A new algorithm for fast generalized DFTs

We give an new arithmetic algorithm to compute the generalized Discrete Fourier Transform (DFT) over finite groups $G$. The new algorithm uses $O(|G|^{\omega/2 + o(1)})$ operations to compute the generalized DFT over finite groups of Lie type, including the linear, orthogonal, and symplectic families and their variants, as well as all finite simple groups of Lie type. Here $\omega$ is the exponent of matrix multiplication, so the exponent $\omega/2$ is optimal if $\omega = 2$. Previously, "exponent one" algorithms were known for supersolvable groups and the symmetric and alternating groups. No exponent one algorithms were known (even under the assumption $\omega = 2$) for families of linear groups of fixed dimension, and indeed the previous best-known algorithm for $SL_2(F_q)$ had exponent $4/3$ despite being the focus of significant effort. We unconditionally achieve exponent at most $1.19$ for this group, and exponent one if $\omega = 2$. Our algorithm also yields an improved exponent for computing the generalized DFT over general finite groups $G$, which beats the longstanding previous best upper bound, for any $\omega$. In particular, assuming $\omega = 2$, we achieve exponent $\sqrt{2}$, while the previous best was $3/2$

On Multidimensional and Monotone k-SUM

The well-known k-SUM conjecture is that integer k-SUM requires time Omega(n^{ceil{k/2}-o(1)}). Recent work has studied multidimensional k-SUM in F_p^d, where the best known algorithm takes time tilde O(n^{ceil{k/2}}). Bhattacharyya et al. [ICS 2011] proved a min(2^{Omega(d)},n^{Omega(k)}) lower bound for k-SUM in F_p^d under the Exponential Time Hypothesis. We give a more refined lower bound under the standard k-SUM conjecture: for sufficiently large p, k-SUM in F_p^d requires time Omega(n^{k/2-o(1)}) if k is even, and Omega(n^{ceil{k/2}-2k(log k)/(log p)-o(1)}) if k is odd. For a special case of the multidimensional problem, bounded monotone d-dimensional 3SUM, Chan and Lewenstein [STOC 2015] gave a surprising tilde O(n^{2-2/(d+13)}) algorithm using additive combinatorics. We show this algorithm is essentially optimal. To be more precise, bounded monotone d-dimensional 3SUM requires time Omega(n^{2-frac{4}{d}-o(1)}) under the standard 3SUM conjecture, and time Omega(n^{2-frac{2}{d}-o(1)}) under the so-called strong 3SUM conjecture. Thus, even though one might hope to further exploit the structural advantage of monotonicity, no substantial improvements beyond those obtained by Chan and Lewenstein are possible for bounded monotone d-dimensional 3SUM

Flight Software Implementation and Verification on IRIS CubeSat

Flight software (FSW) is essential in the operation of a satellite program. It is important to verify the functionality and performance of the FSW on ground before being deployed in space. We discusses the implementation and verification of the FSW of the Intelligent Remote-Sensing and Internet Satellite (IRIS) CubeSats

Floating Point Arithmetic Protocols for Constructing Secure Data Analysis Application

AbstractA large variety of data mining and machine learning techniques are applied to a wide range of applications today. There- fore, there is a real need to develop technologies that allows data analysis while preserving the confidentiality of the data. Secure multi-party computation (SMC) protocols allows participants to cooperate on various computations while retaining the privacy of their own input data, which is an ideal solution to this issue. Although there is a number of frameworks developed in SMC to meet this challenge, but they are either tailored to perform only on specific tasks or provide very limited precision. In this paper, we have developed protocols for floating point arithmetic based on secure scalar product protocols, which is re- quired in many real world applications. Our protocols follow most of the IEEE-754 standard, supporting the four fundamental arithmetic operations, namely addition, subtraction, multiplication, and division. We will demonstrate the practicality of these protocols through performing various statistical calculations that is widely used in most data analysis tasks. Our experiments show the performance of our framework is both practical and promising

Transplantation of Human Umbilical Mesenchymal Stem Cells from Wharton's Jelly after Complete Transection of the Rat Spinal Cord

