748 research outputs found
Minimal Model for Sand Dunes
We propose a minimal model for aeolian sand dunes. It combines an analytical
description of the turbulent wind velocity field above the dune with a
continuum saltation model that allows for saturation transients in the sand
flux. The model provides a qualitative understanding of important features of
real dunes, such as their longitudinal shape and aspect ratio, the formation of
a slip face, the breaking of scale invariance, and the existence of a minimum
dune size.Comment: 4 pages, 4 figures, replaced with publishd versio
Androgens and Development of Posttransplantation Diabetes Mellitus in Male Kidney Transplant Recipients:A Post Hoc Analysis of a Prospective Study
OBJECTIVE: Posttransplantation diabetes mellitus (PTDM) effects up to 30% of all kidney transplant recipients (KTR). Recent studies in mice found that sufficient androgen levels are necessary for β-cell health and adequate insulin secretion. This raises the question whether a similar relationship might be present in KTR. Hence, we hypothesized that dihydrotestosterone and testosterone are associated with the development of PTDM in male KTR. RESEARCH DESIGN AND METHODS: We conducted a post hoc analyses of a prospective single-center cohort study including adult male KTR with a functioning graft ≥1 year posttransplantation. Androgen levels were assessed by liquid chromatography-tandem mass spectrometry. Development of PTDM was defined according to the American Diabetes Association's criteria. RESULTS: We included 243 male KTR (aged 51 ± 14 years), with a median dihydrotestosterone 0.9 (0.7-1.3) nmol/L and testosterone of 12.1 (9.4-15.8) nmol/L. During 5.3 (3.7-5.8) years of follow-up, 28 KTR (11.5%) developed PTDM. A clear association was observed, as 15 (19%), 10 (12%), and 3 (4%) male KTR developed PTDM in the respective tertiles of dihydrotestosterone (P = 0.008). In Cox regression analyses, both dihydrotestosterone and testosterone as continuous variables were inversely associated with the risk to development PTDM, independent of glucose and HbA1c (hazard ratio [HR] 0.31 [95%CI 0.16-0.59], P < 0.001; and HR 0.32 [95%CI 0.15-0.68], P = 0.003, respectively). CONCLUSIONS: Our results suggest that low androgen levels are a novel potential modifiable risk factor for the development of PTDM in male KTR
PENYALAHGUNAAN ASET NEGARA DALAM BENTUK JARINGAN SATELIT UNTUK KEPENTINGAN KORPORASI DIHUBUNGKAN DENGAN UNDANGUNDANG NOMOR 36 TAHUN 1999 TENTANG TELEKOMUNIKASI JO UNDANGUNDANG NOMOR 20 TAHUN 2001 TENTANG TINDAK PIDANA KORUPSI
telekomunikasi sebagaimana dilakukan oleh IM2. IM2 telah menyalahgunakan pita
frekuensi 2.1 Ghz, dan secara melawan hukum beroperasi pada jaringan tersebut sehingga
menimbulkan kerugian negara. Berdasarkan hal tersebut maka penulis tertarik meneliti,
bagaimana Undang-Undang Telekomunikasi jo Peraturan Menteri Komunikasi dan
Informatika dan Undang-Undang Tindak Pidana Korupsi mengatur mekanisme pemanfaatan
aset negara berupa jaringan satelit, mengapa aset negara berupa jaringan satelit kerap kali
disalahgunakan didalam pemanfaatannya oleh korporasi, serta bagaimana upaya yang dapat
dilakukan untuk melindungi aset negara dalam bentuk jaringan satelit terhadap
penyalahgunaan yang dilakukan oleh korporasi.
Penelitian ini menggunakan spesifikasi penelitian yang bersifat deskriftif analitis
dengan pendekatan yuridis normatif dibantu yuridis empiris, data yang diperlukan dalam
penelitian ini dikumpulkan melalui studi kepustakaan dan studi lapangan, kemudian
dianalisis menggunakan teknik analisis data berupa yuridis kualitatif.
Pemanfaatan aset negara berupa jaringan satelit melalui pita frekuensi merupakan
salah satu hak yang dalam pemanfaatannya diatur oleh peraturan perundang-undangan agar
tercipta keadilan, kepastian dan ketertiban, keamanan, keseimbangan, perlindungan dan
pemeliharaan dalam pemanfataannya. Jaringan satelit yang merupakan jaringan satelit aset
negara pemanfaatannya mensyaratkan izin dan pembayaran tarif tertentu, sehingga
konsekuensinya ketika terjadi penyalahgunaan pemanfaatan jaringan satelit, negara akan
mengalami kerugian. Aset negara berupa jaringan satelit kerap kali disalahgunakan didalam
pemanfaatannya oleh korporasi disebabkan beberapa faktor diantaranya faktor hukum itu
sendiri dalam hal ini peraturan perundang-undangannya, faktor penegak hukum, faktor sarana
atau fasilitas yang mendukung pengawasan dan penegakan hukum itu sendiri, faktor
masyarakat, yakni lingkungan dimana hukum tersebut berlaku atau diterapkan, dalam hal ini
yaitu lingkungan korporasi, faktor kebudayaan yakni kurangnya kesadaran hukum korporasi
dalam upaya pemanfaatan aset negara secara berkeadilan dan tertib sesuai peraturan
perundang-undangan yang berlaku, dimana pemanfaatan yang tidak secara berkeadilan akan
membawa negara menuju kepada kehancuran. Upaya yang dapat dilakukan untuk melindungi
aset negara dalam bentuk jaringan satelit terhadap penyalahgunaan yang dilakukan oleh
korporasi harus berangkat dari beberapa faktor yang menjadi penyebab penyalahgunaan
pemanfaatan jaringan satelit diantaranya yaitu melalui upaya preventif berupa revisi
perunang-undangan, pengawasan, sosialisasi sert upaya represif berupa penegakan hukum.
