Judul: Indonesian Stock Market Reaction to the  Russia-Ukraine Invasion (Case Study of Wheat-Based Product Issuers)
Abstrak: Perang antara Rusia dan Ukraina mengakibatkan adanya pembatasan ekspor bagi Rusia dan kerusakan fasilitas serta blokade pada pelabuhan menyebabkan Ukraina tidak bisa melakukan kegiatan ekspor. Kemudian berdampak pada fluktuasi harga komoditas gandum global akibat gangguan rantai pasok komoditas dari kedua negara yang merupakan produsen sekaligus eksportir penting gandum global. Oleh karena itu, pengumuman invasi Rusia terhadap Ukraina berpotensi mengandung information content yang relevan sehingga berpotensi memengaruhi keseimbangan harga pasar dan pada akhirnya terjadilah reaksi pasar. Tujuan dari penelitian ini adalah untuk menganalisis reaksi pasar saham Indonesia yang ditinjau dari abnormal return pada emiten produk berbahan gandum serta perbedaan abnormal return dan trading volume activity sebelum dan sesudah pengumuman. Metode penelitian yang digunakan yaitu event study dengan periode pengamatan (t-10, t+10). Terdapat sembilan emiten yang dipilih melalui teknik purposive sampling. Hasil penelitian menunjukkan bahwa saham emiten produk berbahan gandum di pasar saham Indonesia bereaksi negatif melalui abnormal return mulai sebelum peristiwa hingga sesudah peristiwa selama periode jendela yang ditetapkan. Hasil uji beda menunjukkan bahwa tidak terdapat perbedaan yang signifikan pada abnormal return antara sebelum dan sesudah pengumuman. Berbeda halnya dengan trading volume activity yang menunjukkan hasil bahwa terdapat perbedaan yang signifikan antara sebelum dan sesudah pengumuman., The war between Russia and Ukraine resulted in export restrictions for Russia, and the damage to facilities and blockade of ports caused Ukraine to halt its export activities. Consequently, this had an impact on the fluctuation of global wheat commodity prices due to disruptions in the commodity supply chain from both countries, which are important producers and exporters of wheat globally. Therefore, the announcement of Russia's invasion of Ukraine potentially contains relevant information content that could influence market price equilibrium, ultimately leading to market reactions. The aim of this study is to analyze the Indonesian stock market's reaction, specifically the abnormal return of wheat-based product issuers, and to examine the differences in abnormal return and trading volume activity before and after the announcement. The research method used is an event study with an observation period of (t-10, t+10). Nine issuers were selected using purposive sampling technique. The research findings indicate that the stocks of wheat-based product issuers in the Indonesian stock market reacted negatively, showing abnormal returns both before and after the event during the designated observation period. The test results show that there is no significant difference in abnormal return between before and after the announcement. However, in contrast, the trading volume activity shows a significant difference between before and after the announcement.
Keyword: abnormal return, event study, market reaction, trading volume activity, wheat-based issuers

Judul: Integration of Islamic Stock Markets of OIC Countries Before and During the Russia-Ukraine War Crisis
Abstrak: Pasar saham yang terintegrasi memberikan dampak negatif seperti percepatan co-movement (pergerakan bersama) yang rentan terhadap guncangan ekonomi, maupun krisis pasar global ke pasar domestik. Salah satu krisis yang terjadi pada tahun 2022 adalah perang Rusia-Ukraina yang berdampak pada pasar saham, termasuk pada saham syariah yang dipercaya lebih tahan terhadap guncangan krisis global. Penelitian ini bertujuan untuk meneliti perkembangan, integrasi dan respon lima pasar saham syariah negara OKI pada perang Rusia-Ukraina. Metode yang digunakan adalah VAR/VECM pada indeks DJIMMT25, SPSADS, SPSUAEDS, JII, DJIMT, SPBMIR, dan SPBMIU. Hasil penelitian menunjukkan pergerakan yang sama pada pasar saham UAE dan Arab Saudi, sedangkan Turki mengalami tren positif selama perang. Pasar saham syariah negara OKI selama periode perang Rusia-Ukraina terkointegrasi, sementara pasar saham Malaysia memengaruhi pasar saham syariah empat negara OKI lainnya. Hasil IRF menunjukkan terdapat efek permanen pada volatilitas pasar saham syariah negara OKI akibat guncangan yang diberikan. Namun, respon volatilitas relatif kecil karena kontribusi guncangan lebih didominasi oleh pasar saham itu sendiri, An integrated stock market has negative impacts, such as accelerating co-movement, which is vulnerable to economic shocks and global market crises on the domestic market. One of the crises in 2022 was the Russia-Ukraine war which impacted the stock market, including Sharia stocks which were believed to be more resistant to the shocks of the global crisis. This study examines the development, integration, and response of OIC countries five Islamic stock markets in the Russia-Ukraine war. The method used is VAR/VECM on the DJIMMT25, SPSADS, SPSUUAEDS, JII, DJIMT, SPBMIR, and SPBMIU indices. The results show the same movement in the UAE and Saudi Arabia stock markets, while Turkey experienced a positive trend during the war. The Islamic stock market of the OIC countries during the Russia-Ukraine war was cointegrated. In contrast, the Malaysian stock market influenced the Islamic stock markets of the other four OIC countries. The IRF results show a permanent effect on the volatility of the Islamic stock market in OKI countries due to the shocks given. However, the volatility response is relatively small because the stock market itself dominates the contribution of shocks.
Keyword: co-movement, OIC, Rusia-Ukraine war, sharia stock market integration

Judul: Categorization in Macaca fascicularis.
Abstrak: Categorization is an ability to group individuals or events into different classes mediated by conceptualized mental images. There are several levels of categorization and within a taxonomy the levels are nested. At the most concrete level of categorization, all or most members of the category shared common physical attributes that differ from other categories. The higher the level of category, the fewer common attributes between members of the group. In addition to humans, the ability to categorize has also been proposed in animals. One example of categorization in animal is species discrimination. Using matching-tosample task, present experiment tested ability of the long-tailed macaque (Macaca fascicularis) in discriminating dichotomous-stimuli of different animals. The species has been shown to be able to see photos as representations of real object so I used facial photos of humans and animals for the stimuli. First, I tested their ability to classify humans and macaques into separate group. Second, I tested their ability to discriminate their conspecific from other macaques. And the last, I tested whether the subjects were able to discriminate non-human animals from humans. In all of these experiments I found that the subjects showed high performance in categorizing objects, even when I discarded details of visual informations, such as color and local shapes. The ability to identify objects with reduced representation of physical properties means the subjects were able to generalize attributes of members of the group. This would indicate that the subjects created a higher level abstraction. On the other hand, in discriminating intrageneric macaque species I found that they were able to extract uniqueness of each species. More over, I also found that the subjects were able to put photos of non-human animals that shared very few similarities in physical percepts into one group. I suggested that the subjects could create a more abstract concept based on non-percepts relations as a basis to put the objects into one category. Thus, I concluded that M. fascicularis were able to perform multiple levels of categorizations.
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