BACKGROUND: Human umbilical mesenchymal stem cells (HUMSCs) isolated from Wharton's jelly of the umbilical cord can be easily obtained and processed compared with embryonic or bone marrow stem cells. These cells may be a valuable source in the repair of spinal cord injury. METHODOLOGY/PRINCIPAL FINDINGS: We examine the effects of HUMSC transplantation after complete spinal cord transection in rats. Approximately 5x10(5) HUMSCs were transplanted into the lesion site. Three groups of rats were implanted with either untreated HUMSCs (referred to as the stem cell group), or HUMSCs treated with neuronal conditioned medium (NCM) for either three days or six days (referred to as NCM-3 and NCM-6 days, respectively). The control group received no HUMSCs in the transected spinal cord. Three weeks after transplantation, significant improvements in locomotion were observed in all the three groups receiving HUMSCs (stem cell, NCM-3 and NCM-6 days groups). This recovery was accompanied by increased numbers of regenerated axons in the corticospinal tract and neurofilament-positive fibers around the lesion site. There were fewer microglia and reactive astrocytes in both the rostral and caudal stumps of the spinal cord in the stem cell group than in the control group. Transplanted HUMSCs survived for 16 weeks and produced large amounts of human neutrophil-activating protein-2, neurotrophin-3, basic fibroblast growth factor, glucocorticoid induced tumor necrosis factor receptor, and vascular endothelial growth factor receptor 3 in the host spinal cord, which may help spinal cord repair. CONCLUSIONS/SIGNIFICANCE: Transplantation of HUMSCs is beneficial to wound healing after spinal cord injury in rats

EBV-positive Hodgkin lymphoma is associated with suppression of p21cip1/waf1 and a worse prognosis

<p>Abstract</p> <p>Background</p> <p>About 30-50% of Hodgkin lymphomas (HLs) harbor the Epstein-Barr virus (EBV), but the impact of EBV infection on clinical outcomes has been unclear. EBV-encoded small RNAs (<it>EBER</it>s) are presented in all EBV-infected cells, but their functions are still less understood.</p> <p>Results</p> <p><it>EBER1 </it>was transfected into two HL cell lines, KMH2 and L428, and microarrays were used to screen for <it>EBER1</it>-induced changes. We found that <it>EBER1 </it>suppressed <it>p21</it>^cip1/waf1transcription in HL cell lines. In addition, positive regulators of <it>p21</it>^cip1/waf1transcription, such as p53, EGR1, and STAT1, were decreased. Suppression of <it>p21</it>^cip1/waf1in the <it>EBER1</it>⁺HL cell lines was associated with increased resistance to histone deacetylase inhibitors or proteasome inhibitors, drugs known to cause apoptosis by increasing p21^cip1/waf1levels. On biopsy specimens, EBV⁺HLs had weaker expression of both p21^cip1/waf1and active caspase 3. Clinically, suppression of p21^cip1/waf1in EBV⁺HLs was associated with a worse 2-year disease-free survival rate (45% for EBV⁺HLs <it>vs</it>. 77% for EBV^-HLs, <it>p </it>= 0.002).</p> <p>Conclusion</p> <p>Although the underlying mechanisms are still relatively unclear, <it>EBER1 </it>inhibits <it>p21</it>^cip1/waf1transcription and prevents apoptosis through down-regulation of p53, EGR1, and STAT1. The anti-apoptotic activity of <it>EBER1 </it>may be important in the rescue of Reed-Sternberg cells from drug-induced apoptosis and in the clinical behaviors of EBV⁺HLs.</p

Anti-DKK1 Enhances the Early Osteogenic Differentiation of Human Adipose-Derived Stem/Stromal Cells

: Adipose-derived stem/stromal cells (ASCs) have been previously used for bone repair. However, significant cell heterogeneity exists within the ASC population, which has the potential to result in unreliable bone tissue formation and/or low efficacy. Although the use of cell sorting to lower cell heterogeneity is one method to improve bone formation, this is a technically sophisticated and costly process. In this study, we tried to find a simpler and more deployable solution-blocking antiosteogenic molecule Dickkopf-1 (DKK1) to improve osteogenic differentiation. Human adipose-derived stem cells were derived from = 5 samples of human lipoaspirate. In vitro, anti-DKK1 treatment, but not anti-sclerostin (SOST), promoted ASC osteogenic differentiation, assessed by alizarin red staining and real-time polymerase chain reaction (qPCR). Increased canonical Wnt signaling was confirmed after anti-DKK1 treatment. Expression levels of DKK1 peaked during early osteogenic differentiation (day 3). Concordantly, anti-DKK1 supplemented early (day 3 or before), but not later (day 7) during osteogenic differentiation positively regulated osteoblast formation. Finally, anti-DKK1 led to increased transcript abundance of the Wnt inhibitor SOST, potentially representing a compensatory cellular mechanism. In sum, DKK1 represents a targetable "molecular brake" on the osteogenic differentiation of human ASC. Moreover, release of this brake by neutralizing anti-DKK1 antibody treatment at least partially rescues the poor bone-forming efficacy of ASC