Penegakan hukum harus dilaksanakan tanpa pandang bulu, sebagai bentuk keyakinan atas
doktrin hukum, bahwa setiap orang mempunyai kedudukan yang sama di depan hukum.
Kata Kunci: Penyalahgunaan Aset Negara, Jaringan Sateli
A Continuum Saltation Model for Sand Dunes
We derive a phenomenological continuum saltation model for aeolian sand
transport that can serve as an efficient tool for geomorphological
applications. The coupled differential equations for the average density and
velocity of sand in the saltation layer reproduce both known equilibrium
relations for the sand flux and the time evolution of the sand flux as
predicted by microscopic saltation models. The three phenomenological
parameters of the model are a reference height for the grain-air interaction,
an effective restitution coefficient for the grain-bed interaction, and a
multiplication factor characterizing the chain reaction caused by the impacts
leading to a typical time or length scale of the saturation transients. We
determine the values of these parameters by comparing our model with wind
tunnel measurements. Our main interest are out of equilibrium situations where
saturation transients are important, for instance at phase boundaries
(ground/sand) or under unsteady wind conditions. We point out that saturation
transients are indispensable for a proper description of sand flux over
structured terrain, by applying the model to the windward side of an isolated
dune, thereby resolving recently reported discrepancies between field
measurements and theoretical predictions.Comment: 11 pages, 7 figure
Minimal model for aeolian sand dunes
We present a minimal model for the formation and migration of aeolian sand
dunes. It combines a perturbative description of the turbulent wind velocity
field above the dune with a continuum saltation model that allows for
saturation transients in the sand flux. The latter are shown to provide the
characteristic length scale. The model can explain the origin of important
features of dunes, such as the formation of a slip face, the broken scale
invariance, and the existence of a minimum dune size. It also predicts the
longitudinal shape and aspect ratio of dunes and heaps, their migration
velocity and shape relaxation dynamics. Although the minimal model employs
non-local expressions for the wind shear stress as well as for the sand flux,
it is simple enough to serve as a very efficient tool for analytical and
numerical investigations and to open up the way to simulations of large scale
desert topographies.Comment: 19 pages, 22 figure
Wavelet analysis of epileptic spikes
Interictal spikes and sharp waves in human EEG are characteristic signatures
of epilepsy. These potentials originate as a result of synchronous,
pathological discharge of many neurons. The reliable detection of such
potentials has been the long standing problem in EEG analysis, especially after
long-term monitoring became common in investigation of epileptic patients. The
traditional definition of a spike is based on its amplitude, duration,
sharpness, and emergence from its background. However, spike detection systems
built solely around this definition are not reliable due to the presence of
numerous transients and artifacts. We use wavelet transform to analyze the
properties of EEG manifestations of epilepsy. We demonstrate that the behavior
of wavelet transform of epileptic spikes across scales can constitute the
foundation of a relatively simple yet effective detection algorithm.Comment: 4 pages, 3 figure
Decreased haemoglobin levels are associated with lower muscle mass and strength in kidney transplant recipients
Background: Post-transplant anaemia and reduced muscle mass and strength are highly prevalent in kidney transplant recipients (KTRs). Decreased haemoglobin levels, a marker of anaemia, could adversely affect muscle mass and strength through multiple mechanisms, among others, through diminished tissue oxygenation. We aimed to investigate the association between haemoglobin levels with muscle mass and strength in KTRs. Methods:We included stable KTRs from the TransplantLines Biobank and Cohort study with a functional graft ≥1 year post-transplantation. Muscle mass was assessed using 24 h urinary creatinine excretion rate (CER) and bioelectrical impedance analysis (BIA). Muscle strength was assessed with a handgrip strength test using a dynamometer and, in a subgroup (n = 290), with the five-times sit-to-stand (FTSTS) test. We used multivariable linear and logistic regression analyses to investigate the associations of haemoglobin levels with muscle mass and strength. Results: In 871 included KTRs [median age 58 (interquartile range (IQR), 48–66)] years; 60% men; eGFR 51 ± 18 mL/min/1.73 m2) who were 3.5 (1.0–10.2) years post-transplantation, the mean serum haemoglobin level was 13.9 ± 1.8 g/dL in men and 12.8 ± 1.5 g/dL in women. Lower haemoglobin levels were independently associated with a lower CER (std. β = 0.07, P = 0.01), BIA-derived skeletal muscle mass (std. β = 0.22, P < 0.001), handgrip strength (std. β = 0.15, P < 0.001), and worse FTSTS test scores (std. β = −0.17, P = 0.02). KTRs in the lowest age-specific and sex-specific quartile of haemoglobin levels had an increased risk of being in the worst age-specific and sex-specific quartile of CER (fully adjusted OR, 2.09; 95% CI 1.15–3.77; P = 0.02), handgrip strength (fully adjusted OR, 3.30; 95% CI 1.95–5.59; P < 0.001), and FTSTS test score (fully adjusted OR, 7.21; 95% CI 2.59–20.05; P < 0.001). Conclusions: Low haemoglobin levels are strongly associated with decreased muscle mass and strength in KTRs. Future investigation will need to investigate whether maintaining higher haemoglobin levels may improve muscle mass and strength in KTRs.</p
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