSA assays on 3960 patients. The histopathological and clinical diagnoses of these patients were obtained from records in the departments of Anatomical Pathology, Urological Oncology and Radiation Oncology. The serum PSA levels were correlated with the histopathology reports, using different PSA cut-off values ranging from 5 to 500 ng/ ml, to calculate the sensitivity, specificity, and positive and negative predictive values of each cut-off value of PSA in predicting the presence of prostate cancer.Results. In total, 3 837 (57%) of the 6 733 serum PSA assays were ≤ 4 ng/ ml, 1 045 (15.5%) of the assays were ≥50 ng/ ml, and 798 (11.9%) were~ 100 ng/ ml. Of the total of 3 960 individual patients, 531 (13.4%) had a serum PSA ≥50 ng/ ml and 423 (10.7%) had a PSA ≥ 100 ng/ ml. A serum PSA of ≥ 30 ng/ml had a positive predictive value (PPV) of 90% at a specificity of 87% and sensitivity of 78%, while a PSA ≥ 60 ng/ ml had a PPV of 98% at a specificity of 98% and sensitivity of 65% for the presence of prostate cancer. The PPV reached 99% at a PSA ≥ 100 ng/ ml and 100% at a PSA ≥ 500 ng/ ml, with a specificity of 99% and 100%, but sensitivity of only 53% and 19%, respectively.Conclusions. A serum PSA ≥ 60 ng/ ml has a PPV of 98% for the presence of adenocarcinoma of the prostate, and may be used as a surrogate for histological diagnosis where facilities for obtaining prostatic biopsies are not readily available, thus decreasing costs and patient morbidity
Early diagnosis of prostate cancer in the Western Cape
Background. Early stage prostate cancer does not cause symptoms, and even metastatic disease may exist for years without causing symptoms or signs. Whereas early stage prostate cancer can be cured with radical prostatectomy or radiotherapy, the prognosis of patients with locally advanced or metastatic cancer is significantly poorer.Objectives. ln view of the high incidence of advanced and therefore incurable prostate cancer seen at the oncology clinic of the Department of Urology, Tygerberg Hospital, we started a prostate clinic with the aim of detecting early stage prostate cancer which is potentially curable. A secondary objective was to investigate the question whether there is a higher incidence of prostate cancer among black African men.Patients and methods. Men aged 50 - 70 years were invited by means of media communications (newspaper and radio) to attend our prostate clinic for a free physical examination, including a digital rectal examination (DRE) and serum prostate specific antigen (PSA) assay. If the DRE was clinically suspicious of malignancy and/ or the serum PSA was > 4 ng/ ml, the patient was appropriately counselled and referred for transrectal ultrasound (TRUS)-guided sextant prostate biopsy.Results. In the period June 1997- September 1999 a total of 1056 men attended the prostate clinic. Biopsies were indicated in 160 cases, and were obtained in 114 (71.3%, i.e. 10.8% of the entire cohort). Prostate cancer was detected on first biopsy in 3.5% of the entire group of men (in 35.9% of those with a clinically abnormal DRE, in 41.3% of those with a serum PSA > 4 ng/ ml and in 88.6% of those with an abnormal DRE and serum PSA > 4 ng/ ml. In the 37 men with prostate cancer, the clinical tumour stage was T1 - 2 in 83.8% and T3- 4 in 16.2%. ln the group of patients with clinical stage T1 - 2 tumours, the treatment was watchful waiting in 62.5% of cases, radiotherapy in 20.8% and radical prostatectomy in 16.7%. Analysis of the data according to race showed that in the group of 47 black men there was a higher percentage of clinically abnormal DRE, PSA > 4 .0 ng/ ml and biopsies showing malignancy, and a higher overall prostate cancer detection rate (8.5%).Conclusions. Our prostate cancer detection rate of 3.5% is slightly lower than that reported in larger studies (4.7%), which may be due to the fact that prostate biopsy was performed in only 71% of those who had an indication for biopsy. ln the men diagnosed with clinically localised prostate cancer, potentially curative treatment was given in only 37.5% of cases. This compares unfavourably with the historical cohort of men seen at our oncology clinic, where 53% received potentially curative treatment, and a large European study where potentially curative treatment was given in 89% of cases. Our finding that black men had a higher percentage of clinically abnormal DRE, PSA > 4.0 ng/ ml and biopsies showing malignancy and a higher overall detection rate of prostate cancer should be interpreted with caution, since black men comprised only 4.5% of our overall study cohort.
