An Algorithmic Framework for Computing Validation Performance Bounds by Using Suboptimal Models

Practical model building processes are often time-consuming because many different models must be trained and validated. In this paper, we introduce a novel algorithm that can be used for computing the lower and the upper bounds of model validation errors without actually training the model itself. A key idea behind our algorithm is using a side information available from a suboptimal model. If a reasonably good suboptimal model is available, our algorithm can compute lower and upper bounds of many useful quantities for making inferences on the unknown target model. We demonstrate the advantage of our algorithm in the context of model selection for regularized learning problems

Comparison of conservative treatment versus transcatheter arterial embolisation for the treatment of spontaneously ruptured hepatocellular carcinoma

Purpose: To elucidate the prognostic factors in the spontaneous rupture of hepatocellular carcinoma (HCC) and to determine whether transcatheter arterial embolisation (TAE) is associated with better prognosis compared to conservative treatment. Material and methods: A retrospective multicentre study was conducted involving 71 patients with spontaneous rupture of HCC. A conservative treatment group (Cons T group) included 20 patients, while a transcatheter arterial embolisation group (TAE group) included 51 patients. Results: The median survival time (MST) in the Cons T group was only 16 days and the survival rate was 39% at one month, whereas the MST in the TAE group was 28 days and the one month survival rate was 63%. However, there is no statistically significant difference in the overall survival between Cons T and TAE groups (p = 0.213). Multivariable analysis identified only the presence of distant metastasis as an independent prognostic factor (p = 0.023). A subanalysis including patients without distant metastasis showed that the presence of portal vein tumour thrombosis was a significant prognostic factor (p = 0.015). Conclusions: Distant metastasis appears to be a prognostic factor in spontaneous rupture of HCC. In cases without distant metastasis, portal vein tumour thrombosis could influence the prognosis. Our data failed to prove any benefit of TAE as the primary management

シュセイブン ブンセキ ヲ モチイタ ムササビ （Petaurista leucogenys） ノ オンセイ タイプ ノ ブンルイ

ムササビPetaurista leucogenysは樹上性のリス科の動物である。本種は大きな声で鳴く動物であるが，音声についての研究はあまり行われていない。先行研究では，鳴き交わしに使われる「グルル」や繁殖や警戒時に発される「キョキョ」等のいくつかの音声タイプを発することが明らかになっている。一方で，「グルル」にはサブタイプが確認されているが，その分類方法は主観的であるため，より客観的な方法での分類が求められる。そのため本研究では，東京都高尾山と神奈川県大雄山にて，プレイバック実験によってムササビの音声を効率的に録音し，鳴き交わしに使われる「グルル」と繁殖や警戒の意味を持つ「キョキョ」の2タイプについて，6つの要素（ピーク周波数，ノートの持続時間，コールバウトの持続時間，ノート間隔，パルス数，ノート数）について主成分分析を用いて客観的に音声分類を行った。プレイバックの鳴き声に対する反応と，自然に発される音声を比較したところ，「グルル」は音声に変化がなかったのに対し，「キョキョ」は音声に違いが見られ，第一主成分はパルス数とノートの持続時間，第二主成分はノートの数とコールバウトの持続時間の寄与率が高かった。「キョキョ」はプレイバックに対する鳴き返しの時と，繁殖行動時に自発的に発せられた時で分かれたことから，「キョキョ」にはサブタイプがあり，繁殖の時と警戒の時で異なる音声を発している可能性が示唆された。The Japanese giant flying squirrel (Petaurista leucogenys) is a member of the arboreal Sciuridae. There are few studies conducted on their calls, even though this species produces loud calls. A previous study suggested that they have several call types, for example, the “Gururu” exchange call and the “Kyokyo” call used in alarm and mating contexts. “Gururu” calls were divided into five subtypes ; however, this classification was subjective and dependent on the researcher. We classified the calls of the Japanese giant flying squirrel at Mt. Takao in Tokyo and Daiyuzan in Kanagawa Prefecture, Japan using objective statistical methods such as principal component analysis (PCA) on six measurements : peak frequency, duration of the note, duration of the call bout, inter-note interval, number of pulses, and number of notes. PCA results indicated that the “Gururu” calls were not clearly distinguished between the natural calls and the response call, whereas the “Kyokyo” calls were distinguished with the first axis explained by the number of pulses and note duration, and the second axis explained by the number of notes and call duration. This suggests that the “Kyokyo” call can be classified into two subtypes, along with a sound character and context (alarm and mating)