121 research outputs found
On social networks and collaborative recommendation
Social network systems, like last.fm, play a significant role in Web 2.0, containing large amounts of multimedia-enriched data that are enhanced both by explicit user-provided annotations and implicit aggregated feedback describing the personal preferences of each user. It is also a common tendency for these systems to encourage the creation of virtual networks among their users by allowing them to establish bonds of friendship and thus provide a novel and direct medium for the exchange of data.
We investigate the role of these additional relationships in developing a track recommendation system. Taking into account both the social annotation and friendships inherent in the social graph established among users, items and tags, we created a collaborative recommendation system that effectively adapts to the personal information needs of each user. We adopt the generic framework of Random Walk with Restarts in order to provide with a more natural and efficient way to represent social networks.
In this work we collected a representative enough portion of the music social network last.fm, capturing explicitly expressed bonds of friendship of the user as well as social tags. We performed a series of comparison experiments between the Random Walk with Restarts model and a user-based collaborative filtering method using the Pearson Correlation similarity. The results show that the graph model system benefits from the additional information embedded in social knowledge. In addition, the graph model outperforms the standard collaborative filtering method.</p
Effects of the timolol-dorzolamide fixed combination and latanoprost on circadian diastolic ocular perfusion pressure in glaucoma.
PURPOSE. To evaluate the effect of the timolol-dorzolamide
fixed combination (TDFC) and latanoprost 0.005% on 24-hour
intraocular pressure (IOP), systolic (SBP) and diastolic (DBP)
blood pressure, and diastolic ocular perfusion pressure (DOPP)
in patients with primary open-angle glaucoma (POAG).
METHODS. This was an institutional, randomized clinical trial.
After a 24-hour assessment without treatment, 27 previously
untreated patients with POAG were randomized to 6 weeks’
treatment with twice-daily TDFC (8 AM and 8 PM) followed by
once-daily latanoprost 0.005% (8 PM), or vice versa. One eye
was analyzed per patient. The mean values of IOP, DBP, SBP,
and DOPP (difference between DBP and IOP) were recorded at
each time point, and the 24-hour data are the mean values of
each patient’s measurements over the 24-hour period. The
differences between the values of the first treatment period
and the baseline and the second treatment period and washout
were calculated and analyzed by means of an analysis of variance
model that tested the effects of sequence and treatment.
RESULTS. Both treatments significantly reduced 24-hour IOP
(P <0.0001), but TDFC led to lower 24-hour pressure
(mean ±SD: 15.4 ±1.9 vs. 16.7± 1.7 mm Hg; P=0.004).
Latanoprost did not lead to any significant reduction in mean
24-hour SBP and DBP (SBP: P =0.952; DBP: P=0.831), but
TDFC did (SBP and DBP: P < 0.0001). Both treatments significantly
increased 24-hour DOPP (P < 0.0001), with no difference
between the two medications (P=0.09).
CONCLUSIONS. In previously untreated patients with POAG, TDFC,
and latanoprost equally enhanced 24-hour DOPP: the former by
counteracting the decrease in DBP with a substantial reduction in
IOP and the latter by not affecting DBP and significantly reducing
IO
Towards a design process for computer-aided biomimetics
Computer-Aided Biomimetics (CAB) tools aim to support the integration of relevant biological knowledge into biomimetic problem-solving processes. Specific steps of biomimetic processes that require support include the identification, selection and abstraction of relevant biological analogies. Existing CAB tools usually aim to support these steps by describing biological systems in terms of functions, although engineering functions do not map naturally to biological functions. Consequentially, the resulting static, functional view provides an incomplete understanding of biological processes, which are dynamic, cyclic and self-organizing. This paper proposes an alternative approach that revolves around the concept of trade-offs. The aim is to include the biological context, such as environmental characteristics, that may provide information crucial to the transfer of biological information to an engineering application. The proposed design process is exemplified by an illustrative case study
Twenty-four hour efficacy with preservative free tafluprost compared with latanoprost in patients with primary open angle glaucoma or ocular hypertension
10openopenKonstas A.G.; Quaranta L.; Katsanos A.; Riva I.; Tsai J.C.; Giannopoulos T.; Voudouragkaki I.C.; Paschalinou E.; Floriani I.; Haidich A.B.Konstas, A. G.; Quaranta, Luciano; Katsanos, A.; Riva, Ivano; Tsai, J. C.; Giannopoulos, T.; Voudouragkaki, I. C.; Paschalinou, E.; Floriani, I.; Haidich, A. B
Diffusion under time-dependent resetting
We study a Brownian particle diffusing under a time-modulated stochastic
resetting mechanism to a fixed position. The rate of resetting r(t) is a
function of the time t since the last reset event. We derive a sufficient
condition on r(t) for a steady-state probability distribution of the position
of the particle to exist. We derive the form of the steady-state distributions
under some particular choices of r(t) and also consider the late time
relaxation behavior of the probability distribution. Finally we consider first
passage time properties for the Brownian particle to reach the origin and
derive a formula for the mean first passage time. We study optimal properties
of the mean first passage time and show that a threshold function is at least
locally optimal for the problem of minimizing the mean first passage time.Comment: 15 pages, 4 figure
Vision-related quality of life and symptom perception change over time in newly-diagnosed primary open angle glaucoma patients.
To evaluate the change over time of vision-related quality of life (QoL) and glaucoma symptoms in a population of newly-diagnosed primary open angle glaucoma (POAG) patients. Multicenter, prospective study. Consecutive newly-diagnosed POAG patients were enrolled and followed-up for one year. Follow-up visits were scheduled at 6 and 12 months from baseline. At each visit, vision-related QoL and glaucoma-related symptoms were assessed by the means of the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) and the Glaucoma Symptom Scale (GSS), respectively. Trends over time for NEI-VFQ-25 and GSS scores were evaluated with longitudinal linear mixed models. One-hundred seventy-eight patients were included in the analysis. At baseline, early to moderate glaucoma stages were associated with higher scores for most GSS and NEI-VFQ-25 items, while lower best-corrected visual acuity was associated with lower scores for 4 of the 12 NEI-VFQ-25 items. During the follow-up, all the GSS scores, the NEI-VFQ-25 total score, and 7 of the 12 NEI-VFQ-25 scores significantly improved (p < 0.05). In multivariate model, higher increases of most GSS and NEI-VFQ-25 scores were modeled in patients with low scores at baseline. Vision-related QoL and glaucoma-related symptom perception significantly improved during the one-year follow-up in this population of newly diagnosed POAG patients
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