Observation of the spin-charge thermal isolation of ferromagnetic Ga_{0.94}Mn_{0.06}As by time-resolved magneto-optical measurement
The dynamics of magnetization under femtosecond optical excitation is studied
in a ferromagnetic semiconductor Ga_{0.94}Mn_{0.06}As with a time-resolved
magneto-optical Kerr effect measurement with two color probe beams. The
transient reflectivity change indicates the rapid rise of the carrier
temperature and relaxation to a quasi-thermal equilibrium within 1 ps, while a
very slow rise of the spin temperature of the order of 500ps is observed. This
anomalous behavior originates from the thermal isolation between the charge and
spin systems due to the spin polarization of carriers (holes) contributing to
ferromagnetism. This constitutes experimental proof of the half-metallic nature
of ferromagnetic Ga_{0.94}Mn_{0.06}As arising from double exchange type
mechanism originates from the d-band character of holes
Einstein equations in the null quasi-spherical gauge
The structure of the full Einstein equations in a coordinate gauge based on
expanding null hypersurfaces foliated by metric 2-spheres is explored. The
simple form of the resulting equations has many applications -- in the present
paper we describe the structure of timelike boundary conditions; the matching
problem across null hypersurfaces; and the propagation of gravitational shocks.Comment: 12 pages, LaTeX (revtex, amssymb), revision 18 pages, contains
expanded discussion and explanations, updated references, to appear in CQ
Improved diagnostics targeting c-MET in non-small cell lung cancer: expression, amplification and activation?
Background: Several c-MET targeting inhibitory molecules have already shown promising results in the treatment of patients with Non-small Cell Lung Cancer (NSCLC). Combination of EGFR-and c-MET-specific molecules may overcome EGFR tyrosine kinase inhibitor (TKI) resistance. The aim of this study was to allow for the identification of patients who might benefit from TKI treatments targeting MET and to narrow in on the diagnostic assessment of MET. Methods: 222 tumor tissues of patients with NSCLC were analyzed concerning c-MET expression and activation in terms of phosphorylation (Y1234/1235 and Y1349) using a microarray format employing immunohistochemistry (IHC). Furthermore, protein expression and MET activation was correlated with the amplification status by Fluorescence in Situ Hybridization (FISH). Results: Correlation was observed between phosphorylation of c-MET at Y1234/1235 and Y1349 (spearman correlation coefficient r(s) = 0.41;p 0.05). c-MET gene amplification was detected in eight of 214 patients (3.7 %). No significant association was observed between c-MET amplification, c-MET protein expression and phosphorylation. Conclusion: Our data indicate, that neither expression of c-MET nor the gene amplification status might be the best way to select patients for MET targeting therapies, since no correlation with the activation status of MET was observed. We propose to take into account analyzing the phosphorylation status of MET by IHC to select patients for MET targeting therapies. Signaling of the receptor and the activation of downstream molecules might be more crucial for the benefit of therapeutics targeting MET receptor tyrosine kinases than expression levels alone
Physics of Solar Prominences: I - Spectral Diagnostics and Non-LTE Modelling
This review paper outlines background information and covers recent advances
made via the analysis of spectra and images of prominence plasma and the
increased sophistication of non-LTE (ie when there is a departure from Local
Thermodynamic Equilibrium) radiative transfer models. We first describe the
spectral inversion techniques that have been used to infer the plasma
parameters important for the general properties of the prominence plasma in
both its cool core and the hotter prominence-corona transition region. We also
review studies devoted to the observation of bulk motions of the prominence
plasma and to the determination of prominence mass. However, a simple inversion
of spectroscopic data usually fails when the lines become optically thick at
certain wavelengths. Therefore, complex non-LTE models become necessary. We
thus present the basics of non-LTE radiative transfer theory and the associated
multi-level radiative transfer problems. The main results of one- and
two-dimensional models of the prominences and their fine-structures are
presented. We then discuss the energy balance in various prominence models.
Finally, we outline the outstanding observational and theoretical questions,
and the directions for future progress in our understanding of solar
prominences.Comment: 96 pages, 37 figures, Space Science Reviews. Some figures may have a
better resolution in the published version. New version reflects minor
changes brought after proof editin
Prominence-cavity regions observed using SWAP 174A filtergrams and simultaneous eclipse flash spectra
Images from the SWAP (Proba 2 mission) taken at 174A in the Fe IX/X lines are
compared to simultaneous slitless flash spectra taken during the last solar
total eclipse of July, 11th 2010. Many faint low excitation emission lines
together with the HeI and HeII Paschen Alpha chromospheric lines are recorded
on eclipse spectra where regions of limb prominences are obtained with
space-borne imagers. We consider a deep flash spectrum obtained by summing 80
individual spectra to show the intensity modulations of the continuum.
Intensity depressions are observed around the prominences in both eclipse and
SWAP images. The prominence cavities are interpreted as a relative depression
of plasma density, produced inside the corona surrounding the prominences.
Photometric measurements are shown at different scales and different,
spectrally narrow, intervals for both the prominences and the coronal
background.Comment: 22 pages, 14 figures, accepted to publish in Sol. Phy
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